As the number of people infected with bird flu rises in the U.S., continued restrictions on testing could pose a problem as these cases emerge.
Commercial labs are now developing tests that will be available by prescription, but the tests will still only be recommended for people in close contact with animals and animal products — even as Missouri’s cases remain a mystery and wild migration birds and extreme heat can increase the overflow. possibilities, officials say.
Blood tests have shown that a second person in Missouri was exposed to bird flu without known contact with animals, officials with the U.S. Centers for Disease Control and Prevention (CDC) told reporters Thursday.
This individual lives in the same household as the patient who tested positive for H5N1 several weeks ago, and both individuals developed symptoms at the same time. The second infection was discovered after the first patient tested positive and officials began serological testing only on symptomatic contacts.
Five health care workers who developed symptoms after caring for the first patient were negative for H5N1 on blood tests, and a sixth health care worker tested negative by a PCR test after developing symptoms, officials said.
That means the two positive Missourians did not appear to spread the virus to healthcare workers. But it’s not clear how any of them got sick in the first place.
Because the two positive people developed symptoms at the same time, health officials believe they were likely exposed to a source at the same time — although it is possible that patients developed symptoms at different times in the course of the disease, especially since one patient developed the symptoms. significant health problems.
Strikingly, the original source of their infection has still not been identified. The patients may have had contact with animals or animal products not found on comprehensive health questionnaires, officials said.
Quest Diagnostics announced Wednesday that its test for H5N1 will soon be available with a prescription from a medical provider, and other commercial labs are also developing tests for the public. But the tests are only recommended for people who have close contact with animals or animal products such as raw meat or milk.
In “the vast majority of situations,” most people with flu symptoms do not need an H5N1-specific test, said Nirav Shah, deputy director at the CDC. “It’s really when there is an epidemiological exposure history suggestive of H5 where the H5 test would be warranted.”
None of the Missouri cases would have been detected with such restrictions. However, the CDC still recommends that states regularly monitor positive influenza A tests for H5N1, which is how the first case was found in Missouri.
The first human cases of H5N1 have also been identified in Washington among workers killing H5-infected poultry. The state now has two confirmed and another five suspected cases of bird flu in humans.
It is not clear why so many people became infected, or whether antiviral medications were provided to workers before they came into contact with the sick birds. These drugs are one of the most effective ways to prevent infections, but they do not appear to be widely rolled out among workers who have very close contact with H5N1-positive animals.
“The uptake of Tamiflu has been strong, but there is still more work we can do,” Shah said. He stressed the importance of using personal protective equipment, such as respirators and goggles, and making changes to the way sick birds are culled.
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“Many of these outbreaks occur in places where conditions are cramped, with poor ventilation, with lots of birds, feathers and flying dust,” Shah said. “Improving this can reduce the risk to employees with confidence.”
That’s a particular concern because the outbreak in Washington may have been spread by migratory birds, he said. It’s now the fall migration season and officials are concerned about new cases emerging mainly among poultry – and the workers who come into close contact with them.
So far, there have been 31 confirmed human cases of bird flu in the U.S., as well as the five suspected cases in Washington and the recently confirmed case in Missouri, which will not be included in the official counts because that exposure was verified on only one case. type of blood test.
None of the new human cases in Missouri, Washington or California were serious or required hospitalization, officials said.
Nearly half – 15 – of the human cases have been detected in California on 13 different dairy farms.
Crystal Heath, a veterinarian, took photos and videos of dead cows with X’s along their udders on a huge farm with H5N1 cases in California’s central valley. The cows were lying on the ground near the road, Heath said, raising concerns about biosecurity and the treatment of potentially sick animals.
Eric Deeble, deputy assistant secretary for marketing and regulatory programs at the U.S. Department of Agriculture, said an investigation into the mortality rates of H5-infected cows in California is underway, and he said several factors could be at play, including excessive heat , management practices, and the density and proximity of the animals.