About one to three days after getting a fever, most people also develop a painful rash that is characteristic of poxviruses. It starts with flat red marks that become raised and filled with pus over the course of the next five to seven days. The rash can start on a patient’s face, hands, feet, the inside of their mouth or on their genitals, and progress to the rest of the body. (While chickenpox causes a similar-looking rash, it is not a true poxvirus, but is caused by the unrelated varicella-zoster virus.)
Once an individual’s pustules scab over, in two to four weeks, they are no longer infectious, said Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Canada.
Children and people with underlying immune deficiencies may have more severe cases, but monkeypox is rarely fatal. While one strain found in Central Africa can kill up to 10 percent of infected individuals, estimates suggest that the version of the virus currently circulating has a fatality rate of less than 1 percent.
And the easily identifiable rash of monkeypox, as well as its earlier symptoms, could be considered beneficial. “One of the most challenging things about Covid has been that it can be spread asymptomatically or pre-symptomatically, by people who have no idea that they’re infected,” Dr. Rasmussen said. “But with monkeypox it doesn’t appear that there is any pre-symptomatic transmission.”
Still, as the recent outbreak of cases has shown, there are plenty of opportunities to transmit monkeypox in the first few days of an infection, when symptoms are non-specific, Dr. Rasmussen said.
What to Know About the Monkeypox Virus
What is monkeypox? Monkeypox is a virus endemic in parts of Central and West Africa. It is similar to smallpox, but less severe. It was discovered in 1958, after outbreaks occurred in monkeys kept for research, according to the Centers for Disease Control and Prevention.
Do I need to worry about a rising threat?
The good news is that there is no evidence yet to suggest that the monkeypox virus has evolved or become more infectious. DNA viruses like monkeypox are generally very stable and evolve extremely slowly compared to RNA viruses, Dr. Sigal said. Scientists are sequencing the viruses from recent cases to check for potential mutations, and will know soon if the infectiousness, severity or other characteristics have changed, he said. “But my expectation is that they will not be any different.”
Nevertheless, experts have some explanations for the recent increase in monkeypox cases. Research has shown that incidences of humans contracting viruses from contact with animals — also known as zoonotic spillovers — have become more common in recent decades. Increasing urbanization and deforestation means that humans and wild animals are coming into contact more often. Some animals that carry zoonotic viruses, like bats and rodents, have actually become more abundant, while others have expanded or adapted their habitats due to urban development and climate change.