Researchers who sequenced viruses from wastewater samples from 10 Texas towns found the H5N1 avian flu virus in nine of them, sometimes at levels that rivaled those of the seasonal flu .
Separately, the Centers for Disease Control and Prevention (CDC), in its updates on its response to the H5N1 outbreaks in cattle, said that experiments on ferrets began last week.
The results lean towards an animal source
A team from Baylor College of Medicine and the University of Texas Health Science Center detailed their findings on whole-virome sequencing in a new preprint study.
While many questions remain unanswered about how the virus spreads among dairy cows and how widely it circulates, scientists increasingly view wastewater sampling as a key surveillance tool.
The group reported H5N1 in wastewater from March 4 to April 25. They said 19 of the 23 sewage sites monitored had at least one detection event and that over time H5N1 had become the dominant serotype. They did not name the 10 cities they monitored, and the results have not yet been peer-reviewed.
OnMike Tisza, PhD, first author of the study and assistant professor of virology and microbiology at Baylor, said it’s still not clear where the viruses come from, but the evidence leans toward one animal source, because the researchers saw none. mutations with known links to human adaptation.
He added that the Texas system appears to be the only one using wastewater sequencing technology, but that H5N1 is likely present in wastewater in other areas. If the virus becomes more problematic, Tisza said sewage sequencing could be the best way to identify new adaptive mutations.
CDC launches experiments on ferrets
In a May 10 response update, The CDC said more than 260 people have so far been monitored for symptoms of H5N1 following exposure to infected or potentially infected animals. Of at least 33 patients with flu-like symptoms, no additional human cases have been reported, aside from an initial case in a Texas dairy worker with conjunctivitis.
The CDC said it is still in talks with several states about state-led field epidemiological investigations.
Meanwhile, the group said it was continuing its scientific work to better characterize the virus. Last week, he experimentally infected ferrets with the virus that infected the Texas dairy worker to assess the severity and transmission of the disease in different contact scenarios. Scientists often use ferrets as a model to evaluate flu viruses because they get sick and transmit them the same way humans do.
Results are expected in about 3 weeks, and the CDC said experimental infection of various cell lines would follow.
In other developments:
- The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) reported more outbreaks in poultry in three states, two of which reported H5N1 in dairy herds. Idaho reported two additional poultry outbreaks, both in Jerome County. One occurred on a farm housing 1,000 birds and the other hit a backyard housing 20 birds. Michigan reported another outbreak in Ionia County, which affected a backyard flock. And California reported a detection at a live bird market in San Francisco.
- A group of animal influenza experts from the World Organization for Animal Health and the Food and Agriculture Organization of the United Nations, known as OFFLU, today released a statement on H5N1 in dairy cows, noting that the B3.13 genotype had not previously been detected in poultry. appeared in cattle. Before November 2023, it had only been observed in a few wild birds and a skunk. So far, B3.13 has not been detected outside the United States, but the group said it continues to monitor the situation.
News Source : www.cidrap.umn.edu
Gn Health
