||Tick-Transmitted Horse Disease Detected
on South Texas Ranch
A tick-borne disease known as equine
piroplasmosis has been confirmed on a ranch in South Texas. Additional
testing is being conducted to determine the extent of infection. Horses
on the ranch are quarantined to their premises, and a thorough disease
investigation is underway.
Equine piroplasmosis can affect horses, donkeys, mules or zebras and cause
clinical signs common to many diseases, including poor appetite and weight
Death losses can occur. Some infected equine animals may exhibit few or
no signs of disease. Those animals that survive the acute phase of infection
may continue to carry the parasite, which has been identified as Theileria
equi (formerly known as Babesia equi), for long periods of time.
“Although equine piroplasmosis is not considered to be endemic in
the U.S., cases h ave been detected on occasion,” said Dr. Bob Hillman,
Texas’ state veterinarian and head of the Texas Animal Health Commission,
the state’s livestock and poultry health regulatory agency. “In
June, equine piroplasmosis was detected in Missouri, with a related case
found in Kansas. In 2008, the infection was detected in Florida. These
cases have been closed.”
“As many as 15 tick species are capable of carrying and transmitting
the blood parasite responsible for causing equine piroplasmosis,”
Dr. Hillman explained. “At this time, we do not know which species
of tick is responsible for transmitting infection on the South Texas ranch.
Additional blood and tick samples are being collected and will be submitted
for analysis to the National Veterinary Services Laboratory (NVSL) in
Dr. Hillman said there is no vaccine for equine piroplasmosis, and treatment
generally is not effective against this tick-borne infection. To avoid
spread of the disease, it is important to eliminate contact with ticks
and to prevent the transfer of blood from one equine animal to another.
“Equine owners may want to consult with their veterinarians for
recommendations on preventing tick infestation,” said Dr. Hillman.
“If equine animals exhibit signs of illness, a veterinarian should
be contacted, so appropriate samples may be collected for laboratory testing.
Currently, we have no indication that this tick-transmitted disease has
occurred at other sites in Texas, but maintaining vigilance for this blood
parasite is necessary in determining the extent of this disease situation.”