First Chikungunya Outbreak in Suriname; Clinical and Epidemiological Features

Abstract

Background: In June 2014, Suriname faced the first Chikungunya outbreak. Since international reports mostly focus on hospitalized patients, the least affected group, a study was conducted to describe clinical characteristics of mainly outpatients including children. In addition, the cumulative incidence of this first epidemic was investigated.

Methodology: During August and September 2014, clinically suspected Chikungunya cases were included in a prospective follow-up study. Blood specimens were collected and tested for viral RNA presence. Detailed clinical information was gathered through multiple telephone surveys until day 180. In addition, a three stage household-based cluster with a cross-sectional design was conducted in October, December 2014 and March 2015 to assess the cumulative incidence.

Principal findings: Sixty-eight percent of symptomatic patients tested positive for Chikungunya virus (CHIKV). Arthralgia and pain in the fingers were distinctive for viremic CHIKV infected patients. Viremic CHIKV infected children (≤12 years) characteristically displayed headache and vomiting, while arthralgia was less common at onset. The disease was cleared within seven days by 20% of the patients, while 22% of the viremic CHIKV infected patients, mostly women and elderly reported persistent arthralgia at day 180. The extrapolated cumulative CHIKV incidence in Paramaribo was 249 cases per 1000 persons, based on CHIKV self-reported cases in 53.1% of the households and 90.4% IgG detected in a subset of self-reported CHIKV+ persons. CHIKV peaked in the dry season and a drastic decrease in CHIKV patients coincided with a governmental campaign to reduce mosquito breeding sites.

Conclusions/significance: This study revealed that persistent arthralgia was a concern, but occurred less frequently in an outpatient setting. The data support a less severe pathological outcome for Caribbean CHIKV infections. This study augments incidence data available for first outbreaks in the region and showed that actions undertaken at the national level to mount responses may have positively impacted containment of this CHIKV outbreak.

Fig 1. Study participation profile of the Chikungunya cohort for the prospective study.

Fig 2. Clinical symptoms of viremic CHIKV infected patients at onset, day 7, 14, 30 and 90.

Data collected from the viremic CHIKV infected individuals enrolled in the telephone survey. Actual number of patients at each time point per symptom: 1) D0: fever (n = 98), arthralgia and rash (n = 96), back pain and vomiting (n = 93), myalgia (n = 92), itching (n = 87) and other symptoms (n = 90); 2) D7: arthralgia (n = 83), fever (n = 82), rash (n = 81), myalgia (n = 80), vomiting (n = 78), back pain (n = 77), eye pain (n = 74), itching (n = 73) and other symptoms (n = 75); 3) D14: arthralgia (n = 73), rash (n = 72) and other symptoms (n = 71); 4) D30: arthralgia and rash (n = 86) and other symptoms (n = 84), and 5) D90: rash (n = 86), itching (n = 84), arthralgia (n = 83) and other symptoms (n = 82). Presence of fever was only registered until 7 days after infection.

Fig 3. Number of reported CHIKV cases reported (July 2014-March 2015).

Monthly rainfall (mm, obtained from the Meterological Center in Suriname) is also depicted; for weeks containing overlapping days from two months (i.e. week 31, 36, 40, 44 and 49), rainfall is depicted for the month with the most days in that week.