Anoop M, Issac Aneesh, Mathew Thomas, Philip Sairu, Kareem Nabeel Abdul, Unnikrishnan R, Sreekumar E
Molecular Virology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud P O, Thiruvananthapuram 695 014, Kerala, India.
Indian J Exp Biol. 2010 Aug;48(8):849-57.
Dengue fever, a mosquito-borne viral infection, causes significant morbidity and has become endemic in the Indian subcontinent. Virus strains currently circulating in many parts of the country are not well studied at the molecular level. In the present study, genetic characterization of virus strains from a dengue outbreak that occurred in and around a tertiary care hospital in Ernakulam, Kerala in the year 2008 has been reported. By reverse transcription polymerase chain reaction (RT-PCR), 37 out of 75 (49.3%) clinically suspected cases were positive for dengue viral RNA. Among these, 21 (56.8%) samples showed concurrent infection with multiple serotypes of the virus. Majority of the combined infections were caused by dengue serotype 2 and 3. Co-infections with type 1 and 2 in two patients, and type 1, 2 and 3 in one patient were also observed. The core-pre-Membrane (CprM) junction nucleotide sequencing and phylogenetic analysis revealed that the type 1 strains were related to the viral strains reported from Delhi-2001 and Gwalior-2002 dengue outbreaks, while the type 2 strains were related to the strains from Gwalior-2001 epidemic. Sequences of type 3 strains did not show clear relation to any of the previous Indian isolates, and in the phylogenetic analysis, they formed a distinct lineage within the Indian type 3 strains. This study indicates hyperendemicity of dengue in the region with the presence of multiple serotypes and high rates of co-infection, and local genomic evolution of the viral strains involved in this outbreak.
登革热是一种由蚊子传播的病毒感染疾病，会导致严重的发病率，并且在印度次大陆已成为地方病。目前在该国许多地区传播的病毒株在分子水平上尚未得到充分研究。在本研究中，报告了2008年在喀拉拉邦埃纳库拉姆一家三级护理医院及其周边地区发生的登革热疫情中病毒株的基因特征。通过逆转录聚合酶链反应（RT-PCR），75例临床疑似病例中有37例（49.3%）登革病毒RNA呈阳性。其中，21份样本（56.8%）显示同时感染了该病毒的多种血清型。大多数合并感染是由登革热血清型2和3引起的。还观察到两名患者同时感染了1型和2型，一名患者同时感染了1型、2型和3型。核心-前膜（CprM）连接核苷酸测序和系统发育分析表明，1型毒株与2001年德里和2002年瓜廖尔登革热疫情报告的病毒株有关，而2型毒株与2001年瓜廖尔疫情的毒株有关。3型毒株的序列与之前的任何印度分离株均无明显关系，在系统发育分析中，它们在印度3型毒株中形成了一个独特的谱系。这项研究表明该地区登革热高度流行，存在多种血清型和高合并感染率，以及此次疫情中涉及的病毒株的局部基因组进化。
