Monkeypox re-emergence in Africa: a call to expand the concept and practice of One Health

Abstract

Monkeypox is a re-emerging viral zoonosis that occurs naturally in heavily forested regions of West and Central Africa. Inter-human transmission of monkeypox virus, although limited, drives outbreaks, particularly in household and health-care settings. But the available evidence suggests that without repeated zoonotic introductions, human infections would eventually cease to occur. Therefore, interrupting virus transmission from animals to humans is key to combating this disease. Areas covered: Herein we review laboratory and field studies examining the susceptibility of various animal taxa to monkeypox virus infection, and note the competence of various species to serve as reservoirs or transmission hosts. In addition, we discuss early socio-ecologic theories of monkeypox virus transmission in rural settings and review current modes of ecologic investigation - including ecologic niche modeling, and ecologic sampling - in light of their potential to identify specific animal species and features of the environment that are associated with heightened risk for human disease. Expert opinion: The role of disease ecology and scientific research in ongoing disease prevention efforts should be reinforced, particularly for wildlife-associated zoonoses such as monkeypox. Such efforts alongside those aimed at nurturing 'One Health' collaborations may ultimately hold the greatest promise for reducing human infections with this pathogen.

Keywords: Monkeypox; One Health; orthopoxvirus; zoonosis; .

Figure 1.

Number of human monkeypox cases resulting from the inter-human transmission, Democratic Republic of the Congo, 1980–1984 (Summarized from Fine et al. 1988 [70],) (blue bars). The total number of infections (orange bars) encompasses instances of co-primary cases (i.e. there were 98 episodes of primary zoonotic introduction, involving 114 cases, for which there was no subsequent inter-human transmission). During this time there was only 1 episode that extended to four generations of interhuman transmission, which resulted in five human MPXV infections.

Figure 2.

(a) Documented (laboratory confirmed) cases of monkeypox from 1970- April 2018, in West Africa (Sierra Leone, Liberia, Cote D’Ivoire, Nigeria) (green); *Central Africa excluding DRC (Republic of the Congo, Cameroon, Gabon, Central African Republic)(blue); Other (United States, South Sudan)(yellow). (b) Monkeypox cases notified to the Ministry of Health, DRC 1970–2015. Reported cases are inclusive of reported and laboratory-confirmed cases (DRC MOH, pers comm).

Figure 3.

Potential sources of zoonotic transmission of MPXV to humans. Yellow arrows denote potential MPXV virus transmission routes between (non-human) animals. Blue arrows denote potential routes of virus transmission to humans.