Story at a glance
- There are more than 13,500 known cases of monkeypox in the U.S.
- The virus has been detected in body fluids, on surfaces and in the air.
- Better testing will be important for detecting cases and reducing spread.
There have been more than 13,500 reported cases of monkeypox (MPX) virus in the U.S., according to the Centers for Disease Control and Prevention. This virus is primarily thought to be spread through close and prolonged contact, although it can be detected in the environment and in body fluids. Researchers are also looking at how much the virus can spread at mass gatherings, as well as new techniques to test for MPX.
What we know about how the virus survives in the environment
Some recent studies have focused on sampling the air, surfaces and objects for live monkeypox virus. One paper published in Environmental Microbiology details an MPX case in the U.K. where someone traveled from Nigeria. Researchers analyzed environmental samples using vacuum and surface sampling methods from rooms that adjoined to the patient’s room. The MPX virus was detected in multiple locations in the rooms and up to three days after the patient left the premises.
Another study sampled more widely within a U.K. hospital, testing high-touch areas in patient rooms, personal protective equipment of health care workers and air samples before and during bedding changes. This study is a preprint and has not yet been published in a peer-reviewed academic journal. The scientists found there was widespread surface contamination, with 66 out of 73 samples coming back positive. In addition, three out of four air samples taken during a bed linen change were positive.
The virus could be spreading at mass gatherings
A group of researchers report results from simulations of transmission of MPX virus at large gatherings in a preprint paper, which has not been published or peer reviewed. The team ran simulations to see how much MPX virus could potentially spread in groups, with various levels of close contacts and total number of attendees. They found that on average one case could lead to more than one additional case if they have a high number of group contacts (30 and up) or more than eight close contacts at the event.
However, these simulations are not based on real world data, so it’s important to understand the limitations of what the results mean. They represent a range of possibilities based on the parameters set by the researchers. In real life, actual number of cases resulting from an infectious person could vary due to factors like how much virus people are shedding, how long they are in contact with others and how transmissible the virus is.
More accessible testing is on its way
Unlike with COVID-19, MPX is currently not very easy to test for. Some people are asymptomatic, and people with symptoms like skin lesions may not have very many of them, so they could be getting misdiagnosed. Incubation period is usually six to 13 days but can range from five to 21 days, according to the World Health Organization. And a study published in the New England Journal of Medicine found that the median number of days from onset of first symptoms to first positive PCR test is five days (with a range of two to 20 days). This means that getting tested more than once could be important for detecting MPX.
One research group has posted a preprint report on tests for MPX that can be done on portable genetic sequencing devices. These devices are often used in doctors’ offices and in emergency care clinics. This technique is able to detect specific sequences in the strains that are currently circulating and visualizes it in real-time as fluorescence.