In 2003, 47 people in six Midwestern states contracted monkeypox from pet prairie dogs kept with rodents imported from Ghana, Africa.

Already infecting more than 14,100 people in the United States and more than 41,000 worldwide, today’s outbreak is spreading primarily through close contact between gay and bisexual men. But scientists reported the first presumed dog-to-human transmission in France this month, prompting U.S. and global health officials to step up warnings to prevent the virus from spreading to other pets and animals. I urged you to

This recommendation allows monkeypox to spill into wildlife and rodent populations as human outbreaks spread, allowing the virus to pass back and forth between humans and animals, and the way the virus has historically circulated. stems from concerns that it could give a permanent foothold in a country that does not have .

Before this year’s global pandemic, monkeypox spread mainly in remote areas of western and central Africa, where people contracted the virus after being exposed to infected animals. The contained 2003 outbreak was the first documented case of human infection with the virus outside of Africa.

The current global epidemic is dramatically different from past transmission patterns. Monkeypox is now spread almost entirely through close physical contact between people in major urban areas in the United States, European countries, and Brazil.

However, the first presumed case of animal infection in the current outbreak was reported in France this month. A Parisian couple contracted monkeypox and their pet dog tested positive for the virus after they shared a bed.

WHO officials say a single incident of a pet contracting the virus is not surprising and not a cause for great concern, but it does raise awareness that other species can be infected. If you don’t know, you run the risk of monkeypox starting to circulate in animals.

If monkeypox becomes established in animal populations outside Africa, the virus will have a greater chance of mutating, risking increased transmissibility and severity. Animals can then transmit the virus to humans, increasing the risk of future outbreaks.

Dr Mike Ryan, director of the WHO’s Health Emergency Program, said at a press conference in Geneva last week, “What we don’t want is for diseases to move from one species to another and then to that species. “It is through the process of one animal influencing another that we see the rapid evolution of viruses.”

The Centers for Disease Control and Prevention has not received any reports of pets contracting monkeypox in the United States, said agency spokesperson Kristen Nordland. It can spread from animals to humans.

“Although we don’t yet know which species of animals can be infected with monkeypox, we should assume that any mammal can be infected with the monkeypox virus,” Nordlund said. “We don’t know if reptiles, amphibians or birds can get monkeypox, but it’s unlikely because we know these animals aren’t infected with the same family of viruses as monkeypox. ”

Dr. Rosamund Lewis, WHO’s principal monkeypox expert, said that potentially contaminated waste should be disposed of properly to avoid the risk of infection by rodents and other animals when they rummage through the litter. He said it was important to dispose of it.

“These have been hypothetical risks all along, but people need to have information about how to protect their pets and how to manage their waste so that animals are not exposed to the monkeypox virus in general. I think it’s as important as it is,” Lewis said.

Ryan said vigilance is important, but animals and pets do not pose a danger to people at this time.

“It’s important not to allow these viruses to colonize other animal populations,” Ryan said. .”

Scientists have done some research in Africa, where monkeypox is historically endemic, but lack of funding has limited the research. And we don’t know how many animal species there are that can infect humans.

In the last 40 years, scientists have isolated monkeypox from wild animals only a few times in Africa. They included rope squirrels, target rats, giant bag rats from the Democratic Republic of the Congo, and his two species of monkeys from Ivory Coast. Rodents, not monkeys, are thought to be the African host animal population, but the exact animal host is unknown.

Public health officials do not know whether animals such as raccoons, rats, and rats in close proximity to people in U.S. urban environments can pick up and transmit the virus. Some species of mice and rats can be infected with monkeypox, but not all species are susceptible, according to the CDC.

“We know this is a virus that is transmitted from rodents in West Africa,” said Dr. Peter Hotez, an infectious disease expert at Baylor College of Medicine in Texas. “Rats and other rodents in an urban environment could mean getting a foothold there and becoming permanent fixtures as well – we don’t want that to happen,” he said. Told.

CDC recommends that people with monkeypox avoid contact with animals (pets, livestock, farm animals, wild animals). If a pet becomes ill within 21 days of contact with a monkeypox patient, the animal should be seen by a veterinarian.

According to the CDC, monkeypox-contaminated waste should be placed in dedicated lined bins and should not be left outdoors, as it can expose wildlife to the virus.

In the 2003 outbreak, the CDC was able to quickly administer the vaccine and isolate patients before the virus spread further. There have been no cases of human-to-human transmission of monkeypox. The CDC has since banned the importation of rodents from Africa.

Containing the 2003 outbreak required 10,000 hours of work tracing the virus to Gambian rats and other rodents imported from Ghana to an animal dealer in Texas. According to the former CDC employee who worked on it.

The Food and Drug Administration banned all African rodent imports following the 2003 outbreak. The agency also banned interstate distribution and wild grazing of prairie dogs over concerns that monkeypox could colonize wildlife populations.

Then the US Geographical Survey and the Department of Agriculture captured 200 wild animals in Wisconsin near where humans contracted monkeypox from pet prairie dogs. They found no evidence that the virus had spread to wildlife, and the FDA lifted its ban on interstate distribution of prairie dogs.It is still illegal to import rodents from Africa.

Scientists in California detected monkeypox DNA in a sewage sample this summer. New York is also conducting wastewater monitoring for the virus, but the results have not yet been made public, according to the state health department. Wastewater findings in California have raised concerns among some health experts that the virus could be transmitted to rodents through sewage.

“There’s a risk because of the widespread nature of the infectious disease and the fact that it’s sewage and wastewater,” said Dr. James Lawler, an infectious disease expert at the Global Center for Health Security at the University of Nebraska Medical Center. It’s a concern about entering an animal population and harboring a zoonotic risk, and honestly, if that’s the case, I think it’s game over for us.”

However, it is not clear whether live viruses are present in the wastewater. According to Marlene Wolfe, an Emory University scientist working on the project, the study measured monkeypox DNA in sewage samples, not whether the virus was still infectious.

Wastewater is treated in most urban areas, so the virus is unlikely to survive and replicate in such an environment, said Amira Roess, a former employee of the CDC’s Epidemiology Information Service. Garbage containing contaminants, such as bed sheets and towels, is likely a higher risk than wastewater, Roess said.

“There are wildlife species that rummage through the trash and are more likely to pick up viruses that can replicate. There are many, but it happens,” said Roess, now a professor of epidemiology at George Mason University.

According to RTI International epidemiologist Richard Reissinger, several steps must be taken for the monkeypox virus to escape from humans to animals, and then to humans again to cause another outbreak.

Viruses must circulate in animal populations with a wide geographical distribution, but not cause species mortality so high that lines of transmission are extinguished. must be in contact.

“Each step has a certain probability. If you add up all the probabilities for these steps, the probability is actually quite low,” says Reithinger.

Roess also said that certain viral mutations may be causing monkeypox to spread more efficiently among people in the current outbreak. It can also make it more difficult to give the disease to the virus, she added.

“Not all animals are susceptible. We don’t even know which animals will be affected,” said Papai Oannow, now an associate professor at the University of Washington.

According to Pappaioanou and Roess, the risk of the virus becoming established in US animal populations and causing future human outbreaks is low, but the US needs a more robust surveillance system to prepare for such a possibility. There are major gaps in the ability of public health agencies to monitor infectious diseases in animal populations, the former CDC official said.

“This is a huge gap. We don’t have good systems to monitor humans,” Roess said. “For wildlife, it really depends on who is interested in which pathogens and can convince someone to fund surveillance. A lot of our surveillance is really sporadic.”

Livestock such as cattle, sheep and poultry are monitored by the Department of Agriculture, Papaioanow said. But wildlife monitoring is underfunded and it takes a lot of effort to monitor infectious diseases in these animals, she said.Governments monitoring the health of dogs and cats abroad Local health departments may monitor rodents and run population control programs, but this also requires funding and significant personnel, she added. I was.

“More and more people are moving to cities around the world,” said Papaioanow. “What does it mean to have a reservoir of infection in a highly urbanized city? I don’t know the answer.”