The Philippines confirms first case of H5N9 HPAI in ducks
The Philippines has confirmed its first case of highly pathogenic avian influenza (HPAI) subtype H5N9, detected in ducks in Camaligan, Camarines Sur. The Bureau of Animal Industry (BAI) reported positive test results on April 30, 2025, following routine surveillance conducted by the Department of Agriculture's Regional Field Office V.
This marks the first detection of the H5N9 strain in the Philippines. Previously, the country has encountered other avian influenza subtypes, including H5N1, H5N2, and H5N6.
H5N9 is a rare subtype of highly pathogenic avian influenza A virus. The first H5N9 viruses were identified in poultry in China in late 2013 [1]. Between 2015 and 2017, outbreaks of H5N9 occurred in Europe, most notably in southwestern France, affecting duck and goose farms [2]. More recently, the United States reported its first H5N9 detection in Merced County, California. In November 2024, a duck farm tested positive for both H5N9 and H5N1, resulting in the culling of approximately 119,000 birds by early December.
1. Yu Y, Wang X, Jin T, Wang H, Si W, Yang H, Wu J, Yan Y, Liu G, Sang X, Wu X. Newly emergent highly pathogenic H5N9 subtype avian influenza A virus. Journal of Virology. 2015 Sep 1;89(17):8806-15.
2. European Food Safety Authority, European Centre for Disease Prevention and Control, European Union Reference Laboratory for Avian Influenza, Adlhoch C, Brouwer A, Kuiken T, Mulatti P, Smietanka K, Staubach C, Muñoz Guajardo I, Verdonck F. Avian influenza overview February–May 2018. EFSA Journal. 2018 Jun;16(6):e05358.
