Amidst the ongoing battle against a dairy cattle-related H5N1 flu outbreak in the United States, the World Health Organization (WHO) has disclosed the first documented case of human infection with a distinct strain, H5N2, occurring in an individual in Mexico, who succumbed to complications from the infection.
Both H5N1 and H5N2 strains of the influenza A virus have primarily targeted farmed and wild birds, with reported infections spanning across global avian populations. Since 1996, approximately 900 human cases of H5N1 have been recorded, with a mortality rate of about fifty percent. WHO confirmed the initial human case of H5N2 in a 59-year-old Mexican resident on Wednesday.
The source of the individual’s infection remains undetermined, although WHO has noted previous reports of H5N2 viruses in poultry within Mexico.
As any novel influenza A infection in humans carries significant public health implications, it necessitates immediate reporting to WHO. The organization has assessed the risk to the general populace from H5N2 as low, citing the absence of sustained human-to-human transmission despite known instances of other H5 subtypes infecting humans.
The deceased individual, afflicted with multiple underlying medical conditions, had been confined to bed for three weeks prior to the onset of new symptoms. In mid-April, they experienced fever, shortness of breath, diarrhea, nausea, and weakness, subsequently seeking medical care and being admitted to the National Institute of Respiratory Diseases in Mexico City on April 24, where they succumbed to complications.
A sample analyzed on May 8 revealed positivity for H5N2 upon specialized testing, subsequently confirmed by an alternative laboratory.
Following the case, seventeen hospital contacts exhibited no further instances of infection. However, twelve additional contacts near the patient’s residence were identified, seven of whom displayed symptoms, though subsequent testing failed to detect Covid-19 or any influenza strains. Scientists are currently analyzing blood samples for antibodies indicative of prior infections.
An H5N2 outbreak had been previously reported in March at a backyard poultry farm in a neighboring state to where the individual resided. WHO has yet to establish a definitive link between this case and recent poultry outbreaks.
Influenza viruses typically circulate among birds but can sporadically transmit to other species, including humans, through direct contact with infected animals or contaminated environments.
Type A flu strains, depending on their original host, can manifest as avian flu, swine flu, or other forms of animal influenza viruses.
In humans, avian flu infections may lead to mild to severe upper respiratory tract infections, with potential fatality. Complications such as conjunctivitis, gastrointestinal symptoms, and encephalitis are also plausible outcomes.
