SCOTT SIMON, HOST:
When health officials reported last week that someone in Missouri tested positive for bird flu, it raised the question, how did that person get infected? Unlike the 13 other human cases of H5 bird flu reported this year, that individual had no obvious connection to infected animals. NPR's Pien Huang takes on that mystery.
PIEN HUANG, BYLINE: On August 22, a patient was hospitalized in Missouri. At a media briefing on Thursday, Dr. Nirav Shah, deputy director at the Centers for Disease Control and Prevention, says they had significant underlying medical conditions.
(SOUNDBITE OF ARCHIVED RECORDING)
NIRAV SHAH: The individual presented with acute symptoms of chest pain, nausea, vomiting, diarrhea and weakness and was hospitalized for reasons related to those underlying medical conditions.
HUANG: The patient took some antivirals, got better, went home. And then a sample from the patient tested positive for an unusual type of flu - H5. Shah says public health officials suspect that it's connected to the current outbreak of H5N1 in birds and dairy cows. But unlike the other cases this year, this person didn't work on a farm.
(SOUNDBITE OF ARCHIVED RECORDING)
SHAH: Did they visit a farm, a fair or a zoo or have any other potential exposure to animals? Were they in contact with anyone who was sick? Did they consume any sort of raw dairy products?
HUANG: The answer so far is no.
(SOUNDBITE OF ARCHIVED RECORDING)
SHAH: Thus far, epidemiologists have not found a clear source of exposure.
HUANG: Researchers hope that testing a patient sample with the virus might give more clues. Jacco Boon is a virologist at Washington University in St. Louis.
JACCO BOON: We hope that through identifying the genetic sequence of this virus, that we can get closer to understanding what the source of this infection may have been.
HUANG: But CDC says there may not be enough virus in the sample to fully sequence it. Dr. Jeanne Marrazzo with the National Institutes of Health says it seems unlikely that this person in Missouri caught the virus from another human or passed it on.
JEANNE MARRAZZO: There is, at this time, no evidence to suggest human-to-human transmission. But that is, of course, our worst fear because once you go there, then obviously all bets are off.
HUANG: She spoke at a recent meeting of an NIH advisory panel. The previous human cases have involved close contact with infected animals or the virus in their secretions. The risk to the general public is considered low. Still, researchers of pandemic threats are quite concerned. Seema Lakdawala studies how flu spreads at Emory University.
SEEMA LAKDAWALA: I think that this is looking pretty bad. My biggest concern right now is that the USDA does not have a handle on how widespread this outbreak is.
HUANG: Lakdawala says there's no universal testing of dairy farms across the country. According to USDA, the rate that new dairy herds are getting infected seems to have slowed considerably. Still, the virus continues to spread. Last month, California became the 14th state to find bird flu in dairy cows. Lakdawala says that heightens the risk to humans.
LAKDAWALA: And the more cows are infected, the more virus is in their milk and then in a byproduct of our milk products that we consume.
HUANG: Products that have been pasteurized or heated to kill pathogens are considered safe to eat and drink, but more sick cows puts more farmworkers at risk, more veterinarians, more domestic and wild animals that might drink from lagoons of disposed infected milk. All this gives the virus more opportunities to make more copies of itself and to boost its standing as the next pandemic threat.
Pien Huang, NPR News.
SIMON: And on Friday, the CDC disclosed that a person living with the Missouri resident became ill on the same day, but they say it's likely the two people were exposed to the same source rather than infecting one another. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
