A ProMED-mail post ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Thu 28 Jan 2010
Source: Horsetalk [edited]

Screening reveals more piroplasmosis cases in US

The enhanced screening program of racehorses in New Mexico continues to pick up cases of equine piroplasmosis.

The US Department of Agriculture (USDA), in its latest report to the World Organization of Animal Health (OIE), on 25 Jan 2010, said the screening program had so far tested more than 3000 horses for the blood-borne parasitic disease. 13 horses had returned positive tests.

The department, in its report a month earlier, on 24 Dec 2009, said 1300 horses had been tested, with 3 positive as of 15 Dec 2009.

The New Mexico Livestock Board euthanized 5 of the horses. The remaining positive horses are under isolated quarantine.

"Preliminary results of the investigation indicate that the transmission of the organism may have resulted from management practices -- use of shared needles or substances between horses) rather than by a tick vector," said Dr John Clifford, deputy administrator for the department's Animal and Plant Health Inspection Service.

Dr Clifford said a comprehensive investigation into all cases was continuing.

The New Mexico cases are unrelated to the outbreak that was first identified in a ranch in Kleberg County, Texas.

As of 20 Jan 2010, equine piroplasmosis has been found in 364 horses directly linked to that Texas property.

The positive horses either currently live, or previously lived, on the ranch, or lived on premises immediately next door, or were dangerous contacts (positive foal born to an infected mare, or temporarily boarded on index premises).

The positive horses are currently located in 12 states, with 289 of them still on the index ranch in Texas. The remaining horses are on premises in Texas, Alabama, California, Florida, Indiana, Louisiana, Minnesota, North Carolina, New Jersey, Tennessee, Utah, and Wisconsin.

Georgia is now free of equine piroplasmosis positive horses.

"Over 1600 horses have been tested for equine piroplasmosis as part of the epidemiological investigation," Dr Clifford says.

-- Communicated by:
ProMED-mail

[It is interesting to note that epidemiologically the New Mexico situation is not linked to the Texas situation. However, the causative agent had to have come from somewhere. In order of the disease to be passed by needles it still had to originate from somewhere. Has the index case for the New Mexico been located? Was the index case related to the Texas situation and returned to Texas? - Mod.TG]