One Health refers to the relationship between human, animal and environmental health. In order to truly appreciate how each of these components interacts with one another, we have to understand where human health parallels animal health, and where they are different.

(Image source)

I had the opportunity to attend the 2nd Zoobiquity Conference a few weeks ago, held at the UCLA Ronald Reagan University Medical Center. The main driving force behind this conference was Dr. Natterson-Horowitz M.D., who co-wrote the book Zoobiquity: What Animals Can Teach us About Health and the Science of Healing. In the book, the authors outline some of the fundamental similarities between human and animal health and what we can learn about medicine as a whole by broadening our perspectives to include all species.

The conference remained true to the subject of the book and brought veterinarians and physicians together to discuss health issues as they relate to each profession. The morning session was in the format of case discussions about various themes, such as cancer, diabetes, obesity and even bullying. Each panel had a representative from the veterinary as well as the human medical field, who presented their approach and challenges about the specific cases. Afterwards, presenters had a chance to sit down and foster a discussion on how this particular disease differs from species to species, or relates, and audience participation was encouraged.

One such example of this was evident during the discussion about osteosarcomas, from both a human veterinary perspectives. As I learned at the conference, human osteosarcomas can affect younger individuals and seldom metastasizes to the lungs. On the contrary, in the veterinary field, these bone tumors in dogs develop later in life and by the time a radiologic diagnosis has been made, the tumor has generally already spread to the lungs. Learning from these differences, physicians can look to veterinarians in order to understand better the pathogenesis involved in metastatic osteosarcomas. The Zoobiquity Conference moved beyond physical ailments and looked and mental wellbeing as well. It was eye-opening to see some of the striking similarities between bullying in children and aggressive behaviors between household cats. In both species, the victim is often an individual exhibiting submissive behaviors that are evident to the perpetrator.

The afternoon portion of the conference consisted of a guided visit to the Los Angeles Zoo where stations were set up demonstrating some of the concepts put forth by zoobiquity. These stations included comparison of echocardiographic appearance of heart diseases between gorillas and humans or lead ingestion in children and California condors.

Thanks to all the organizers of the 2nd Zoobiquity Conference, this was a great experience. (Image source)

It was incredible to see an audience filled with medical professionals from both the human and veterinary fields and the presentations did an excellent job at looking at medicine from a comparative perspective. So where does zoobiquity fit in relation to One Health? In my mind, zoobiquity refers to the similarities between medicines across species, whereas One Health is about how the health of different species and the environment can affect one another. The first step in promoting One Health is recognizing that health professionals can learn a lot by bridging the divide between species and by allowing veterinarians and physicians to sit down together and discuss similar cases, and the Zoobiquity Conference did just that.

For more information about Zoobiquity:

Zoobiquity website

Advertisements

It’s nice to get back out there and do some more international work. After all, this is globalhealthvet and I was looking forward to gain new experiences promoting veterinary public health abroad. I got exactly what I wanted a few weeks ago when I went to Nicaragua, on a student-led initiative to promote veterinary care on Ometepe Island.

This trip was organized by veterinary students from the International Veterinary Student Association (IVSA) chapter at Oregon State University for the 5th consecutive time and this year, the group included 30 veterinary students and 8 veterinarians.

Ometepe Island, which is on Lake Nicaragua, is home to 35 000 inhabitants who rely heavily on agriculture for survival. In this rural environment, there can be limited access to veterinary care and a large part of the animal population has not received basic treatments. After taking a ferry to the island, the group was driven in small buses to Hacienda Mérida, which is where the clinic was set up. It was obvious from the ride through the island that people of Ometepe were living in remote conditions and that they did not always benefit from amenities such as telephone or paved roads. This is has a strong impact on health of both the people and their animals as medical care may not be readily available.

Ometepe Island, with its 2 volcanoes: Concepción (left) and Maderas (right)

The trip lasted for 7 days and the clinic was set up in a shed on the hacienda’s premises. Students were responsible for bringing supplies such as medications, centrifuges and microscopes. Fortunately, a lot of the supplies from previous trips was stored at the hacienda.

During the 7-day trip, a total of 774 patients were treated: 272 small animals for wellness exams/90 surgeries; 159 large animal patients/17 surgeries; 343 animals seen on farm calls by the mobile unit

Once up and running, the clinic consisted of several different stations. Personnel at intake was responsible for triage of patients as well as basic history. Small animals and their owners then moved on to wellness examinations, performed by students. There, the patients had their blood drawn and basic medications were given depending on abnormalities found on physical examination. Every animal also went home with a 6-month supply of deworming medications as well as flea/tick preventive. Blood samples were analyzed under the microscope for proper platelet numbers (a sometimes challenging job, as the humidity degraded the slides rapidly) and several SNAP tests were available to diagnose blood-borne pathogens such as heartworm or Ehrlichia. If patients were deemed healthy enough for surgery, they moved on to the induction station where all the proper medications were prepared for the upcoming operation. Surgeries were performed the same day and patients went home after recovery. This was very much student-led and as veterinarians, we were there to provide advice to students and help out if needed.

There was also a significant large animal aspect to this work and farmers would bring donkeys, horses or pigs to the clinic for treatments and surgeries. Finally, a mobile team was also able to travel throughout the island and provided a unique way to care for animals that were unable to come to the clinic, usually cattle herds.

Veterinary students performing wellness examinations

On the small animal aspect, most patients presented with severe malnutrition, emaciation, intestinal parasites as well as fleas and ticks. Our canine patients often had generalized lymphadenopathy, which can be a sign of underlying infections like Ehrlichia or Leishmania, both present in this region. Due to the limited diagnostics available, a specific cause for disease was not always evident however, animals requiring antibiotic treatment were given appropriate medications. It is likely that the patient’s poor nutritional condition exacerbated some of the underlying diseases that they may have had and we were able to provide people with nutritional supplements for their animals. It is also important to remember that most infectious diseases seen during this trip were zoonotic, and treating the animal definitely helped reducing the chances of human infection. In total, 90 surgeries were performed, mostly spays & neuters in dogs and cats, although other procedures included an abdominal hernia repair in a puppy or an enucleation in a chicken (all successful, great job students!).

On the large animal side, the focus was also on parasite treatment and prevention, but also surgeries like equine and porcine neuters. The mobile team also performed field treatments and pregnancy checks in cattle herds.

The mobile unit allowed us to treat cattle herds throughout the island

The students did an amazing job organizing this trip to Nicaragua and showed impressive ability to work in conditions that can prove challenging (which included an earthquake during the clinic). This trip represents a great opportunity for them to practice their skills with a hands-on approach and recognize the impact of veterinary medicine in developing countries; they will no doubt make great veterinarians.

Working in remote areas of Nicaragua, but also Peru and Morocco, I have seen the impact of neglect on the health of animals. It is important to remember that in a country where people are struggling to survive, promoting animal health does not always take

Flyers I made about leptospirosis & taeniasis – Community-specific education should be a key part to any public health program in developing countries.

precedent. It is obvious that principles of One Health in these places go beyond the management of zoonotic disease. People depend on their animals for survival and poor conditions or disease in a herd of cattle can greatly impact revenues of the farmers, and thus their health. Therefore, a crucial part of working in the developing world is education. Veterinarians and other health professionals should educate people about the impact of animal health on their own health, whether it is about zoonotic diseases prevention or promotion of healthy food animals that will be able to produce more for the farmers.

It was great to have the opportunity to steer the public health discussion (speaking Spanish helps…)

Following this philosophy, our trip to Nicaragua had a strong educational component and I was asked by the organizers to participate in a public health session for those attending the clinic. Working in a place with a different culture and language can sometimes create barriers when trying to explain public health concepts and therefore visual aides can prove to be very helpful. To this end, the students and veterinarians had designed a couple of posters outlining these concepts and I designed informational flyers about 2 diseases commonly seen in Nicaragua. The discussion was very well received and had great participation from the attendees.

This trip is a great example of how a motivated group of people can organize a successful and long-lasting global health program that has a big impact on a local community. This was organized by veterinary students from OSU, who were able to secure funding and supplies, and has been successful for the past 5 years. I had a great experience during this trip, learned a lot and I definitely hope to be able to participate in the next trip in 2013.

The entire Nicaragua team! Thanks to Hacienda Mérida and all the students from OSU for making this experience so awesome (Image source)

In my opinion, vector-borne diseases represent the most classical example of how One Health integrates human and animal medicine. These diseases usually affect both animals and people and are transmitted by insects, which are very dependent on the environment for their survival and spread.

Mosquitoes such as this Culex sp. act as vectors for West Nile Virus infection in animals and people (Image source)

One great example of this is the disease West Nile Virus (WNV) and its accidental introduction in the Americas. WNV is a present worldwide and is transmitted by mosquitoes such as Culex spp.

West Nile virus was first seen in the USA in 1999 in New York City, where health officers noticed a new type of encephalitis spreading through the city. While they were trying to diagnose the disease, wild birds on the premises of the Bronx Zoo were dying in large numbers. This sounded the alarm for the veterinary pathologist at the zoo who collected samples from the dead birds and tried to have them analyzed. The veterinarian was turned down several times as most authorities thought that she was dealing with an “animal-only” problem which was unrelated to the outbreak in the human population. However, her samples were tested by the Army and West Nile Virus was found to be the culprit of both the animal and human outbreak. It took the virus about 5 years to spread from the East Coast to the West Coast of the USA, disseminated by mosquitoes and bird reservoirs. It was later speculated that the virus entered the country by boat through introduction of mosquitoes that laid eggs in old tires that accumulated some standing water.

Life cycle of West Nile Virus (Image source)

In people, the syndrome is usually mild and some individuals will not even notice they’ve been exposed, others will have a mild flu-like disease and recover on their own. In about 1% of cases, however, the virus can invade the brain and cause severe neurologic symptoms which can be life-threatening. This disease is called Neuroinvasive West Nile and affects more commonly those who are immune-suppressed such as the elderly or people suffering from chronic diseases.

A wide range of animal species can suffer from WNV infection as well and it is commonly seen in birds. Some birds do not suffer from the disease and act as reservoir, in which the virus multiplies and spreads through the bite of mosquitoes. Other birds, especially crows, are very susceptible to illness and will often suffer from sudden death (as seen in the Bronx Zoo in the original outbreak). These birds are the ones that people use the most to monitor WNV in the environment, and an increase in crow deaths in summer months is often associated with West Nile activity. Other animals that can be affected by the disease include dogs, where the infection is somewhat mild and horses, in which the disease can be much more severe. In equids, infection often leads to severe neurologic signs such as ataxia and can lead to death. Because of this, a vaccine against WNV in horses has been developed and is widely used. There is also some evidence that, at least in birds, the virus may be transmitted from one animal to another by direct contact, since it is present in oral secretions; however mosquitoes remain the most common mode of transmission.

Dead crows in Los Angeles County can be reported to the County’s Veterinary Public Health Program. The mouth of the bird is then swabbed and tested for WNV antibodies.

West Nile Virus has now a pretty strong hold in the Americas and eradication methods would be difficult to put in place. Some insist that the presence of the disease has become normal and that monitoring for the disease has become useless, as we already know the virus has implanted itself. However, as the current outbreak in Texas shows, WNV has made a comeback and several people have been affected, including 87 deaths (as of this post’s publication date). This shows that there should not be any laxity in zoonotic disease surveillance. One of the aspects that make WNV an interesting model for One Health is the relationship between human and animal infections. Experimentally, a zoonosis will affect animals first and then spread to people. West Nile Virus follows this pattern almost exclusively. As we enter hot summer months such as August, we usually see a sharp increase in cases in animals such as crows as well as horses, followed by an increase in human cases about a month after. Monitoring the impact of the disease in wildlife will surely give us an idea of how it will affect human populations later in the season so that health professionals can be ready for it.

I am taking an active participation to this disease surveillance working in public health in Los Angeles County and one of my duties is to routinely test for West Nile in dead wildlife such as crows. The test used is an antigen test, which enables us to determine if the animal was infected at the time of death. As far as this season, I have seen a sharp increase in positive birds since the beginning of August but overall numbers of positive birds is less than it was at the same time in 2011. Other parts of California, however, have reported increase in both animal and human cases.

The Vectest is an antigens test used to detect WNV infection in crows. Two of the three birds tested on this picture were positive – A dark red line represents the control and a faint red line below it (red arrow) shows the positive result.

In order to reduce likelihood of contracting West Nile virus, these guidelines should be followed:

  • Wearing long-sleeves shirts during times of increased mosquito activities (dusk & dawn)
  • Making sure there is no standing water around the house where mosquitoes can breed
  • Horse owners should also vaccinate their animals for protection during peak WNV activity, under the guidance of a veterinarian

Global West Nile virus distribution in 2011. Since its introduction into the Western Hemisphere, West Nile Virus is considered to be present worldwide, unfortunately, not every country has the ability or resources to monitor and report the disease to public health organizations (Image from the OIE’s World Animal Health Information Database – WAHID)

Finally, there is no arguing that there are changes in our weather pattern. This may lead to an increase in rainfall or more extreme temperatures. Mosquito distribution depends greatly on these factors and some studies have shown that a small increase in average temperatures can lead to a wide spread of diseases classically thought to be tropical in nature, such as Dengue Fever or even Malaria (study).

More information on West Nile Virus:

CDC – West Nile Virus

Center for Food Security and Public Health – West Nile Virus Technical Sheet

Microbe World – One Health and the lessons learned from the 1999 West Nile Virus Outbreak

Rabinowitz PM & Conti LA. 2010. Human-Animal Medicine. Saunders Elseviers ed.

World Organisation for Animal Health (OIE) – West Nile Fever factsheet

I wrote a post a few weeks ago about the risks associated with dog biting, and the human component of this issue. As a follow up to this post, I had the occasion to ask a few questions to Irith Bloom, dog trainer in Los Angeles, California. Irith is the owner of The Sophisticated Dog, a science-based animal training company, and also member of the 2020 Healthy Pets Healthy Families coalition, spearheaded by Los Angeles County’s Veterinary Public Health Program. As such, she is highly involved with dog bite prevention efforts, especially regarding understanding dogs’ behaviors in relation to biting. Below are her answers to my questions and also don’t forget to check out her website: The Sophisticated Dog.

1. In your opinion, what are some reasons that cause dogs to attack or bite people?

“Dogs usually bite because they are feeling threatened or frightened.  In some cases, a dog may feel threatened because an approaching person is unfamiliar, or appears strange in some way.  In other cases, a dog may be frightened by the behavior of a familiar person.  A dog may also feel nervous for reasons completely unrelated to the humans around, such as strange things or animals in the environment.

Unfortunately, people often create situations where a bite is more likely by ignoring warning signals the dog is giving (see Question 3 for more on warning signals).  People can also be bitten due to what is called redirected aggression, which means the dog is already extremely agitated and bites a person more or less by accident simply because the person is nearby.  (For example, when two dogs are involved in a fight, if a person steps in to separate the dogs, one or both of the dogs will often bite the person, without appearing to intend to do any harm to the person.  Unfortunately, damage from bites like this can be very severe.)

The common factor in most bites, whether to a person or to another animal, is that the dog feels so uncomfortable about a situation that he feels he has no choice but to use his teeth.

2. What are some mistakes that people make around dogs that result in a bite?

The biggest mistakes that lead to bites are cornering dogs and ignoring signals that a dog is feeling uncomfortable.  Another mistake that can lead to bites is punishing a dog for behaving in an anxious manner, or for giving obvious warning signals.

Let’s start by addressing the first topic – cornering dogs.  Dogs, like most animals, choose between fight and flight when they are scared.  When a dog is cornered, flight is not an option, so the dog more or less has to choose “fight” – which in many cases means “bite.”  It’s never a good idea to corner a dog, even if the dog seems completely relaxed.

The good news is that most dogs give a lot of signals saying “back off” before they actually go as far as biting.  The bad news is that many people do not know how to read those signals, so a dog may be forced into a position where the dog feels biting is the only option. (See the answer to Question 3 for tips on how to read dogs better.)

Another common mistake people make is punishing a dog for being scared or anxious.  This actually strengthens the dog’s impression that a situation is dangerous; not only is something scary around, but now the dog is being punished by a human she trusts.  This makes the dog more likely to bite, both in the moment, and the next time the same kind of situation comes up.

Another way that people accidentally make dogs more likely to bite is by punishing the warning out of the dog.  The most common mistake people make in this regard is punishing a dog for growling.  A growl is basically a dog’s way of saying “I am uncomfortable.  Please let me out of this situation, or I may have to bite.”  When you punish a dog for growling, there are two likely outcomes, both of which are bad.  The first is that the dog will immediately bite.  The second is that the dog will learn to suppress the growl, so the next time the dog will not growl first to say “please stop,” but will simply bite right away instead.

In other words, when you punish a dog for growling, you are making it more difficult for the dog to communicate without using her teeth.  When a dog growls, back off immediately.  Then try to figure out what made the dog so uncomfortable (so you can avoid that situation in the future, at least until you have done some training, as discussed in Question 4), and remember to mentally thank the dog for warning you, instead of simply going straight to biting.

In summary, here are some tips for avoiding bites:

  1. Avoid cornering dogs.
  2. Learn to read warning signals from dogs (see Question 3).
  3. If a dog growls at you, back off immediately.
  4. Never punish a dog for acting nervous.
  5. Never punish a dog for growling (you don’t want to punish the warning out of the dog).

3. How can you tell if a dog is scared/anxious or ready to bite?

There are many signals dogs give when they are nervous.  The list of behaviors seen in these situations is quite long, so I will only include the most common ones.  Here are some things to look for:

  • Yawning when the dog is not tired
  • Licking the lips (or just flicking the tongue in and out of the mouth) when there is no food around
  • Panting even though it’s not warm
  • Raising one paw and holding it up tentatively
  • Turning the head away
  • Curving the body or turning the whole body away
  • Blinking rapidly
  • Lowering the head
  • Tucking the tail between the legs
  • Trying to move away from a situation.
  • Freezing in place (standing very stiffly)
  • Staring
  • Raising of the hackles (this is when the hair on the back of the neck, and sometimes even the whole spine, stands up)

When dogs are cornered or otherwise forced to remain in a scary situation despite giving the signals mentioned above, they may escalate to more obvious signals, such as the following:

  • Drawing their lips back to show their teeth
  • Flattening their ears back
  • Growling
  • Snarling
  • Lunging
  • Air-snapping (biting the air with a loud clap of the jaws)

Note that if a dog lunges and air-snaps at a person, that is actually a warning.  The dog did not try to bite and “miss”; dogs have very good control of their jaws.  An air-snap means the dog made a conscious decision not to bite.

All of these signals are warnings from the dog.  The dog is telling you the situation is too much for him, and that a bite may follow.  These warnings need to be taken seriously, even when the warning is relatively subtle (e.g., a lip lick).  In fact, noticing subtle warning signals is the best way to prevent a bite.

The video at the following link shows examples of some of the more subtle signals dogs send, and can be a helpful tool for learning to identify the types of behavior that indicate a dog is anxious or scared.

Click on the image to see the video

4. What are your recommendations on how to behave around a stressed/aggressive dog?

The number one consideration must always be safety.  In general, if a dog is giving signs that she is anxious, it’s a good idea to back away from the dog calmly and slowly.  If a dog has flattened her ears and is growling or snarling at you, you should also try to put a physical barrier (such as a door) between you and the dog if possible.  This is especially important if the dog involved is a stranger to you, and is loose.

If the dog is only showing subtle signs of anxiety, such as lip licking or turning away, it may be enough to give the dog an opportunity to move away to a distance that is comfortable for her, but you have to be sure there is enough room between you and the dog to allow her to escape the area if she chooses.

If the dog you are dealing with is your own dog, after creating some distance between you (or allowing the dog to create distance), make a mental note of what made the dog so uncomfortable.  Then find a trained professional who uses force-free methods to help you come up with a training plan that will help your dog learn to feel more comfortable in that type of situation.  Here are some good online sources for trainers who can help you teach your dog to feel more relaxed in situations that used to scare her:

5. Any other recommendations for dog owners?

Be proactive! Teach your dog to feel comfortable in a wide range of situations.  An excellent way to do this is to give your dog treats in new situations, so that he learns to expect good stuff whenever something strange happens.  The more you practice this, the more your dog will learn to handle a variety of situations calmly.

If you are dealing with a strange dog, or one you don’t know very well, keep in mind that dogs, like people, take time to make friends and develop trust.  Your own dog may not mind if you corner him accidentally, but a dog who does not know you well may find that frightening.  Similarly, a dog may not mind a hug or a kiss from his person, but a hug or kiss from a stranger can seem very threatening (imagine how you would feel if a perfect stranger walked up to you on the street and gave you a big hug and kiss).

I’d also like to point out a distressing statistic: Children nine years old and younger are bitten more often than any other age group.  Most of these bites could be prevented with careful management and education.  If you have children or get lots of child visitors, be sure to supervise carefully any time children are around a dog, even if the dog is generally happy to hang around with children.  Give dogs periodic breaks from interactions with children (who sometimes nag dogs), and watch dogs for signs of stress when they are around children.

Never leave a child unsupervised with a dog.

It’s also important to teach children that dogs are not toys, and that they need to be treated gently and respectfully.  Explain to children that dogs don’t particularly like hugs and kisses – and that even if their own dog is willing to tolerate these things, someone else’s dog might not like it.  In addition, instruct children to stand perfectly still, with their hands folded together, looking at the ground, if a strange dog runs up to them.  Most dogs are excited by screaming and movement, and a quiet, still child is in much less danger of being bitten than one who is squealing and running around.

Finally, whether you are dealing with a dog you know well or a strange dog, remember that you catch more flies with honey than with vinegar.  Kindness, praise, food treats, and toys are good ways to make friends.  Yelling, intimidation, and physical punishment are not.  Dogs are armed with very powerful weapons (their teeth), and scaring them using threats or violence is likely to get you bitten.  If you treat dogs with respect and kindness, they will generally return the favor.”

– Thank you very much Irith for this great Q&A! This is very useful information to understand the issue of dog biting from the dog’s perspective. Hopefully this will help reduce dog bite incidence, especially in children.

As we move from the theory and discussion of One Health principles to their application, we must focus on creating partnerships with other health fields and provide a unified, coherent effort against the public health challenges we face today or will face in the future.

One way to do that is to bring all stakeholders together and work together to address specific health issues that need to be changed. The 2020 Healthy Pets Healthy Families (2020 HPHF) coalition, aims to improve several health-related issues using an evidence-based perspective. Anchored in a One Health approach, this task force brings leaders from various backgrounds including animal, human and environment for a collaborative effort to improve public health. This coalition is inspired by the Healthy People initiative, a model that has been in place since the 1980s, and meets quarterly to discuss their progress.

The Coalition has identified 7 focus areas, or specific issues, that will be addressed and improved. These are:

  • “Pet Obesity: Pet obesity is skyrocketing, just like with people. What can help? Walking the dog! Studies show that walking the dog helps people get the recommended amount of exercise. By exercising together, owners and their pets can get healthy.
  • Second-hand smoke: Pets can develop cancer after being exposed to second hand smoke. They can become ill after accidentally eating cigarette butts. A recent study supported the idea that educating smokers about the risk to pets may motivate them to quit.
  • Spay-Neuter: Pets that are spayed or neutered have a reduced risk of certain cancers, and are less likely to roam, be hit by a car or bite someone.
  • Vaccine preventable diseases: By increasing pet vaccination, we not only protect pets from these diseases, we also reduce the financial and emotional costs that these illnesses inflict on the community.
  • Disaster Preparedness and pets: Preparing the family pets for disasters helps start the process of preparing the whole family.
  • Bite Prevention: Approximately 2% of the population is bitten every year. Most animal bites can be prevented.
  • Zoonotic Disease and Parasite Prevention: Zoonotic diseases are those transmissible between people and pets. Approximately 60% of the pathogens that can infect people are zoonotic. Pets owners can take many simple steps to protect themselves and their pets. Keeping a pet free of fleas, ticks and other parasites, protects not only the pet, but the family and neighborhood, from a variety of diseases. Pet owners that pick up the poop safeguard the community from contamination.” (Source: 2020 HPHF website)

At this early stage in the coalition, the goal is to gather data from various organizations that can be tracked in order to measure positive changes at the end of the decade. The task force will also create a public document outlining the scope of the problem and give more background information on 2020 HPHF; this publication will be available in December 2012. The next steps include establishing intervention strategies for each focus group that will take place over the next 8 years.

The 2020 Healthy Pets Healthy Families brought together veterinarians, physicians, animal behaviorists, professors from Western University and various other parties interested in improving both animal and human health.

Stay tuned for more developments on this exciting effort which applies One Health principles for the benefit of animals and people alike.

I had the opportunity to recently attend to the event “Hoarding Forum 2012 – People Hoarding Animals and Things, Is it Capacity, Mental Illness or Life Style?”, held on June 25th, 2012 in Los Angeles and organized by the County of Los Angeles – Department of Mental Health. In the form of a discussion forum, the aim was to bring the community together and pin point several key factors that would help us understand the drivers behind hoarding. In a true One Health fashion, one of the main speakers was Dr. Jyothi Robertson, veterinarian working for UC Davis and Oakland Animal Services in California, who addressed an audience mostly consisting of human health professionals. Through her excellent presentation, called “The Tipping Point – Understanding and Responding to Animal Hoarding”, Dr. Robertson shared her experience in managing hoarding cases as well as some of the characteristics of people engaging in such practices (Check out her website: Shelter Strategies).

Dr. Robertson’s presentation on the veterinary perspective of animal hoarding generated a lot of interest from the audience.

There are several concerns related to hoarding, including animal abuse or neglect and public health issues for the people involved. Animal abuse is illegal in the USA and perpetrators can be prosecuted if found guilty.

Hoarders of animals often have the feeling that, by adopting dogs and cats, they are saving them from harm and providing them with a better life. However, the number of animals in a house can become so high that owners may not be able to keep track of all of them anymore and the pets themselves may have little access to food/water, or veterinary care.

This can lead to situations of abuse/neglect, in which animals become emaciated, malnourished and have chronic diseases. This is exacerbated by the fact that hoarders can be reluctant to accept the unhealthy condition of their pets, in spite of the clear evidence. Unfortunately, many of these animals need aggressive treatment to survive such conditions and in some extreme cases, they may even die inside a house without the owner realizing it or willing to give them up. Furthermore, this neglect of the animals’ condition can often lead to a self-neglect of the hoarder’s own health status.

One of the main threats to public and individual health related to extreme hoarding includes threats caused by zoonotic diseases. As mentioned previously, animals can be unhealthy, which is often reflected by heavy flea or tick infestation. These vectors can carry diseases such as cat-scratch disease, plague or murine typhus capable of infecting the pet owners themselves, and also spill over to neighboring houses.

The environment inside the house can also be a source of danger through several ways. Firstly, extreme hoarders are often overwhelmed by the sheer number of animals and cannot keep up with maintaining a clean house, which can lead to a state of squallor. As a result, animal urine or feces can accumulate. High urine levels lead to increased ammonia in the air, which cause (at very high levels) direct damage to the organism, such as irritation of airways, pulmonary edema or coughing. Furthermore, this squalor is also significant health threat by reducing safety in the house or causing potential fire hazards when windows and doors are covered for example.

A panel of different stakeholders including the Fire Department, law enforcers and mental health professionals came together to discuss their approach to hoarding during a case discussion.

This hoarding forum touched on several important points regarding the hoarding of things and animals. When it comes to animals, one commonly used definition of hoarding given by Dr. Robertson includes:

  • Failure to provide for the animals
  • Inability to recognize effects of this failure
  • Denial or minimization
  • Obsessive persistence

Unfortunately, there is a high rate of recurrence of hoarding and very few success stories of long-lasting resolution. Therefore, it is important to understand and address the complex underlying problems and potential causes that may lead some people to become hoarders, such as psychological issues like depression, loneliness or low self-esteem. Some attendees advised for a step-wise approach for cleaning a hoarder’s house, focusing on following safety regulations and guidelines, which may lead to more compliance. This forum re-iterated the need for a One Health strategy if we are to successfully manage animal hoarding situations. Alongside veterinarians assessing animals’ health, the human component of hoarding must also be addressed and mental health professionals must be part of a multidisciplinary team leading to a long-lasting beneficial relationship with hoarders, who are victims themselves of the condition.

More information:

Hoarding of Animals Research Consortium

Oakley B, et al. 2011. Pathological Altruism. Oxford University Press Ed.

Shelter Strategies

The “Five Freedoms” commonly used to assess animal welfare, neglect or abuse

The scope of the problem

Every dog can bite (Photo source)

Much of the reaction to dog bites have been the implementation of breed-specific legislation with the intent to reduce the number of large dog breeds such as Pit bull-type dogs or Rottweilers (breeds most often targeted by such legislations). While it is logical that bigger dogs can inflict more severe bites, research has shown that such legislations do not address the underlying causes of dog bites – managing and understanding dogs’ behaviors. As it turns out, every dog can bite, and a special report from the Journal of the American Veterinary Medical Association (JAVMA) from 2000 has linked about 30 different dog breeds to about 200 fatal dog attacks between 1979 & 1998. These included Dachshunds, a Yorkshire terrier and a Labrador retriever. The authors further mention that breed-specific legislations do not address the fact that a dog of any breed can become dangerous when trained to be aggressive. Another limitation of such legislations is that identifying dog breeds is not as easy as one may think. In fact, experts can often disagree on what makes up a specific breed and due to extended cross-breeding, DNA testing can yield a myriad of results that does not necessarily reflect the animal it came from, as shown by this study. For example, some of the most commonly targeted dogs include “Pit bulls”. As it turns out, “Pit bull” does not officially refer to a breed but rather a loose description of characteristics that a dog may have, which is why the official term is: “Pit bull-type breed”.

Breed-specific legislation do not address the underlying issues of dog aggression – mismanagement of dogs behaviors. This dog is a former victim of dog fighting. (Photo source)

In fact, the 2001 AVMA’s Canine Aggression Task Force warns that isolating and targeting a few breeds deemed dangerous can lead to a false sense of accomplishment when it comes to reducing severe dog bites, because it does not address the reasons behind dog aggression. Other experts such as the American Humane Association argue that breed-specific legislations are difficult and costly to enforce and can have unintended consequences such as black-market or indiscriminant breeding of affected dogs (after all, breeds most involved in bites are the most popular ones). So what should we do to reduce dog bites to people? In order to provide an appropriate alternative to breed-specific legislation, let’s take a closer look at the problem.

The situation in the USA

The first piece of data to consider is that the United States, as of 2001, is the country with the most pet dogs/people, with 53 million pet dogs nationally. This creates an environment where there is a high rate of contact between people and dogs, which can be a risk factor for being bitten.

In fact, the CDC reports that about 4.5 million Americans are bitten every year, and 1/5th of these injuries require medical attention. These numbers reflect the scope of the problem in the countries like the USA. However, in order to properly address this issue, it is important to look at the populations at risk. Is everyone equally affected by dog bites or are there specific groups that public health officials need to focus their attention on? A closer analysis of the problem shows that half of bite victims are children under 12 years old. Another group particularly at risk is the elderly, specifically those 70 years old and over; even if they represent only 10% of those bitten, almost a 4th of these bites can be fatal.

Kids are at higher risk of being bitten by dogs. Proper dog training and monitoring children’s interaction with dogs is essential to prevent bites. (Photo source)

Another important variable to look at is the background of the bite itself. It is indeed interesting to see in the previously mentioned JAVMA study that 58% of the people involved were bitten by an unrestrained dog in their own property.  What stands out from this study is that a great majority (75%) of dog bites were done by dogs that victims knew and inside their owner’s homes. Finally, the cost of dealing with dog bites can be significantly high, and the insurance industry in the USA has paid more than $ 1 billion in dog-bite claims annually.

Furthermore, bite statistics also show that the great majority of dogs involved in fatal attacks were males (about 92%), of which 94% were intact (not neutered). This suggests an important behavioral component that relates adult intact male dogs to the tendency of biting.

Los Angeles County is a county of about 10 million residents, there is a high rate of interaction between people and dogs. In fact, dog bites to people have increased between 2006 and 2009 in one report and LA County is one of the US’ top locations for dog bites. This is why bites are one of the main focus area of the 2020 Healthy Pets Healthy Families initiative (Stay tuned! – I will talk about this program and my involvement with it in further detail in an upcoming post).

This work consists of managing bite reports sent by bite victims or clinicians, which serves several purposes. The 1st reason why it’s crucial to report all dog bites to local Department of Public Health is to get a better understanding of the issue in the county. As I’ve mentioned previously, dog bites in LA County have increased. Does this mean that more dogs are biting people or that more people are reporting bites? Only with the most complete data can officials truly understand the scope of the issue and focus their attention on specific groups or areas that are at higher risk.

The 2nd reason why reporting bites is crucial is for rabies prevention. The veterinary staff at VPH puts a lot of effort in following through on each bite report to make sure the animal is properly quarantined and monitors if there are any signs of the disease. While rabies in dogs has become very rare in LA county, the severity of the disease warrants extreme precautionary measures to make sure people are not exposed (For more information about rabies, check out my previous post).

Recommendations

If breed-specific legislation show mixed results in protecting people from dog bites, what are actual recommendations that can help address the problem? Looking beyond such legislation, the most significant factor to look at is addressing behavioral factors…of the dog but most importantly people. Indeed, it is the belief of many experts that many bites occur from our lack of understanding of dog behavior, especially fear, and our inability to recognize warning signs that a dog is about to bite.

This dog exhibits typical fear behavior and may bite if approached. (Photo source)

There are many recommendations on how to avoid dog bites, but most of them revolve around a couple of main themes: being aware of the dog’s language and appropriate dog training and ownership.

Teaching pets submissive behaviors like rolling over are great ways to establish the owner as dominant and reduce dog aggressivity. (Photo source)

Such recommendations include:

–          Consult a veterinarian or professional before getting a dog – Many dogs have different personalities or needs. For example, a dog with a lot of energy can become frustrated and have unpredictable behavior if that need is not met. For these dogs, frequent exercise or outdoor activities is recommended.

–          Socialize & don’t abuse pets – Owners that don’t train their dog are not in control when a risky situation arises. Also, puppies who engage in “play bite” can grow up to become biters as they have not been taught otherwise. Furthermore, a dog that is abused will be afraid and this fear of people will translate into aggression.

Puppies often engage in play-biting. However, it is the owner’s responsibility to properly suppress such behaviors as the dog gets older (Photo source).

–          Supervise children when around dogs – As previously mentioned, children are highly affected by dog bites. Kids should be taught appropriate petting behaviors and be monitored during interactions with dogs.

–          Remain calm around an unfamiliar dog – Running away or trying to challenge an unknown dog can cause the dog to attack.

–          Do not try to touch a dog when it’s eating, sleeping or looks injured – Many dogs will feel threatened by people approaching them if they are injured. It’s not aggression; the dog is simply scared and trying to protect itself.

–          Spay/neuter dogs – As demonstrated by the figures above, a large number of fatal bites were inflicted by intact male dogs. These dogs have higher levels of testosterone and are more prone to dominant behaviors such as aggression. Likewise, intact females can attract roaming male dogs and may also bite when protecting their young.

 

Note: Impact in developing countries

The situation in developing countries is somewhat different and the threat of rabies is still very present. In fact, two of the most recent rabies fatalities (as of this post’s publication date) came from individuals exposed to rabid dogs in India and the Philippines. However a dog bite can be fatal in other ways, as not everyone in developing countries have access to appropriate medical facilities where bites can be treated aggressively. In this context, additional focus should be on stray dog spay/neuter & vaccination programs.

Stray dog in Peru.

For more information & recommendations on dog bites:

American Humane Association – KIDS: Kids Interacting with Dogs Safely

American Veterinary Medical Association – Dog Bite Prevention

Los Angeles County Departmen of Public Health, Veterinary Public Health – Dog bite Prevention

National Canine Research Council – Breed and Behavior

Veterinary Partner – Defensive Dog BehaviorChild Safety with Dogs,

Voelker R. 1997. Dog bites recognized as public health concern. Journal of the American Medical Association. Volume 277, Issue 4, pp.278-280.

usda.gov

Last week (April 24th, 2012), a case of Bovine Spongiform Encephalopathy (BSE) was identified in a single animal in Central California.  This case, recorded in a dairy cow, is the 4th ever case in the USA and was discovered through the USDA’s BSE Surveillance Program, which is a very stringent system allowing officials to detect the disease at very low levels. The USDA is still investigating the case but the appropriate measures have already been taken, and the affected animal did not enter the human food chain, therefore preventing any spread to people. Furthermore, the affected cow’s progeny has been tracked down and is currently being tested for the disease and the dairy farm where the animal originated is under quarantine. The Department further emphasized that beef is still safe to consume.

The disease, commonly known as Mad Cow, is caused by abnormal molecules called prions that, once ingested, travel to the animals’ brains causing degenerative changes leading to neurologic signs such as tremors, incoordination or seizures. The disease is not infectious and does not transmit from a live animal to another animal. However, transmission can occur through ingestion of parts of affected animal that contain the prion, such as the brain or spinal cord tissue. This is why BSE has traditionally been associated with a practice consisting of feeding beef-based diets to cows, in order to promote protein intake. This practice is, however, illegal now in most countries, including the US and that has led to a decrease in BSE worldwide.

BSE causes degenerative changes in the patient’s brain, characterized by vacuole formation (http://www.sciencedaily.com)

Transmissible spongiform encephalopathies can nevertheless appear spontaneously in some animals, although very rarely, and it appears that this is what happened in this case. Similar diseases exist in other animal species such as Scrapie in sheep or Chronic Wasting Disease (CWD) in wild deer. Whether or not these diseases can be transmitted to humans remain unclear.

People eating beef containing nervous tissues (brains, spinal cord) of a cow with BSE can a disease called variant Creutzfeldt-Jakob Disease (vCJD) and is closely related to the human-only disease Creutzfeldt-Jakob Disease (CJD). Symptoms of vCJD are very similar to those of BSE in cows and can include tremors, confusion, dementia or difficulty walking. There is unfortunately no treatment or cure for the disease and one of the challenges (in both animals and people) is that the incubation period (amount of time until symptoms appear after exposure) can be very long and it can take decades for the disease to manifest itself.

This case was very promptly detected by the USDA during routine testing and shows the importance of continued disease monitoring like BSE. Although very rare however, they can cause significant public health problems and also critically injure a country’s agriculture. Sometimes, the public opinion is to cut resources for disease monitoring programs that have not detected any disease for some time. However, the fact that such programs do not observe any positive does not reflect failure or lack of usefulness. On the contrary, if we stop looking for these diseases we might miss the next epidemic.

Michael Alpers presenting the movie “Kuru – Science and Sorcery” at the One Health Congress in Melbourne, Australia about his pioneer work leading to the discovery of prion diseases

More information:

CDC – Bovine spongiform encephalopathy

FDA – All about BSE

OIE – Number of BSE cases reported worldwide

Hello everyone, I would first like to wish to all of you a great and prosperous year 2012 and I would like to thank all of those who have visited the website as well as supported me and left comments.

I want to start the year talking about one of the most recognized zoonotic diseases in the world: rabies. However, in spite of its somewhat “famous” status, I have observed that some people miss some key facts regarding this disease

As a small animal practitioner, rabies prevention through pet vaccination is a cornerstone of my work and I always take the time to educate clients about the risks posed by the disease, but also proper management of animals to reduce likelihood of transmission to animals and people. As such, I have noticed some discrepancies between what people know about rabies and what I believe are other important points.

Rabies is caused by a virus from the Rhabdoviridae family and it is present generally worldwide except some parts of the world such as Hawaii or New Zealand. Several European countries have also become rabies-free after intensive wildlife vaccination programs.

The Common Vampire Bat is a species of bat often implicated in rabies transmission to livestock in Latin America. (wikipedia.org)

One of the greatest misconceptions comes from the belief that it only affects dogs. However, the virus can be found in virtually every mammal, including dogs, cats, bats, cows, horses, sheep and several wildlife species. In fact, there have been several outbreaks of rabies in livestock recently in cows in Costa Rica and Peru in November and December 2011 as well as in a horse in Colorado in April 2010. Transmission is done by a bite of from an infected animal, when virus particles are inoculated into the muscle of another animal, or human.

Once the virus enters the hosts, it replicates in the muscle and travels to the brain inside neurons. Animals and people affected with rabies can usually show a wide range of neurologic clinical signs such as pain, difficulty walking, lack of coordination, or aggression. Some animals, however, can also exhibit what is known as “dumb rabies”, showing signs of depression and lethargy. The disease is progressive in nature and as more organs become affected, patients can also exhibit difficulty swallowing (commonly recognized as fear of water) and sensitivity to light. Patients eventually die from asphyxiation as their respiratory muscles stop working. Clinical signs in animals in people can appear between 10 days to several months after being bitten.

Pets can be exposed to rabies when they come into contact with wild animals such as this skunk. (http://www.globalanimal.org)

There is virtually no treatment against rabies, and affected animals are usually required to be euthanized to protect human health as  well as prevent unnecessary suffering of the patient. Treatment options in people who have been bitten by an unvaccinated animal are also scarce, usually limited to post-exposure prophylaxis (PEP). Essentially, PEP is injection of hyper-immune serum into the wound of an infected person to prevent further virus replication. For this to work, timing is critical and once the virus has entered the nerves, PEP will be of little use. This is why those who have been bitten must go to the hospital as soon as possible to receive PEP treatment. Once people start exhibiting symptoms, prognosis is very poor and these individuals will unfortunately most likely die. There has been a newly developed treatment protocol known as the Milwaukee Protocol that has had some success in treating and curing a handful of people showing symptoms of rabies. This treatment is, however, very challenging and requires the affected person to be put in a coma for a long time. There has been to date only 6 people who have survived rabies using this or similar protocol and if we compare with the number of infected people in the world (about 50 000), the mortality rate for rabies remains approximately 100%.

Rabies has been known for hundreds of years and was one of the first diseases to which a vaccine was created in the 1800s by Louis Pasteur. However, the virus remains prevalent worldwide and affects about 50 000 people yearly. As with many zoonotic diseases, the developing world can be more severely affected and some risk factors for rabies in animals and people include: large population of stray dogs and cats, dog fighting, or close contact between humans and wildlife.

However, rabies can also cause problems in developed countries. An article published in the Journal of the American Veterinary Medical Association (JAVMA) compiled all rabies cases (human and animals) for the year 2010 in the USA. Rabies in pets is usually well controlled in this country, however, several other species of animals can host the disease in the wild, depending on geographical location. The East Coast of the US is characterized by raccoon hosts while on the West Coast, skunks predominate. In other parts of the countries, foxes are also known to harbor the disease. During the year 2010, there has been several reported cases of rabies in domestic animals: 303 cats, 71 cattle, 69 dogs, 37 horses and 6 goats/sheep. Looking at these numbers, it is obvious that the major misconception that dogs only can be affected by the disease doesn’t hold as canine cases come in third place after cats and cattle. It is also important to remember that all these animals are potentially sources of the disease in people. Reported cases in wildlife included raccoons (2246), skunks (1448), bats (1430), foxes (429) and rodents/rabbits (33). These numbers represent the reported cases, meaning that these animals were submitted to laboratory for testing, thus it is likely that the actual numbers were higher. Finally, there have been 2 cases of human rabies during 2010, both fatal. One case was seen in a migrant worker in Louisiana who had been bitten by a vampire bat in Mexico about 10 days before showing symptoms of rabies. The second case was a man in Wisconsin who was hospitalized with difficulty swallowing. Viral testing revealed a strain commonly seen in bats of the area.

Distribution of wildlife terrestrial hosts of rabies. Bats are not terrestrial animals and are not depicted on this map. (http://www.cdc.gov)

It is important to notice that both of these people were infected after being bitten by bats, thus showing how important this species is when it comes to zoonotic transmission of rabies. In fact, the latest case of rabies in the US was seen in Massachusetts over the end of December 2011. The patient started exhibiting neurologic signs after having been bitten by a bat (once again) and is currently (as of January 2012 when this post was written) hospitalized in critical condition. This is the first case of human rabies in Massachusetts in over 70 years. These cases remind us that, while in many parts of the US, canine rabies cases have gone down, bats are often the most important vector for human rabies.

Considering the severity of the disease, there are several guidelines that people should follow to reduce their likelihood of infection. One of the most important is to stay away from wildlife, especially those animals that are exhibiting strange behavior including aggression or absence of fear. As previously mentioned, bats play a very important role in transmission of rabies and should not be handled by people who are not qualified. Animal control authorities should be called if someone notices a bat in their house. These animals  have small sharp needle-like teeth so bites can often go unnoticed.

There are good vaccines available against rabies, both in animals and people, and those in close contact with animals should definitely be up to date on rabies vaccination. These include people working in veterinary clinics, animal shelters and, in my opinion, livestock workers as well. Likewise, all cats and dogs should be current on their vaccines. Some cat owners may feel that their indoor cat is not at risk of contracting rabies compared to animals that go outside regularly. While that may be true, the severity of the disease warrants strong preventive measures to be put in place in order to protect pets and animal owners alike. In some instances indoor cats may find their way outdoors accidentally and become exposed to rabies. Also, it is not uncommon for bats to be able to enter homes and cats can be attracted by a bat struggling on the floor of a home.

Unvaccinated animals biting people or other pets must be put under strict quarantine or euthanized. (http://www.ccac.ca)

In fact, the diagnosis of rabies in animals usually involves some significantly drastic measures and the issue arises if an unvaccinated  pet/animal bites a person. Laws of different cities/countries may differ on the subject, however, they do follow the same general guidelines. If an unvaccinated animal bites a person, that pet may be required to be put in quarantine at the owner’s expense or even be euthanized in order to submit the brain for laboratory analysis. Maintaining appropriate vaccination status in pets is an easy and simple way to prevent such measures to be taken to protect the public.

In many countries, especially in the developing world, rabies is maintained by stray dogs and cat populations. It is therefore also important to take steps to reduce stray animal numbers and spaying/neutering pets is a great way to achieve that.

Finally, just as in any public health issue, population education is essential to ensure that the public is aware of the risks caused by rabies and the steps they can take to reduce the incidence of the disease in both animals and people.

Dog vaccination programs help greatly in managing rabies in developing countries. (http://www.rabiescontrol.net)

For more information on rabies:

World Health Organization – Rabies

Centers for Disease Control and Prevention – Rabies

Los Angeles County Veterinary Public Health – Rabies control manual

Rabinowitz PM & Conti LA. 2010. Human-Animal Medicine. Saunders Elseviers ed.

Posted by: glamielle | November 25, 2011

The pet veterinarian as a public health advocate

The role of the veterinarian in promoting public health does not always involve work in developing countries or tropical places. Zoonotic diseases, or diseases common between animals and people, are present worldwide, including in the homes of pet owners.

It is clear that the importance of pets in today’s households is significant, and it is thus crucial for animal owners and physicians to take into account the pet when looking at disease dynamics in a family. Indeed, pets can serve as a source of infection to people, and vice versa, and the close contact that many have with their companion animals puts them at higher risk of infection from these pathogens. This is why the veterinarian should be an active member of a family’s health team and work together with family physicians when evaluating how the pets’ health can affect households.

In order to assess this risk of transmission of zoonosis from pets to humans, it is important to focus our attention on several groups who are at higher risk of infection. These usually include children, the elderly, pregnant women or those with depressed immune systems like those individuals with HIV, cancer or other chronic conditions.

Due to close contact with their pets, children are at higher risk of contracting diseases from companion animals. (http://leerburg.com/308.htm)

This does not mean that people should refrain from having pets and, if the animals are treated properly, the benefits of having a pet definitely outweigh the risks. What needs to be done is to realize that these animals should be maintained healthy in order to reduce likelihood of transmission of disease to people.

More than half of infectious diseases in people are shared with animals, including some of the more famous diseases like rabies, plague or influenza. However, there are more pathogens that pets can harbor and can infect people.

Roundworms & hookworms

Roundworms, specifically by Toxacara canis and Toxacara cati, are nematodes of the dog and cat that are commonly affect veterinary patients. Often seen in younger animals, toxacariasis is transmitted by ingestion of eggs from the environment or from contaminated

Child affected with ocular larva migrans from Toxacara infection (sunnysidevet.net)

meat, although nursing puppies an also acquire the parasite from the milk of an infected female. The disease in animals is usually mild and is characterized by gastrointestinal inflammation, distended abdomen and lack of weight gain. In some severe cases, worms migrating from the intestinal tracks to other organs such as liver or lungs can cause a more severe clinical appearance such as respiratory disease. Humans also get infected from ingestion of eggs from contaminated soil, or sometimes on animal’s fur. The parasite can also be present in larval form in tissues of a wide range of species such as cattle or birds, and as such, eating infected meat represents another transmission pathway. The disease in people is represented by two major processes: ocular-larva migrans and visceral-larva migrans. In ocular-larva migrans, parasites migrate to the eyes of the affected person, where they can generate strong inflammatory response. Visceral-larva migrans is characterized by larval migration to internal organs, where the parasite can become dormant. This disease is usually mild although inflammatory response can rarely lead to severe symptoms. In both of these syndromes, children are at higher risk of infection due to their close contact with dogs and cats as well as potentially contaminated soil or sand.

Cutaneous larva migrans from Ancylostoma infection. (ruby.fgcu.edu/courses/davidb/50249/web/clm1.htm)

Hookworms are also a common occurrence in veterinary patients. Caused by Ancylostoma or Uncinaria species, these infect dogs and cats, especially kittens and puppies as well as stray animals. Infected hosts shed eggs into the environment and the parasite needs to hatch and develop into a larva before becoming infective to other species. Disease in dogs and cats is usually mild and characterized by weight-loss and diarrhea however, severe infection can lead to anemia. One important characteristic of hookworms is that the larvae living in the environment have the ability to directly enter the skin or mucous membranes of hosts, which is how humans most commonly get infected. People walking barefoot outdoors can have hookworm larvae enter through the skin, causing intensely itchy and inflammed lesions where the parasite is seen migrating under the skin. Rarely, hookworms in people can cause pulmonary and gastrointestinal symptoms.

While hookworms and roundworms are some of the most common parasitic zoonoses of pets, it is important to remember that other parasites of dogs and cats can be transmitted to people, such as tapeworms (Dyplidium sp.) and whipworms (Trichuris sp.). In all these cases, frequent deworming of dogs and cats leads to a decreased chance of infection in people

Giardia

Giardia lamblia are unicellular protozoans that are present in both animals and people. Commonly found in the intestinal tract of many animal species including wildlife, the parasites are shed in the feces and can survive well in water sources. Clinical appearance in both animals and humans is similar, commonly showing gastrointestinal involvement. Dogs and cats most often have watery diarrhea that may be bloody, depending on the severity of the infection. Vomiting, lethargy and decreased appetite can also be present. Diagnostics is usually done through evaluation of a fecal sample by identifying the parasite its cyst form directly under the microscope, although other tests like ELISA can detect the microbe more efficiently. Humans show very similar symptoms, including diarrhea and abdominal pain. Treatment in both animals and people include medicating with drugs such as metronidazole or fenbendazole. In my experience, giardiasis in animals can be challenging to treat and using a single drug may not do the trick. The current recommended treatment includes using metronidazole and fenbendazole together for better control.

Stained Giardia protozoans in their trophozoite forms (cdc.gov)

It is important to recognize that, both in animals and people, the parasite can be present in asymptomatic individuals, which suggests that it is part of the natural flora. This means that those who show significant disease from an infection may be more sensitive to it, such as kids (and puppies) or the immune-compromised.

Finally, while Giardia is one of the most commonly recognized zoonotic diseases from pets, it is important to realize that, in practice, it may not be the most important. There are in fact several different strains of Giardia lamblia, and each strain commonly affects a specific host. For example, Giardia types C and D only infect dogs, while type F only infects cats – human infection from these strains is not likely to cause disease in people, who are usually colonized by type A2. Some strains, however can infect a wide range of species, including people, and those are the ones that have zoonotic potential.

Giardia Assemblages A1 and B are the only ones capable of zoonotic infection (Weese JS & Fulford MB. 2011).

Toxoplasma

Toxoplasmosis, caused by protozoan Toxoplasma gondii, is mainly a parasite of cats, however the it can be found in several other animal species and humans. The disease is generally mild in both animals and people and usually goes unnoticed in healthy individuals. As such, there can be a significant proportion of the population that has had previous infection and is therefore protected, as evidenced by their elevated blood antibodies to the protozoan. Cats are the primary reservoir for T. gondii and acquire the infection from feeding on raw diets or other animals such as rodents. In felids that are infected for the first time, a large number of oocysts can be shed in the environment and thus infect other animals and people if ingested. It is important to recognize that these oocysts take 1-5 days before being infective to other species but can survive in the environment, including water sources, for long periods of time.

Disease in both healthy cats and humans usually provides good lifelong immunity to further infection, however some cats can have short-lived diarrhea diarrhea and symptoms in people are usually non-specific including headache, fever and swollen lymph nodes. While infection in healthy individuals is generally asymptomatic, the issue with T. gondi arises when it is found in special populations, specifically pregnant women and the immune suppressed, where it can cause severe illness. Toxoplasmosis is a well-recognized disease that can affect foetal development leading to abortion and neonatal death, as well as neurologic signs later on in life such as blindness, deafness or mental retardation. While previous infection in women usually generates appropriate life-long protection against the disease, a previously uninfected pregnant woman will not be able to generate sufficient immunity to prevent toxoplasmosis in the foetus.

Likewise, the parasite can cause significant disease in those with depressed immune systems in people suffering from AIDS or undergoing chemotherapy, leading to symptoms such as encephalitis. Another important aspect of toxoplasmosis infection is the potential for latency, meaning that the parasite will become inactivated in organs of healthy individuals and remain embedded for the rest of their lives. Previously healthy people who become immunosuppressed can thus suffer from symptomatic toxoplasmosis from re-activation of these hidden cysts without the need for new exposure to the parasite.

Due to the possibility of severe disease in the population at-risk, some clinicians advocate for complete removal of cats in households of pregnant women or HIV-positive patients. This drastic measure can, however, be avoided by proper management of the pet cat as well as good hygiene. Proper hygiene habits are always mandated when dealing with animals, including pets, and frequent handwashing or avoiding contact with cat feces (especially 1-5 days old), but also dirt or sand, is essential. People at risk should refrain from handling cat feces if possible, however, if they are unable to do so, the use of gloves is definitely warranted, as well as washing litter box and utensils with warm water. Reflecting the situation in humans, immunosuppressed cats are at higher risk of disease, leading to longer oocyst shedding time, and maintaining a healthy pet is an integral part of disease management in people. Cats usually have a good habit of grooming themselves however, in unthrifty or ill animals, grooming may be reduced and the cats may carry more Toxoplasma oocysts on their fur. Keeping cats indoor is also a very good way to prevent infection, as they will not be exposed to rodents that may carry the protozoan. Since it takes a few days for the oocyst in cat feces to become infective, frequent, daily cleaning of the litter box is a very effective way to prevent human infection. Finally, it is interesting to notice that, although cat ownership has increased in the US, the incidence of toxoplasmosis as been decreasing.

Ringworm

Ringworm (Microsporum canis) infection in a person. (dermnetnz.org)

Ringworm, or dermatophytosis, is one of the most common zoonotic diseases that affects a wide range of animals, especially cats, as well as people. It is caused by a group of fungus that can be found on the skin of many pets and can be spread to other individuals through direct contact, such as petting, but also fomites (couch, bedding) and fleas. Animals usually have a mild localized skin infection characterized by an area of hair loss and skin inflammation that may or may not be itchy. Likewise, in people, ringworm is characterized by circular skin lesions and is not usually severe if the individual’s immune system is working normally. Children tend to be at higher risk of infection due to their closer contact with pets. Not all cases of human ringworm are caused by a zoonotic species of fungus and it is important that physicians dealing with dermatophytosis infection in a family recommend veterinary examination of the pets to help control the outbreak.

About half of ringworm infections can glow under ultraviolet light (http://www.monvt.eu/)

Salmonella

Gram-negative staining of Salmonella sp. (textbookofbacteriology.net)

Salmonella are bacteria that are part of the intestinal flora of a wide range of animal species, especially cattle, and are mostly known as a food-borne pathogen. Symptoms in humans include diarrhea that can sometimes be severe and life-threatening. When it comes to pets, the traditional hosts of Salmonella include reptiles and birds and it is very important that people, and especially children, wash their hands after handling these animals. The bacteria are not common natural flora of dogs and cats and infection in these species usually doesn’t last more than a few weeks. In severe cases, gastrointestinal signs may occur. Therefore, the risk of transmission of Salmonella from dogs and cats to people is very low. This risk, however, can greatly increase in dogs and cats that are fed raw diets. I have seen from personal experience in the clinic that a significant number of people prefer to feed their pets raw diets. It is important to educate animal owners that these diets are usually not processed to the extent of other available pet foods and thus, contamination with bacteria such as Salmonella and E. coli will be transmitted to the pet. In fact, a study from 2008 has shown that dogs fed raw diet are 23 times more likely to shed Salmonella in their feces compared to dogs fed processed food, thus increasing chances of infecting people.  This is why it is generally contraindicated to feed such diets, especially in households where there are people at higher risk of infection such as children or immunocompromised individuals.

Methicillin-resistant Staphylococcus aureus (MRSA)

Culture and antibiotics sensitivity testing is used to determine resistance in bacteria. Each dot represents a different antibiotic used; the clear area around each dot represents the degree of sensitivity to that specific antibiotic. (http://www.staph-infection-resources.com)

The rise of antibiotic-resistant bacteria has become an important issue in both human and veterinary medicine. Specifically, MRSA is a growing issue in human healthcare contexts such as hospitals. There are two recognized forms of MRSA infection in people: hospital-associated and community-associated. Staphylococcus aureus can be a common bacteria living in the upper respiratory tract and on the skin of humans. In healthy people, the bacteria generally does not cause disease, however, in people whose immune system is

depressed or skin is broken after a wound or surgery, MRSA can be the source of a significant infection. The challenge in the management of MRSA infections stems from the fact that the bacteria may be resistant to a wide range of antibiotics and, thus, treatment options can rapidly become limited.

S. aureus is not considered a common flora of dogs and cats, which are colonized by different staphylococcal species such as S. intermedius. Therefore, MRSA is usually not a natural occurrence in pets. The bacteria can, however, survive on the skin and nasal passages of household pets but colonization is usually self-limited and clears up on its own in about 14 days. In terms of disease in pets caused by MRSA, it is safe to assume that the same principles from human medicine apply and that the bacteria can be pathogenic in animals with wounds or depressed immune system. There is a consensus, however, that MRSA in animals is considered a reverse zoonosis, meaning that humans are the ones infecting pets. This is supported by the fact that, as previously mentioned, MRSA infection in pets is usually transient. Furthermore, studies have shown that dogs infected with MRSA reflect infection in the human population. This is significant because affected individuals can infect their pets, which can in turn re-infect their owners. This is the reason why collaboration between physicians and veterinarians is crucial when trying to get rid of an infection and thoroughly control MRSA in a household.

Human and animal health are intricately linked, and that may be even more apparent when it comes to companion animals. Most pet owning families share a close bond with their dogs and cats which can put them at greater risk of zoonotic infections, however this does not mean that they should give their animals away and not be exposed to the benefits of animal companionship. What needs to be done is to treat these pets as members of the family and thus provide them with appropriate care to ensure they remain healthy. The general guidelines to prevent transmission of zoonoses from pets to humans are very similar regardless of the diseases in questions: prevent pet contact with wildlife, frequent deworming, maintaining up-to-date vaccines and proper hygiene practices. Dealing with health problems in pets at an early stage is also more likely improve the animal’s health, reduce costs of treatment and decrease likelihood of transmission of disease to people.

Pet veterinarians play a crucial part in maintaining a healthy family. (http://www.ct.gov/dph/cwp/view.asp?a=3143&q=388948)

Resources:

Rabinowitz PM & Conti LA. 2010. Human-Animal Medicine. Saunders Elseviers ed.

Weese JS & Fulford MB. 2011. Companion animal zoonoses. Blackwell Publishing.

« Newer Posts - Older Posts »

Categories