Unexpected bird flu cases prompt CDC testing guidelines to be tightened

Public health officials are recommending broader testing and increased use of antiviral flu drugs for workers who may be exposed to avian influenza on poultry and dairy farms.

The Centers for Disease Control and Prevention on Thursday released updated recommendations following a new study of 115 dairy farm workers in Colorado and Michigan that found that 7% appeared to have been infected with avian influenza, but only half of those workers recalled having it. symptoms. CDC officials said the study suggests that asymptomatic workers who perform jobs that expose them to high risk of exposure on poultry and dairy farms may be at increased risk of infection.

The Centers for Disease Control and Prevention had previously recommended testing only among workers who developed symptoms after exposure to infected animals. Officials are now recommending that workers exposed to an infected animal get tested, even if they don’t have symptoms.

“We in public health need to cast a wider net in terms of who is offered a test so that we can identify, treat and isolate these people,” said Nirav D. Shah, principal deputy director of the CDC.

The agency also recommends giving workers Tamiflu, an antiviral flu medicine, if they were not wearing protective equipment during exposure to a high-risk infected animal—regardless of whether they have symptoms. Examples of high-risk exposures include exposure to raw milk from an infected cow or exposure to the virus during the culling of infected poultry, Shah said.

The CDC said it will update its recommendations on personal protective equipment for farms and workers to take into account the risk of infection. Workers in certain occupations are at higher risk of infection. Of the 7% of infected dairy workers in Colorado and Michigan, all said they cleaned a milking parlor and 88% milked cows, the study said.

Shah said the updated precautions are aimed at keeping workers healthy and slowing the spread of the H5N1 virus, known as avian flu.

“The less room we give this virus to spread, the less chance it has to cause harm or change,” Shah said. “And the best way to limit the space for the virus to spread is to test, detect, treat and isolate as many human cases as possible.”

The CDC’s updated recommendations are based in part on a study of 115 dairy workers in Colorado and Michigan. Blood tests showed that eight workers were infected with bird flu, but only four of them recalled having symptoms. The most common symptom among those who experienced it was red, watery and itchy eyes.

None of the infected workers in the study wore respirator masks while performing their duties, and less than half used protective eyewear.

The researchers reported that workers were interviewed an average of 49 days after exposure to infected cows. Their responses were based on what they recalled about workplace safety precautions during infection.

Bird flu has spread rapidly through U.S. dairy farms since it was discovered in wild birds in Texas last year. Farm workers in many states have been infected, but there has been no evidence that the virus can be transmitted from person to person.

Bird flu did not affect the supply of dairy products to the country. Milk is safe to drink if it has been pasteurized, a process that kills pathogens.