Half of Barro Colorado's ocelots have Feline Immunodeficiency Virus

An ocelot (Leopardus pardalis). Photo by the US Fish & Wildlife Service

Half of ocelots tested at Barro Colorado had feline AIDS
by Eric Jackson, from other media

In a paper published in the Journal of Wildlife Diseases, a team of scientists from Colorado State University, the New York State Museum and Sciences Services and the Smithsonian Tropical Research Institute (STRI) outlined the disease patterns they found among 12 Barro Colorado Island ocelots whose blood they tested. They found a high rate of Feline Immunodeficiency Virus (FIV, which is commonly, but somewhat imprecisely, known as feline AIDS) but none of the other diseases that are endemic among Panama's domestic cat and dog populations. Half of the ocelots tested positive for antibodies to FIV. Through the use of automated cameras, scientists estimate the island's ocelot population at about 30.

The study's importance is that it adds to the knowledge about vulnerabilities of isolated wild animal populations to exotic diseases. It is thought that some local wild animal extinctions are caused when diseases endemic among domestic or feral animal are introduced into populations where they had not previously existed. Dogs, cats and other domesticated animals are not allowed on Barro Colorado Island, which was a large forested hilltop partly occupied by a mango grove when Gatun Lake was flooded to make the Panama Canal. The resulting island has been a scientific research outpost since the 1920s and has been the location of many famous scientific discoveries in the fields of tropical biology and ecology.

Wild ocelot populations studied in a Bolivian national park typically had been exposed to many of the pathogens found among domestic cat and dog populations. But because those ocelot populations are only relatively isolated from human settlements --- habitations are far away, but people hunt with dogs in the wild areas that are those ocelots' habitat --- questions remained whether the same diseases that afflict the domesticated animals are also endemic among wild animals.

At Barro Colorado, the answer, with the exception to FIV, is no. The high rate of the one viral infection that was found is believed to be the result of the island's relatively dense ocelot population.

So what are the implications for Barro Colorado's ocelots? "Unknown," say Samuel P. Franklin, Roland W. Kays, Julie A. TerWee, Jennifer L. Troyer, Sue VandeWoude and Ricardo Moreno (the latter a biologist working for STRI). It is known that one ocelot fitted with a radio collar on Barro Colorado Island swam to the mainland and that other wild feline species (pumas, jaguars, and more commonly, margays and jaguarundis) come and go between the island and the mainland. Thus the island's ocelots are only relatively isolated --- there is the possibility of their catching diseases from other wild cat species, or from ocelots migrating onto the island and bringing them with them. But the reasearchers' hunches are that they found an ocelot-specific strain of FIV that their instruments were not sensitive enough to distinguish from other strains, that the disease is endemic among ocelots and that Barro Colorado's ocelots are protected from domestic animal diseases by their isolation on the one hand but vulnerable to high infection rates of the diseases they do get because they are a small an concentrated population.

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