Exportation of Monkeypox Virus From the African Continent

Abstract

Background The largest West African monkeypox outbreak began September 2017, in Nigeria. Four individuals traveling from Nigeria to the UK (2), Israel, and Singapore became the first human monkeypox cases exported from Africa, and a related nosocomial transmission event in the UK became the first confirmed human-to-human monkeypox transmission event outside of Africa. Methods Epidemiological and molecular data for exported and Nigerian cases were analyzed jointly to better understand the exportations in the temporal and geographic context of the outbreak. Results Isolates from all travelers and a Bayelsa case shared a most recent common ancestor and traveled to Bayelsa, Delta, or Rivers states. Genetic variation for this cluster was lower than would be expected from a random sampling of genomes from this outbreak, but data did not support direct links between travelers. Conclusions Monophyly of exportation cases and the Bayelsa sample, along with the intermediate levels of genetic variation suggest a small pool of related isolates is the likely source for the exported infections. This may be the result of the level of genetic variation present in monkeypox isolates circulating within the contiguous region of Bayelsa, Delta, and Rivers states, or another more restricted, yet unidentified source pool.

Reemergence of Human Monkeypox and Declining Population Immunity in the Context of Urbanization, Nigeria, 2017–2020

“…States that reported >10 confirmed cases within a year were Rivers (36), Bayelsa (31), Lagos (19), and Delta (17) ( Table 3). Exported cases in the United Kingdom, Singapore, and Israel had epidemiologic linkages to clusters in these states with the highest numbers of monkeypox cases (18,19).…”

“…States that reported >10 confirmed cases within a year were Rivers (36), Bayelsa (31), Lagos (19), and Delta (17) ( Table 3). Exported cases in the United Kingdom, Singapore, and Israel had epidemiologic linkages to clusters in these states with the highest numbers of monkeypox cases (18,19). Most states with confirmed cases were concentrated in the South-West (3), South-South (6), and South-East (4) zones, with sporadic spread to the North-West and North-Central zones, which include highly populated states such as the Federal Capital Territory (FCT), Nasawara, and Plateau (Table 3).…”

Here, There, and Everywhere: The Wide Host Range and Geographic Distribution of Zoonotic Orthopoxviruses

“…Meanwhile, the infection contracted by the British care worker confirms human-to-human MPXV transmission [ 96 ]. Other cases of MPXV infections outside of Africa were reported in Israel (2018) and Singapore (2019), for travelers who imported the disease from Nigeria [ 98 , 99 ].…”

“…Currently, MPXV is mostly observed in Africa; CPXV in Europe and Asia; BPXV in Asia and the Middle East; and VACV in South America [ 53 , 54 , 55 , 56 , 119 , 140 , 160 , 162 , 168 , 205 ]. Although the factors that restrict the geographic distribution of some zoonotic orthopoxviruses are still unknown, their distribution range has been increasing as MPXV has been exported to parts of the USA [ 77 ], United Kingdom [ 96 ], Israel [ 98 ], and Singapore [ 99 ]. Legal or illegal trade of animals or animal-derived products, migration of animal populations, and traveling and migration of people are some factors that can contribute to the geographic dissemination of orthopoxviruses on local or global scales.…”

Smallpox Eradication: African Origin, African Solutions, and Relevance for COVID-19

“…We are now facing a decision on whether smallpox vaccine should again be used in areas where monkeypox is endemic. 19 Operational innovations: The use of operations officers—managerial experts—was a major innovation in the West and Central African program. These persons were conversant with epidemiology and control, and became experts in logistics, communications, transport, personnel, and equipment—especially proper storage of vaccines.…”