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Bird flu is back in the USA and once again threatening turkey production.
The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed that eight of the nine H7N8 avian influenza incidents that were reported on 16 January were low pathogenic avian influenza.
Additional testing is taking place on a ninth flock.
The incidents were identified as part of surveillance testing in the control area surrounding the initial highly pathogenic H7N8 avian influenza (HPAI) case in Indiana.
The pathogenicity of a virus refers to its ability to produce disease.
Birds with low pathogenic avian influenza (LPAI) often show no signs of infection or only have minor symptoms. HPAI viruses spread quickly and cause high mortality in domestic poultry. H7 LPAI viruses have been known to mutate into HPAI viruses in the past.
Dr John Clifford, USDA Chief Veterinarian said: “It appears that there was a low pathogenic virus circulating in the poultry population in this area, and that virus likely mutated into a highly pathogenic virus in one flock.
“Through cooperative industry, state and federal efforts, we were able to quickly identify and isolate the highly pathogenic case, and depopulate that flock.
“Together, we are also working to stop further spread of the LPAI virus, and will continue aggressive testing on additional premises within the expanded control area to ensure any additional cases of either HPAI or LPAI are identified and controlled quickly.”
APHIS is working with the Indiana State Board of Animal Health and the affected poultry industry on a joint incident response.
State officials quarantined the additional affected premises and depopulation of birds has already begun. Depopulation prevents the spread of the disease. Birds from the flock will not enter the food system.
The critical nature of the outbreak was highlighted at the recent International Production & Processing Expo in Atlanta.
Dr Guillermo Zavala (pictured), Avian Health International, during his presentation at the Seminario Técnico para Maximizar la Efficienca de la Industria Avícola programme said: “Avian Influenza is a critical challenge for the industry. Between 2013 and 2015, it caused the greatest losses in Canada and the USA (H5H7).
“In Mexico and Central America, there were outbreaks of H5N2 and H7N3; while in Chile, H7N3, H1N1 and H4 were present.” said.
In his presentation on “Emerging Diseases in the American Continent” (Enfermedades Emergentes en el Continente Americano), Dr Zavala said that avian influenza (AI) circulates mainly among wild birds in lake areas. It is also transmitted via insufficient biosecurity measures and infrastructure errors.
Dr Zavala remarked that vaccines do not eradicate AI, but help to prevent the virus, and preventive measures need to be accompanied by biosecurity.
Dr Zavala also discussed other diseases, such as Erysipelas, Infectious Bronchitis, Infectious Laryngotracheitis and Mycoplasma, which are making an appearance again in commercial poultry. He remarked that they are less common thanks to increased biosecurity measures. However, they are still around.