Individual has been treated, recovered; no ongoing transmissions
The migration of wild birds, believed to be carriers of the Avian Influenza virus, is ramping up in Missouri and across the nation.
On Sept. 6, the Centers for Disease Control (CDC) confirmed its first case of human avian influenza (H5) in a Missouri resident.
Test results for the sequence are not yet complete.
“Identification of the neuraminidase (the “N”) in the patient specimen is pending further sequencing, and attempts to sequence the genome of the virus also are underway at CDC,” a CDC report stated.
The case is the first in a human where no apparent exposure to a sick animal has been identified. An investigation by the Missouri Department of Health and Senior Services (MDHSS) is ongoing.
Missouri DHSS reports that the patient, who was hospitalized, had underlying medical conditions, was treated with influenza antiviral medications, subsequently discharged, and has recovered. No ongoing transmission among close contacts or otherwise has been identified.
This is the 14th human case of H5 reported in the United States during 2024 and the first case of H5 without a known occupational exposure to sick or infected animals. H5 outbreaks in cattle have not been reported in Missouri, but outbreaks of H5 have been reported in commercial and backyard poultry flocks in 2024. H5N1 bird flu has been detected in wild birds in that state in the past.
“The results of this investigation will be particularly important in light of the current lack of an obvious animal exposure,” the CDC said. “It is important to note that, while rare, there have been novel influenza A cases where an animal source cannot be identified.”
According to the CDC, the main concern is that no onward transmission is occurring.
“Findings from the ongoing investigation will inform whether guidance changes are needed,” the agency said.
Based on available data, CDC’s current assessment is that the risk to the general public from H5N1 remains low. CDC’s recommendations related to H5 virus have not changed at this time. As always, circumstances may change quickly as more information is learned.
Since April 2024, 13 human cases of avian influenza A(H5) virus infection have been reported in the United States. Four of these cases were associated with exposure to sick dairy cows and nine were associated with exposure to avian influenza A(H5N1) virus-infected poultry.
On the animal health side, the United States Department of Agriculture (USDA) reports that 197 dairy cow herds in 14 U.S. states have confirmed cases of avian influenza A(H5N1). That number continues to grow, says the USDA. Although no avian flu cases have been reported in Missouri herds, adjacent states -Iowa, Kansas and Oklahoma – have reported cases.
The USDA reports that since April 2024, there have been A(H5) detections in 35 commercial poultry flocks and 21 backyard flocks, with a total of 18.68 million birds affected.
An environmental assessment published by the Environmental Protection Agency (EPA) in December 2023 indicates that land-applied meat-processing sludge can be a vector for the virus.
The Missouri Department of Natural Resources is poised to approve over 150 permits for the land-application of meat-processing sludge and human biosolids in southwest Missouri, primarily to acreage in Barry County.
