New Jersey Department of Agriculture

Memo

To: Veterinarians

From: Nancy E. Halpern, DVM, New Jersey State Veterinarian

Date: August 21, 2008

Re: Equine Piroplasmosis (EP)

Reminder: EP is a reportable disease if suspected or diagnosed and must be reported to the Department of Agriculture without delay, and in any case, within 48 hours at (609) 292-3965 (N.J.A.C. § 2:2-1.1 and 1.5).

On Wednesday August 13, 2008, the Florida State Veterinarian notified the USDA Animal and Plant Health Inspection Services (APHIS) that a horse in Manatee County, FL, was positive for Babesia equi, or equine piroplasmosis. This horse was clinically ill, and the initial samples were taken by an accredited veterinarian and submitted to the University of Florida, College of Veterinary Medicine, where the initial positive was recorded. Upon notification to the State and APHIS, a foreign animal disease investigation was initiated, the premises of origin was placed under quarantine by the State authorities, and the horse was euthanized and necropsied. The National Veterinary Services Laboratory (NVSL) has confirmed the laboratory finding on the index horse.

The investigation included testing contact horses on the premises, with a total of 22 contact horses tested. Initial tests found four additional horses on the original premises positive for Babesia equi. One note of concern is that infection may have been spread from the index horse to other horses on the premises of origin through common needle sharing among the horses. At least six premises have been identified as contact premises and are being scheduled for testing. Diagnostic testing, tick identification, and traceback procedures are ongoing, but are hampered by the severe weather in the state. APHIS is supporting the State authorities in these efforts.

The finding of equine piroplasmosis was reported to the World Organization for Animal Health (OIE) on August 15, 2008. Chief Veterinary Officers for Mexico and Canada (and the European Union) have also been notified as a courtesy. APHIS will work with trading partners as necessary to help minimize any potential impacts on the export of horses from the United States.

Equine piroplasmosis is a tick–borne protozoal infection of horses. Piroplasmosis may be difficult to diagnose, as it can cause variable and nonspecific clinical signs. The symptoms of this disease range from acute fever, inappetence, and malaise, to anemia and jaundice, sudden death, or chronic weight loss and poor exercise tolerance. The disease may be fatal in up to 20% of previously unexposed animals.

A domestic EP reactor is defined as any horse residing in the United States that tests positive for EP (Babesia caballi and/or Babesia equi).

Any veterinarian testing horses for EP must notify the State Veterinarian at 609-292-3965. The following samples should be sent to the Division of Animal Health Laboratory for a charge of $26.00:

Serologic testing will require the following samples:

• 2-4 ml of clear serum for antibody tests and
• 3-5 ml of EDTA (blood smear and PCR)

Serologic testing will require the following testing protocol:

• cELISA positive = greater than 40.0 percent inhibition
• IFA (positive at 1:80) may be used as a supplemental test if the cELISA is inconclusive

For further information about testing for this disease, please contact Dr. Beatriz Miguel, Director Animal Health Laboratory at 609-292-1270 or via email at beatriz.miguel@ag.state.nj.us.

Response to positive tests:

1.       Horses that test positive will be isolated from contact animals and retested for confirmation.

2.       All horses residing at the farm or equine facility, or that are otherwise part of the same herd, are considered contact horses and will be tested.

3.       All contacts within 30 days will be traced both forward and back.

4.       Contact horses that test negative should be retested in 30 days.

a.       If a contact horse remains negative on retest, the horse should be considered a non-reactor (test negative horse).

5.       Upon confirmation, the following options will be considered on a case-by-case basis:

a.       Strict quarantine: Quarantine should be continuous and isolation maintained separate and apart from other horses in a permanent tick-free facility. This facility should be surrounded by a no-vegetation zone ten feet wide and double-fenced on all sides. Paddocks or turn out areas should be free of trees, shrubs, or woody vegetation, and any grass should be kept mowed short. Acaricide applications to horse and facility will be at the discretion of State entomologists and regulatory officials.

b.      Treatment with strict quarantine: Treatment with imidocarb dipropionate (ImizolTM) should be administered by a State, Federal, or Federally-accredited veterinarian.

                                                               i.      Release from quarantine should occur only after two (2) negative cELISAs have been obtained at intervals following completion of the therapy as follows:

1.       B. caballi --- tests to be conducted on days #180 and #210 post-treatment

2.       B. equi --- tests to be conducted on days #180 and #210 post-treatment

                                                             ii.      Only two (2) attempts at treatment for seroconversion should be permitted.

1.       If the first therapeutic regime fails, a second can be permitted with timing and dosage at the discretion of the attending veterinarian.

c.       All aforementioned conditions should apply with initial testing at day #180 and final testing at day #210 post-treatment.

d.      Euthanasia and disposal : under NJDA supervision

e.       Transportation out of the country It is the owner’s responsibility to work with the authorities in the destination country to allow for the export of the reactor and arrange for transportation.

                                                               i.       Horse should be transported to the export facility under APHIS permit and seal.