Given the rapid spread of bird flu in California dairies, health officials at the moment are conducting weekly testing on all dairy farms within the state, expanding their initial efforts given latest evidence that some infections are going undetected and there could also be unknown routes of transmission.
But farm employees, unlike employees on poultry and fur farms in Finland, won’t be vaccinated. Why not?
On Friday, health experts provided information concerning the latest findings concerning the virus.
Q: The federal government has vaccines in its strategic national stockpile that protect against H5N1, the virus that causes bird flu. Why don't we use them?
A: The virus doesn’t spread between people, said Erica Pan, a California state epidemiologist. Cases in California have been mild. And antiviral oral medications work against the virus. “We remain proactive when things change,” she said.
Q: Will this yr's flu vaccines help protect us?
A: There will not be enough information to know whether our existing flu vaccines would protect us, said microbiologist Dr. Bobbi Pritt from the College of American Pathologists. It's unlikely; This yr's vaccine is designed to dam the 2 circulating subtypes of influenza A and the one circulating subtype of influenza B – not bird flu.
Scientists are developing a vaccine for cattle that may help reduce the danger of exposure, Dr. Ben Bradley, also from the College of American Pathologists. But it should be unimaginable to vaccinate wild birds.
Q: There are 36 confirmed human cases of bird flu in California. But could some people be asymptomatic and due to this fact missed?
A: So far, the state is just specializing in cases involving individuals with known illness. Wastewater surveillance is one method to monitor the virus – nevertheless it primarily captures viruses shed by flying birds. There can be increasing evidence that wastewater comprises fragments of dead viruses from the milk we pour down the drains.
Some people could also be asymptomatic or only mildly unwell, so that they don't hassle going to the doctor, Bradley said. And it’s difficult to detect live viruses in people. That's because nose and throat swabs used to detect COVID don't at all times detect the virus. Most cases in California were discovered through an eye fixed swab.
“California has a very robust public health testing program. Not all states have an equally robust program,” said Dr. Donald Karcher, President of the College of American Pathologists. “So it’s very likely that we’re missing cases in other parts of the country.”
Q: Why does the virus cause severe respiratory illnesses in some people but mild illnesses reminiscent of conjunctivitis in others?
A: There are two tribes, Pritt said. Genotype D1.1, which is present in birds, caused very serious illness in an elderly person in Louisiana and an adolescent in Canada. The B3.13 genotype observed in cows caused mild illness in dairy employees.
“At this point, the B 3.13 strain does not appear to be associated with severe disease, but we need to keep an eye on it,” Pritt said.
The disease may be influenced by the route of infection, Bradley added. Dairy employees can have had a splash of infected milk of their eyes.
Q: Dairies are frustrated because although they’re taking protective measures, they’re still getting infections. What's up?
A: “We don't know. That’s what the research is aimed at,” said state veterinarian Dr. Annette Jones. “It just seems like something else is causing the spread.” Possibly asymptomatic but infected latest cattle are being brought onto farms. Or possibly someone neglected to scrub their shoes before work.
Cows may be asymptomatic for several weeks, she added, and due to this fact could inadvertently transmit disease.
Q: Is bird flu affecting the state's milk supply?
A: Even if a dairy has sick cows and is quarantined, the cattle typically don’t die from the disease. Unlike birds, they get well, Jones said. As soon because the virus isn’t any longer detected, the dairy can resume selling milk.
Q: Are eggs secure?
A: Because chickens show signs of disease and die so quickly, authorities can be certain that eggs from infected flocks don't reach the market, Jones said. In addition, sick chickens don’t are likely to transmit the virus to their eggs.
Q: Why is the disease so different in cattle and birds?
A: The D1.1 strain has been well studied in birds and is taken into account highly contagious. And it’s seasonal, as poultry are infected by migratory waterfowl. This fall, 51 industrial farms and nine backyard herds in 13 counties were affected. It can be very serious. To alleviate their suffering and reduce the danger of spread, herds have to be culled. “It’s basically a death sentence for a poultry flock,” Jones said.
The virus only spread to cows this spring, so we don't yet know much about the way it behaves. So far it will not be seasonal. This B 3.13 strain doesn’t cause as much disease in cows because it does in poultry. Only 1 to 2% of cows die. So the state's response is different and focuses on containment, not euthanasia. So far, 679 out of 984 dairies have been quarantined. Of these, 66 are virus-free again.
For the primary time, officials discovered the cow strain in poultry herds. You don't know why. Maybe rodents sneak from one farm to a different.
Q: At what point should we worry about an outbreak amongst humans?
A: Most concerning are the 2 U.S. cases with no clear connection to cows or birds – one in Michigan, one in Oakland, Bradley said. “If we saw more of these cases,” he said, “that would worry me.”
There can be concern because blood tests show antibodies to previous exposure, suggesting there are asymptomatic cases and the actual variety of infections is higher, he said.
Another bad sign could be a spike in flu cases in the summertime outside of the normal flu season, indicating spread.
“If we see more human adaptation, that will raise alarm bells,” Bradley said. “It says, 'This is something we need to test for more aggressively.'”
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