Objective: A response team was deployed to rural Oddar Meanchey Province, Cambodia, in mid-August 2023, immediately after a cluster of patients with acute febrile illness was reported. The team aimed to identify the cause of the outbreak and analyse the epidemiological characteristics and associated risk factors. Methods: This retrospective cohort study involved all residents of Prasat Rumdoul Village. A case was defined as a resident with a fever >=38°C or a history of fever with symptoms such as cough, sore throat or coryza occurring from 18 July to 18 August. Demographic data, information about infection prevention practices and clinical information were collected using structured questionnaires and analysed using binomial regression. Laboratory samples were collected, and confirmatory laboratory tests and environmental investigations were also conducted. Results: Among the 126 villagers, 95 cases were identified (attack rate: 75.3%); 52 (54.7%) were female, and the median age was 29 years. Prolonged close contact with individuals who had influenza-like illness significantly increased the risk of infection (adjusted risk ratio [ARR]: 2.19, P = 0.002). Protective factors included mask-wearing (ARR: 0.26, P = 0.003) and regular handwashing (ARR: 0.85, P = 0.012). No villagers had been vaccinated against influenza within the past 1 year. Laboratory tests confirmed influenza type B/Victoria as the causative agent. Poor adherence to preventive measures and crowded living conditions contributed to the outbreak. Discussion: The outbreak was caused by influenza type B/Victoria, the same strain circulating in nearby Thailand. Public health interventions to improve vaccine accessibility and hygiene-promotion activities would be useful for preventing future outbreaks.

Late initiation of antiretroviral therapy (ART) is associated with worse health outcomes for people living with HIV. In 2019, Cambodia implemented a same-day policy allowing people with HIV to start ART on the day they were diagnosed. Using case data collected by Cambodia’s National Center for HIV/AIDS Dermatology and STDs, this study examined trends and factors influencing late ART initiation among newly diagnosed HIV cases attending three clinics in Kampong Thom province from 2014 to 2023. Factors linked to late ART initiation (defined as starting treatment >1 day after diagnosis) were assessed using descriptive statistics and logistic regression. Statistical significance was set at P < 0.05. The study included 741 newly diagnosed HIV cases, with a mean age of 45.7 years at diagnosis (standard deviation: 10.2); 57.1% (423) of cases were female and more than 70% (504/704) were employed. In the 5-year period before the implementation of same-day ART initiation (2014–2018), 91% (325/356) of cases had late ART initiation. In the subsequent 5-year period (2019–2023), the proportion of cases with late ART initiation averaged 23%, and in 2023 was just 3%. Late ART initiation was more common at the Baray Santuk clinic (adjusted odds ratio: 3.94, 95% confidence interval: 1.99–7.81, P < 0.001), likely due to a lack of staff dedicated to HIV care. The findings demonstrate that same-day ART initiation is feasible in resource-limited settings and that adequate staffing can further improve prompt ART initiation.