Pandey B D, Igarashi A
Department of Virology, Institute of Tropical Medicine, Nagasaki University, Japan.
Microbiol Immunol. 2000;44(3):179-88. doi: 10.1111/j.1348-0421.2000.tb02480.x.
Comparative nucleotide sequencing was carried out on dengue type 2 virus (DEN-2) strains isolated from patients in Northeast Thailand during the epidemic season in 1993. The patients exhibited different clinical manifestations ranging from dengue fever (DF) to dengue haemorrhagic fever (DHF)/dengue shock syndrome (DSS). The results classified 19 DEN-2 strains into 3 subtypes according to nonsynonymous amino acid replacements. The strain isolated from a DSS patient eliciting secondary serological response belonged to subtype I, whereas 13 strains isolated from DHF patients with secondary response and 2 strains from DF patients with primary response belonged to subtype II. On the other hand, 3 strains isolated from DF cases evoking either primary or secondary response belonged to subtype III. These results suggest that subtype III virus infection could result in clinically milder manifestation irrespective of the serological response compared with subtype I or II viruses. The RNA secondary structure predicted for the 3' noncoding region showed 4 different structures (A, B, C, and D). The result also indicates that different subtypes of DEN-2 serotypes are circulating in a single epidemic in Thailand.
对1993年流行季节从泰国东北部患者中分离出的2型登革热病毒（DEN-2）毒株进行了比较核苷酸测序。这些患者表现出从登革热（DF）到登革出血热（DHF）/登革休克综合征（DSS）的不同临床表现。结果根据非同义氨基酸替换将19株DEN-2毒株分为3个亚型。从引发二次血清学反应的DSS患者中分离出的毒株属于I型，而从有二次反应的DHF患者中分离出的13株毒株和从有初次反应的DF患者中分离出的2株毒株属于II型。另一方面，从引发初次或二次反应的DF病例中分离出的3株毒株属于III型。这些结果表明，与I型或II型病毒相比，III型病毒感染无论血清学反应如何都可能导致临床症状较轻。预测的3'非编码区RNA二级结构显示出4种不同结构（A、B、C和D）。该结果还表明，DEN-2血清型的不同亚型在泰国的一次单一流行中传播。
