Here's the latest on H5N1—avian flu—and some resources tracking the virus

Over a year ago I shared some maps that were tracking the H5N1 avian flu outbreak. At the time, the virus had been detected in more than 150 wild and domestic avian species. It had also jumped from birds to mammals and scientists had found the virus in over a dozen mammal species. Worldwide, foxes, bears, mink, whales, seals, and more had died in quick and horrific fashion. 

Unfortunately, things are looking worse a year later. It's time to share those maps again along with some more resources so that you can stay up to date on the latest avian flu news. The maps I shared last year are now tracking H5N1 in dairy farms and in poultry and goats. Today, Nature published a piece explaining that genomic analysis is suggesting that H5N1 has been spreading in cows across the United States for months, but scientists are still trying to get access to more information to fully assess the situation. So far the USDA has confirmed H5N1 in 34 dairy herds in nine states.

The University of Nebraska Medical Center's Global Center for Health Security is keeping up to date on the rapidly evolving situation. CIDRAP, the Center for Infectious Disease Research and Policy at the University of Minnesota is also closely following H5N1 developments. They recently published an article describing the prevalence of H5N1 in the U.S. commercial milk supply—it's shown up in one in five samples, according to the US FDA, with the highest concentrations in areas with H5N1 outbreaks in dairy cattle. CIDRAP explains:

Donald Prater, DVM, acting director of the FDA Center for Food Safety and Applied Nutrition (CFSAN), shared the new findings with state health officials who took part in a scientific symposium on H5N1 hosted by the Association of State and Territorial Health Officials (ASTHO). The results come in the wake of earlier findings this week from more limited FDA sampling, along with similar findings from a smaller set of samples tested by a lab that's part of the National Institute of Allergy and Infectious Diseases Centers of Excellence for Influenza Research and Response (CEIRR) Network.

Scientists are still trying to understand what kind of risks viral particles in milk pose to humans, but there are gaps in the current knowledge base concerning whether pasteurization kills H5N1, how long the virus lives in raw milk, and what other dairy products might be affected. Again, CIDRAP:

. . . the FDA still has a long list of data gaps to fill, including identifying the risk of infection to humans via oral consumption and validating that existing pasteurization methods can inactivate H5N1. Other data gaps include how long the virus survives in raw milk and the infectious dose of viruses. Though a major concern is retail milk, Prater also said the FDA needs to see if contamination is occurring in other products, such as cheese made from raw milk. 

We already know that cats on dairy farms have been testing positive for and dying from H5N1. These cats are presumably either drinking infected milk, coming into contact with infected birds, or breathing aerosolized virus from infected cows (H5N1 is airborne, just like COVID-19). BNO News published a piece yesterday on four more cats that have died from avian flu, explaining:

Four more cats have tested positive for H5N1 bird flu in connection with a growing outbreak in dairy cows in the United States. . . 

Sonja Olsen, the Associate Director of Preparedness and Response at CDC's Influenza Division, reported three new cases in cats on Thursday and state officials reported a fourth case on Friday.

"The reports we heard were of cats having neurologic symptoms, rapid decline, and death," Olsen told BNO News.

Three of the new cases were found at two dairy farms in Curry County, New Mexico and all of them died, according to the state's Agriculture Department. The fourth case was found at a dairy farm in Wood County, Ohio.

BNO News adds that "So far, at least 7 cats have been infected in the current outbreak. All of them died."

Two of the most prominent wastewater data analysis sites are also keeping close track of H5N1. Check out Biobot Analytics for up to date information. Wastewater SCAN also recently posted their latest snapshot of Influenza A based on wastewater data (they don't currently separate out Flu A from H5N1 so that data is lumped together for now under "Influenza A"):

Influenza: Nationally, Flu A is in the "High" category with no trend up or down. >50% of individual sites are in the "Medium" or "Low" category. Flu B is in the "Low" category nationwide & in some regions since IBV was detected in <50% of samples tested over the last 2 weeks.

I'll do my best to keep up with the latest news and report back as I can! In the meantime, stay safe, friends!

Previously: Cow gives man bird flu