NAHSS Activity Updates, April 2009
CDC Hosts Animal-Human Interface Meeting
Representatives from Veterinary Services attended the Centers for Disease Control and Prevention (CDC) Influenza Animal-Human Interface Meeting earlier this month. The meeting was held to update the progress of CDC-funded influenza animal-human interface research activities, enhance communication and coordination among investigators, CDC, and animal health authorities involved in influenza initiatives at the animal-human interface. Participants also continued planning of animal and public health agency roles, responsibilities, notification, communication, and plans of action related to the detection of potential or confirmed human novel swine influenza A infections in the United States. In late 2008, USDA-VS entered into a collaborative agreement with CDC to conduct surveillance for swine influenza virus (SIV) among U.S. swine. Increasing animal and public health concerns about the formation of novel swine influenza strains, the lack of national and local epidemiologic data on SIV and SIV strain prevalence, cross-species transmission of influenza and outdated diagnostic reagents led to the collaborative effort.
Contagious Equine Metritis Outbreak Update
On December 15, 2008, the State of Kentucky confirmed that a quarter horse stallion on a central Kentucky premises was positive for Taylorella equigenitalis, the bacterium that causes contagious equine metritis (CEM). CEM is a transmissible, exotic, venereal disease of horses. By December 31, testing had confirmed three Indiana stallions as positive for T. equigenitalis. The stallions were tested as a result of exposure to a positive stallion while they were kept at a breeding facility in Kentucky. As of April 15, the National Veterinary Services Laboratories had confirmed 18 stallions and 5 mares positive for T. equigenitalis. The positive stallions were located in six States: one in Georgia, three in Illinois, three in Indiana, four in Kentucky, one in Texas, and six in Wisconsin. The positive mares were located in three States: two in California, two in Illinois, and one in Wisconsin. One of the positive mares was inseminated by natural breeding; the other four positive mares were bred by artificial insemination. All of the positive horses are epidemiologically linked cases. None of the positives has been identified as the source of the outbreak.
As of April 15, locations had been confirmed for an additional 750 horses exposed to T. equigenitalis. The 23 positive and 750 exposed horses were located in 47 States. There were 135 exposed or positive stallions in 21 States and 638 exposed or positive mares in 45 States. All positive horses and all exposed horses were placed under quarantine or hold order, and testing and treatment protocols were implemented. The epidemiological investigations are continuing.
Of the 135 stallions, 34 have now completed their entire testing and treatment protocol and been determined to be negative for T.equigenitalis. Of the 34 that are now negative, 26 were exposed stallions and 8 were stallions that had previously tested positive. Those eight stallions, four from Kentucky, three from Indiana, and one from Texas, are now free of T.equigenitalis after being treated and re-tested. Another 68 exposed stallions are negative on their initial sampling cultures but must complete additional testing requirements before being declared free of the bacterium. Of the 638 mares, 347 have completed testing and treatment and are negative for T.equigenitalis. An exposed horse is one that was bred to a positive horse, either naturally or via artificial insemination, or one that is otherwise epidemiologically linked to a positive horse, as determined by State and Federal animal health officials.
CSF Annual Report Provides Surveillance Data
The annual report of the VS classical swine fever (CSF) surveillance program for fiscal year (FY) 2008 was released to internal VS stakeholders. The goals of the CSF surveillance program are to rapidly detect CSF virus in U.S. swine and monitor the risk of introduction of CSF into U.S. swine. In FY 2008, a total of 6,965 animals were tested as part of the CSF surveillance program from these populations: sick pigs submitted to veterinary diagnostic laboratories, swine condemned at slaughter by the Food Safety and Inspection Service, and feral swine. In addition, FADDL tested 11,244 serum specimens for CSF antibodies; this total represents specimens from waste-feeder operations; high-risk herds in Florida, Texas, and Puerto Rico; and specimens submitted for other purposes. All tested specimens were determined to be negative for CSF. In addition to this testing, 12 swine FAD investigations were conducted in FY 2008; six of these were clinically compatible with CSF. All were confirmed negative on testing.