Asymptomatic circulation in Humans in the Wake of a Monkeypox Outbreak among Chimpanzees in Cameroon
Guagliardo SA1, Monroe B1, , Moundjoa C3,1, Athanase A2,1, Okpu G1, Pasi O1, Panayampalli S1, Burgado JB1, Townsend M1, Epperson S1, Doty J1, Reynolds MG1, Dibongue E2,McCollum AM1
1 US Centers for Disease Control and Prevention, Cameroon
2 Ministry of Health, Cameroon
3 Ministry of Livestock,Cameroon
Citation: Guagliardo SA, Monroe B, Moundjoa C*, Athanase A, Okpu G et al (2020) Asymptomatic circulation in Humans in the Wake of a Monkeypox Outbreak among Chimpanzees in Cameroon. SciTech Infectious Diseases 2020. Mauritius
Received: January 21, 2020 Accepted: January 23, 2020 Published: January 23, 2020
Background: Monkeypox virus is a zoonotic Orthopoxvirus (OPXV) that causes smallpox-like illness in humans. In Cameroon, human monkeypox cases were conﬁrmed in 2018, and outbreaks in captive chimpanzees occurred in 2014 and 2016.
Methods: We investigated the OPXV serological status among staff at a primate sanctuary (where the 2016 chimpanzee outbreak occurred) and residents from nearby villages, and describe contact with possible monkeypox reservoirs. We focused speciﬁcally on Gambian rats (Cricetomys spp.) because it is a recognized possible reservoir and because contact with this species was common enough to render sufﬁcient statistical power. We collected one 5-mL whole blood specimen from each participant to perform a generic anti-OPXV ELISA test for IgG and IgM antibodies and administered a questionnaire about prior symptoms of monkeypox-like illness and contact with possible reservoirs.
Results: Our results showed evidence of OPXV exposures (IgG positive, 6.3%; IgM positive, 1.6%) among some of those too young to have received smallpox vaccination (born after 1980, n = 63). No participants reported prior symptoms consistent with monkeypox. After adjusting for the education level, participants who frequently visited the forest were more likely to have recently eaten Gambian rats (OR: 3.36, 95% CI: 1.91–5.92, P < 0.001) and primate sanctuary staff were less likely to have touched or sold Gambian rats (OR: 0.23, 95% CI: 0.19–0.28, P < 0.001).
Conclusion: The asymptomatic or undetected circulation of OPXVs in humans in Cameroon is likely, and contact with monkeypox reservoirs is common, raising the need for continued surveillance for human and animal disease.