乌鸦传媒

BALTIMORE -- A rising number of monkeypox outbreaks in central and western Africa emphasizes the need for increasing surveillance in the region, as well as concern that the disease is becoming a human pathogen, researchers said here.

This year, 88 suspected cases of monkeypox have been reported through October, as well as evidence of three independent zoonotic transmission events, reported Reena H. Doshi, PhD, of the CDC in Atlanta, and colleagues.

Monkeypox is a zoonotic orthopoxvirus, clinically similar to smallpox, as the smallpox vaccine is protective against it, Doshi explained in a at the American Society of Tropical Medicine & Hygiene annual meeting. It is endemic to certain regions of west and central Africa, is transmitted through direct contact with either infected animals or patients, and its natural reservoir is suspected to be small rodents.

Known outbreaks of the virus in Likouala, a of the Democratic Republic of the Congo, have been sporadic, with one in 2003 and one in 2010-2011. Doshi added that while monkeypox is a reportable disease, its background rate is unknown and mainly reliant on anecdotal reporting.

Researchers focused on a specific potential outbreak of 43 cases, tracing the timeline from one fisherman and his son, seeking care for a rash and illness in the town of Enyelle in January, to laboratory-confirmed monkeypox in February and eight more suspected cases of the virus reported in March.

Teams were deployed to towns with suspect cases, which were identified based on clinical signs and symptoms, and dried blood specimens were collected for serological testing. For those with active disease, crust and vesicle fluid was tested via PCR.

Case definitions were as follows:

• Suspected case: Unexplained rash or fever
• Possible case: ≥2 clinical criteria and one epidemiologic criteria or an orthopoxvirus-specific positive IgM test
• Probable case: ≥2 clinical criteria and an orthopoxvirus-specific positive IgM test
• Confirmed: Detection of orthopox DNA by PCR

Of the 43 suspected cases, seven were confirmed, 13 were probable, two were possible, 14 were suspected and six were excluded. Those who had confirmed or suspected cases were a median age of 10 years, and 13 were girls. Three of the cases had died. Doshi said that there was never more than one case on any given day during the time of the investigation (March 22, 2017 to April 4, 2017).

Researchers identified cases from four different towns, but were unable to epidemiologically link cases across towns. Doshi also identified potential confounding factors in identifying whether monkeypox was endemic or epidemic. She said there was confirmed transmission of varicella zoster virus and reports of measles transmission in the region and added that monkeypox is often confused with other rash illnesses.

Susan Fisher-Hoch, MBBS, of UTHealth School of Public Health in Brownsville, Texas, said that it was no surprise that sporadic, small outbreaks of this disease occur, but did not see it as any potential global threat.

"These outbreaks are local and have never been known to spread, and case to case transmission is not the rule," Fisher-Hoch, who was not involved in the study, told 乌鸦传媒. "Most cases are from local rodent populations, which is why it is not considered an international threat of any kind. The outbreaks are self-limiting."

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