Many human bird flu infections went undetected, study uncovers

There may be more human cases of bird flu than previously thought as a study has found that 7% of workers on dairy farms where cows were infected with the virus contracted it themselves.
The research published in the CDC’s Morbidity and Mortality Weekly Report, was led by disease detectives at the US Centers for Disease Control and Prevention in partnership with state health departments in Colorado and Michigan.
The study noted that although the workers were catching bird flu, these numbers didn’t reflect in official counts. In light of these findings, the agency has suggested that all workers on farms with infected cows should be tested even if they don’t have any visible symptoms. Earlier, testing was recommended only for workers with symptoms after exposure to cows.

Previously, the CDC recommended testing of only those workers who had symptoms after exposure to infected cows. Now, officials say all workers on farms with infected cows should be tested, even if they don’t have symptoms. The agency has suggested testing and treatment
Additionally, the agency has recommended antiviral medication Tamiflu to even those workers who have had a high-risk exposure to infected animals when they weren’t wearing personal protective equipment. Earlier, only those with symptoms were given Tamiflu.

Out of 115 people who were tested, eight came positive for antibodies which suggested that they had been infected with bird flu. Only four out of these recalled having any symptoms, but it was indication of a very mild illness. The reported symptoms included eye redness or conjunctivitis, fever, runny nose, sore throat, sneezing and diarrhea.

None of the workers wore the recommended PPE. They either reported cleaning the milking parlor or themselves milked the cows. Only one of them said they knew the cows they were working with were infected with H5N1.
A total of 46 human cases of H5N1 were reported in the United States this year so far. However, these workers identified in the new study won’t be added to the case count as their infection wasn’t active.