Federal officials say there’s no sign bird flu is spreading
WASHINGTON — Public health officials are still trying to determine how a Missouri resident contracted bird flu without any contact with an infected animal, but they said Thursday there was no evidence of human-to-human transmission. Occurs in small enclaves or on a wider scale.
The Missouri case marks the 14th person this year to be infected with highly pathogenic avian influenza (H5N1), an ongoing outbreak among poultry and dairy cows, but marks the first time a person without exposure to the animals has been diagnosed with the disease. Virus.
Nirav Shah, principal deputy director of the U.S. Centers for Disease Control and Prevention, said in an interview with reporters, “The evidence shows that this is a one-time case, and this does happen with new influenza.”
“So far, we have not seen any evidence that this individual lives in an area with unusual levels of flu activity,” Shah said during the hour-long briefing. “There has been no increase in emergency room visits for the flu in Missouri. , and there has been no increase in laboratory testing of influenza cases.”
He said the state’s public health laboratory is subtyping all positive influenza A cases following the Centers for Disease Control and Prevention’s recommendation to continue detailed surveillance this spring.
He said the practice is how doctors and public health officials identify this case and may be how they diagnose future rises in an “overwhelming” number of states taking additional staging steps.
have several types Influenza viruses are classified by the letters A, B, C, and D. According to the CDC, there are at least 130 subtype combinations of influenza A.
“So the bottom line is, our influenza surveillance system is designed to find the needle in the haystack,” Shah said. “As this case and others show, it’s working. In this case, we found such a needle, but we don’t know how it got there.
The Missouri patient, who had serious underlying medical conditions, presented to his health care provider with “acute symptoms of chest pain, nausea, vomiting, diarrhea, and weakness,” according to the Centers for Disease Control and Prevention (CDC), and in August He was taken to the hospital on the 22nd. The patient’s identity has not been disclosed due to privacy concerns.
Missouri Department of Health and Senior Services declare Diagnosis on September 4, as did the Centers for Disease Control and Prevention (CDC) in a separate report statement.
Missouri DHSS noted that the patient recovered and was discharged home, while the CDC noted that the state has reported cases of H5N1 in commercial and backyard poultry flocks this year.
The patient had not been exposed to any livestock or poultry and did not indicate on the detailed questionnaire that they had consumed any food that could transmit the virus, such as raw milk.
Shah said by phone that public health officials are technically classifying this as an H5 rather than an H5N1 case because they are working to more fully sequence the virus, although that may not be possible.
The CDC has begun cataloging the genetic sequence of the virus, but because the patient’s viral RNA levels were “extremely low,” the agency may not be able to “generate a complete influenza genome, including neuraminidase or the N portion of the virus,” he said. .
“We are working hard, but ultimately, a complete sequence may not be technically feasible due to the low concentration of viral RNA,” Shah said. “The data we have and the data generated to date show that H5 viruses are closely related to those in dairy cows. closely related (H5N1) viruses.”
He said the CDC is “continuing to look for evidence of genetic changes that may indicate increased likelihood of transmission.” None have been identified yet.
Demit Daskalkakis, director of the CDC’s National Center for Immunization and Respiratory Diseases, said the risk to people from contracting avian influenza remains low.
“We continually evaluate the risk in each case and with each change, and we continue to believe the risk is low,” Daskalakis said. “If a change occurs, we will reassess the risk on an immediate basis.”
Shah said that while the CDC investigation is ongoing, the farther away public health officials get from a case without finding any new diagnoses, the less likely they are.
“We’re beyond the typical 10-day window of transmission,” Shah said. “So as each day goes by, the likelihood of this happening deep underwater is decreasing.”
