Second case of bird flu confirmed in US dairy worker, CDC reports

File photo.

23rd May 2024 – (Chicago) The US Centers for Disease Control and Prevention (CDC) announced on Wednesday (May 22) that a second human case of bird flu has been identified in the United States. The infection occurred in a dairy worker from Michigan, marking an expansion of the bird flu outbreak. However, the CDC reassured the public that the risk remains low.

During a press briefing, the CDC stated that there is currently no evidence of human-to-human transmission of bird flu. Since March, the CDC has conducted tests on nearly 40 individuals, including the Michigan worker. A dairy worker from Texas was previously confirmed to be infected in April.

Nine states, including Michigan and Texas, have reported bird flu cases in dairy herds since late March. Scientists believe that the outbreak may be more widespread, as the US Food and Drug Administration discovered H5N1 particles in approximately 20% of retail milk samples.

Similar to the case in Texas, the Michigan patient experienced only eye symptoms, according to the CDC. The worker had mild symptoms and has since recovered, as confirmed by the Michigan Department of Health and Human Services. The individual had regular exposure to livestock infected with bird flu.

The CDC highlighted the possibility of identifying additional human cases due to the high levels of the virus found in raw milk from infected cows and the extent of spread among dairy cows.

Nirav Shah, the CDC’s principal deputy director, reported that the Michigan patient’s sample was received on Tuesday and the positive test result was confirmed that evening. The investigation is in its early stages, and investigators are assessing whether the worker was provided with or wore protective equipment.

While a nasal swab from the Michigan worker tested negative for influenza in the state, an eye swab tested positive for the H5N1 virus at the CDC.

The US Department of Agriculture (USDA) believes that unpasteurized milk is the primary means of transmitting the virus among cows, although the exact mode of transmission remains unknown. As a preventive measure, the USDA began requiring dairy cows to test negative before being transported across state lines in late April.

Dr. Amesh Adalja, an infectious disease expert at the John Hopkins Center for Health Security, expressed the likelihood of additional cases stemming from exposure to infected cows and their milk among farm workers. Ensuring comprehensive testing is crucial in capturing these cases, he emphasised.