by Headlines are flying after the Department of Agriculture confirmed that the H5N1 bird flu virus has infected dairy cows across the country. Tests have detected the virus among cattle in nine states, primarily in Texas and New Mexico, and most recently in Colorado, Nirav Shah, principal deputy director at the Centers for Disease Control and Prevention, said at the event 1 May at the Foreign Affairs Council. Relationship.
Other animals have been infected with H5N1, including at least one in Texas. But what scientists fear most is if the virus would spread effectively from person to person. That did not happen and may not have happened. Shah said the CDC considers the H5N1 outbreak to be a “low risk to the general public at this time.”
Viruses evolve and outbreaks can change rapidly. “As with any major outbreak, this is moving at the speed of a bullet train,” Shah said. “What we’re going to talk about is a picture of a fast moving train.” What it means is that what is known about H5N1 bird flu today will inevitably change.
With that in mind, KFF Health News explains what you need to know now.
Who gets bird flu?
Mainly birds. In recent years, however, the H5N1 bird flu virus has been jumping from birds to mammals around the world. The growing list of more than 50 species includes seals, goats, skunks, cats, and wild bush dogs at UK zoos. At least 24,000 sea lions died in outbreaks of H5N1 bird flu in South America last year.
What makes the current outbreak in cattle unusual is that it is spreading rapidly from cow to cow, but the other cases – apart from the sea lion infections – appear to be limited. Researchers know this because the genetic sequences of the H5N1 viruses pulled from cattle this year were almost identical.
The cattle outbreak is also a matter of concern because the country has been caught off guard. Researchers examining the genome of the virus suggest that it spilled from birds into cows late last year in Texas, and has since spread among many more cows than tested.
“Our analyzes show that this has been circulating in cows for four months or so, right under our noses,” said Michael Worobey, an evolutionary biologist at the University of Arizona in Tucson.
Is this the start of the next pandemic?
Still. But it’s worth thinking about because a bird flu pandemic would be a nightmare. More than half of people infected by older strains of H5N1 bird flu viruses from 2003 to 2016 died. Even if death rates are not as severe as the H5N1 strain currently circulating in cattle, the consequences could sicken many people and leave hospitals overwhelmed to deal with other medical emergencies.
Although at least one person has been infected with H5N1 this year, the virus may not lead to a pandemic in its current state. To reach that terrifying status, a pathogen must sicken many people on multiple continents. And to do that, the H5N1 virus would have to infect tons of people. That will not happen when the virus is being released from farm animals to humans from time to time. Rather, the virus must mutate to spread from person to person, like the seasonal flu, as a respiratory infection that is primarily transmitted through the air as people cough, sneeze and breathe. As we learned in the depths of Covid-19, it is difficult to stop airborne viruses.
That hasn’t happened yet. However, H5N1 viruses now have a lot of room to evolve as they replicate within thousands of cows. Like all viruses, they mutate as they replicate, and mutations that improve the virus’ survival are passed on to the next generation. And because cows are mammals, the viruses may thrive within cells that are closer to us than the birds’.
The evolution of a pandemic-ready bird flu virus could be aided by a type of superpower that many viruses possess. That is, they sometimes exchange their genes with other strains in a process called reassortment. In a study published in 2009, Worobey and other researchers traced the origin of the H1N1 “swine flu” pandemic to events where different viruses that caused swine flu, bird flu, and human flu mixed and matched. their genes within pigs they were at the same time. by infection. Pigs don’t have to be involved this time, Worobey warned.
What happens if someone drinks milk contaminated with a virus?
Cow’s milk, as well as powdered milk and infant formula, sold in stores is considered safe because the law requires all milk sold commercially to be pasteurized. This process of heating milk at high temperatures kills bacteria, viruses and other harmful organisms. Tests have identified fragments of H5N1 viruses in milk from grocery stores but confirm that the virus bits are dead and therefore harmless.
However, H5N1 viruses have been shown to live in unpasteurized “raw” milk, which is why the FDA and other health authorities strongly advise people not to drink it. Doing so could make a person seriously ill or worse. But even then, it is unlikely to start a pandemic because the virus – in its current form – does not spread as efficiently from person to person as seasonal flu does.
What should be done?
A lot! Due to a lack of surveillance, the US Department of Agriculture and other agencies allowed the H5N1 bird flu to spread under the radar in cattle. To handle the situation, the USDA recently mandated that all lactating dairy cattle be tested before being moved to other states, and that the results of the tests be reported.
But just as Covid tests for international travelers in early 2020 allowed the coronavirus to spread undetected, many cases would only be tested on cows that move across state lines.
Such limited testing will not reveal how the virus is spreading among cattle – information that is desperately needed for farmers to stop it. One of the main hypotheses is that viruses are being transferred from one cow to another through the machines used to milk them.
To boost testing, Fred Gingrich, executive director of a nonprofit organization for farm veterinarians, the American Association of Livestock Practitioners, said the government should offer funds to cattle farmers who report cases so they have an incentive to test. But to do so, he said, reporting only causes reputational damage on top of financial loss.
“These outbreaks have a significant economic impact,” Gingrich said. “Farmers lose about 20% of their milk production in an outbreak because animals stop eating, they produce less milk, and some of that milk is abnormal and then cannot be sold.”
The government has made the H5N1 tests free to farmers, Gingrich said, but has not budgeted money for veterinarians who must sample the cows, carry samples and file paperwork. “The tests are the least expensive part,” he said.
If testing on farms remains elusive, evolutionary virologists can still learn a lot by analyzing genomic sequences from H5N1 viruses sampled from cattle. The differences between sequences tell a story about where and when the current outbreak started, the path it travels, and whether the viruses are acquiring mutations that pose a threat to humans. But this critical research has been hampered by the USDA’s slow and incomplete posting of genetic data, Worobey said.
The government should also help poultry farmers prevent H5N1 outbreaks since those kill many birds and pose an ongoing threat, said Maurice Pitesky, an avian disease specialist at the University of California-Davis.
Waterfowl such as ducks and geese are the usual sources of outbreaks on poultry farms, and researchers can detect their proximity using remote sensing and other technologies. Farmers can focus their attention on zones of potential consequences by giving them zero. This may mean routine surveillance to detect early signs of infection in poultry, using water cannons to disperse migrating flocks, relocating farm animals, or temporarily bringing them into barns. “We should be spending on prevention,” Pitesky said.
What is the risk to people of getting H5N1 bird flu?
No one really knows. Only one person was diagnosed with the disease in Texas this year, in April. This person worked closely with dairy cows, and had a mild case of an eye infection. The CDC found out about them because of its surveillance process. Clinics are supposed to notify state health departments when they diagnose farm workers with the flu, generally using tests that detect flu viruses. State health departments then confirm the test, and if it’s positive, they send a person’s sample to a CDC lab, where it’s checked for the H5N1 virus, specifically. “So far we’ve had 23,” Shah said, “all but one of which have been negative.”
State health department officials are also monitoring about 150 people, he said, who have spent time around cattle. They are checking in with these farm workers through phone calls, text messages, or in-person visits to see if they develop symptoms. And if that happens, they will be tested.
Another way to evaluate farm workers is to check their blood for antibodies against the H5N1 bird flu virus; a positive result would indicate that they may have been unknowingly infected. But Shah said health officials are not doing this work yet.
“It’s not a good sign that we’re four months in and we haven’t done this,” Worobey said. “I’m not really worried about a pandemic right now, but we should start acting like we don’t want it to happen.”
This article was originally published on NBCNews.com
