Is bird flu in cattle here to stay?

As of Tuesday, data from the academic research organization WastewaterSCAN show that levels of H5 influenza have been rising in wastewater samples from a facility in Boise, Idaho.

Asked about whether the region’s health department was investigating, or if there was any idea where the H5 was coming from, Surabhi Malesha, communicable disease program manager at Central District Health in Idaho, said there was no way to know if the H5 signal was from H5N1 or another influenza subtype.

She said testing for H5 in wastewater had only recently started and therefore “there is no way to compare this data from last year or the year before, and so we don’t know what a baseline detection of H5 looks like.”

“Maybe we see H5 detections like this on a regular basis, and it is not of public health significance or importance. ... How do we define normalcy when we have nothing to compare the data to?”

She said the findings were “not a public health concern” and her agency and the state “do not need to really investigate into this, because this could be H5N1, or could be any other H5 strains, and it really does not affect the public in general.”

Dennis Nash, distinguished professor of epidemiology and executive director of City University of New York’s Institute for Implementation Science in Population Health, said that given the current situation, the wastewater sample should be considered H5N1 “until proven otherwise. The only other H5 we know about is H5N2. And a man in Mexico City just died from that.”

Nash said health officials should be trying to determine the source of the virus found in the wastewater: a nearby dairy herd, a milk processing site or raw milk that was dumped down the drain.

Idaho has reported 27 infected herds, although according to Malesha, none has been reported in the Central District.

“You want to do everything you can to prevent these types of viruses from emerging, because once they do, we don’t have a whole lot of control over them,” Topham said. “Because when the horse is out of the barn, it’s gone. So I think the question is, what do we need to do to keep this in check?”