, the etiologic agent of melioidosis, is predicted to be ubiquitous in tropical regions of the world with areas of highest endemicity throughout Southeast Asia (SEA). Nevertheless, the distribution of and the burden of melioidosis in many SEA countries remain unclear. In Cambodia, only two human endemic cases of melioidosis were reported through 2008 and since then only a few hundred cases have been described in the literature. This is in sharp contrast to the annual burden of thousands of cases in surrounding areas. To further investigate the prevalence of melioidosis in Cambodia, we used a recently developed O-polysaccharide-based rapid enzyme-linked immunosorbent assay to detect-specific antibodies in serum samples obtained from 1,316 febrile illness or sepsis patients from 10 different provinces. Based on a cutoff value derived through culture-confirmed melioidosis cases, the proportion of positive samples in our cohort was approximately 12%. Regression analysis indicated that the odds of obtaining a positive result were 2.2 times higher for males than females controlling for age and province (95% confidence interval: 1.6-3.2, < 0.001). Consistent with this, 9.2% of females were positive versus 18.2% of males ( < 0.001). Notably, 22.5% of grain or rice farmers were positive versus 10.1% of subjects with occupations not involving regular contact with soil. Positive results varied significantly by province. Collectively, the results of this study suggest that the true burden of melioidosis in Cambodia is greater than has previously been reported.

Background In 2020, the Kingdom of Cambodia experienced a nationwide outbreak of chikungunya virus (CHIKV). Despite an increase in the frequency of outbreaks and expanding geographic range of CHIKV, diagnostic challenges remain, and limited surveillance data of sufficient granularity are available to characterize epidemiological profiles and disease dynamics of the virus. Methods An ongoing and long-standing cross-sectional study of acute undifferentiated febrile illness (AUFI) in Cambodia was leveraged to describe the disease epidemiology and characterize the clinical presentation of patients diagnosed with CHIKV during the 2020 outbreak. Participants presenting with AUFI symptoms at ten study locations provided acute and convalescent blood samples and were tested for CHIKV using a reverse transcription-polymerase chain reaction (RT-PCR) and serological diagnostic methods including IgM and IgG. Acute and follow-up clinical data were also collected. Results From 1194 participant blood samples tested, 331 (27.7%) positive CHIKV cases were detected. Most CHIKV positive individuals (280, 84.6%) reported having a fever 3 to 4 days prior to visiting a health facility. Symptoms including chills, joint pain, nausea, vomiting, and lesions were all statistically significant among CHIKV positive participants compared to CHIKV negative AUFI participants. Cough was negatively associated with CHIKV positive participants. Positivity proportions were significantly higher among adults compared to children. No significant difference was found in positivity proportion between rainy and dry seasons during the outbreak. Positive CHIKV cases were detected in all study site provinces, with the highest test positivity proportion recorded in the rural northeast province of Kratie. Conclusions Surveillance data captured in this study provided a clinical and epidemiological characterization of positive CHIKV patients presenting at selected health facilities in Cambodia in 2020, and highlighted the widespread distribution of the outbreak, impacting both urban and rural locations. Findings also illustrated the importance of utilizing both RT-PCR and serological testing for effective CHIKV surveillance.

The objective of this prospective cohort study was to assess the incidence of dengue, chikungunya, respiratory viruses, and diarrheal etiologies among periurban and rural Cambodians with confirmed acute febrile illness. During a 2-year period (2016–2017), 612 participants aged 6 months to 30 years who exhibited vector-borne febrile illness (median [interquartile range] age, 8.0 [4–11] years), in which 288 (48.0%) were female, were tested for acute dengue virus and chikungunya virus infection. A total of 67 (11.2%) clinical specimens were positive for dengue virus by either nucleic acid detection (n = 23 [34.3%]; dengue serotype 1 [n = 5] and dengue serotype 2 [n = 18]) or dengue IgM capture enzyme-linked immunosorbent assay (n = 44 [65.7%]), and only 8 specimens were both positive. Clinical presentations included fever (100%), headache (74.1%), muscle aches (27.2%), and joint pain (17.3%). Forty-two of the 612 participants were diagnosed with chikungunya (7.0%) by anti–chikungunya virus enzyme-linked immunosorbent assay (IgM) or chikungunya-specific reverse transcription polymerase chain reaction. By understanding the incidence of diseases causing morbidity and mortality in rural areas within Cambodia, mitigating strategies can be developed to reduce infections.