Chikungunya in Indonesia: Epidemiology and diagnostic challenges

Abstract

Background

Chikungunya virus (CHIKV) is often overlooked as an etiology of fever in tropical and sub-tropical regions. Lack of diagnostic testing capacity in these areas combined with co-circulation of clinically similar pathogens such as dengue virus (DENV), hinders CHIKV diagnosis. To better address CHIKV in Indonesia, an improved understanding of epidemiology, clinical presentation, and diagnostic approaches is needed.

Methodology/Principal findings

Acutely hospitalized febrile patients ≥1-year-old were enrolled in a multi-site observational cohort study conducted in Indonesia from 2013 to 2016. Demographic and clinical data were collected at enrollment; blood specimens were collected at enrollment, once during days 14 to 28, and three months after enrollment. Plasma samples negative for DENV by serology and/or molecular assays were screened for evidence of acute CHIKV infection (ACI) by serology and molecular assays. To address the co-infection of DENV and CHIKV, DENV cases were selected randomly to be screened for evidence of ACI. ACI was confirmed in 40/1,089 (3.7%) screened subjects, all of whom were DENV negative. All 40 cases initially received other diagnoses, most commonly dengue fever, typhoid fever, and leptospirosis. ACI was found at five of the seven study cities, though evidence of prior CHIKV exposure was observed in 25.2% to 45.9% of subjects across sites. All subjects were assessed during hospitalization as mildly or moderately ill, consistent with the Asian genotype of CHIKV. Subjects with ACI had clinical presentations that overlapped with other common syndromes, atypical manifestations of disease, or persistent or false-positive IgM against Salmonella Typhi. Two of the 40 cases were possibly secondary ACI.

Conclusions/Significance

CHIKV remains an underdiagnosed acute febrile illness in Indonesia. Public health measures should support development of CHIKV diagnostic capacity. Improved access to point-of-care diagnostic tests and clinical training on presentations of ACI will facilitate appropriate case management such as avoiding unneccessary treatments or antibiotics, early response to control mosquito population and eventually reducing disease transmission.

Author summary

Chikungunya virus (CHIKV) is often-overlooked as an etiology of fever in tropical and sub-tropical regions. Lack of diagnostic testing capacity in these areas combined with co-circulation of clinically similar pathogens such as dengue virus (DENV), hinders CHIKV diagnosis. The present study characterized the epidemiology, clinical presentation, and diagnostic approaches to better understand the CHIKV in Indonesia. We screened blood samples collected from children and adults with acute fever admitted to 8 hospitals in Indonesia from 2013–2016. Blood samples negative for DENV infection and a subset blood samples from confirmed DENV cases were then screened for acute CHIKV infection (ACI). ACI was confirmed in 40/1,089 (3.7%) screened patients, of whom initially received other diagnoses such as dengue fever, typhoid fever, and leptospirosis. All patients were considered as mildly or moderately ill, consistent with the Asian genotype of CHIKV. Given the unspecific clinical presentations of ACI, public health measures should support development of CHIKV diagnostic capacity. Improved access to point-of-care diagnostic tests will facilitate appropriate case management, such as avoiding unnecessary treatments or antibiotics, early response to control mosquito population, and eventually reducing disease transmission.