28 April 2009

3 minute read

North America

The preventive quarantine had been imposed on the three counties more than a year ago to prevent the spread of dangerous cattle fever ticks, says the Texas Animal Health Commission.

Further south in Zapata and Starr counties, however, more fever tick-infested ranches are being detected at a disturbing rate, and concerns remain for sustainable fever tick program funding, fever tick surveillance and the approval of new products for treating fever tick hosts.

Cattle fever ticks are capable of carrying and transmitting ‘babesia,’ a blood parasite deadly to cattle. Although the ticks were eradicated from the U.S. in 1943, the vigilance against the pest cannot end, due to its existence in Mexico. A permanent fever tick quarantine line a few hundred yards to five miles wide runs along the U.S. border through eight south Texas counties, and is patrolled on horseback by the USDA’s Tick Force to protect against stray “ticky” livestock and wildlife crossing the Rio Grande.

Livestock moved from the permanent quarantine zone must be individually inspected by USDA or TAHC inspectors, treated and permitted to leave the zone. More problematic, however, is wildlife movement. Deer, elk, nilgai and other species of captive or free-ranging wildlife can play host to the tick, moving it from pasture to pasture. Regardless if they are moved by inappropriate livestock movement or wildlife, sporadic cattle fever tick incursions occur, requiring producers and state and federal animal health agencies to take aggressive actions, such as temporary preventive quarantines, to prevent the spread of the potentially deadly pest. In 1973, the largest outbreak occurred, with 170 tick-infested premises detected in Texas. Last federal fiscal year (October 1, 2007-September 30, 2008) came in second, with 132 infested premises found. In the first seven months of FY 2009, 89 fever tick-infested premises already have been detected, and if the rate continues, this could be the worst year for fever ticks since eradication was achieved in 1943.

“The release of 375,000 acres in the temporary preventive quarantine area means that livestock on 255 premises in Maverick, Dimmit and Webb counties can now be moved without restrictions, although everyone in south Texas must remain vigilant for this foreign livestock pest. The temporary quarantine in these counties had been imposed since August 2007 and was adjusted in April 2008,” said Dr. Bob Hillman, executive director of the TAHC, the state’s livestock and poultry health regulatory agency. The temporary preventive quarantine will remain in effect for 247,388 acres, encompassing 28 ranches.

Since October 1, two tick-infested premises have been detected in Maverick County and one in Webb County, both of which are in the permanent quarantine zone. Another tick-infested premises was detected in Dimmit County and remains under quarantine. Infested, exposed and adjacent premises remain under movement restrictions and treatment requirements until repeated inspections indicate the livestock and premises are fever tick-free.

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