The United States has seen over a dozen cases of H5N1 bird flu in humans this year. While current evidence suggests this virus spreads to humans primarily through infected animals, a recent case in Missouri has raised eyebrows. The Centers for Disease Control and Prevention (CDC) reported on September 6th that a person in Missouri contracted H5N1 despite having no known contact with infected animals. This case is particularly concerning as it deviates from the established pattern of transmission.
The Missouri patient, who had underlying health conditions, experienced symptoms such as chest pain, diarrhea, vomiting, and weakness. They were hospitalized in August and have since recovered. Notably, the patient initially tested positive for influenza A, a broader group of viruses that includes seasonal flu viruses, but tested negative for those subtypes. Subsequent testing confirmed the presence of H5N1. While the CDC has not definitively identified the source of transmission, they have ruled out human-to-human transmission based on available data.
The Missouri case has sparked debate among experts about the effectiveness of current tracking methods. Dr. Nahid Bhadelia, founding director of the Center on Emerging Infectious Diseases at Boston University, expressed concerns about the lack of robust surveillance for H5N1 in cattle. The case occurred in a state that had not detected the virus in cattle, despite a historical record of 600,000 poultry infections. This suggests that infected herds may have gone unnoticed.
Dr. Seema Lakdawala, an associate professor of microbiology at Emory University, echoed these concerns, stating that the USDA (Department of Agriculture) is not conducting enough testing to accurately chart the virus’s geographic distribution. She emphasized the need for more comprehensive testing of dairy farms, highlighting that only a tiny fraction of dairy cows in Missouri have been tested for H5N1.
The lack of widespread testing raises questions about the potential for raw milk to be a source of infection. The CDC warns against consuming raw milk, as infected cows can harbor millions of infectious virus particles per milliliter of milk. While it is not known whether drinking raw milk can transmit bird flu, it is a known vector for other germs.
The Missouri case underscores the importance of proactive measures to understand and contain the spread of H5N1. While the CDC continues to maintain that the risk to the general public remains low, experts advocate for increased surveillance and testing, especially in cattle and raw milk. The need for a more comprehensive approach to tracking and managing the virus is crucial in preventing a potential epidemic.
