During the last major monkeypox outbreak in the United States 19 years ago, domesticated prairie dogs caught the virus in close quarters with infected rodents. The disease eventually spread to dozens of people who bought the playful and cuddly prairie dogs as pets.
At that time, veterinarian Lisa A. Murphy was attending a class on exotic animal diseases in Wisconsin, the same state where the first positive case was reported in 2003.
Soon the room filled with ringtones and vibrations as experts from top agencies like the USDA received reports of the outbreak.
“The instructors’ cellphones were blowing up, and they were being kicked out of the room,” said Murphy, now associate director of the Infectious and Zoonotic Disease Institute at the University of Pennsylvania School of Veterinary Medicine.
Although veterinarians only treat animals, things can get a little murky when it comes to diseases that can be transmitted between species. Shortly after participating in the training, Murphy received a call from someone with a sick pet. He immediately warned that their health may also be at risk.
“Veterinarians, we are trained to recognize zoonotic diseases. “Even though we’re not human doctors, if there’s a public health risk to human health, that training becomes a very important part of our job,” he said.
In 2003, an outbreak of monkeypox in the United States reported 47 cases in about three months in six Midwestern states. By comparison, during roughly the same time period in this year’s outbreak, there were 7,102 monkeypox cases in all states except Montana and Wyoming, and 28,220 cases in 88 countries worldwide. Something has changed.
“What we’re seeing this year is completely different from what we saw in 2003, which is animal-to-human transmission. The spread of the current outbreak appears to be similar from person to person,” Murphy said. “That doesn’t mean there hasn’t been or can’t be human-to-animal or animal-to-human transmission, but the whole flavor of this disease is very different.”
Public health officials are working hard to test and vaccinate people to limit the spread of the virus in the United States and around the world. As part of the process, they’re looking for the monkeypox virus in sewage — toilet water that may contain the virus shed in urine or feces. Experts do the same thing with the coronavirus and other viruses because it’s a good way to determine how many people have contracted the germ.
But some questions remain: If the virus is present in sewage, can monkeypox spread to rats or other urban rodents that eat garbage? If so, could the virus become permanently established in the US with rats or mice?
We spoke to experts to find out whether viral DNA found in sewage actually poses a threat to the spread of monkeypox, and what people infected with the virus can do to limit its spread in the event of a leak.
Monkeypox is considered endemic in at least six countries
In some countries, all of them in Africa, monkeypox circulates freely among one or more local wildlife species, known as animal reservoirs. If people come into contact with those animals, the virus can sometimes be transmitted to humans. During the current global epidemic, there are concerns that animals may play a role in making the disease globally endemic, becoming a permanent fixture in countries where it has not previously existed.
The virus was discovered half a century ago, in 1958, and much is known about how it behaves. Even so, there are still many unanswered questions, especially when it comes to the version currently circulating: Why are we seeing higher levels of human-to-human transmission than ever before? Which animals can and cannot get it, especially our pets, and can animals spread it back to us?
We know that many species of animals can be affected by monkeypox. Whether they can get it from humans or vice versa is less known.
Monkeypox can affect a particularly wide range of animals. The CDC has warned of infections in monkeys, anteaters, hedgehogs, squirrels, squirrels and, of course, prairie dogs. For other common species, including many domesticated pets – dogs, cats, gerbils, guinea pigs, hamsters, mice, rats and rabbits – their potential to transmit monkeypox is not yet known. However, all of these animals have previously been observed with other diseases in the orthopoxvirus family.
Not every animal infected with a zoonotic virus can transmit it from every possible host. It is not yet known which animals can transmit monkeypox from humans and which animals can transmit the virus back to us.
“There’s a perception that disease is moving freely between animals and humans, but that’s not necessarily the case,” Murphy said. “In the example of monkeypox in 2003, it appeared to be rodents – rodents – humans. After that, it did not pass from humans to rodents or other animals.”
Experts are investigating whether monkeypox has genetic changes that make it more likely to spread to humans. However, the strain affecting people around the world is “almost identical” to the virus that caused a 2017-18 outbreak in Nigeria, said Heather Koehler, an assistant professor at Washington State University’s School of Molecular Biology. Virus-host interactions in monkeypox. The outbreak also involved human-to-human transmission, resulting in at least 12 confirmed or suspected cases of the disease.
“We didn’t invest the resources to understand the transmission that was there,” he said. “We know there is an animal reservoir that is being driven closer to the human population, so there are more spills. But at some point, there has to be a critical threshold before you infect enough people that you can spread the infection from person to person. Maybe we haven’t seen it yet.”
SARS-CoV-2 is the most modern example of the temperamental nature of zoonotic transmission. There are many cases where people can transmit the coronavirus to other species. The first was a dog in Hong Kong. After that, there were countless stories of animals in zoos and sanctuaries around the world being infected with the virus, including two tigers owned by Carol Baskin. Tiger King hunger. Reports of wild deer with antibodies raise concerns that the species could be a reservoir for the next great COVID infection. But so far, few people have contracted the disease from animals – only a few in direct contact with mink farms.
“Some diseases go to a dead end in a way. In order for COVID to be transmitted from deer to deer, the virus must have mutated into something. That’s a concern,” Murphy said. “Over time, as this virus hangs around in deer, what does it pick up along the way that allows it to bounce back and infect humans or other species?”
Monkey pox in sewage, but don’t flush bleach down the toilet.
The Sewerage Coronavirus Alert Network (SCAN), which tests sewage solids in areas near San Francisco and Sacramento for the virus, recently announced the discovery of monkeypox in samples from the Bay Area. The idea of testing wastewater for viruses originated with polio in the 1940s. The disease, once a childhood scourge, paralyzed more than 15,000 Americans each year in the 1950s before a vaccine was available. It was eradicated in the United States in 1979, but travelers to other countries are sometimes infected. But recently in New York, the polio virus was found in sewage from an unvaccinated person who may have been paralyzed in July, marking the first case of polio in the US since 2013.
SCAN was launched in 2020 to detect the presence of SARS-CoV-2, but it has since expanded to test for other infections, including respiratory syncytial virus (RSV) and influenza.
“This tool has been around for a long time, but it’s really experienced a renaissance with new investments as a public health tool during COVID,” said Marlene Wolff, assistant professor of environmental health at Emory University and leader of SCAN.
News of monkey disease in sewage has led some to spin hypothetical scenarios. In theory, if sewage can infect rodents, and rodents can become permanent reservoirs of the virus, and if the rodents transmit the virus back to humans through their feces, then that would be… bad.
But experts say it’s too much.
“I know there’s going to be more research on how monkeypox can spread to surfaces and things that people touch more than sewage,” Wolfe said.
Some of these flames have been fueled by the new announcement in 2007 that orthopoxviruses can survive in stormwater, especially in cold conditions, for days or weeks. But Dr. Saahir Khan, an infectious disease specialist at the USC Keck School of Medicine, noted that lab conditions are very different from what happens in the real world.
“Just because you can have a virus living on Earth and grown in a lab and viable, that doesn’t mean it can be a real source of human infection,” he said. “There was a lot of panic at the beginning of the COVID-19 pandemic because research showed that the virus can live on surfaces for a long time and everyone was washing their food. And of course we found that transmission from surface contact is very rare.”
Furthermore, the SCAN testing method only looks for genetic material, which does not necessarily represent a live, infectious virus. Their test is highly sensitive and amplifies the DNA of the virus 1000 times. A SCAN for SARS-CoV-2 can detect one or two cases per 100,000 population. The reliability of their test in monkeys is still being determined. Murphy said a sewage doomsday scenario isn’t entirely impossible, but requires too many contingencies to worry about in the first place.
“It’s impossible, but not impossible. Because sewage contains viral DNA or RNA, it is very different from viable virus, which is a potential threat to infectious diseases,” he said. “But even if there aren’t any viruses in there, you don’t want to ingest that.”
Some people who subscribe to this theory have suggested that people with monkeypox flush bleach down the toilet as a public health precaution. Take it from Wolfe, the wastewater virus expert — don’t.
“I’m all for cleaning your toilets, but I’m telling people to pay attention to the transmission routes we have information about, and if they’re affected, try to interrupt them by following public health guidelines,” he said. “Spilling bleach down your toilet is absolutely not part of the guidelines.”
It’s too late to stop monkeypox from becoming a global endemic because… people
There is a growing belief among infectious disease experts that the window to prevent monkeypox from becoming a global endemic may have closed. Khan suggests that theorizing how monkeypox might have entered global society should start with the primary driver of new infections: humans.
“I haven’t seen any convincing reports of someone getting monkeypox without being in close contact with someone with monkeypox,” he said. “I think it could be endemic in the human population forever, even if there is no animal reservoir.”
Khan believes the disease won’t cause severe disease or public disruption like SARS-CoV-2, but he worries about what an increase in infections could mean for people who are immunosuppressed, such as people with severe HIV. received an organ transplant.
“When and at this point I would say when are it’s going to become an endemic disease, where there’s going to be a section where this virus is at risk of serious complications,” he said. “You know, having another disease is never a good thing.”