Evaluation of elution methods for recovery of highly pathogenic avian influenza (H5N1) virus from infected duck feathers

Abstract

In view of the tenacity of viruses in the feathers, many workers have suggested the importance of using feathers as the diagnostic material for epidemiological surveillance of highly pathogenic avian influenza (HPAI) H5N1 virus infections. In this study, we have compared the efficiency of two different processing methods, immersion method and trituration method for elution of HPAI H5N1 virus from the feathers of avian influenza negative ducks in terms of virus isolation in 9-to 11-day-old embryonated specific pathogen free chicken eggs and viral RNA detection by haemagglutinin gene based real-time RTPCR. The recovery of virus by immersion method in terms of percent infectivity in 3 replicates was 96.67, 93.33 and 96.67, whereas in trituration method, percent infectivity was 26.67, 20 and 16.67. In real-time RTPCR, viral RNA could be detected in 17 out of 18 samples by immersion method and from only 2 out of 18 samples by trituration method. The study revealed that the immersion method gave higher viral infectivity percentage and could also be easily detected by real-time RTPCR. We conclude that immersion method of virus elution could be useful for processing of shed duck feathers present in the environment for epidemiological screening against HPAI H5N1 virus infections.