On May 22nd ProMED reported on a case of presumed H5N1 infection in a dairy worker in Michigan. This is the second U.S. case associated with ovine Influenza-H5N1. The male worker was in contact with cows on a farm with infected animals. He experienced mild conjunctivitis and has recovered,
Federal and Michigan health agencies have commenced an investigation. A nasal swab from the worker tested negative for the virus, but an eye swab tested was positive, "indicating an eye infection," according to the U.S. Centers for Disease Control and Prevention (CDC).
It is generally considered that the risk to the public remains low, but farm workers directly exposed to infected animals are at higher risk, suggesting the need for PPE.
Dr. Nirav Shah Deputy Director of the CDC said “the case was not unexpected and it's possible more infections could be diagnosed in people who work around infected cows.” Federal officials have tested 40 people since the first cases in dairy cows were diagnosed in late March with Michigan responsible for 35 assays.
Dr. Shah praised Michigan officials for actively monitoring farm workers. He said health officials there have been sending daily text messages to workers exposed to infected cows asking about possible symptoms, and that the effort helped officials identify this case.
“It is encouraging that no additional cases were identified” according to Dr. Michael Osterholm, an epidemiologist at the University of Minnesota. He added “There's no sign to date that the virus is causing flu-like illness or that it is spreading among people”.
The virus has been found in high levels in the raw milk of infected cows, but pasteurized products sold in grocery stores are safe because heat treatment inactivates the virus.
The ProMED Moderator, J.H. commented “Presumably the sample was tested using PCR, and in combination with the mild clinical signs, the case was called positive.
It will be interesting to see if virus isolation and/or genetic sequencing indicate the presence of replicating virus” He added. “Regardless, Michigan's efforts to monitor and test workers on infected farms should be applauded, especially in light of the resistance/reluctance to testing workers that has been seen in other impacted states”.