Influenza A H5N1 was detected in dairy cows in six States in the U.S.
- April 7, 2024
- Posted by: OptimizeIAS Team
- Category: DPN Topics
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Influenza A H5N1 was detected in dairy cows in six States in the U.S.
Subject: Science and tech
Section: Health
Context:
- In March 2024, the first detection of H5N1 in dairy cows occurred in the U.S., with outbreaks in Texas and Kansas and cases in six states overall, affecting the dairy and meat industries.
Avian Influenza spreading globally and affecting different species:
- A new lineage (2.3.4.4b) of avian influenza (Bird flu), spreading globally since late 2020 via migratory birds, has impacted birds worldwide, with economic losses and ecological damage. Rarely, it has infected mammals, including over 200 species and recently polar bears in Antarctica, with potential spillover to humans having a high fatality rate.
- In Texas, wild birds and cats near affected farms also tested positive for H5N1, with the full extent of cow infections unknown due to mild symptoms and lack of routine testing.
- A human H5N1 case was reported in Texas in April 2024, linked to contact with infected cows, marking the second U.S. case following one in Colorado in 2022. Human infections are rare, with over 800 cases reported to the WHO since 2003, showcasing a variety of symptoms and a 53% case-fatality ratio.
- Southeast Asia raised concerns in January 2024 with two human H5N1 cases in Cambodia, one fatal, and a recent fatal case in Vietnam, highlighting the ongoing threat of this virus to both animals and humans.
Genomic insights:
- Sequencing of H5N1 from Texas cows and a human case showed both belonged to clade 2.3.4.4b, with a minor mutation in the human strain potentially indicating adaptation to mammals, though not increasing human transmissibility. CDC maintains the public health risk is low.
- Since late 2021, this clade has been in U.S. wild birds, causing poultry outbreaks and rare mammal infections, including the Texas cases.
- Global incidents in 2023, like seal deaths in Russia and marine mammal infections in Peru, alongside U.K. reports of otter and fox deaths from H5N1, indicate a potential for cross-species transmission.
- The ongoing situation underscores the importance of continued disease surveillance and genomic analysis to manage and understand H5N1’s evolution and interspecies adaptability.
Highly pathogenic Avian Influenza (HPAI):
- The viral disease HPIA or avian influenza, especially the H5 and H7 strains, mostly affects birds.
- These strains are highly pathogenic and have been reported in domestic poultry, resulting in high mortality if they manage to reach wild bird populations.
- It spreads among birds and mammals due to predators and scavengers feeding on infected birds. Marine mammals have also been found to be infected.
- Earlier, HPAI H5N1 spread rapidly in South America and the southern end of the continent to Tierra del Fuego and led to mass scale death of South American Sea lions. The Falkland Islands are at the most risk.
- Threatened species from HPAI:
- Avian groups like gulls and skuas, birds of prey such as hawks and caracaras, terns and shorebirds.
- Among marine mammals, fur seals, sea lions, southern elephant seals and dolphins.
- It can spread to humans also.
Source: TH