A health staff member prepares a COVID-19 test at the Histopath Diagnostic Specialists pre-departure area at the airport.
The Omicron variant has some strange quirks. It does not resemble Delta, the dominant strain.
Scientists are wondering if it came from humans or animals.
One of the most promising theories is that Omicron emerged from a person with an illness.
Omicron looks odd to scientists who study coronaviruses.
The variant has spread to nearly 30 countries since it was first detected in Botswana. Scientists are trying to figure out how many of the mutations could make Omicron more transmissible then Delta, which could make vaccines less effective, or lead to more severe disease. The answers are pending.
Omicron is not like the common coronaviruses like Alpha or Delta, and many of its strange mutations have not been seen in other versions before. Scientists think that Omicron's closest ancestors were in the mid-2020s.
Andrew Read, who studies the evolution of infectious diseases at Pennsylvania State University, told Insider that it's not the son or daughter of Delta. It branched off earlier from the humans. So where is that water source? Was it a population of people or a group of animals?
The answer is being debated by scientists.
One of the most promising theories is that Omicron came from a person with an HIV infection. People with weakened immune systems are more likely to be a cause of the disease.
Charity Dean, a former official at the California Department of Public Health, told Insider that the theory may explain why Omicron has such a wacko combination of genes.
She said that it was more likely that this was the result of ongoing evolution inside a single host.
Some scientists aren't sure if Omicron developed in an animal. According to a professor at a medical school, Omicron carries several key genes that could have helped the coronaviruses.
The professor of emerging infectious diseases at the London School of Hygiene and Tropical Medicine told Insider that it could be that the virus moved into a wild animal population and then we didn't see it for a while and it came back. We don't have a lot of evidence of that.
The coronaviruses are likely to have evolved in people who are immunocompromised.
A health worker tests a migrant from Haiti for HIV and syphilis in Mexico.
There are more than two dozen brand new Omicron mutations. Scientists say that Omicron likely evolved in an immune compromised host and needs plenty of opportunities to replicate to develop that many mutations.
We don't know how long an animal's infections can last, whereas we know that humans can have chronic infections.
A case study published in the New England Journal of Medicine in 2020 shows that the coronaviruses can persist for five months in a man with antiphospholipid syndrome. It developed a number of key changes in other variants of concern.
The Alpha variant is thought to have developed in a person with an immune deficiency.
Omicron reminds me of how the Alpha variant came about in the UK. "That's why people have thought about it being a single patient."
The variant's early origin could be explained by the animal theory.
A mammal travels along the water's edge in a South Carolina salt marsh.
Scientists say it's possible for the coronaviruses to cause chronic illness. The white-tailed deer outbreak last winter and the Dutch mink farms outbreak in June 2020 may be evidence of that.
"I don't see why the virus would be easier in an animal than in a human," he said. We were worried about the variant that got passed through the outbreak of the mink, but they didn't prove to be any more beneficial than the current strains.
The first Omicron case was detected on November 9, when the variant's lineage dates back to last year. It would have been difficult to spot Omicron in animals.
"We're not embarrassed about the recent increase in the amount of data that's being collected on us," Read said. The animals are far away from the cameras.
It's probably too late to find a patient.
A passenger from a flight from South Africa is tested for COVID-19 at Amsterdam Schiphol airport on December 2, 2021.
Omicron's origin may never be known by scientists.
If we found the Omicron variant in a wildlife population, that would be a smoking gun. He said that the continued spread of the variant increases the chances that it will reach animal species eventually. There is a small window to see if animals were the original hosts.
Scientists should not do too much sampling for the variant in wild animals since our interactions with them increase the odds of new pathogens emerging.
"I don't want people chasing bats because we might cause more trouble than we're trying to fix," he said.
It would be difficult to find an original human host for the variant.
"If we found a patient with Omicron, we wouldn't know if they were patient zero or not," Read said.
Scientists are left with no information to make their best guesses.
Read said that his money was on the person who was immunocompromised.
Business Insider has an original article.
