Coloured transmission electron micrograph of H5N1 virus particles
Science Photo Library
A person in Louisiana has died from a bird flu virus known as H5N1. This is the first known death related to the virus in the US. The Louisiana Department of Health (LDH) has not identified additional H5N1 cases in the state nor found evidence of person-to-person transmission, indicating that the risk to the general public remains low.
The person was hospitalised for the virus in December, after contracting it from infected or dead birds in their backyard. They experienced severe respiratory symptoms. It was the first serious case of H5N1 in the US. The LDH announced their death on 6 January and said that they were older than 65 and had underlying health conditions.
In total, 66 people in the US have tested positive for H5N1, according to the US Centers for Disease Control and Prevention (CDC). Most of them developed mild symptoms, such as eye redness, and worked with infected cows or chickens.
H5N1, which has killed tens of millions of wild and domestic birds worldwide, has been circulating in dairy cows across the US for almost a year now. Genetic analysis of samples collected from the person in Louisiana indicate that the person was infected with the D1.1 genotype of the virus, which is similar to the viruses recently detected in wild birds, but distinct from the version spreading in cattle. There is no evidence that the virus can transmit between people.
The analysis also identified several changes that may improve the virus’ ability to bind to cells in the upper airways of humans, which largely lack receptors for most bird flu viruses. According to the CDC, it is likely these changes happened after the person was infected – any time someone contracts a bird flu virus, it gives it a chance to evolve and become better at spreading between us. One of the changes was also seen in a person who fell severely ill with H5N1 in Canada in November.
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