America’s top bird flu expert says the virus outbreak in cows suggests the virus is one step closer to spreading to humans.
In an interview with Statistical newsDr. Vivien Dugan, who also heads the CDC’s flu division, insisted the risk to the general public was still “low.”
But he admitted that repeated infections in livestock suggested the virus could become endemic in the species, increasing the risk of H5N1 spreading to humans, who have close contact with the animals.
He also warned that officials were having trouble tracking infections because many farmers were not coming forward to get tested.
The map above shows states that have reported bird flu infections in livestock.
Dr. Dugan warned: ‘These viruses change. If this were seeded in cows and became a virus endemic to cows, it would certainly increase the risk to people.
‘And certainly, our pandemic planning [operation] We’ve been thinking a lot about this and trying to be as attentive as possible…
‘[The aim is] Try to understand not only the current risk, but also the future risk so that we are as prepared as possible. But the risk could be quite big.”
He added: “That’s probably why I’m not sleeping much right now.”
Dr. Dugan also warned that the CDC was struggling to track the virus and establish whether it had spread to people in other states.
After a person tested positive for the virus in Texas, it would be normal practice for their close contacts’ blood to be tested for antibodies to the virus, called a serology test, which would indicate whether the virus had spread.
But he said this could not be carried out because farmers in close contact with the case refused to be tested.
A tick indicates foods that tested positive for bird flu, while a cross indicates those that were tested for bird flu but were not found to contain the virus.
It would also be common practice for the CDC to monitor those on farms with infected livestock that were showing symptoms of illness.
But he said that, again, in many cases, health officials “haven’t been as successful” in getting them tested.
The low number of people tested for the disease (25 tested and 100 monitored so far) appears to underline these difficulties.
Dr. Vivien Dugan, director of the CDC’s influenza division.
For comparison, among poultry workers who have been dealing with H5N1 for more than two years, the CDC has tracked more than 8,000 people for symptoms.
He also said that in some cases the agency had trouble accessing states because they had to be invited by local health departments, an invitation that did not always arrive.
“We had a team pretty much in place six weeks ago when this really started to appear on our radar,” he added.
‘But this is not the typical response situation for poultry workers. These are milk producers.
‘Some states have been able to contact workers directly and actively monitor. Others, of course, have not been so successful.’
Scientists are concerned that bird flu will establish itself in a new species because this suggests that it has acquired mutations that allow it to infect and spread among new animals and people.
So far, a total of 36 cattle herds in nine states have tested positive for bird flu, and there are fears the virus could spread through the air after tests detected the pathogen in the lungs of a cow.
The virus has also been found in their milk and in supermarket milk, cottage cheese and sour cream, which could be possible routes of transmission to humans.
But officials say they pose no risk because the virus they contain “is not live.” The products are treated with pasteurization, where they are heated and cooled rapidly to kill any microbes they contain.
However, tests on ground beef, infant formula and powdered milk have found no traces of the virus.
U.S. officials have repeatedly been criticized for not sharing data publicly, including on whether pasteurized milk is still safe to drink.
Some scientists have said they will no longer consume milk until the FDA shares more data, although they called the recent evidence “reassuring.”