Monkeypox virus (MPXV), of the genus Orthopoxvirus, was identified in captive cynomolgus monkeys in Copenhagen in 1958 (1). The first documented case of human MPXV infection was reported in a patient from the Democratic Republic of the Congo in 1971 (2). Other outbreaks have occurred, including a large one in the United States in 2003, in which 47 confirmed and probable human cases of MPXV infection were identified after importation of wild rodents from Ghana (3). Phylogenetic analyses of MPXVs have revealed 2 distinct clades, West African and Congo Basin (4). In the past decade, human MPXV infections also have increased in Central and West Africa (5).

Ecologic niche modeling shows that Sierra Leone is in a geographic region suitable for transmission of MPXV (6). Several cases of human MPXV have been detected in West Africa, including a case in Sierra Leone in 1970 and another in March 2014 (5). We report confirmation of an MPXV infection in Sierra Leone in March 2017.

A 35-year-old man from Kpaku village, Galliness Perri chiefdom, Pujehun district, in southern Sierra Leone near the border with Liberia, sought treatment on March 16, 2017, for fever, body pain, malaise, dysphagia, and enlarged cervical lymph nodes. The patient reported hunting and eating squirrels ≈10 days before becoming ill, and traveling to Pelewahun gee bu in Bo district 3 days before his symptoms began. On March 17, he began having generalized vesicular skin eruptions. Clinicians sent vesicular swab specimens and blood samples collected on March 28 (12 days after the patient sought treatment) and on May 10 (day 55 after the patient sought treatment) to the Sierra Leone–China Friendship Biologic Safety Laboratory in Freetown, Sierra Leone.

Read more at CDC…