A person with prior health complications who had contracted bird flu died in Mexico in April, with the source of exposure to the virus unknown, the World Health Organization (WHO) announced on Wednesday.
WHO stated that the current risk of bird flu virus to the general population is low.
The 59-year-old resident of the State of Mexico had been hospitalized in Mexico City and died on April 24 after developing a fever, shortness of breath, diarrhea, nausea, and general discomfort, according to WHO.
“Although the source of exposure to the virus in this case is currently unknown, A(H5N2) viruses have been reported in poultry in Mexico,” WHO said in a statement.
This case marks the first laboratory-confirmed human infection with an influenza A(H5N2) virus globally and the first avian H5 virus reported in a person in Mexico, according to WHO.
Scientists indicated that this case is unrelated to the outbreak of H5N1 bird flu in the United States, which has so far infected three dairy farm workers.
Mexico’s Health Ministry also stated that the source of infection had not been identified. The victim had no history of exposure to poultry or other animals but had multiple underlying medical conditions and had been bedridden for three weeks prior to the onset of acute symptoms, the WHO reported. The individual had chronic kidney disease and type 2 diabetes.
“That immediately puts a person at risk of more severe influenza, even with seasonal flu,” said Andrew Pekosz, an influenza expert at Johns Hopkins University. How this individual became infected “is a big question mark that at least this initial report doesn’t really address thoroughly.”
In March, Mexico’s government reported an outbreak of A(H5N2) in an isolated family unit in the western Michoacan state. The government said these cases did not pose a risk to distant commercial farms or human health.
Following the April death, Mexican authorities confirmed the presence of the virus and reported the case to WHO. The Health Ministry said there was no evidence of person-to-person transmission in the case, and farms near the victim’s home were monitored. Other people in contact with the individual tested negative for bird flu, the health ministry and WHO confirmed.
Bird flu has infected mammals such as seals, raccoons, bears, and cattle, primarily through contact with infected birds. Scientists remain alert for changes in the virus that could signal an adaptation to spread more easily among humans.
The United States has reported three cases of H5N1 human infection after exposure to cows since an outbreak was detected in dairy cattle in March. Two individuals had symptoms of conjunctivitis, while the third also had respiratory symptoms.
Although the death in Mexico involved a different strain than the one currently infecting cattle in the United States, both are H5 avian viruses.
Pekosz noted that since 1997, H5 viruses have continuously shown a propensity to infect mammals more than any other avian influenza virus. “So it continues to ring that warning bell that we should be very vigilant about monitoring for these infections because every spillover is an opportunity for that virus to try to accumulate those mutations that make it better infect humans,” Pekosz said.
In May, Australia reported its first human case of A(H5N1) infection, with no signs of transmission. However, it has found more poultry cases of H7 bird flu on farms in Victoria state.
Source: Reuters
