Dutta Prafulla, Khan Siraj Ahmed, Hazarika Naba Kumar, Chetry Sumi
Arbovirology Group, Entomology Division, Regional Medical Research Centre, Dibrugarh, Assam, India.
Department of Microbiology, Gauhati Medical College and Hospital, Guwahati, Assam, India.
Indian J Med Microbiol. 2017 Jul-Sep;35(3):389-393. doi: 10.4103/ijmm.IJMM_16_127.
Northeast Region of India possesses an abundant number of Aedes mosquitoes, the common vector for Dengue and Chikungunya (CHIK). Dengue is reported every year from Assam, but active surveillance for CHIK virus (CHIKV) infection is lacking in this part of India. Therefore, this present study has been undertaken to detect any CHIKV infection during a dengue outbreak in Assam.
A total of 42 dengue negative samples collected from Guwahati were screened for the presence of CHIK IgM antibodies. Further, all the samples were processed for CHIKV RNA detection by reverse transcriptase-polymerase chain reaction (RT-PCR). Phylogenetic analysis was done by Maximum Likelihood method using Kimura-2 parameter model.
No IgM positivity was found in the processed samples; however, 7 samples were positive for CHIKV by RT-PCR. Phylogenetic analysis revealed that the circulating CHIKV belonged to Eastern, Central and Southern African genotype. Sequence analysis showed two uniform nucleotide substitutions and very less amino acid substitution.
Silent existence of CHIKV beside dengue is reported from this study. Therefore, CHIKV diagnosis should be included as a regular practice for active surveillance of the disease and its accomplishment before commencing an outbreak.
印度东北地区有大量伊蚊，是登革热和基孔肯雅热（CHIK）的常见传播媒介。每年都有来自阿萨姆邦的登革热报告，但印度这一地区缺乏对基孔肯雅病毒（CHIKV）感染的主动监测。因此，本研究旨在检测阿萨姆邦登革热疫情期间是否存在CHIKV感染。
对从古瓦哈蒂收集的42份登革热阴性样本进行CHIK IgM抗体检测。此外，所有样本均通过逆转录聚合酶链反应（RT-PCR）进行CHIKV RNA检测。采用最大似然法和Kimura-2参数模型进行系统发育分析。
处理后的样本中未发现IgM阳性；然而，7份样本通过RT-PCR检测CHIKV呈阳性。系统发育分析表明，传播的CHIKV属于东非、中非和南非基因型。序列分析显示有两个一致的核苷酸替换，氨基酸替换很少。
本研究报告了登革热疫情期间CHIKV的隐匿存在。因此，在疫情爆发前，应将CHIKV诊断作为该病主动监测及其防控的常规做法。
