‘This is how pandemics start’: H5 bird flu in Missouri patient with no known link to sick animals

Experts theorise the patient might have consumed raw milk infected with H5N1, which is currently circulating among US cattle

Scientists are racing to understand how a person in Missouri who had no contact with animals became infected with H5 bird flu.
The case was confirmed by the US authorities on Friday and experts have theorised that the patient might have consumed raw milk infected with H5N1, which is currently circulating among US cattle or picked it up from contact with an infected animal, unknowingly. 
The nightmare scenario – although highly unlikely – is that the virus has begun to spread between humans under the radar. 
The case marks the first time a patient in the ongoing H5N1 outbreak in the US has become sick without known exposure to infected animals. Thirteen other human cases have been reported this year, all in farm workers who interacted with sick cattle or birds.
The patient was hospitalised on August 22 and has since recovered, according to the CDC. 
The case was detected through the state’s seasonal flu surveillance system, indicating there could be more flying under the radar.
Avian influenza began spreading in US dairy cattle last December. Since, over 200 herds across 14 states have become infected, none of which have been in Missouri. The state has reported H5N1 cases in wild birds and poultry however, a possible route of infection.
The main worry among experts is that an unexplained H5 infection raises the possibility of person-to-person transmission, something which the World Health Organization (WHO) warned would be of “enormous concern” due to its potential to trigger a global pandemic. 
“This is how pandemics start,” Kruitka Kuppali, a spokesperson for the Infectious Disease Society of America and former WHO medical officer, told The Telegraph.  “We need to scale up preparedness and response efforts.”
The 2009 swine flu pandemic was first detected in a similar way when two children in California with no known contact with pigs or each other were diagnosed with an H1N1 flu infection, previously circulating in swine.
Another theory is that the person consumed raw milk infected with H5N1, which has killed several barnyard cats who are thought to have consumed the liquid off farm floors in the US this year.
Around three per cent of the US public – some 10 million people – consume raw dairy, many of which think it’s a ‘superfood’, according to the National Institutes of Health, the US government’s primary public health research body.
“The obvious question I would ask is: Have you ruled out that they’re not someone who’s got a big tub of raw milk in their fridge? Because that just seems like such an obvious route for a cryptic infection,” Thomas Peacock,  an influenza virologist at the Pirbright Institute, told Stat News.
Lisa Cox, a spokesperson for the Missouri Health Department, said that the patient had not reported consuming raw milk. However, Dr Peacock noted that people aren’t always completely reliable in epidemiological investigations, so it still can’t be completely ruled out.
“It would be important to know if they had any exposure to raw dairy and to do a full epidemiological investigation regarding potential exposures that may have occurred in the community, home, or at work,” added Dr Kupplai.
The CDC has said Missouri health officials are conducting an on-the-ground investigation to look for the source of the infection, although it is unclear when they will share the results of their findings.
Scientists hope the virus will be quickly sequenced and uploaded to GISAID, an international database that keeps track of dangerous new flu strains.
This would offer clues on whether the person was infected with the variant circulating in cattle, or if there had been any adaptations suggesting the virus has better adapted to spread between humans.
Contact tracing has found no additional cases, and the CDC still considers the risk to the general public low.
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