While H7N9's rising toll in China, the extraordinary spread of HPAI H5N8 across Europe, and H5N6's sudden expansion into South Korea, Japan, and Taiwan have occupied most of our attention this winter, venerable H5N1 - which had been on the decline around the globe until a little over two years ago - has been making some inroads of its own.
- In 2014, H5N1 picked up several key mutations in Egypt (see Eurosurveillance: Emergence Of A Novel Cluster of H5N1 Clade 22.214.171.124) which appear to have increased its transmissibility from poultry to humans, sparking the biggest human outbreak on record (see EID Dispatch: Increased Number Of Human H5N1 Infection – Egypt, 2014-15).
- H5N1 returned to West Africa in December of 2014 - after an absence of roughly 7 years - and since then has become entrenched in Cameroon, Burkina Faso, Cote d'Ivoire, Ghana, Niger, Togo, and Nigeria (see The Challenge Of Avian Flu Surveillance In Sub-Saharan Africa).
- In 2015, in Novel H5N1 Reassortment Detected In Migratory Birds – China, we looked at the emergence and spread of clade 126.96.36.199c and made special note of its apparent neurotropic qualities.
- And in the spring and summer of 2016 we saw reports of large outbreaks in Iraq - the first confirmed reports out of that nation in a decade prompting this warning from the FAO last September.
Earlier today we looked at reports of outbreaks (and suspected human cases) in Indonesia - and now we have an OIE notification of the first detection of H5N1 in Malaysia in nearly a decade.
First the OIE report, then I'll return with a bit more:
H5N1 was a relatively early arrival to Malaysia, with the first reported outbreak in August of 2004 - involving a small poultry flock in the village of Pasir Pekan - coincidentally only a few miles from the site of today's report.
Eight small outbreaks were reported in the region over the next few months, and then nothing until 2007, when a small outbreak was reported in Petaling district, in the State of Selangor. That was the last reported outbreak to the OIE.
While other Southeast Asian countries like Thailand, Cambodia, Vietnam, Laos, and Indonesia have all battled the virus for years - and have detected hundreds of human infections - H5N1 was never more than a footnote in Malaysia.
Although a poultry outbreak in a remote village in northern Malaysia is hardly a big story, it serves to remind us that H5N1 remains worthy of our attention as it revisits old haunts, gains new territories, and continues down its own unpredictable and multi-pronged evolutionary pathways.