I’m scheduled to give a talk to an audience at the Beardsley Zoo in Connecticut next month on topics relevant to ecological health and conservation medicine. These emerging field disciplines are popular right now, just as veterinary epidemiology has become a hot topic among interdisciplinary collection-based research programs. They are not just popular. These health science disciplines are vital areas for researching the implications of the human-wildlife interface in regions of the world where wildlife coexists closely with human populations.
While perusing wildlife health resources I realized that I missed some recent epizootics or at least notable reports of disease outbreaks in wildlife. The Wildlife Conservation Society just released some news regarding the cause of a 2007-2008 die-off among two of the 9 extant species of howler monkeys. Altogether 59 monkeys in northeastern Argentina succumbed to this arbovirus (arthropod-borne virus) some of which were a subspecies of brown howler monkeys (Alouatta guariba). Although found in relatively high densities even in fragmented habitat, hunting and disease have impacted otherwise sustainable populations of these large leaf-eating monkeys.
Jungle Yellow Fever refers to the sylvatic or wild life cycle which persists with in New World monkey populations in forest habitat. The acute viral hemmorhagic disease which has it’s origins in Africa is also now endemic in Latin America. Infected Old World primates are typically asymptomatic, but the virus takes it’s toll on the more susceptible Central and South American primates which have not co-evolved with the disease. Aedes spp. mosquitoes serve as vectors of this viral pathogen and if they feed on unvaccinated populations of humans, the disease is easily transmitted and may persist in “urban” transmission cycles.
Yellow fever refers to the jaundice that affects some human patients. The disease, if not treated, can be lethal. As people continue to encroach upon wild lands and deforestation rates increase in tropical regions, the potential for the sylvatic disease transmission cycle to evolve into an intermediate and/or urban transmission cycle becomes increasingly likely. As people and monkeys increasingly attempt to co-exist, threats to human health from Yellow Fever will persist without the intervention of immunization and mosquito control programs. Yellow fever exemplifies a human health risk that can be assessed and addressed though surveillance programs targeted at wild primates. In this case brown howler monkey populations which are already threatened by human activities serve as indicators of disease outbreaks in areas inhabited by humans.
Some zoos in Latin America, including facilities in Belize warn people not to purchase monkey as pets, mentioning several reasons, one of which is concern over diseases like Yellow Fever. Yellow fever like all arboviruses is considered a zoonotic disease because the transmission cycle involves insect vectors and people. However, no direct transmission occurs between primates and people.
According to ISIS the only pair of brown howler monkeys (Alouatta guariba guariba – Northern Brown Howler) in captivity (on record) are housed at the Fundacao Zoo-Botan. de Belo Horizonto. I believe the animal photographed above is a red howler monkey.