A SHARED CONDITION
South Texas horse owners, epidemiologists share the work to control a tick-borne parasite
By Heather Smith Thomas E
quine piroplasmosis (EP) is a blood- borne parasitic infection in horses, mules and other equines, transmitted primarily by competent ticks in coun-
tries where this disease is endemic. In the U.S. transmission is mainly by blood transfer or use of the same needle on different horses. South Texas horse owners, the USDA and
Texas Animal Health Commission (TAHC) employed antiprotozoal medications to treat the disease and are having positive results. EP is caused by 2 protozoa that invade red
blood cells, Theileria equi and Babesia caballi. Infected animals can be carriers for long
periods. This disease is endemic in many re- gions around the world, including South and Central America and Mexico. In 1962 a control program for B. caballi
began in south Florida to eradicate this dis- ease — with quarantine of infected animals,
spraying ticks and movement controls to pre- vent spread. The U.S. was declared free of EP in 1988.
To prevent reintroduction, all imported horses are tested for the presence of antibodies to T. equi and B. caballi. In August 2005 the of- fi cial import test was changed from the CFT (Complement Fixation Test) to the c-ELISA (Competitive Enzyme-Linked ImmonoSorbent Assay) test, which is more sensitive in detect- ing antibodies in chronically infected animals. A few horses have been found serologically
positive without clinical signs of the disease. Most of these were imported prior to the test change in 2005. A random national sampling in 2007 found 54 positive horses per 100,000 for B. caballi and 7 horses per 100,000 for T. equi, according to Dr. Angela Pelzel-McClus- key, epidemiologist, USDA-APHIS Veterinary Services.
MORE 60 The Cattleman January 2014
thecattlemanmagazine.com
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