Human Monkeypox: Current State of Knowledge and Implications for the Future

Abstract

The zoonosis human monkeypox (MPX) was discovered in 1970, twelve years after the discovery of monkeypox virus (MPXV) in a Danish laboratory in 1958. Historically confined to West Africa (WA) and the Congo basin (CB), new epidemics in Sudan and the United States of America (USA) have fuelled new research highlighting environmental factors contributing to the expanded geographical spread of monkeypox virus (MPXV). A systematic literature review was conducted in MEDLINE^® (Ovid), MEDLINE^® (PubMed) and Google Scholar databases using the search terms: monkeypox, MPXV and "human monkeypox". The literature revealed MPX has classic prodromal symptoms followed by a total body rash. The sole distinguishing clinical characteristic from other pox-like illnesses is the profound lymphadenopathy. Laboratory diagnosis of MPX is essential, a suitable test for endemic areas is under development but not yet available. For the time being anti-poxvirus antibodies in an unvaccinated individual with a history of severe illness and rash can suggest MPX infection. The reservoir host remains elusive yet the rope squirrel and Gambian pouched rat appear to be the most likely candidates. Transmission includes fomite, droplet, direct contact with infected humans or animals and consumption of infected meat. Though smallpox vaccination is protective against MPXV, new non-immune generations contribute to increasing incidence. Environmental factors are increasing the frequency of contact with potential hosts, thus increasing the risk of animal-to-human transmission. Increased risk of transmission through globalisation, conflict and environmental influences makes MPX a more realistic threat to previously unaffected countries. Health worker training and further development and accessibility of suitable diagnostic tests, vaccinations and anti-viral treatment is becoming increasingly necessary.

Keywords: MPX; MPXV; human monkeypox; monkeypox.

Figure 1

Timeline of reported human monkeypox outbreaks. Source: based on data from Centers for Disease Control and Prevention [6], Formenty et al. (2010) [21], Learned et al. (2005) [22], International Federation of Red Cross and Red Crescent Societies (2016) [23], Damon et al. 2006 [24].

Figure 2

Flow diagram of systematic review. Source: based on PRISMA statement [31].

Figure 3

Monkeypox rash. Source: Centers for Disease Control and Prevention [6].