A dog in France has monkey pox, and scientists fear that spreading more animals will not be able to eradicate the virus

Key points:

1. Historically, monkeypox viruses have been transmitted from animals to humans in Africa.

2) Some scientists worry that as the human epidemic expands, monkeypox may spread from humans to animals in the United States, making the virus more difficult to eradicate.

3) Scientists say the likelihood of such an event occurring is low, but a more robust animal monitoring system is needed to prepare for this possibility.

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In 2003, 47 people in six Midwest states were infected with monkeypox from pet marmots kept by rodents imported from Ghana, Africa.

Today's outbreak has infected more than 14,100 people in the United States and more than 41,000 worldwide, mainly through close contact between gay and bisexual men. But scientists reported the first human-to-human pet transmission in a dog in France this month, prompting U.S. and global health officials to step up warnings to ensure the virus doesn't spread to other pets and animals.

The proposal stems from concerns that monkeypox may spread to wild animal or rodent populations as the human outbreak spreads, allowing the virus to spread back and forth between humans and animals and giving the virus a permanent foothold in countries that have not historically spread.

Before this year's global outbreak, monkeypox was mainly spreading in remote areas of West and Central Africa, where people contracted the virus after coming into contact with infected animals. The outbreak was brought under control in 2003 and was the first recorded case of human infection with the virus outside Africa.

The current global outbreak is very different from the past pattern of transmission. Monkeypox is now spread almost exclusively through close physical contact between people in the United States, European countries and major urban areas of Brazil.

But this month in France reported the first hypothetical case of animal infection in the current outbreak. After a couple in Paris contracted monkeypox and shared a bed with an animal, a pet dog tested positive for the virus.

WHO officials have said that a single incident of pet infection with the virus is not surprising or causes significant concern, but if people do not know that monkeypox can infect other species, monkeypox has the potential to start spreading among animals.

If monkeypox occurs in animal populations outside Of Africa, the virus will have more opportunities to mutate, resulting in a higher risk of transmission and severity. Animals may then transmit the virus to humans, increasing the risk of future outbreaks.

At a press conference in Geneva last week, Dr Mike Ryan, director of who's Health Emergencies Programme, said: "We don't want to see diseases move from one species to another and then stay in that species. ” . “ It is through the process by which an animal influences the next, the next, and the next that you can see the rapid evolution of viruses. ”

Kristen Nordlund, a spokeswoman for the agency, said the U.S. Centers for Disease Control and Prevention has not received any reports of monkeypox infections in pets. But according to the CDC, the virus can be transmitted from humans to animals or from animals to humans.

"While we are still learning which animals will be infected with monkeypox virus, we should assume that any mammal can be infected with monkeypox virus," Nordlund said. "We don't know if reptiles, amphibians or birds will be infected with monkeypox, but that's unlikely because these animals have not been found to be infected with viruses in the same family as monkeypox."

Dr Rosamond Lewis, the World Health Organization's chief monkeypox specialist, said it was important to properly dispose of potentially contaminated waste to avoid the risk of infection when rodents and other animals rummaged through the garbage.

"While these have always been hypothetical risks, we think they are important enough that people should understand how to protect their pets and how to manage their waste so that animals generally don't come into contact with monkeypox viruses," Lewis said.

Ryan said that while it's important to be vigilant, animals and pets don't pose a risk to people at the moment.

"It's important that we don't allow these viruses to establish infection variants in other animal populations," Ryan said. "A single contact or infection of a particular animal is not unexpected."

Rodents of Africa:

Although scientists have done some research on monkeypox in Africa, their work has been limited by a lack of funding. So scientists don't know how many different kinds of animals can carry the virus and spread it to humans.

Over the past 40 years, scientists have isolated monkeypox from wild animals in Africa only a few times. They include rope squirrels, target rats and giant kangaroos from the Democratic Republic of the Congo, as well as two species of monkeys from Côte d'Ivoire. Rodents, rather than monkeys, are thought to be host animal populations in Africa, although the exact animal host is unclear.

Public health officials don't know whether animal types that are close to humans in U.S. urban environments — raccoons, rats and rats — will infect and transmit the virus. According to the CDC, some types of mice and rats can be infected with monkeypox, but not all species are susceptible.

"We know this is a virus that spreads from rodents in West Africa," said Dr. Peter Hotz, an infectious disease specialist at Baylor College of Medicine in Texas. "Does a rat or other rodent in an urban environment mean that it's gaining a foothold there, and it's also becoming more like a permanent fixture — we don't want that to happen," he said.

The CDC advises people with monkeypox to avoid contact with animals – pets, livestock, domestic animals and wild animals. If a pet gets sick within 21 days of contact with a person with monkeypox, the animal should be evaluated by a veterinarian.

According to the CDC, waste contaminated with monkeypox should be placed in specially lined bins and should not be left outside as wild animals may be exposed to the virus.

Outbreaks in the United States in 2003

In the 2003 outbreak, the CDC was able to quickly vaccinate and isolate patients before the virus spread further. There are no cases of human-to-human transmission of monkeypox. The CDC subsequently banned the import of rodents from Africa.

According to Marguerite Pappaioanou, a former CDC official in charge of the outbreak, it would take 10,000 hours to contain the 2003 outbreak to trace the virus back to Gambian rats and other rodents imported from Ghana to animal dealers in Texas.

After the 2003 outbreak, the U.S. Food and Drug Administration banned the import of all African rodents. The agency also banned the interstate distribution of prairie marmots and their release into the wild for fear that monkeypox could spread among wildlife populations.

The U.S. Geological Survey and the Department of Agriculture then trapped 200 wild animals in Wisconsin near where humans infect monkeypox from their pet marmots. They found no evidence that the virus had spread to wild animals, and the FDA lifted a ban on the distribution of prairie marmots between states. Imports of rodents from Africa remain illegal.

Wastewater problems

This summer, scientists in California detected monkeypox DNA in sewage samples. According to the state health department, New York is also conducting wastewater monitoring for the virus, but the results have not been publicly released. The california wastewater survey results have raised concerns among some health experts that the virus could infect rodents through sewage.

Dr. James Lawler, an infectious disease specialist at the Center for Global Health Safety at the University of Nebraska Medical Center, said: "There are risks due to the widespread nature of the infection and the fact that it is sewage and wastewater. "It's a worrying issue involving getting into animal populations and having a reservoir of zoonotic risk, and honestly, if that's the case, I think our game is over."

But it is unclear whether live viruses are present in the wastewater. Marlene Wolfe, a scientist at Emory University who worked on the project, said the study measured monkeypox DNA in sewage samples, not whether the virus was still contagious.

Amira Roess, a former official at cdc's Epidemiological Intelligence Service, said wastewater in most urban areas is treated, so the likelihood of the virus surviving and replicating in this environment is low. Ross said garbage containing contaminated materials, such as bed sheets or towels, may pose a higher risk than wastewater.

"Some wild animals will rummag through your garbage, and then they're more likely to be infected with viruses that can replicate." There are a lot of hypotheses, but it did happen," said Ross, who is now a professor of epidemiology at George Mason University.

Low probability

Richard Reithinger, an epidemiologist at RTI International, said the monkeypox virus had to take several steps to spread from humans to animals and back to humans, leading to another outbreak.

Reithinger said the virus must spread across geographically widely distributed animal populations, but would not cause such a high mortality rate in the species that the transmission route was stifled. Humans also need to have some degree of regular contact with animals.

"There is a certain probability at every step. Once you add up all the probabilities of these steps, the probabilities actually become very low," Reithinger said.

Ross said monkeypox may also spread more efficiently in populations with current outbreaks because of some kind of viral mutation. She added that if the virus has adapted to humans, it may be more difficult for people to transmit the disease to animals. Pappaioanou said it also depends on the species of animals exposed to the virus.

"Not all animals are susceptible. We don't even know which ones are," said Papayo Anu, who is now an associate professor at the University of Washington.

Better monitoring is needed

Pappaioanou and Roess said that while the virus is entrenched in U.S. animal populations and the risk of causing future human outbreaks is low, the U.S. needs a stronger surveillance system to prepare for this possibility. Former CDC officials say there is a significant gap in the ability of public health agencies to monitor infectious diseases in animal populations.

"It's a very big gap. We don't have a good human surveillance system," Ross said. "For wild animals, it depends on who is interested in what pathogen and whether they can convince someone to fund surveillance." A lot of our surveillance is sporadic."

Pappaioanou said livestock such as cattle, sheep and poultry are monitored by the Ministry of Agriculture. But wildlife surveillance is underfunded and monitoring these animals for infectious diseases requires a lot of work, she said, adding that there are no government agencies overseas responsible for the health of cats and dogs. She added that local health authorities may monitor rodents and develop population control plans, but this will also require funding and significant staffing.

"More and more people around the world are moving to cities," Papaianu said. "What does it mean to have a source of infection in a highly urbanized city? We don't know the answer. ”