H5 avian flu: third person in the United States tests positive in connection with outbreak in dairy cattle

CNN
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A third person in the United States has tested positive for H5 avian influenza in connection with an ongoing outbreak in dairy cattle, the Michigan Department of Health and Human Services announced Thursday. This is the second human case reported in the state and the fourth in the United States.

This time, in addition to some eye symptoms seen in previous H5N1 cases, the farmworker reported a cough and other respiratory symptoms more typical of human flu infections, the health department said.

“This individual had respiratory symptoms including cough, congestion, sore throat and watery eyes,” Dr. Nirav Shah, principal deputy director of the U.S. Centers for Disease Control and Prevention, said Thursday. from a press briefing.

“What respiratory symptoms tell us, more than anything, is that this virus, like many viruses, can present itself in many ways, and for this reason we must remain vigilant and not alarmed,” he said. -he adds.

Experts said the addition of respiratory symptoms does not necessarily indicate that the virus has become more dangerous or that it can spread more easily from person to person. Instead, they say, the person likely developed pulmonary symptoms due to the route of infection, perhaps from breathing infectious aerosols in the milking parlor instead of rubbing their eyes with contaminated hands .

“In the first case in Michigan, eye symptoms appeared after direct splash of infected milk into the eye. In this case, respiratory symptoms developed after direct exposure to an infected cow,” Dr. Natasha Bagdasarian, Michigan’s medical director, said in a press release. “Neither individual was wearing full personal protective equipment (PPE). This tells us that direct exposure to infected livestock poses a risk to humans and that PPE is an important tool to prevent spread among people who work on dairy and poultry farms. We have not observed any signs of sustained human-to-human transmission, and the current health risk to the general public remains low.

About 220 people are being monitored in Michigan due to potential exposure to the virus, Shah said.

Michigan, the state with the largest number of dairy herds infected, is also starting blood tests to determine how many workers might have antibodies to the H5N1 virus, which would reflect past infections or exposures.

The CDC agreed that the risk to the general public remains low. But this case highlights the high risk for those who work with infected animals.

The CDC has recommended that dairy workers wear personal protective equipment to reduce their risks. The U.S. Department of Agriculture has offered financial support to farms housing infected animals to ensure workers are protected.

“Previously we focused on the importance of eye protection, given the conjunctivitis in the first two cases, but this case also highlights the importance of barrier protection, such as masks and other forms of protection for dairy workers, especially those who work with affected cows,” Shah said.

Research is underway into how infections are transmitted between cows and from cows to people who work with them.

This is the third human infection known to be caused by this highly pathogenic form of avian influenza currently infecting dairy cattle in the United States. None of the three people had contact with each other, but all worked with livestock, suggesting that these are examples of cow-to-human transmission. The other two cases concerned eye infections or conjunctivitis. The most recent worker had mild eye symptoms but had not been diagnosed with conjunctivitis.

The person had direct contact with infected livestock and informed local health authorities that they felt ill. Their symptoms are described as mild.

The patient received the antiviral drug oseltamivir, the same active ingredient as Tamiflu, and is isolating at home. Their family members did not develop any symptoms, but they were also offered antiviral medications as a precaution. None of the other workers at the dairy farm have fallen ill and they are being monitored, the CDC said.

“Given the wide-ranging interactions between humans and dairy cows as well as contaminated milking equipment, it is not surprising that there are more human infections,” said Dr Seema Lakdawala , an infectious disease specialist at Emory University who studies how the virus is transmitted in dairy barns.

“Whenever the virus is able to replicate in a person, it can adapt to humans and acquire molecular characteristics that allow it to replicate in the respiratory tract and spread from person to person,” said Lakdawala.

Influenza viruses are classified according to two of the proteins found on their outer envelope: the H proteins, or hemagglutinin, and the N proteins, neuraminidase. CDC testing has confirmed that this third person carries a flu virus with an H5 protein, and the agency will do further sequencing to determine if the N part of the virus is N1, as suspected. He hopes to have these results in the coming days.

The CDC confirmed Wednesday evening that the person had an infection with the H5 influenza virus and forwarded the results to the Michigan Department of Health and Human Services.

The U.S. Department of Health and Human Services announced last week that it was moving forward with a plan to repackage 4.8 million doses of an H5N1 vaccine stored in bulk in the Strategic National Stockpile . Bulk supplies would be placed in multidose vials so they could be more easily distributed and administered.

Officials said Thursday that before the vaccine is administered, it would have to go through certain regulatory steps. They also said there are currently no plans to offer or recommend the doses to any specific group of people.

The fill-and-finish process to repackage the vaccines will take at least a few months, officials said during the press briefing.

In the meantime, the Michigan Department of Health advises people who work on poultry or dairy farms to get a seasonal flu vaccine.

“This will not prevent infection with avian flu viruses, but it may reduce the risk of co-infection with avian flu and influenza viruses,” the department said.