Recent chikungunya outbreak in Sri Lanka 2006-2007

Abstract

BACKGROUND: Chikungunya(CHIK) is a viral disease transmitted by Aedes mosquitoes. Cases with symptoms of CHIK had been reported from several parts of Sri Lanka in 2006-2007. Laboratory testing of samples is a prime requirement for confirmation of transmission. OBJECTIVES: To confirm CHIK infection in suspected patients by rapid Reverse Transcription Polymerase Chain Reaction Assay(RT-PCR), find out manifestations specific for CHIK infection and study the transmission of CHIK virus by vector mosquitoes. METHODOLOGY: Serura. samples and information on clinical manifestations were collected from 189 chikungunya-suspected patients from different geographical areas in Sri Lanka from September 2006 to September 2007. Samples were tested for Chikungunya RNA by RT-PCR. Amplified products were visualized by agarose gel electrophoresis. Adult mosquitoes were also collected from chikungunya case-reported stations. They were tested for Chikungunya RNA through RT-PCR-followed by agarose gel electrophoresis assay. RESULTS: Of the CHIK-suspected patients reported from all parts of the island 86/189 (45.5%) were positive for CHIK virus. Of the PCR positive 06, all had fever with either arthralgia or arthritis or both. Headache (95.3%) and backache (84.6%) were also common among above patients. Eight percent (4/50) of both species of Aedes mosquitoes were RT-PCR positive. DISCUSSION: RT- PCR is important in early diagnosis of the infection and differentiation from dengue fever. The most common clinical symptoms observed were fever with either arthralgia, arthritis or both. Both Aedes aegypti and Aedes. albopictus are important in transmitting the disease.