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Prevention of Disease Transmission in Primate Conservation

JANETTE WALLIS

a

Department of Psychiatry and Behavioral Sciences, Oklahoma University Health Sciences Center, Oklahoma City, Oklahoma, USA

INTRODUCTION

The close relationship between humans, apes, and monkeys allows for easy inter-species transmission of diseases.

1

In fact, the susceptibility of nonhuman primatesto human diseases has led to the development of very strict husbandry standards andprocedures in captive settings.

2

As a result, personnel in laboratory environments arerequired to wear facemasks and gloves, and to take other protective measures toensure the safety and health of their primate subjects—as well as their own. Yet,when living in their natural habitat, these same nonhuman primates are often unpro-tected from human diseases that can have deadly consequences. Many field researchmethods require gaining close proximity and, thus, can place primate subjects at riskof exposure to human-carried pathogens. Additional risks arise through improperwaste disposal or nonhygienic conditions of humans residing near the study site.

3

The more closely related a nonhuman primate to humans, the greater the numberof pathogens that may be exchanged. In some cases, an organism that is relativelynonvirulent in its host may be extremely virulent in a different species.

4

Many patho-gens may be involved: bacterial, mycoplasmal, spirochetal, fungal, parasitic, andviral. These can spread by physical contact, airborne transmission, ingestion, andthrough arthropod vectors.

5

This paper describes several cases of possible diseasetransmission under natural conditions and discusses strategies for prevention.

EXAMPLES OF POTENTIAL PROBLEMS

When disease occurs in a free ranging primate population, it is often difficult toproperly diagnose the illness, let alone identify the origin of the problem. We are leftwondering whether the disease could have had a human connection. If so, how canwe prevent a recurrence? Clearly, if humans can

introduce

a disease, then humanscan

prevent

the introduction of the disease. Examples of nonhuman primate diseasesthat may have had a human origin are as follows.

Chimpanzees and a Polio-like Virus.

In 1966, an outbreak of a “polio-like” virusoccurred at Gombe National Park, Tanzania. Six chimpanzees died from the disease and

a

Address for correspondence: Department of Psychiatry & Behavioral Sciences,Oklahoma University Health Sciences Center, Oklahoma City, OK 73190, USA. Voice:405-271-5251, ext. 47612; fax: 405-271-3808.

janette-wallis@ouhsc.edu

692 ANNALS NEW YORK ACADEMY OF SCIENCES

at least six others were paralyzed for life.

6

Two years prior to that, there was a similaroutbreak among the free ranging chimpanzees at Beni, Zaire.

7

Chimpanzees and Respiratory Disease.

The main study population of chimpan-zees at Gombe National Park has suffered a number of respiratory illnesses. Each ofthese events affected a large number of chimpanzees, killing many.

3,6

Gorillas and Scabies.

In 1996, a severe outbreak of skin disease occurred in thegorillas (

Gorilla gorilla

) living in the Bwindi Impenetrable National Park, Uganda.

8

All four members of one group were affected and an eight-month-old infant died.Skin scrapings and skin biopsy confirmed the presence of

Sarcoptes scabiei.

Gorillas and Possible Measles.

During early 1988, the mountain gorillas living inthe Parc National des Volcans, Rwanda, experienced an outbreak of respiratory ill-ness. Six deaths occurred and 27 additional cases were successfully treated.

9

Anal-ysis of serum and tissue samples indicated a wide array of causes, includingpneumonia and vegetative endocarditis and, in one case, the likelihood of measles.

Baboons and Yaws.

In 1989, several troops of baboons at Gombe were afflictedwith yaws, which spread as a venereal disease.

3

Baboons and Parasites.

In a study of five troops of baboons at Gombe (Tanzania),three troops were found infected with

Schistosoma mansoni.

The baboon troop withthe most contact with people showed the highest prevalence of infection.

10

Similarresults were obtained for the baboons at Amboseli National Park in Kenya.

11

FINDING SOLUTIONS

Finding solutions to the disease transmission problem requires changing thebehavior and policies of our own species. No single group can successfully addressthe problem, however. All concerned individuals need to work together to effect apositive change. Among the groups that should be involved are the following.

Field Researchers.

It is incumbent upon researchers to help develop proper pro-cedures regarding hygiene, sanitation, and waste disposal of humans living in theanimals’ habitat. Preventive health seminars can help provide park and research per-sonnel with important information about disease control and setting up strict healthstandards.

Park Personnel and Government Officials.

An obvious component in the diseaseprevention process is the habitat country’s government officials. They set policy, lim-it or encourage tourism, issue permits for foreigners to conduct research, and givepermission for medical treatment when wild primates are ill. It is imperative thatgovernment officials be involved in all steps of the process to effect change.

Local Villagers.

Local populations are a necessary part of all aspects ofconservation.

12

We must be very cautious with how we educate local populationsabout the disease transmission issue. There are two key points to remember: (1) Wemust not give the impression that animal health is more important than that ofhumans. (2) We must make certain that our message is presented calmly and doesnot backfire causing overreaction and extermination of nonhuman primates as a per-ceived health threat.

Tourists.

Many national parks in habitat countries are tapping into the importantfinancial resource of tourism. “Ecotourism” is a developing industry, heralded bymany as an important conservation activity. Tourists often spend thousands of U.S.

693WALLIS: PRIMATE CONSERVATION

dollars to travel to the home of exotic animals, thus they may be resistant to keepinga distance from the animals. Park personnel and researchers can provide literature orinformal lectures to educate tourists about health risks.

Veterinarians and other Health Care Providers.

There is a growing awareness inthe veterinary community of the need to address wildlife conservation. Wildlifemedicine helps maintain the health of endangered species and decreases the impactof pathogens from humans and domestic animals on free ranging animals.

13

CONCLUSIONS

This review has briefly introduced the topic of disease transmission betweenhumans and nonhuman primates living in natural habitats. The prevention of suchdisease transmission is an important task for primate conservationists—both in ourwork to protect existing populations and to fight the further decline of threatened orendangered species.

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