Differences in Transmission and Disease Severity Between 2 Successive Waves of Chikungunya. (25th April 2018)

• Record Type: Journal Article
• Authors: Gordon, Aubree; Gresh, Lionel; Ojeda, Sergio; Chowell, Gerardo; Gonzalez, Karla; Sanchez, Nery; Saborio, Saira; Mercado, Juan Carlos; Kuan, Guillermina; Balmaseda, Angel; Harris, Eva
• Is Part Of: Clinical infectious diseases. Volume 67:Number 11(2018)
• Page Start: 1760
• Page End: 1767
• Publication Date: 2018-04-25
• Subjects: chikungunya -- Nicaragua -- cohort study -- attack rate -- epidemic; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciy356
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract : Chikungunya was recently introduced into the Americas. Relatively little data exist about the introduction of chikungunya into naive populations. This study examines differences in transmission intensity and clinical severity between 2 epidemics of chikungunya in a single cohort in Nicaragua. Abstract: Background: Chikungunya, an arboviral disease, caused massive epidemics in Central and South America in 2014–2016. In a prospective pediatric cohort study, we examined the introduction of chikungunya in a naive population and investigated transmission and clinical characteristics. Methods: Children presenting to the study health center with a chikungunya-like illness or undifferentiated fever were tested for chikungunya virus (CHIKV) infection by reverse transcriptase-polymerase chain reaction (RT-PCR) and serological assays. Inapparent CHIKV infections in the intervening year were determined by seroconversion in healthy blood samples collected annually. Results: A total of 4353 children participated in the cohort study from March 2014 to February 2016 during the 2 epidemic waves of chikungunya. A total of 539 cases of chikungunya were documented, for an incidence rate of 80.2 cases per 1000 person-years (95% confidence interval [CI]: 73.7, 87.2); and a total of 893 CHIKV infections were documented, for an incidence rate of 137.1 infections per 1000 person-years (95% CI: 128.4, 146.4). The seroprevalence of anti-CHIKV antibodies increased linearly with age, with seroprevalence of >45% in 14-year-old children at the end of Epidemic 2. Symptom presentation varied between the epidemics, with Epidemic 2 exhibiting both a higher symptomatic-to-inapparent ratio (1:1.20 in Epidemic 1 vs. 1:0.65 in Epidemic 2) and more severe clinical presentation among cases. The mean reproduction number was also greater in Epidemic 2 than in Epidemic 1. Conclusions: The intensity of transmission and severity of clinical presentation varied between the 2 epidemics, with higher transmission intensity associated with greater disease severity.