Another person in the United States has been infected with bird flu, but this time public health officials are not sure how the person contracted the highly pathogenic avian influenza virus (HPAIV).
Fortunately, the patient recovered, but according to the Centers for Disease Control and Prevention (CDC), this is the 14th person to have avian flu in the United States this year and the first with “no known recent contact with animals.”
All previous human cases have occurred among workers at poultry or dairy farms who contracted the virus from sick animals, making this new case a mystery the CDC is desperately trying to solve.
An adult patient at a Missouri hospital tested positive for the avian virus on August 22. Previously, only poultry and wild birds in the state had tested positive for the H5N1 virus.
The patient initially tested positive for influenza A, but it did not match any known human subtypes. Further testing revealed that the patient had some form of avian influenza, which is currently spreading among wild and domestic birds and mammals throughout the United States, Europe, South America, Africa, parts of Asia, and Antarctica.
The person has no known contact with animals, but it is possible that he may have been unknowingly exposed to an infected animal.
CDC officials are now sequencing the viral genome from this recent human case to better understand where the pathogen came from and how it adapted to infect mammals like us.
Because the Missouri patient has not transmitted the virus to close contacts and there have been no confirmed cases of person-to-person transmission so far, the CDC still considers the threat of avian flu to the general public to be “low.”
“The risk of sustained transmission and infection among the general public remains low,” the Missouri Department of Health and Senior Services confirmed.
However, the fact that these patients were hospitalized is a worrying sign. At this point, it is unclear whether their severe symptoms are due to the virus itself or to underlying conditions.
In an exclusive interview with The Guardian in July, CDC Deputy Director Nirav Shah said his team was closely monitoring any worsening cases of bird flu in humans, as this could signal that the virus may be mutating in a way that poses a risk to public health.
“When we see people who have absolutely no connection to farms or contact with chickens exhibiting signs and symptoms, that is extremely concerning,” Shah said at the time.
The recent case in Missouri is the first case of bird flu detected as part of the national flu surveillance system, in which any strange forms of influenza are sent for further testing.
