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Animal Health Trust |
Interim Report – October 2011 #4 (14.10.11)
ROMANIA
Equine Infectious Anaemia (EIA)
A case of EIA, confirmed in Dobroudja, Romania on 12th September 2011, was reported by RESPE on 14th October based on information received from the French Ministry of Food, Agriculture and Fisheries. It is not clear whether the affected horses showed clinical signs or have been euthanased. Epidemiological investigations are ongoing and restrictions are in place.
UNITED STATES OF AMERICA
Eastern Equine Encephalomyelitis (EEE)
As of October 12th, the total number of equine cases of EEE in the USA stands at 54. Over the past two weeks, an additional 13 cases were confirmed of which 11 occurred in Wisconsin, bringing that state's total for the year to date to 31, the highest number so far recorded by any state in the country. The remaining states with respective totals of diagnosed cases of EEE are as follows: New York (11 cases), Florida and Louisiana (3 cases each), Michigan and North Carolina (2 cases each), Mississippi and Vermont (single cases each).
West Nile Encephalitis (WNE)
There has been an increase of 10 in the national total of cases of WNE since 28th September 2011. Equine cases of the disease have been recorded in 24 states. The highest number of cases has been recorded in California (13), followed by Pennsylvania (10), North Dakota (5), Ohio (4), Arizona, Georgia, Indiana, Tennessee and Wisconsin (3 cases each), New Mexico, New York, Oregon and Texas (2 cases each), and single cases in Connecticut, Delaware, Florida, Iowa, Kentucky, Massachusetts, Minnesota, Mississippi, Nebraska, Nevada and Virginia.
Equine Herpes Virus-1 Neurological Disease
Several outbreaks of EHV-1 neurological disease (or equine herpesvirus myeloencephalopathy; EHM) were confirmed in the USA in September 2011. The first was an isolated case in Richland, Michigan, involving a 23-year-old mare that had to be euthanased on 1st September after developing clinical signs highly suggestive of EHM. The mare was positive for a neuropathogenic strain of EHV-1. None of the other horses on the premises displayed any signs of illness. The source of infection for this case of EHM was not determined. All appropriate precautions were taken to prevent spread of the virus off the affected premises.
In mid-September, another outbreak of EHM occurred in Sonoma County, California. The index case was a 15-year-old Oldenburg mare that was confirmed positive for a neuropathogenic strain of EHV-1. The virus was also detected on nasal swabs from two additional horses, contacts of the affected mare, both of which had fevers but exhibited no neurological signs. The affected premise was quarantined. There was no evidence of spread of EHV-1 to 13 other horses on the premises.
An additional but epidemiologically unrelated outbreak of the EHM occurred in Tuolumne County, California, also in mid-September. A neuropathogenic strain of EHV-1 was detected in eight horses on the premises, of which six exhibited neurological signs and two only had fever. One of the neurologically affected horses had to be euthanized. The index case in this outbreak, a mare, was treated symptomatically and recovered. All of the infected horses were isolated and appropriate precautions taken to prevent spread of the disease off the premises. There was no epidemiological link between this outbreak and the major occurrence of EHM in May 2011 related to the National Cutting Horse Championship Show in Ogden, Utah.
A further outbreak of EHM occurred about mid-September in San Joaquin County, California that was linked directly to the affected premises in Tuolumne County. Two horses which had been on the Tuolomne County premise between 4th and 10th September, were confirmed positive for a neuropathogenic strain of EHV-1. One horse exhibited neurological signs while the other only developed a fever. Appropriate precautions were implemented without delay and there was no spread of infection off the affected premises.
A fifth occurrence of EHM has also been reported in the USA involving a horse admitted to the Equine Hospital at the University of Tennessee Veterinary Medical Center in mid-September, displaying signs of neurological disease suspicious of EHM. The animal’s condition rapidly deteriorated and it was euthaniased several hours after admission. Presence of a neuropathogenic strain of EHV-1 was confirmed. Five other horses located in the same premise that the index case originated from were also diagnosed as infected with a neuropathogenic strain of the virus. All five horses which were in stable clinical condition were kept isolated from other horses on the premises. There was no evidence of further spread of infection on the farm of origin of the index case nor in the Equine Hospital at the University of Tennessee Veterinary Medical Center.
Strangles (Streptococcus equi)
An outbreak of strangles was diagnosed at a riding stable in Michigan. The disease was confirmed in at least four horses on the premises, which had a population of approximately 70 horses. The premise was quarantined on confirmation of the disease and no additional cases were reported.
Regards
International Collating Centre