Reemergence of Chikungunya virus in Cambodia

Abstract

Chikungunya virus (CHIKV), probably Asian genotype, was first detected in Cambodia in 1961. Despite no evidence of acute or recent CHIKV infections since 2000, real-time reverse transcription PCR of serum collected in 2011 detected CHIKV, East Central South African genotype. Spatiotemporal patterns and phylogenetic clustering indicate that the virus probably originated in Thailand.

Figure 1

Spatiotemporal pattern of chikungunya cases showing the 6 provinces in which cases occurred and the most likely route of virus introduction into Cambodia, 2011. Adapted, with permission, from www.nationsonline.org/oneworld/map/cambodia-administrative-map.htm.

Figure 2

Phylogenetic tree based on the whole genome of chikungunya virus (CHIKV). Viruses were identified by using the GenBank accession number, country code, and year of isolation. Boldface indicates strains from Cambodia; circles indicate isolates from Preah Vihear Province; triangles indicate strains from Battambang Province. Arrow indicates enlarged Indian Ocean outbreak strains. All 8 strains from Cambodia carried the A226V mutation. Numbers represent the bootstrap support obtained for respective branches (>70). The tree was rooted by o’nyong-nyong virus (GenBank accession no. AF079456, UGA96-ONNV). ECSA, East Central South African genotype. Scale bars indicate nucleotide substitutions per site.