Battling to eradicate cattle fever ticks in South Texas, the Texas Animal Health Commission (TAHC) has temporarily quarantined 152,716 acres in Starr and Hidalgo counties. And, in nearby Zapata County, five-mile quarantine perimeters are being drawn around fever-tick infested pastures. A map of the temporary quarantine zone is posted on the TAHC web site at www.tahc.state.tx.us.
A foreign pest, the cattle fever tick can carry and transmit Babesia, a blood parasite that can kill adult cattle. Although it prefers cattle, the fever tick can survive and be carried on horses, deer, elk, aoudad sheep and a number of other deer species.
Since October 2008, (the beginning of the 2009 federal fiscal year) 127 fever tick-infested premises in eight South Texas counties have been detected and quarantined. This year’s infested premises tally will eclipse last year’s count of 132, and could exceed the record set during the 1973 fever tick outbreak – 170 infested premises.
Bob Hillman, Texas state veterinarian and head of TAHC, says the USDA Tick Force and TAHC teams work inward from the outer edges of the temporarily quarantined area, inspecting ranches with cattle, horses and wildlife hosts to determine the outermost spread of the fever tick infestation. Not only do animals become tick-infested, but so do the pastures, as fever ticks may wait in the grass for months before finding a suitable host animal.
When infested premises are detected, the animals and pasture are quarantined for nine months or longer. Cattle are inspected and treated, while horses are sprayed and wildlife are provided medicated feed or enticed to treatment stations to rub against pyrethrin-coated posts while they eat.
Once cattle are “tick-free,” the cattle may be moved to a new site, allowing the pasture to be vacated for months, causing the ticks to starve. Greater success is achieved, however, by leaving cattle in place and continuing to inspect and regularly treat the animals.
“The longer it takes to eradicate this fever tick incursion, the greater are the chances fever ticks will be spread to other states, which will raise the costs exponentially,” Hillman says. “More people, more national resources and new tick-fighting products are needed now to get this potentially deadly pest out of the U.S.”
Though the fever tick was declared eradicated from the U.S. in 1943, it has never been wiped out in Mexico, which serves as a continuous source for reinfestation in Texas. USDA’s Tick Force has fewer than 60 riders to patrol the 900 miles of the Rio Grande on horseback from Del Rio to Brownsville, and apprehend “ticky” Mexican cattle, horses, deer, elk and susceptible species that cross the river. But, today, 60% of the fever tick infestations are encroaching deeper into the "free" areas of the state, Hillman says.
-- Carla Everett, TAHC