The Centers for Disease Control and Prevention (CDC) said on Thursday that it has not been able to identify a “clear source” of exposure in Missouri’s first human avian influenza case.
The patient, who had underlying medical conditions, was hospitalized on Aug. 22. Nirav Shah, principal deputy director at the CDC, said the patient experienced chest pain, nausea, vomiting, and diarrhea.
Shah said during a call with reporters that the patient was not “severely ill” and did not require intensive care. The patient was treated with antiviral medications and has since recovered.
According to Shah, public health officials have tried to determine whether the patient visited a farm or other locations with potential animal exposure, but they found no clear source of exposure.
The patient also has not reported consuming any raw milk or dairy products. Shah said the investigation into the source of exposure is still ongoing, but added that evidence points to this being “a one-off case.”
Shah said there has been no sign of unusual influenza activity in the area in which the patient resides, nor has there been an increase in emergency room visits or laboratory detection of human influenza cases in Missouri.
The CDC has begun characterizing the virus through genetic sequencing, but due to the patient’s “extremely low” concentration of viral genetic material, officials were unable to generate a full genome for analysis, he said.
“That’s why we’re just calling this H5 at this juncture,” Shah said.
“The data that we do have and that have been generated thus far show an H5 virus that is closely related to the H5 virus circulating among dairy cows,” he added.
This case marked the 14th human bird flu infection reported in the United States this year. The CDC maintained that the risk to the general public from avian flu remains low.
Missouri has not reported any H5 infections in dairy cattle, although there have been some cases reported in commercial poultry or backyard flocks and wild birds, according to the CDC.
