Mpox in Kayamba Village, Nsama District, Zambia: A Case Series Report
Authors: Kennedy Salipako1,2,4, Nelia Phiri1,3, Wallace Luhanga1,4, James Ondya3, Nyambe Sinyange1,2
Affiliations: 1Zambia Field Epidemiology Training Program, 2Zambia National Public Health Institute, 3Nsama District Health Office, 4Northern Provincial Health Office
Corresponding author: Kennedy Salipako, ken.sali@yahoo.com
Abstract
Background: Mpox is a zoonotic viral disease historically endemic to Central and West Africa, with recent emergence in non-endemic regions, including Zambia. On May 27, 2025, Nsama District recorded its first suspected Mpox case, prompting an investigation into a household cluster in Kayamba Village. This case series study aimed to describe the epidemiological, clinical, and temporal characteristics of the affected household cluster.
Methods: A descriptive case series study was conducted involving four epidemiologically linked household members (one confirmed and three probable cases). Demographic and outpatient clinical data were collected via a structured questionnaire in KoboToolbox and clinical record review. Specimens from the confirmed case were processed at the Zambia National Public Health Reference Laboratory. Data were cleaned in Microsoft Excel and analyzed using R statistical software.
Results: Four Mpox cases (three males, one female) were identified in a seven-member household (median age: 34.5 years; range: 13–44). The index case, a 44-year-old HIV-positive male, tested PCR-positive. Symptom onset ranged from May 27 to June 17, 2025. One additional adult male was HIV-positive. Time from symptom onset to healthcare ranged from 1 to 17 days. The household secondary attack rate was 50% (3/6).
Conclusion: The investigation confirmed localized household transmission of Mpox in Nsama District, involving four epidemiologically linked cases. It demonstrated significant intra-household transmission and heightened risk among people living with HIV. Timely case identification, specimen collection, and active contact tracing are critical to containment. Continued surveillance and community engagement are essential, particularly during the 21-day observation period following the last case, to prevent wider transmission and guide public health response.
Keywords: Mpox, household transmission, case series, HIV comorbidity, Zambia
Introduction
Mpox, caused by the monkeypox virus (Orthopoxvirus genus), is a zoonotic disease of increasing global public health concern. First identified in monkeys in 1958 and subsequently in humans in 1970 in the Democratic Republic of Congo, Mpox was long considered a rare, self-limiting illness confined to forested regions of Central and West Africa. However, over the past two decades, the global epidemiological landscape has shifted. In 2022, multiple countries outside Africa reported significant outbreaks, highlighting the virus's capacity for sustained human-to-human transmission.
In Zambia, Mpox has not historically been recognized as a notifiable disease, and no endemic transmission had been documented until recently. However, the emergence of suspected and confirmed cases in different parts of the country, including rural areas, has raised concerns about silent transmission chains and gaps in surveillance. Understanding the transmission dynamics, risk factors, and clinical presentations of Mpox in the Zambian context is vital for national preparedness and regional public health response.
On May 29, 2025, a suspected Mpox case was reported at Kampinda Rural Health Centre in Nsama District, Northern Province, a district with no prior Mpox history. This triggered an urgent field investigation. During the investigation, four epidemiologically linked cases (one confirmed, three probable) were identified within a single household in Kayamba Village. This event represents the first documented household cluster in the district and provides critical insights into the potential community transmission of Mpox in rural Zambia.
