What to know about the first human case of H5N2 bird flu
Is there a new strain of bird flu to be worried about?
First Human Case of H5N2 Bird Flu Reported in Mexico
On Wednesday, the World Health Organization (WHO) announced the unsettling confirmation of the first human case of H5N2 bird flu. The victim, a 59-year-old man from Mexico, succumbed to the illness in April. This development has stirred concerns regarding the potential spread of bird flu among humans, particularly as the man had no documented exposure to poultry or other animals, as stated by WHO.
Understanding H5N2: A New Threat?
H5N2 is among the various strains of avian influenza viruses. But does it pose a significant risk to human health?
Dr. Troy Sutton, an assistant professor of veterinary and biomedical sciences at Penn State, notes that exposure to H5 viruses in Mexico is not unexpected, given their prevalence among poultry and wild birds since the mid-1990s. However, unlike other avian influenza strains like H1 and H3 viruses, H5 viruses seldom infect humans.
These viruses are categorized based on two surface proteins: hemagglutinin (H) and neuraminidase (N). H5N2 belongs to the H5 family of bird flu viruses, primarily affecting wild birds. According to the Centers for Disease Control and Prevention (CDC), there are nine known subtypes of H5 viruses.
Should Concerns Rise?
The patient in Mexico exhibited severe symptoms, including fever, nausea, diarrhea, and shortness of breath, prior to hospitalization and subsequent demise. Dr. Sutton highlights the significance of the patient’s underlying health conditions, which likely exacerbated the infection.
Despite thorough investigations by WHO, the source of the man’s infection remains elusive. The absence of direct exposure to poultry or animals raises concerns about potential human-to-human transmission or unidentified cases.
Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, reassures that human-to-human transmission is unlikely. However, the low pathogenic nature of the H5N2 virus suggests it is less likely to cause severe illness.
Unanswered Questions and Future Research
Experts emphasize the need for further genetic sequencing of the H5N2 virus to assess its potential risk to humans. Dr. Paul Offit, an infectious disease expert, stresses that the virus’s ability to spread among humans depends on its adaptation to human receptors.
While the focus remains on H5N2, Dr. Osterholm underscores the urgency of monitoring H5N1, which has affected numerous dairy cows across the United States. The possibility of mutations in H5N1 raising the risk of human transmission demands vigilance and further research.