Introduction
In the USA, it seems that a single transmission event between wild birds and dairy cows led to the spread of avian flu to cattle. The virus strains had mixed in wild birds.
Outbreak Origin
The outbreak of avian flu in dairy cows in the USA last year may have started with a single contact with infected wild birds. This is the result of a US study published in the prestigious journal "Science" on April 25.
Spread and Impact
The event occurred in late 2023 after a mixing of virus strains in wild birds, allowing the Highly Pathogenic Avian Influenza (HPAI) subtype H5N1 to infect cattle. The first case of H5N1 in dairy cows in Texas was confirmed in March 2024. The study, involving the National Center for Animal Diseases and Iowa State University, traced the development of the disease through genetic sequence data. After the initial event, the viruses spread across the United States through asymptomatic or pre-symptomatic animals from Texas to other states and were then transmitted from dairy cows to other host species.
Monitoring and Prevention
Since avian flu viruses have the potential to jump to humans, the virus strains, their mutations, and transmission pathways are closely monitored to prevent further outbreaks.
