The monkeypox (mpox) virus, a DNA-containing orthopoxvirus with a lipid envelope (virion size ~250 nm), was first identified in Denmark in 1958 in monkeys imported from Africa for medical research. The first human case of mpox was reported in 1970 in the Democratic Republic of Congo with sporadic reports of human cases occurring in Africa mainly from contact with primates and rodents.
The virus resurfaced in May 2022 as a global human pathogen (1) and, as of March 2023, has caused nearly 87 thousand lab-confirmed cases with 112 fatalities in 110 countries (WHO; March 2023). Even though the spread of the virus has slowed, it is still considered a threat to human health globally. Also, for the first time, the WHO has recorded a sustained chain of virus transmission in areas with no direct or immediate epidemiological links to regions of West or Central Africa. In other words, the virus has spilled out of its normal geographical confines to become a worldwide health threat!
The mpox virus is closely related to the smallpox virus, albeit a lot less severe. Its clinical presentation though mimics that of smallpox. As a zoonosis, it is primarily an infection of animals but can also infect humans in direct contact with infected animals. Humans can also acquire it from close contact with other infected humans. Person-to-person spread occurs mainly from virus in lesions on skin and mucous membrane. A limited supply of at least two types of prophylactic vaccines is available against the virus (2), and currently recommended only for those at a high risk of contracting the virus.
Mpox virus can also spread through respiratory droplets and via contaminated fomites. Although the virus has been found in semen and vaginal fluids as well as in breastmilk and blood, it is not known if transmission can occur through exposure to such fluids. Infection during pregnancy can vertically spread the virus to the developing fetus. A recent report from Spain has documented mpox virus spread in a tattoo parlor (3).
The potential of mpox virus to survive in and spread indoors via aerosols has not been explored thus far. However, if the smallpox virus is taken as an example (4), it would not be surprising to see mpox also show the capacity for airborne spread.
Only laboratories with containment (biosafety) level 4 can handle the live virus.
CREM Co Labs is able to use the Ankara strain of vaccinia virus (ATCC VR-1508) as a surrogate for mpox virus to assess its environmental survival and test microbicides against it.
Literature cited:
- Thornhill JP, Barkati S, Walmsley S, et al. Monkeypox Virus Infection in Humans across 16 Countries – April-June 2022. N Engl J Med. 2022;387(8):679-691. doi:10.1056/NEJMoa2207323
- Rizk JG, Lippi G, Henry BM, Forthal DN, Rizk Y. Prevention and Treatment of Monkeypox. Drugs. 2022;82(9):957-963. doi:10.1007/s40265-022-01742-y
- Viedma-Martinez M, Dominguez-Tosso FR, Jimenez-Gallo D, et al. MPXV Transmission at a Tattoo Parlor. N Engl J Med. 2023;388(1):92-94. doi:10.1056/NEJMc2210823
- Wehrle PF, Posch J, Richter KH, Henderson DA. An airborne outbreak of smallpox in a German hospital and its significance with respect to other recent outbreaks in Europe. Bull World Health Organ. 1970;43(5):669-679.