Recent data suggest that monkeypox DNA can also be detected in a variety of body fluids of those infected. That includes respiratory and nasal secretions, spit, urine, feces and semen — meaning a flushed tissue from someone with monkey pox can register the virus in wastewater.
If a pathogen’s genetic footprint can persist in wastewater for more than 24 hours, SCAN can probably detect it. Covid-19 viral RNA remains in wastewater for more than 10 days. While Monkeypox DNA appears to exceed the 24-hour threshold, there is no public inquiry into how long it lasts.
One question remains how much monkeypox DNA has to get into the wastewater before SCAN can actually detect it. SCAN can sniff covid from the wastewater of just two infected people in 100,000.
Even in a state like California, which keeps sewage and water drainage separate, rain dilutes the amount of viral DNA in wastewater. To explain that, SCAN normalizes its estimates using a virus with a well-known expected amount: pepper mild mottle virus. Healthy people secrete the harmless virus after eating pepper and pepper-based products, making it the most abundant RNA virus in human feces (conveniently, it is also very stable in water).
There is no evidence that you can contract monkeypox from wastewater itself. What causes human-to-human transmission is prolonged, close contact with an infected person who exposes you directly to their rash, body fluids or respiratory droplets, according to the World Health Organisation. Bed linen and clothing from people with monkey pox can also spread the virus.
Monkeypox has its own vaccine. The smallpox vaccine, which the US has in its national stockpiles, also protects against that. But public access to monkey pox testing, treatment and vaccines is still limited. Investigating wastewater can help public health officials detect monkeypox outbreaks without widespread testing and determine where resources should be invested.
Wastewater surveillance can also detect new variants of monkeypox, two of which are currently circulating in the US. Virtually all current outbreaks are caused by the West African strain of Monkeypox, for which SCAN has a specific test. This species is more contagious but far less deadly than the other species known as the Congo Basin clade. In recent years, monkeypox has killed 3 to 6 percent of those it infects, and it is more deadly in young children. Monkeypox has killed three people worldwide this year.
SCAN is currently the only attempt to release data on monkeypox in wastewater. “The Bay Area is at the forefront of wastewater monitoring because, after all, we are Silicon Valley,” says Boehm. “But it’s not like California has monkeypox in its wastewater and nowhere else.”