A strain of highly pathogenic avian influenza has been silently spreading in US cattle for months, according to preliminary analysis of genomic data. The outbreak is likely to have begun when the virus jumped from an infected bird into a cow, probably around late December or early January. This implies a protracted, undetected spread of the virus — suggesting that more cattle across the United States, and even in neighbouring regions, could have been infected with avian influenza than currently reported.
These conclusions are based on swift and summary analyses by researchers, following a dump of genomic data by the US Department of Agriculture (USDA) into a public repository earlier this week. But to scientists’ dismay, the publicly released data do not include critical information that would shed light on the outbreak’s origins and evolution. Researchers also express concern that the genomic data wasn’t released until almost four weeks after the outbreak was announced.
Speed is especially important for fast-spreading respiratory pathogens that have the potential to spark pandemics, says Tulio de Oliveira, a bioinformatician at Stellenbosch University in South Africa. The cattle outbreak is not expected to allow the virus to gain the ability to spread between people, but researchers say it is important to be vigilant.
“In an outbreak response, the faster you get data, the sooner you can act,” says Martha Nelson, a genomic epidemiologist at the National Center for Biotechnology Information (NCBI) in Bethesda, Maryland. Nelson adds that with every week that goes by, the window for controlling the outbreak narrows. “Whether we’re not too late, to me, that’s kind of the million dollar question.”