Survey of H5N1 avian flu in sewage across the U.S. indicates minimal dissemination.
On Monday, nonprofit organization WastewaterSCAN released data showing detection of the H5 protein from the flu virus in sewage from 14 treatment plants across 5 states, mainly in Texas and Michigan. This could indicate that the ongoing outbreak in dairy cattle is largely confined to states with reported cases of affected herds.
Dr. Alexandria Boehm, a professor of civil and environmental engineering at Stanford University and director of WastewaterSCAN, stated that detections of H5 are only present in certain locations. Their research tested for H5 across 190 monitoring sites across the US in the past two weeks. However, nine states—South Carolina, Missouri, Oklahoma, New Mexico, Arizona, Wyoming, Montana, North Dakota, and Oregon—are not part of the WastewaterSCAN network, so their sewage was not included in the surveillance.
H5 was also detected in Iowa and Minnesota, where no infected dairy herds have been identified, but both states have experienced recent H5N1 outbreaks in poultry.
The source of H5 in wastewater is unknown; it could stem from permissible discharges of leftover or unused raw milk into wastewater treatment plants. Boehm cited an example of this occurring in Amarillo, Texas, where unused milk used in a dairy processing plant was discharged into the treatment facility. The virus's origin may not be linked to all areas, though, as there's a possibility of human infections or transmission from less likely sources like infected wild animals and stormwater runoff potentially containing viruses from bird droppings.
Despite H5 appearing in sewer systems, people should not be overly alarmed, according to Boehm. She described this as an additional tool to monitor the virus during the outbreak.
The limited testing of cattle has sparked concerns among experts since the farm workers who are at most risk of contracting the virus from infected cattle may live on reduced incomes and might not wish to undergo testing, resulting in potential consequences of missing work without compensation.
As of Tuesday, 81 dairy herds with infected cows have been identified in nine states: Michigan, Idaho, and Texas. The USDA issued a mandatory order in late April, requiring cattle to test negative for H5N1 before they can be transported across state borders; however, many farmers have been hesitant to let officials into their farms for further surveillance.
The US Centers for Disease Control and Prevention (CDC) is surveying human infections through a network of clinics submitting respiratory virus test results to the agency and public health labs. Additionally, they are planning an epidemiological study to better understand the risk of virus transmission between animals and humans on farms.
In a May 29th study, the CDC estimated a 72-77% chance that one human case of H5N1 would be detected in an emergency room or urgent care clinic monthly, provided symptoms were comparable to seasonal flu, and there were at least 100 H5N1 cases in the population. To detect novel influenza cases, they urged healthcare providers to remain vigilant for indications of flu and ex (n) (n) (n) (n) (n) \ \ \ \ (u) \ (n) (n) (n) (n) \ \ \ \ (u) \ (n) (n) (n) (n)erase the possibility of (u) \ (n) (n) (n) (n) \ \ \ \ (u) \ (n) (n) Spread through the air in animals or via direct contact, the CDC raised concerns that the virus could potentially mutate into a form easily transmitted among humans. The CDC then urged healthcare providers to remain attentive for signs and symptoms of flu, maintain high rates of testing, and forward any specimens that test positive for influenza A to public health labs for further examination.
It's crucial to conduct an epidemiological study to understand how the virus spreads and could potentially mutate into a form more easily transmitted among humans. The CDC suggested that remaining vigilant and conducting high rates of testing could help detect any potential changes in the virus. They encouraged healthcare providers to forward any specimens that test positive for influenza A to public health labs for further examination.
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Despite the detection of H5 in Iowa and Minnesota, no infected dairy herds have been identified in these states.The WastewaterSCAN network does not include nine states where H5 was not tested for in sewage.
