USDA’s Animal and Plant Health Inspection Service (APHIS) released a preliminary epidemiology report for the highly pathogenic avian influenza (HPAI) and low pathogenic avian influenza (LPAI) cases confirmed in Indiana.

Officials confirmed one case of HPAI H7N8 and eight cases of LPAI H7N8 in Indiana in January. Following these avian influenza findings, APHIS joined forces with the Indiana Board of Animal Health and the poultry industry to complete a series of epidemiologic, geospatial, and laboratory-based investigations.

“The preliminary findings reinforce the need to remain vigilant in the upcoming months and to maintain good biosecurity practices,” APHIS says. “Biosecurity is one of the most important steps any producer can take to protect the health of their birds.”

Among the investigation’s findings include:

-Genetic analyses of these viruses indicate that all viruses are of North American wild bird lineage, the HPAI and LPAI viruses are highly similar, and the LPAI virus mutated to HPAI at a single farm.

-APHIS sampled wildlife on infected premises but did not detect the new H7N8 virus.

-One of the factors examined was the weather. The weather in Dubois County, IN was warmer and wetter than past years, which may have contributed to the introduction and persistence of the virus. More detailed geospatial analysis is ongoing.

-APHIS used an in-person questionnaire to examine physical and management characteristics of infected premises. There were specific practices identified as risk factors in the 2015 outbreak. The initial analysis showed that farmers in Indiana had eliminated some of these practices from their routine. However, a few of those practices were still seen on the affected farms. APHIS is now collecting similar information on non-infected farms to help further interpret the infected case data.

The full report can be found here.