According to new sequencing data from Centers for Disease Control and Prevention, at least two variants of monkeypox are currently circulating in the United States.
Although 22 cases have not been sequenced by the CDC, two cases were genetically identical to a 2021 infected man from Texas who had traveled to Nigeria. Both were found in two people who traveled to Africa recently — a Florida man and a Virginia woman.
The remaining U.S. sequenced cases are similar to the genetic codes from Europe and a 2021 infected Maryland resident who went to Nigeria.
Jennifer McQuiston (deputy director, CDC’s High Consequence Pathogens and Pathology division), said that although they are similar, their genetic analysis proves they’re not related to one another. She spoke about the variants during a Friday press conference.
McQuiston and other experts in disease said that this information suggests that the U.S. cases are the result of two outbreaks rather than one. This complicates our understanding of their origins.
McQuiston stated that it is likely that monkeypox virus has spread to Nigerians in at least two instances over the past few years. The virus could have also been transmitted to humans through close contact with the animal that keeps it.
This raises questions about the longevity of monkeypox outside Africa, and how transmissible it is.
Anne Rimoin, an epidemiology professor from UCLA Fielding School of Public Health said, “This is almost like turning on a new TV series. We don’t know which episode we’re on.” “We are just beginning to understand some of the origin story.”
Global.health, which collects data on infectious diseases, reports that nearly 900 monkeypox cases were reported in Africa since May. The largest outbreak in the Western Hemisphere in 2003 was 47 U.S. cases. These people were infected with pet prairie dogs. No human-to-human transmission has been documented.
Experts are looking into various explanations for the rapid growth of current outbreaks. One possibility is that the virus spread quickly due to a few factors. Monkeypox could have evolved to be more effective at transmitting from human to human. The virus could have been undiscovered for some time.
Tedros Adhanom Ghebreyesus, WHO Director General, suggested this week that the third option was likely.
Andrew Read, a Pennsylvania State University professor who studies the evolution and spread of infectious diseases, suggested that “we might be seeing [the variants] right now because we are looking so hard.”
McQuiston stated that a large-scale previous outbreak would not be missed.
She said, “It is possible that there could be monkeypox cases within the United States that went unnoticed previously,”
Read questioned the notion that the virus is becoming more transmissible. He pointed out that monkeypox appears to be spreading faster among close friends than scientists previously observed.
Monkeypox, a DNA virus that does not mutate at the same rate as other RNA viruses such as the coronavirus, is called Monkeypox. Read noted that DNA viruses are known for having long genomes. Moneypox’s genome, however, is seven times bigger than the coronavirus.
He said, “The fact it has lots of genes means that all kinds of things can happen.”
Columbia University epidemiology professor Stephen Morse said that it is worth investigating whether one variant spreads faster than the other.
He said, “If a specific variant was capable of more cycles human-to-human transmissions, that would be significant to know.”
Rimoin stated that it was too early to determine if monkeypox evolved in any meaningful manner.
She said that just because the outbreak is large, it doesn’t necessarily mean that virus itself has changed.
Experts believe that the U.S. epidemic can be contained. However, they are concerned about continued transmission.
Read stated that “I worry a lot about it becoming very common in humans.” “The possibility that it becomes more common and more easily transmissible over time, like we had with Covid would be very, very unfortunate.”
Rimoin stated that the more cases are spread, the more difficult it is to contain them. However, Rimoin noted that this does not mean that it is impossible.
Experts can stop monkeypox transmission by testing people who have symptoms and isolating infected patients.
