Human Health Care Providers and Veterinarians Need to Communicate

It is not uncommon for patients to ask me whether an illness in a pet could be related to symptoms they are experiencing. For example, a patient suffering from allergies caused by mold in her house told me about her dog that was being treated by a veterinary allergist. Was it possible that human and dog were dealing with the same problem?

What are physicians or other health care providers supposed to do with such questions and information? Physicians receive no training in veterinary diseases and are not taught how to appropriately respond to these issues. Should a doctor ask more questions about the dog’s illness? Ask to speak to the veterinarian? Is this a useful line of inquiry or mere frivolous waste of time?

Over 60% of U.S. households include at least one pet (Hoff1999), and this proportion is increasing. Often the degree of medical care that the pets are receiving equals or exceeds the medical care happening for humans in the household. There is a basic rule that veterinarians are not allowed to treat human patients (but veterinarians tell me that their clients often ask for medical advice about zoonotic diseases and other conditions). Physicians, for their part, are not supposed to diagnose or treat animals (but tell that to the rural family doctor I met this week who is regularly asked to take care of goats and cows and dogs). At the same time, there are growing similarities between veterinary medicine and human medicine. (Rabinowitz and Conti 2010) Both disciplines use similar blood tests, urine test, and radiological studies to diagnose disease. Both use similar (but not always identical) medications to treat infections, diabetes, and even mental illness. And there can be value in seeing the numerous similarities between medical conditions that manifest in an animal and a human, as physicians such as Barbara Natterson have noted (see her zoobiquity website http://www.zoobiquity.com )

There are a number of specific reasons why physicians and veterinarians need to communicate and collaborate. Contact with pets or other animals can increase the risk of zoonotic (animal to human) disease transmission, especially for children and immunocompromised individuals (Pickering et al 2008, Kaplan et al 2009, NASPHV 2011), and veterinarians can contribute to effective prevention of such transmission. Veterinarians can also work with clients to reduce the risk of animal bites from pets. Beyond the risk of infections and injuries, people may share chronic health problems such as obesity with their companion animals, and be willing to engage in joint preventive behaviors such as exercise programs (Kushner et al 2006). The strength of the human-animal bond may affect psychosocial health, as well as access to medical care (for example; a patient unwilling to leave pets at home to go to the hospital). Drug-seeking patients may request pain medication and other controlled medications from veterinarians on the pretense that it is needed for their pets (LeBourgeois et al 2002).

In addition, illness in an animal may be a “sentinel event” indicating environmental risk for humans (see the Canary database www.canarydatabase.org for more information on this). An example would be allergies due to a common allergen in the environment, or a dog that is diagnosed with a tick-borne disease giving warning about risk to humans who walk  in the same suburban areas as the dog.

Despite all of these apparently obvious reasons for communication and collaboration between veterinarians and human health care providers, real life examples appear to be rare. The practice of medicine is increasingly evidence-based (as it should be), and the lack of published studies documenting the benefit of such encounters between professionals makes it hard to change current practice patterns. At the same time, there are also no studies showing a lack of benefit of such teamwork! In other words, these ideas, however obvious and promising, remain virtually untested.

What are needed are good pilot projects and studies to begin documenting proof of concept of collaboration between human and animal health professionals. These studies could test the acceptability and effectiveness of clinical protocols and materials such as templates for referrals between veterinarians and their human health counterparts. As information begins to flow between the disciplines, the evidence will be able to point future practice patterns in the correct direction. I (and many others) will welcome that day.

References:

Hoff GL, Brawley J, Johnson K. Companion animal issues and the physician. South Med J. 1999; 92:651-9.

Kaplan JE, Benson C, Holmes KH, Brooks JT, Pau A, Masur H. Guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. MMWR Recomm Rep. 2009;58(RR-4):1-207.

Kushner RF, Blatner DJ, Jewell DE, Rudloff K. The PPET Study: people and pets exercising together. Obesity 2006;14:1762-70.

LeBourgeois HW 3rd, Foreman TA, Thompson JW Jr. Novel cases: malingering by animal proxy. J Am Acad Psychiatry Law. 2002;30:520-4.

National Association of State Public Health Veterinarians, Inc. (NASPHV); Centers for Disease Control and Prevention (CDC).Compendium of measures to prevent disease associated with animals in public settings, 2011: MMWR Recomm Rep. 2011 May 6;60(RR-04):1-24.

Pickering LK, Marano N, Bocchini JA, Angulo FJ. Exposure to nontraditional pets at home and to animals in public settings: risks to children. Pediatrics. 2008; 122:876-86.

Rabinowitz PM, Conti LA. Human Animal Medicine: Clinical Approaches to Zoonoses, Toxicants and other Shared Health Risks. Elsevier 2010; 432 pp.

“Contagion” and Emerging Infectious Diseases from an Occupational and Environmental Medicine Perspective.

The past two decades have seen some remarkable emergence of new and deadly pathogens, from SARS to avian influenza H5N1 and the novel 2009 H1N1influenza strain. It is often pointed out that a majority of recent emerging infections are “zoonotic” (transmitted from animals to people) in origin. The movie “Contagion” follows on this theme by depicting a novel virus sweeping the globe. About halfway through the movie, we learn that the virus has genetic sequences from both bats and pigs, implying that at some point “the wrong bat met up with the wrong pig”.

At the end of the movie, there is a montage that hints at the origin of the new lethal virus. Fruit bats in disturbed rain forest are seen flying and having contact with pigs in a large barn. The montage follows the pigs and presumably the virus as the pigs go to market and slaughter and into a restaurant in Asia where blood on the chef’s hands and apron appears to infect the business traveler character played by Gwyneth Paltrow, who then becomes the “index” patient spreading the epidemic from person to person around the globe.

This bat-to-pig-to-human scenario hearkens back to the real emergence of a novel virus called "Nipah virus" from a fruit bat reservoir in Malaysia into pig farms located close to areas of recently logged rain forest (see review by Chua 2003 ) . In 1999, Nipah virus caused a new and fatal encephalitis in Malaysian pig workers and a milder disease in pigs. It is thought that the movement of sick pigs spread the disease to other parts of the country, often infecting other pig workers.

The Nipah outbreak in Malaysia is a reminder about how often it is the people working closely with animals or their products who first experience disease from a viral or bacterial pathogen crossing from animals to humans.

Similarly, with SARS, while we now think that the virus may have emerged from a natural reservoir in bats and spread to humans via intermediate host animals such as civets, the initial animal to human transmission events may have involved workers in animal markets, who have been found to have elevated rates of antibodies to the virus, suggesting that they had become infected through their work with animals (CDC MMWR 2003).

With avian influenza, the majority of human case have been among people performing tasks associated with poultry production, trade, and consumption, such as working on farms, in animal markets, or butchering and preparing poultry for consumption.

 

And with the 2009 H1N1 virus, while the emergence events remain unknown there is a suspicion that one of the key events was zoonotic transmission from swine influenza viruses to humans working closely with the animals.

So, what if emerging infectious diseases can be seen as a problem of animal workers? It might lead us to pay greater attention to these workers than we do currently.

Agricultural animal workers work worldwide across a large spectrum of activities, from backyard farms to large industrialized facilities, to large and small slaughter facilities to animal markets. They deal on a daily basis with a wide range of hazards, from injuries, to inhalation of dusts, to the possibility of infection from the animals.  Regardless of whether these animal workers are members of the “informal work sector”  (such as workers on family farms), or salaried employees in large mechanized facilities, in general, in contrast to, say, factory workers, there are no regular programs to monitor or foster their health and safety. Their health and safety concerns, including their risk of occupational infections, are ‘off the radar’ of most physicians who practice the specialty “occupational and environmental medicine” (the diagnosis, treatment, and prevention of diseases caused by exposure to hazards at work and in the environment). In addition, due to their often marginal economic status,  they may also not be receiving medical care benefits or have access to regular basic medical care.

In the U.S., many agricultural animal workers are recent immigrants who may be less aware of their health and safety conditions, and due to language and cultural barriers less likely to access such information if it is provided by the employer or others.

What is needed is more awareness of the work these people do and better ways to help them do it in a healthy way that reduces the risk of disease transmission. Ironically, doing so may be also be better for animal health, since we have seen that “zoonotic” pathogens can sometimes move in both directions, from animal to human or from human to animal (‘humanosis’ or ‘reverse zoonosis’). An example is H1N1 influenza, which, as it spread globally, demonstrated many more instances of humans apparently infecting animals (pigs, cats, etc.) than the other way around. So keeping animal workers healthy may help keep animals healthy as well!

In addition to the occupational medicine aspects of emerging zoonotic infections, it is also important to look at the environmental aspects. When Nipah virus emerged in Malaysia, it was related to the way that the farms were impacting the forest ecosystem. And many of the recent episodes of food safety problems seem to be caused by persistence of  pathogens in the environment related to the way that animal waste and human waste are handled.

Perhaps in the future there can be greater emphasis on a “One Health” approach to animal agriculture, one that brings together experts in agriculture, veterinary medicine, environmental health, and human occupational health, and that emphasizes the value of healthy workers and healthy animals, and the need to raise animals in such a way that the environment is enhanced. It would seem that to take our attention off of any of these three issues (the health of animals, animal workers, and the environment), and their interrelationships, in our push as a society to produce greater amounts of animal protein to feed a growing human population is to risk big problems in the long run.

High altitude cattle and comparative medicine

A recent article in the New York Times is a reminder of the potential for new approaches to comparative medicine outside of the typical research laboratory. For years, veterinary researchers have studied the effect of high altitude on cattle grazing in mountainous areas of New Mexico and elsewhere. These studies have revealed important findings about the chronic effect of hypoxia on the cardiovascular system, including insight into the condition of hypoxic pulmonary hypertension that is an important disease in humans. The researchers have also been able to study the effect of genetic susceptibility on these physiologic responses, and to develop clinical approaches for early diagnosis of altitude illness. The recent research reported in the Times actually builds on studies of high altitude cattle in Colorado and other parts of the Southwestern US that have gone on over the past 100 years. And while we have learned a lot about human pulmonary hypertension (a disease that develops in individuals with sleep apnea and other hypoxic conditions) from “Brisket disease” in cattle, there are also preventive lessons to learn from animals that are evolutionarily adapted to high altitude, such as certain types of llamas, rodents, and yaks. These adaptations can involve not only much thinner blood vessels in the lungs, but also a lack of the response to low oxygen that is seen in cows and persons who develop pulmonary hypertension.  These findings reinforce the fact that there is much to learn from studies of naturally occurring animal populations that can influence both human medicine, veterinary medicine, and our understanding of the effects of environmental factors on health.