HQ Team
November 9, 2024: US farm workers exposed to bird flu who do not show symptoms and do not wear personal protection equipment should be tested for the virus, according to the nation’s national public health agency.
“Simply put, the less room we give this virus to run, the fewer chances it has to cause harm or to change,” said Centers for Disease Prevention and Control (CDC) Principal Deputy Director, Dr Nirav Shah.
“And the best way to limit the virus’s room to run is to test, identify, treat and isolate as many cases as possible in humans and as quickly as possible,” he said in a CDC transcript of a news conference.
There have been 46 human cases of H5N1 so far in the US in 2024. The flu has infected about 450 dairy farms in 15 states, according to the US Department of Agriculture’s Animal and Plant Health Inspection Service.
Serological study
A recent study on 115 farm workers in Colorado and Michigan revealed that workers exposed to cows infected with H5N1 virus showed seven per cent of them had evidence of prior infection. Of that, only half of the workers remembered having symptoms of the disease.
The serological study conducted from June to August revealed “eight of the 115 samples, were seropositive against HPAI, or highly pathogenic avian influenza,” said Dr Demetre C. Daskalakis, Director of the National Center for Immunization and Respiratory Diseases.
All eight were Spanish speakers and reported milking cows or cleaning the milking parlour, supporting these as higher-risk activities.
High-risk activities include an unprotected splash in the face with raw cow milk on the poultry setting or an event that might have happened during a depopulation or culling event where the individual was not wearing appropriate protection equipment.
‘None protected’
“None (of the eight workers) wore respiratory protection, and less than half wore eye protection, highlighting the need for better tools to support worker protection,” Dr Demetre said.
Principal Deputy Director Shah said: “That means that 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 those individuals.”
“The purpose of this expansion, informed by the new serology data, is to actively identify exposed workers with H5N1, even if their symptoms are so mild as to be unnoticeable, so that those workers, too, can be offered treatment and isolation,”
“This active case finding reduces the likelihood that a mild infection could turn into a severe infection, or that the infection spreads to anyone else,” Shah said.
Tamiflu
The CDC also expanded a recommendation for the use of Tamiflu for exposed, asymptomatic workers who had a high-risk exposure to an H5N1-infected animal without having worn adequate equipment.
“It reduces the likelihood of an asymptomatic case being symptomatic because they’re receiving Tamiflu, and thus, it lowers the risk and the chances of onward transmission to close contacts,” Shah said.
H5N1 bird flu symptoms may include fever or chills, eye redness or irritation, and respiratory symptoms, such as cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and tiredness.
