U.S. CDC Now Reports That 7 Percent of Tested Dairy Farmworkers Were Possibly Infected with the H5N1 Virus!
Nikhil Prasad Fact checked by:Thailand Medical News Team Nov 08, 2024 3 hours, 28 minutes ago
Medical News: The United States Centers for Disease Control and Prevention (CDC) recently published a study revealing that approximately 7% of tested dairy farmworkers might have been infected with the H5N1 avian influenza virus. Conducted in collaboration with the Michigan Department of Health and Human Services (MDHHS) and the Colorado Department of Public Health and Environment (CDPHE), the investigation focused on dairy farmworkers exposed to herds with confirmed H5N1 cases. Researchers aimed to evaluate the potential transmission of this virus from cattle to humans and to understand related health risks for workers.
U.S. CDC Now Reports That 7 Percent of Tested Dairy Farmworkers Were Possibly Infected with the H5N1 Virus
This
Medical News report delves into the key findings and broader implications of the U.S. CDC’s recent serologic study, which was carried out from June to August 2024 on dairy farms in Michigan and Colorado. The study presents significant data that could influence public health policy and the way farmworkers interact with animals infected by avian influenza viruses.
Details of the Study
In early 2024, highly pathogenic avian influenza (HPAI) A(H5) viruses were detected in the United States within dairy cattle, a previously unrecognized animal host. These infections raised concerns about potential transmission to humans, especially farmworkers directly handling these animals. The CDC's study sampled 115 dairy farmworkers across Michigan and Colorado, where HPAI A(H5) infections had been confirmed among dairy cattle. Blood samples were taken to test for antibodies against the virus, and the workers were also interviewed about their recent health, work duties, and use of personal protective equipment (PPE).
The study found that 7% of tested workers showed antibodies indicating recent exposure to the H5N1 virus. Most of these individuals were involved in tasks such as milking cows or cleaning milking parlors, which placed them in close contact with potentially infected animals. Notably, the majority of seropositive individuals reported mild or no symptoms during the exposure period, indicating that some H5N1 infections might go unnoticed due to their mild nature.
Key Findings on Transmission and Exposure
While past HPAI infections in humans have primarily been linked to poultry, the CDC’s report is one of the first to suggest the possibility of dairy cattle acting as an intermediate host for the virus. This development could increase the potential risk to workers on dairy farms, particularly those who interact closely with cows.
The study highlighted several critical insights into transmission risk. Workers who cleaned milking parlors, where virus-contaminated milk or respiratory secretions might be present, faced a notably higher risk. All seropositive individuals reported cleaning or milking tasks, while few of them recalled any direct physical symptoms at the time of exposure. This finding emphasizes the need for heightened surveillance and enhanced protective measures for dairy workers who frequently handle potentially infected animals.
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Importance of Personal Protective Equipment (PPE)
One striking result from the study was the minimal use of recommended PPE among dairy farmworkers, even after confirmed cases of HPAI infections in their herds. CDC guidelines suggest that workers in close contact with infected animals wear eye and respiratory protection. However, fewer than 40% of workers used eye protection, and only 21% used respiratory masks such as N95 respirators.
This lack of PPE adherence, especially in environments where workers handle potentially infected milk or animal waste, could be a significant factor in the virus's transmission risk. The CDC has emphasized the importance of reinforcing PPE use, especially for tasks like cleaning, which may expose workers to higher viral loads. Enhanced training and accessible protective equipment may help prevent future transmission to workers.
Health Implications and Monitoring
The study reported mild symptoms in many workers, including red, itching eyes, sore throats, and occasional respiratory issues. Among those with antibodies, about half reported some symptoms, but none showed signs of severe illness. Previous studies on avian influenza viruses suggested that some strains could cause severe respiratory disease in humans. The current findings, however, suggest that many H5N1 infections in dairy workers might be asymptomatic or present with only mild symptoms.
This pattern of mild or absent symptoms complicates disease monitoring efforts. Workers may not recognize the need to report minor symptoms or seek medical attention. Public health authorities may thus need to adopt more proactive health monitoring on affected farms to detect cases early, including routine screenings for mild symptoms in workers exposed to infected herds. Such measures could help reduce the spread of the virus and prevent escalation to more severe disease.
Broader Public Health Implications
The CDC study underscores the urgent need for effective public health measures to prevent HPAI transmission among humans. While dairy farmworkers may not have shown severe illness, any case of zoonotic transmission (animal to human) raises concerns about viral adaptation and potential mutations that could enable easier human-to-human transmission.
The study suggests that regular surveillance of dairy herds for HPAI and public health outreach on farms are crucial for early identification of infected herds. Rapid detection of infected cattle and timely monitoring of exposed workers can mitigate transmission risks. Educational efforts tailored to farmworkers - often non-English speakers - should include clear guidance on using PPE and recognizing HPAI symptoms.
Conclusion
The CDC’s findings serve as a critical reminder of the need to bolster biosecurity and disease monitoring measures in animal husbandry industries. The evidence of H5N1 virus exposure among dairy farmworkers highlights a potential public health concern. Moving forward, implementing better protective measures, increasing PPE accessibility, and enhancing educational outreach to farmworkers could be key steps in minimizing zoonotic transmission risks.
The study findings were published in the peer-reviewed journal: Morbidity and Mortality Weekly Report.
https://www.cdc.gov/mmwr/volumes/73/wr/mm7344a3.htm
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Read Also:
https://www.thailandmedical.news/news/reassorted-strain-of-h5n1-bird-flu-virus-discovered-in-cambodia
https://www.thailandmedical.news/news/h5n1-bird-flu-infections-keep-rising-among-humans-dairy-farms-and-poultry-farms-across-america
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