CDC study finds silent bird flu infections in milk veterinarians
According to a new study from the centers for the control and prevention of diseases, three dairy veterinarians, including one that only worked in states without known bird flu eruptions in cows, had undiscovered bird flu infections. The results are based on antibody tests of 150 veterinarians who work in 46 US states.
The results were not entirely surprising, explained experts, but indicated that the virus, known as H5N1, could infect cows and people in more states than were officially reported.
“We don't know the extent of this outbreak in the USA,” said Seema Lakdawala, virologist at Emory University. “There are clearly infections that miss us.”
Since the outbreak of bird flu in dairy cows was first reported last March, the virus was confirmed in more than 950 herds in 16 countries. It was also found in 68 people, of whom 41 contact with sick cows. Most people had slight symptoms.
The new study, which was published in the flagship and mortality report of the CDC, was initially planned for publication a few weeks ago, but was delayed by the break of the Trump administration for the public communication of health and science authorities.
“It is important for the willingness of public health that we have this data,” said Dr. Nahid Bhadadelia, the director of the Boston University Center for aspiring infectious diseases.
The study was held at a veterinary conference last September. Participating veterinarians in 46 different states and in Canada. Of the 150 veterinarians recorded in the study, 25 of them stated that they worked with cows that were known from which they had or were suspected of bird flu.
Three of the veterinarians tested positively for antibodies against the virus. None of these three veterinarians had reported that they had worked with cows that were assumed that they had bird flu. (You had worked with infected poultry.) Nobody remembered Flulik symptoms.
One of the veterinarians only worked in Georgia and South Carolina with cows, states that no affected herds had reported.
“I think we all suspected that there may be many other countries in which the virus is not recognized,” said Dr. Bhadadelia.
Dr. Lakdawala said she was surprised that none of the 25 veterinarians who knew that they had worked with infected cows had tested positively for antibodies. But it is possible that those who knew that they worked with infected animals “take more precautionary measures,” she said.
None of the three veterinarians who have been positively tested for antibodies reported to wear masks or safety glasses. Such precautions are not recommended when working with healthy animals in non -affected regions, the study says.
Just as veterinarians are infected, it remains unclear, and veterinarians may have less contact with virus loaded milk than the agricultural workers who spend their days in milking parlors, said Dr. Lakdawala.
“The veterinarians with whom we spoke on these farms are involved in all aspects of care for these animals,” she said. “You are over this cows everywhere and look at it all.”
The results showed the need for far more tests, such as experts, including the examination of asymptomatic milk workers and cattle veterinarians as well as extended tests of the nation's milk supply.
The US Agriculture Ministry announced a national program for testing milk samples from milk in December. Until February 7, 40 states were enrolled and tests were actively carried out. In Nevada, the mass testing of milk recently showed that dairy herds had been infected with a new version of the virus, which differed from the one that spread in dairy cows last year.
“The states that have not been tested on board Bulk milk tests should do so, just because they had not infected herded herds that they have a little scope,” said Dr. Bhadadelia.
When the study was carried out last autumn, the virus in 14 states and in 14 people, four of whom had contact with dairy cows, was demonstrated in herds of dairy.
Apoorva Mandavilli has contributed to the reporting.
