Preventative Methods to Reduce the Spread of Cattle Fever Ticks on Wildlife and Protect Local Endangered Species in South Texas

Abstract

Reintroduction and dispersal of the livestock and wildlife pest, southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini), along the U.S.-Mexico border in the southernmost counties of Cameron and Willacy has been attributed mostly to nilgai antelope, Boselaphus tragocamelus (Pallas), and to a lesser extent, white-tailed deer, Odocoileus virginianus (Zimmerman). Nilgai are competent hosts of R. microplus, have large home ranges, and are distributed from southern Texas into northeastern Mexico where R. microplus, a vector of bovine babesiosis, is endemic. The study documents movement of nilgai and white-tailed deer through gaps in game fencing previously built to redirect movements of the endangered ocelot, Leopardus pardalis (L.), to wildlife crossings. Game fencing limits movement of nilgai and white-tailed deer and thus reduces the spread of cattle fever ticks. Additional game fencing is proposed to limit movement of tick-infested nilgai, white-tailed deer, and further redirect ocelots to crossings to avoid mortality on roads. In other parts of Cameron and Willacy counties where road mortality to ocelots is not an issue, game fencing is designed with large openings to block nilgai but allow free movement for endangered feline species. This research demonstrates how efforts to protect livestock from an exotic pest can also merge with goals of protecting endangered species in the same environment.

Nilgai antelope display no signs of infection upon experimental challenge with a virulent Babesia bovis strain

“…Further, wildlife can readily cross the border between Mexico and the USA [ 16 ]. Treatment of these hosts to reduce cattle fever tick infestations is problematic and challenging [ 17 ]. The abundance of these ungulate hosts has drastically transformed the ecology of this disease system since it was eradicated in the mid-1900s.…”