Mpox DNA Turned Up on High-Touch Hospital Surfaces During Sierra Leone Outbreak
During the 2025 mpox outbreak in Sierra Leone, hospital surfaces were not sterile bystanders. They carried monkeypox virus DNA in a pattern that pointed straight toward the places patients and staff touch most often: doors, shared equipment, and busy clinical workspaces.
Sampling in two referral hospitals found mpox DNA on 6 of 89 high-touch surfaces, a positivity rate of 6.7%. The detection rate was 4.0% in Freetown and 10.3% in Bo, a difference that may reflect variation in infection prevention and control practices or in how often patients with mpox moved through the sampled areas. The study was intentionally observational and practical. Investigators swabbed surfaces in routine clinical and nonclinical settings without disrupting cleaning schedules, offering a snapshot of environmental contamination under real-world conditions rather than an idealized laboratory scenario.
Doors Emerged as the Most Contaminated Fomites
The concentration of positives on doors was hard to miss. Of 28 doors sampled, 2 were PCR-positive, and doors accounted for one-third of all positive surfaces. Other contaminated sites included a delivery bed, a weighing scale, a medical ward instrument tray, a laboratory, an office bathroom, and an eye clinic table. In other words, the signal was not confined to isolation rooms or obvious patient-contact zones. It reached across care spaces where movement, hand contact, and shared workflow are part of the daily rhythm of a resource-constrained hospital.
That pattern matters because mpox spreads through close contact, and contaminated surfaces can function as intermediate vehicles when hand hygiene, cleaning frequency, or disinfection technique is inconsistent. Doors are especially vulnerable in that chain. They are touched repeatedly by patients, visitors, clinicians, porters, and cleaners, often between hand-to-face moments or before donning and removing gloves. In facilities facing a large outbreak, the door handle can become one of the most efficient mechanical amplifiers of environmental contamination.
Ct Values Suggest DNA Presence, Not Proven Infectivity
The PCR cycle threshold values for positive samples ranged from 32.34 to 37.91. Those numbers argue for detectable viral genetic material, but they do not establish that live virus remained capable of infection. The investigators appropriately avoided overcalling infectivity. Culture-based work in other settings suggests that viable virus becomes less likely at higher Ct values, especially above 30, and the values seen here sit in that higher range.
Still, the absence of proven infectivity does not make the finding trivial. Environmental DNA can serve as a marker of recent contamination, and in an outbreak setting it signals where IPC practices may be weakest. A surface does not need to be teeming with viable virus to reflect repeated contamination pressure. In a crowded hospital, the contamination pattern can reveal the fault lines: doors left uncleaned, reusable equipment not consistently disinfected, and hand hygiene opportunities that are missed in the flow of care.
The study also sits within a broader biological reality. Since 2022, the global spread of mpox clade IIb has altered transmission dynamics, and sustained human-to-human spread has been documented more often. Sierra Leone’s outbreak, which began in January 2025 and became one of the country’s largest recorded clusters, created the background conditions for environmental contamination to accumulate in healthcare facilities. High community transmission increases the chance that patients, staff, and visitors bring virus into clinical spaces, and weak IPC systems can then allow contamination to persist on frequently used surfaces.
Resource-Limited Settings Need Targeted Disinfection, Not Broad Assumptions
The study’s most actionable message is narrow and concrete: cleaning should be focused where contact is highest. Doors, bed rails, shared equipment, and other high-touch surfaces deserve frequent disinfection during active outbreaks. Hand hygiene remains central, but the findings argue for a more disciplined environmental approach as well. In low-resource hospitals, staff time, cleaning supplies, and trained personnel are limited. Prioritizing the most contaminated surfaces is a practical way to direct those scarce resources.
The sampling strategy also strengthens the operational value of the findings. By avoiding surfaces known in advance to be contaminated and by sampling during routine hospital activity, the investigation captured a realistic environmental burden rather than a curated one. That makes the result more useful for public health planning in similar settings across West Africa, where the background level of transmission and the strain on hospital systems can be substantial during outbreaks.
One sentence captures the bedside consequence: a contaminated door handle can become a missed prevention step repeated dozens of times a day.
What the Study Can and Cannot Prove
Several limitations keep the findings in their proper frame. The design was cross-sectional, so it cannot show how contamination changed over time or whether cleaning efforts altered the signal. Sampling was purposive rather than exhaustive, which limits generalizability. Cleaning frequency was not measured, and no direct link was made between surface contamination and a documented nosocomial transmission event. Viability testing was also not performed, so the study cannot tell us whether the detected DNA represented infectious virus.
Even so, the detection of mpox DNA on high-touch hospital surfaces during an active outbreak is difficult to dismiss. It points to environmental hygiene gaps that deserve attention now, not after a larger cluster develops. It also supports the idea that simple periodic environmental surveillance could help hospitals identify weak IPC points, guide staff training, and decide where disinfectant and supervision are needed most urgently.
The public health lesson is immediate and specific: during mpox outbreaks, the surfaces that get touched most often may also be the surfaces most likely to carry the burden of poor infection control.