6 people tested after exposure to Missouri bird flu patient. What we do & don’t know
.jpg "Bird flu samples are tested in a New York lab in 2022. In 2024, the bird flu has been spreading between poultry, cattle and now humans. But health officials still say human-to-human infection is unlikely.")
Seven people who came into contact with Missouri’s avian flu patient later showed symptoms of a respiratory illness, the U.S. Centers for Disease Control and Prevention announced Friday, Sept. 27.
Officials are testing blood samples from five health care workers who were exposed to the patient and one household contact who became sick on the same day as the patient, but was not tested at the time. These blood tests will look for H5N1 antibodies, which would indicate a recent infection of the bird flu.
A sixth health care worker developed symptoms shortly after exposure to the sick patient, but tested negative for the flu. This indicates that their symptoms were likely from a different respiratory virus, such as COVID-19.
The CDC was quick to note that, as of Friday, Sept. 27, none of the five other people have gotten back positive antibody results for the avian flu, which made the unexpected jump from birds to mammals earlier in 2024.
“To date, only one case of influenza A(H5N1) has been detected in Missouri,” the agency wrote, using the scientific name for the avian flu. “No contacts of that case have tested positive for influenza A(H5N1).”
Here’s what we know about the ongoing investigation.
When will we find out whether additional Missourians caught bird flu?
The CDC expects to release the results of the blood antibody tests “in the coming weeks,” spokesperson Jasmine Reed said via email. Local experts said they haven’t heard anything more specific.
The test itself only takes around 24 hours, said Dr. Dana Hawkinson, the medical director of infection prevention and control at the University of Kansas Health System.
“It’s probably more about transit time at this point,” he said.
That’s where delays have arisen, according to Lisa Cox, a spokesperson for the Missouri Department of Health and Senior Services.
“Shipment of specimens to CDC Atlanta from health care workers (was) delayed late last week due to the hurricane and the need to ensure safe receipt,” she said. “We don’t have a timeline from (the) CDC at this time.”
Still, at least two of the blood samples were collected during the week of Sept. 16. Hurricane Helene didn’t make landfall until the end of the following week, according to the Associated Press. It’s possible that the CDC already knows the results of some or all of the tests but hasn’t yet announced them publicly.
“There very well could be results there — maybe they’re waiting to collect everything and then present it all at once,” Hawkinson said. “But what we’re talking about would all be speculation at this point.”
How and when did the bird flu patient’s contacts develop symptoms?
Missouri’s first human case of the bird flu was announced Sept. 9, and it struck experts as unusual because the patient reported no recent exposure to livestock or other animals. The 13 other confirmed human cases in the U.S. during the current outbreak have all been among livestock workers or their family members.
On Friday, Sept. 20, the CDC shared that one household contact became sick on the same day as the Missouri patient. Experts say this timeframe makes a human-to-human transmission within the household unlikely.
“The simultaneous development of symptoms in two people does not support person-to-person spread but suggests a common exposure,” the CDC wrote.
The identity and location of the Missouri patient are being kept private by health officials.
Six health care workers also exhibited respiratory virus symptoms after coming into contact with the patient, the CDC reported. One tested negative for influenza at the time, and the other five did not get tested while they were sick. Instead, their blood is now being tested for avian flu antibodies.
Can bird flu be transmitted between humans?
Scientists already believe that human-to-human transmission of the avian flu is technically possible. But the virus doesn’t spread easily between humans, and no further cases have been identified in Missouri since late August.
That means that even if the health care workers’ antibody tests come back positive, it won’t mean that they went on to infect other people with the avian flu.
“We know that it has historically been very hard to transmit H5N1 from one person to another, so I think a cluster of six or eight people having it, I would say, is unlikely,” Hawkinson said.
Reed from the CDC added that experts are closely monitoring the virus for any mutations that would make it easier to transmit between humans.
“There have been no changes in the virus known to enhance its ability to infect or spread between people,” she said in an email. “More than 10 days (i.e., more than two incubation periods) have passed since either the case or any of their contacts reported symptoms with no sign of ongoing spread.”
Hawkinson added that respiratory virus symptoms, like the ones the seven additional people experienced, aren’t consistent with past reports of the avian flu in humans. Missouri was also experiencing a surge of COVID-19 around the time they occurred.
“The other people who have been positive for H5N1 — the dairy workers, the poultry workers — I believe most all of them had presented with symptoms of conjunctivitis, so red teary eyes,” he said. “Very few would have had respiratory symptoms. And it sounds like all of these (Missouri) patients had respiratory symptoms as well.”
Hawkinson recommended taking common-sense measures like hand-washing to curb the transmission of all respiratory viruses. He also suggested wearing basic personal protective equipment, like gloves and a face mask, when interacting with backyard chickens or other livestock animals.
“Just having one (positive) test, I don’t think that should necessarily sound alarm bells,” he said. “I think we do need to continue to be vigilant, and this is why we have to task our public health systems with doing these investigations.”
Do you have more questions about the avian flu in Missouri or Kansas? Ask the Service Journalism team at kcq@kcstar.com.
This story was originally published September 30, 2024 at 5:27 PM.
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