A recent study conducted in the Czech Republic suggests that the H5N1 avian influenza virus, highly contagious, could be transmitted through the air under certain environmental conditions.
The research, carried out by government veterinarians, analyzed an outbreak on a poultry farm with strict biosecurity measures, where the virus managed to spread without direct contact with infected animals.
Outbreak on a poultry farm and possible airborne virus spread
The outbreak occurred in February 2024 at a high-security poultry farm that had filtered well water, one-way ventilation, and fences to prevent the entry of wild birds. Despite these measures, the virus spread within the breeding facility, causing the death of thousands of chickens.
Veterinarians traced the origin of the virus and found that it came from a duck farm located 8 kilometers away, where a massive outbreak had been recorded days before. Within just two days, 5,000 ducks died, and eventually the entire flock of 50,000 birds was culled to contain the infection.
Wind as a possible virus transmission route for H5N1
The team led by Dr. Kamil Sedlak, director of the State Veterinary Institute in Prague, ruled out all traditional transmission routes and concluded that the most likely cause was virus spread through the wind.
Researchers analyzed meteorological data and found that, during those days, the ideal conditions for the virus to travel through the air were present:
- Steady winds from west to east, directly towards the poultry farm.
- Dense cloud cover, blocking ultraviolet light, which usually destroys viruses in the air.
- Temperatures between 4 and 10 °C (40-50 °F), optimal for virus survival.
The first chickens to die were those located near the ventilation grilles, suggesting that the virus entered the facility through the air.
Experts confirm the possibility of airborne virus transmission
The World Health Organization (WHO) had already considered the possibility of airborne virus transmission, although proving it has been a challenge. Dr. Richard Webby, director of the WHO Collaborating Centre for Influenza Ecology, explained that while avian flu does not easily infect humans, airborne transmission could be more common than believed.
Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, mentioned that this transmission mechanism could explain unusual cases, such as that of three veterinarians who tested positive for H5N1 antibodies after attending a conference without direct contact with infected birds.
Recommendations to prevent airborne virus spread
Dr. Montserrat Torremorell, professor of Veterinary Medicine at the University of Minnesota, suggested that poultry farms should consider improving their ventilation systems and adding air filters in the barns to prevent virus spread.
She also recommended strengthening personal protection measures and restricting access to farms to reduce the possibility of contagion.
The findings of this study were published on the bioRxiv preprint server and still need to undergo peer review to confirm their conclusions.
Avian influenza in Antarctica: first confirmed case in marine mammals
A team of Spanish researchers from the Severo Ochoa Molecular Biology Center (CBMSO-CSIC), under the Ministry of Science, Innovation, and Universities (MICIU), in collaboration with the research project on Antarctic penguins ecology PERPANTAR of the National Museum of Natural Sciences (MNCN-CSIC), has identified the highly pathogenic avian influenza virus in the carcass of a southern elephant seal in Antarctica.
This finding represents the first confirmed case of highly pathogenic avian influenza infection in marine mammals in Antarctica, suggesting the disease’s expansion to other animal groups with unknown consequences for Antarctic fauna and ecosystems.
Virus expansion in the white continent
Spain has deployed a molecular diagnostic laboratory in Antarctica following the massive mortality of various animal species in southern South America.
The first definitive evidence of virus expansion in Antarctica was reported this past February when Spanish scientists Antonio Alcamí and Ángela Vázquez detected the infection in samples from skuas (jaegers) collected by Argentine scientists near the Primavera Antarctic base.
Cover photo: Reuters/Amr Abdallah Dalsh
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