This yr in the USA, 14 individuals have examined optimistic for avian influenza, or fowl flu. 9 of these grew to become contaminated after coming into contact with poultry, and 4 acquired the virus from publicity to dairy cows. The supply of the remaining, most up-to-date case stays a thriller.
The Facilities for Illness Management and Prevention confirmed the case on September 6. Initially detected by the Missouri Division of Well being and Senior Companies, it’s the first identified case of human fowl flu within the nation with no identified publicity to a sick or contaminated animal. On Thursday, well being officers mentioned they hadn’t decided how the particular person acquired the virus.
“Proper now, proof factors to this being a one-off case,” mentioned Nirav Shah, the CDC’s principal deputy director, throughout a information briefing.
But the case is troubling, as a result of it raises the potential for an alternate supply of transmission, both from an individual or an unknown supply. Well being officers say there isn’t any proof of person-to-person unfold right now. The CDC says its surveillance system has not picked up any uncommon flu exercise within the nation, and the danger to most of the people stays low.
“Our influenza surveillance system is designed to search out needles in haystacks,” Shah mentioned within the briefing. “On this case, we discovered such a needle, however we don’t know the way it acquired there.”
The Missouri case is the primary to be detected via the nation’s nationwide flu surveillance system versus focused testing of animals. This yr, the H5N1 flu virus has been liable for wiping out poultry flocks throughout the nation and infecting 200 dairy herds in 14 states—the most recent in California. It’s more and more spilling over to other mammals, together with foxes, mice, raccoons, and home cats. With extra animals harboring the virus, there may be larger potential for human an infection.
It’s not identified whether or not that occurred within the Missouri case, however it’s one avenue well being officers say they’re investigating.
“Whatever the supply, it’s regarding, as a result of it means that there’s a whole lot of the virus on the market,” says David Boyd, a virologist at UC Santa Cruz who research influenza. “This means that there’s widespread transmission amongst animal sources.”
On August 22, an grownup affected person was hospitalized in Missouri for causes associated to underlying medical circumstances and occurred to additionally check optimistic for influenza. The affected person’s specimen was then despatched to the Missouri State Public Well being Laboratory, which decided that it didn’t match the at the moment circulating seasonal flu viruses.
That triggered further testing by the CDC, which final week confirmed it was a kind of fowl flu, or H5. The company was conducting further testing to find out the virus subtype—the “N” a part of H5N1. On Thursday, well being officers mentioned the affected person had a really low focus of viral genetic materials and, due to this, they haven’t been capable of generate a full genome, together with the N a part of the virus. Nevertheless, their knowledge reveals that the specimen is carefully associated to the H5 virus circulating in dairy cows.
