Clinical and epidemiologic evaluation of a 2020 chikungunya outbreak in Cambodia

Abstract

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 Chikungunya virus: A reemerging cause of acute febrile illness in the high jungle of northern Peru

“…In our study, the presence of vomiting was frequent and had statistical significance. This is consistent with other studies and reviews that indicate that vomiting is frequent in the clinical presentation of CHIKV infection without being a determinant clinical sign by itself [28,29].…”

National dengue surveillance, Cambodia 2002–2020

“… 12 , 45 , 46 Chikungunya virus re-emerged in Cambodia in 2011 with introduction of the east-central South African genotype, 47 but burden was not routinely assessed in national surveillance and outbreaks may have gone undetected until a large epidemic in 2020. 12 , 48 During this outbreak, the National Dengue Control Programme introduced arboviral differentiation RT–PCR in its sentinel surveillance programme. The 2020 outbreak consisted of 7014 suspected cases across 23 provinces; in 2021, a total of 1421 cases were reported across 15 provinces.…”

Serological and molecular evidence of chikungunya virus infection among febrile outpatients seeking healthcare in Northern Malawi

“…However, in a study done in Cambodia [ 40 ], the authors recommended that the significant and commonly reported symptoms of CHIKF should be acknowledged in the classification of clinical criteria for associating potential positive cases when using a syndromic approach in limited resource settings to make a differential diagnosis of CHIKF. This criteria may be particularly useful during the earliest stages of CHIKF outbreak to help health workers to identify potential suspected CHIKF patients and refer them for further laboratory testing for confirmation as lack of access to accurate rapid diagnostics creates a challenge [ 40 , 41 ]. Furthermore, serological diagnosis requires assessment of titers in convalescent samples hence creates minimal value for acute treatment decisions particularly during outbreaks.…”