The U.S. Centers for Disease Control and Prevention has now identified 8 cases of swine influenza in people in the southwestern U.S. over the past month. At this point, there is no known pig contact involving these 8 people and the virus has not been identified in U.S. swine.
The virus strain identified in the U.S. cases is a multiple reassortant containing a swine variant similar to some Eurasian viruses. This genetic combination has not previously been recognized in swine or human isolates in the U.S. and there is no indication that the virus exists in swine.
Recent reports indicate that the human influenza season in Mexico has been more severe this year than previously. Mexican officials have cited swine influenza as the cause of many of these cases. CDC has evaluated 14 samples from Mexico. Seven of these samples have tested positive for swine influenza. Preliminary genetic analysis indicates similarities with the virus isolated from the U.S. human cases.
Industry focus at this point is to prevent the introduction of this virus into the U.S. swine herd. Extra precautions should be taken when dealing with herds exhibiting clinical signs consistent with influenza. Producers should be reminded that influenza is a zoonotic disease and they should pay extra attention to personal hygiene (hand-washing, showering, etc.) and avoid contact with pigs if they or someone in their family is experiencing flu-like symptoms.
Employees should be encouraged to visit their physician if they have symptoms associated with a flu-like illness. Visitors should be discouraged from visiting the farm and particularly accessing areas where animals are housed.
Veterinarians should submit diagnostic samples (lung tissue and nasal swabs from acutely ill, febrile pigs) to the veterinary diagnostic lab particularly in cases of swine influenza vaccine failure.
At this point, there is no evidence that this virus is present in the U.S. swine herd. USDA is sampling pigs to determine if this virus is present. For oficial information from the CDC, click here.
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