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New Threats Emerge: Bird Flu Spreads to U.S. Dairy Cows, New COVID Variant Surfaces


A new threat is spreading through American farms: bird flu, also known as avian influenza. While this virus usually affects birds, recent outbreaks of the H5 strain have been found in U.S. dairy cows. There have even been two cases of dairy workers getting sick. This shows that bird flu can spread beyond birds, raising worries about the millions of immigrant workers in these industries.

A new COVID variant – known as FLiRT – is also emerging, even as millions of Americans declare they are done with COVID-19 vaccine updates. Experts at a recent Ethic Media Services panel predict a summer surge of Covid, as the more contagious variant takes hold.

Dr. Maurice Pitesky, an Associate Professor at the UC Davis School of Veterinary Medicine, provided insights into the recent surge in avian influenza during a recent press briefing. With a research focus on highly pathogenic avian influenza (HPAI) disease modeling, Dr. Pitesky detailed the factors contributing to the spread of this virus.

“Avian flu has been with us since 2012,” Dr. Pitesky noted. “What accounts for the current surge is the unique reassortment and combinations of the virus facilitated by migratory waterfowl like ducks and geese. These birds can travel thousands of miles and interface with other flyways, particularly in the Arctic, creating new virus strains.”

Dr. Pitesky explained that the main reservoirs of avian influenza are waterfowl. The interactions among different flyways in the Arctic breeding grounds allow for unique virus reassortments. These reassorted viruses can then be brought back to regions like California through migratory patterns, leading to new outbreaks.

The reduction of natural habitats for waterfowl exacerbates the problem. “When waterfowl migrate into North America, they might be roosting and feeding in areas where we have human agriculture,” Dr. Pitesky said. This proximity increases the likelihood of transmission between wild birds and domesticated animals, such as chickens and dairy cows.

Dr. Pitesky highlighted several transmission routes, including fecal shedding by infected birds, aerosol transmission, and even the involvement of other species like feral cats. Shared equipment and man-made water habitats near dairies and poultry farms also contribute to the virus’s spread.

Globally, the avian flu has impacted six continents, which is unprecedented in terms of both geography and the range of species affected. Dr. Pitesky compared the situation in China to the U.S., noting differences in vaccination policies. “China vaccinates against HPAI, which has both economic and political implications. However, in the U.S., we do not vaccinate, partly to avoid asymptomatic spread of the virus,” he explained.

The conversation also touched on the occupational risks faced by workers in the poultry and dairy industries, many of whom are immigrants. “It is an occupational hazard,” Dr. Pitesky acknowledged, “and underreporting is likely, especially among undocumented workers who may not report symptoms due to job insecurity.”

Efforts to mitigate these risks include funding from the USDA for personal protective equipment. However, Dr. Pitesky pointed out challenges such as cultural barriers and the impracticality of wearing protective gear in hot climates.

Dr. Peter Chin-Hong, Professor of Medicine and Director of the Immunocompromised Host Infectious Diseases Program at UCSF, has shed light on this concerning development, emphasizing the complexities and potential underreporting of human cases related to this outbreak.

According to Dr. Chin-Hong, avian flu has been known to affect humans for decades, with approximately 880 cases reported globally over the past 30 years, carrying a grim fatality rate of about 50%. However, recent cases in dairy cattle have added a new layer of concern. Two confirmed human cases in dairy workers displayed relatively mild symptoms, primarily conjunctivitis, or red eye. This contrasts sharply with the severe respiratory distress typically associated with avian flu, raising questions about the virus’s evolving nature.

“Many dairy workers are likely visiting community clinicians with symptoms that aren’t immediately recognized as avian flu,” said Dr. Chin-Hong. “This suggests that the actual number of cases could be significantly higher than reported.”

Dr. Chin-Hong and Dr. Maurice Pitesky, Associate Professor at UC Davis School of Veterinary Medicine, both agree that the true extent of human infection is likely underreported, particularly among immigrant workers in the poultry and dairy industries. These workers often face multiple barriers, including fear of deportation, lack of paid sick leave, and limited access to healthcare, which deter them from reporting symptoms or seeking medical attention.

“The current culture in these industries means workers show up even when sick because they need the income,” Dr. Chin-Hong explained. “Additionally, the fear of immigration enforcement prevents many from seeking help.”

Dr. Chin-Hong explained that avian flu, particularly the H5N1 strain, is highly pathogenic and can spread through respiratory droplets and contaminated surfaces. The two recent human cases, reported in Texas and Michigan, involved symptoms limited to red eyes and quick recovery, unlike previous severe cases of avian flu which presented with respiratory failure and high mortality.

“In these cases, the virus doesn’t seem as deadly, but we can’t be complacent,” warned Dr. Chin-Hong. “Historically, avian flu has led to severe outbreaks in humans due to our lack of immunity.”

Public anxiety has also been fueled by reports suggesting that avian flu could be present in milk and meat products. Dr. Chin-Hong clarified these concerns, noting that while fragments of the virus have been found in milk samples, they were not viable infectious particles. Pasteurization effectively kills the virus, making pasteurized milk safe for consumption.

However, the risk remains with raw milk and unpasteurized products. A recent study in the New England Journal of Medicine demonstrated that infected milk could cause illness in mice, underscoring the dangers of consuming raw dairy products.

The federal government has responded by providing funding for protective equipment and compensation for affected farms, but Dr. Chin-Hong believes more needs to be done. Enhanced surveillance, better protection for workers, and comprehensive health policies are crucial to prevent further spread.

“We need to address the root causes of underreporting and ensure that workers are protected both medically and economically,” Dr. Chin-Hong urged. “Only then can we hope to control this outbreak and safeguard public health.”

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