2024-07-24 22:07:51
Il The highly pathogenic H5N1 avian influenza virus can spread from livestock to livestock, potentially increasing the risks to humans.. The spread of the pathogen from birds to dairy cattle in several US states has led to direct mammal-mammal spread: it has occurred between cows, and from cows to cats and a raccoon. A team from the American Cornell University discovered this. “This is one of the first times we have seen evidence of effective and mammal-to-mammal transmission of the highly pathogenic H5N1 virus,” said Diego Diel, professor of virology and director of the Laboratory Health Care Virology, College. of Geriatric Medicine of the US university, corresponding author of a forthcoming study in ‘Nature’.
Sequencing of the entire viral genome did not reveal any mutations that would lead to increased H5N1 transmission in humans, although the data clearly show mammal-to-mammal transmission. Which is worrying because the virus can adapt to mammals, Diel warns.
Human cases of avian influenza
There have been 11 human cases of avian influenza reported in the United States so far, the first from infected birds in April 2022, all with mild symptoms. Of these infections, 4 are linked to outbreaks of H5N1 in dairy cattle and 7 to poultry farms, including 4 cases reported in recent weeks in Colorado. These patients were infected with the same virus strain known in cows, leading researchers to suspect that the virus came from dairy farms in the same area. Although the pathogen is capable of infecting humans and replicating in their bodies, the effectiveness of these infections is currently low. “The fear – explains Diel – is that potential changes could occur that could lead to the reintroduction of the virus to mammals, its spread in humans and its transmission well between humans in the future”. Therefore it is important to continue monitoring the pathogen in animals and humans, warns the scientist.
Dimensions
The Department of Agriculture of the United States – USDA, among the institutions that finance the new research – support programs for testing on the H5N1 virus, at no cost to the producers. According to Diel, to contain any further evolution of the pathogen, tests for the initial diagnosis of infection, measures for greater permanent protection and isolation in case of positive will be required.
In the US, H5N1 infections were first identified in January 2022 and have caused the death of over 100 million domestic birds and thousands of wild birds. Scientists at Cornell University’s Health Research Center and Texas A&M Medical Center – where another corresponding author of the new work, Kiril Dimitrov, works – were among the first to report the virus. in dairy cows. The cows may have been infected by wild birds, reporting symptoms such as reduced appetite, changes in stool, difficulty breathing and reduced milk production. In cattle, a high tropism of the virus (ability to infect certain cells or tissues) for the mammary gland and a high viral load in the milk of infected animals have been observed.
Through comprehensive genetic sequencing of virus strains, patterns and epidemiological information, researchers determined cases of cow-to-cow transmission when infected Texas cattle were moved to an Ohio herd with a healthy cow. Monitoring also showed that the virus was spread to cats, raccoons and wild birds that died on farms. Cats and raccoons can get sick from drinking raw milk from infected animals. In the case of wild birds, although we do not know how they got the disease, scientists suspect environmental pollution or the air that comes out when they give milk or wash the toilets.
#Infectious #disease #alert #research #risks #humans