Indicators for suspicion of avian influenza on duck farms

Wageningen Bioveterinary Research (WBVR) investigated if and to what degree mortality and production data could signal possible outbreaks of highly pathogenic avian influenza (HPAI) on duck farms. The results, published in Pathogens, could be used to provide guidelines to farmers and veterinarians to report suspected outbreaks.

Data was collected on the daily mortality, egg production, feed and water intake of flocks of breeding and broiler ducks. The data was collected from ducks that were healthy (Netherlands) and ducks that were infected with avian influenza (Netherlands, Germany, UK and USA). Data from the healthy ducks was used to establish a baseline in the daily mortality and production parameters. Data from infected birds was used to see what the effect of infection is on the daily mortality and production and to evaluate the accuracy of the early detection thresholds.

For broiler flocks, a daily mortality rate of over 0.3% (after the first week of production) was found to be a reliable indicator for a possible HPAI infection. A decrease in the daily food and water intake of more than 7 g or 14 ml (after the first week of production), respectively, were found to be sensitive indicators of infection (but with poor specificity).

For breeding ducks, limited data was available. Mortality thresholds were found to be poor indicators of infection. However, a consecutive drop in egg production larger than 9% was shown to be an effective indicator of a HPAI outbreak.

Article: Elbers, A., Gonzales, J. L. (2021). Mortality levels and production indicators for suspicion of highly pathogenic avian influenza virus infection in commercially farmed ducks. Pathogens, 10(11), 1498, doi: 10.3390/pathogens10111498

The article belongs to a Special Issue of Pathogens: Advanced Research on Avian Influenza Virus (AIV)

[SOURCE: Wageningen University & Research]