A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
During the 2025 mpox outbreak in Sierra Leone, we assessed environmental contamination in 2 hospitals. Of 89 surfaces sampled, 6 (6.7%) surface samples, primarily from doors, were PCR-positive for monkeypox virus. Our findings highlight monkeypox virus surface contamination in healthcare settings and help prioritize infection prevention and control targets in resource-limited settings.
Mpox, caused by monkeypox virus (MPXV), is a zoonotic disease historically endemic to Central and West Africa ( 1 ). Since 2022, the global spread of MPXV clade IIb has altered transmission dynamics, and reports of sustained human-to-human transmission have increased ( 2 , 3 ). Environmental contamination by MPXV has been identified, including recovery of infectious virus particles in healthcare facilities where infection prevention and control (IPC) resources might be limited ( 4 , 5 ). Beginning in January 2025, Sierra Leone experienced a substantial mpox outbreak, representing one of the country’s largest recorded clusters, which strained public health resources. Data on environmental contamination in healthcare settings in Africa during active mpox outbreaks remain scarce. We conducted surface sampling in 2 major urban hospitals in Sierra Leone to assess the presence of MPXV and identify high-risk contamination sites to inform local IPC strategies.
The study was conducted in June 2025 at Connaught Hospital in Freetown, the capital and largest city of Sierra Leone, and Bo Government Hospital in Bo, Sierra Leone. Both facilities are referral centers currently managing suspected and confirmed mpox cases during the national mpox outbreak. We sampled 89 high-touch surfaces in clinical and nonclinical areas, including patient beds, door handles, bathroom fixtures such as toilet seats and faucet taps, and nonsingle-use medical equipment such as medical instrument trays and blood pressure cuffs that are supposed to be sterilized after every use. We swabbed each surface for ≈3 minutes by using a polyester-tipped applicator premoistened with viral transport media, by following a standardized protocol ( 6 ). We standardized surface area swabbing by using a template. Our sampling did not target specific rooms with known mpox patients and was conducted without interfering with routine cleaning schedules, to reflect typical environmental conditions. The study was approved by the Sierra Leone Ethics and Scientific Review Committee (protocol no. 010/05/2025) and the University of Manitoba Health Research Ethics Board.
We extracted DNA by using KingFisher Flex (Thermo Fisher Scientific, https://www.thermofisher.com ), a robotic magnetic bead–based system. We performed real-time PCR targeting the MPXV B6R gene by using published primers and probe sequences ( 7 ). The 40-cycle assay included negative and positive controls. We set thermal cycling conditions to 95°C for 2 minutes, followed by 40 cycles of 95°C for 15 seconds, and 60°C for 1 minute. We established a positive cycle threshold (Ct) cutoff of <38 on the basis of other environmental MPXV studies ( 8 ).
Of the 89 surfaces sampled, 6 (6.7%) surface samples were PCR-positive for M…