US - The United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) has released a preliminary epidemiology report for the highly pathogenic and low pathogenic avian influenza cases confirmed in Indiana in January.
Animal health officials confirmed one case of HPAI H7N8 and eight cases of LPAI H7N8 in Indiana in January. This was a short incident, where the cases were quickly reported.
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.
In the report, APHIS outlines the findings of those investigations to date, which 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, Indiana 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 agency said that the preliminary findings reinforce the need to remain vigilant in the upcoming months and to maintain good biosecurity practices. Biosecurity is one of the most important steps any producer can take to protect the health of their birds. Biosecurity information, training resources, and a producer self-assessment are all available through the APHIS website.
Further reports into the spread of the virus in Indiana are expected in future.