Correlation between dengue virus serotypes in dengue patients and in mosquitoes at patients’ houses and surrounding in Northeastern Thailand

Abstract

Purpose: Dengue virus (DENV) is the most important causative agent of arthropod-borne viral disease in the tropical and subtropical regions of the world. DENV is transmitted between human to human via mosquitoes, Aedes aegypti and Aedes albopictus. By the late 2000s, the dengue was widespread among regions in Thailand and dengue hemorrhagic fever (DHF) had become a leading cause of hospitalization and death. Meanwhile dengue surveillance by mosquitoes control has been performed immediately after case report. To understand the role of dengue surveillance in Northeastern Thailand, DENV serotypes were investigated in mosquitoes at patients’ houses and surrounding area during 2016-2018. Methods & Materials: One hundred and eighty-eight mosquito pooled samples were collected from 97 dengue fever-suspected patients’ houses in 4 provinces in Northeastern Thailand – Khon Kaen, Roi Et, Kalasin and Mahasalakham province. DENV and serotyping were investigated in all pooled mosquito samples by two step reverse transcription quantitative polymerase chain reaction (RT-qPCR) using 5 sets of primer. The plasma samples of dengue fever-suspected patients from 8 hospitals were determined for DENV serotype by RT-PCR Results: DENV-RNA was found in 28.87% (28/97) of dengue-suspected patients and consisted of DENV-1 (15%), DENV-2 (7%), DENV-3 (17%), and DENV-4 (61%15). Meanwhile, DENV-RNA was found in 34.04% (64/188) of mosquito pools and consisted of DENV-1 (43%), DENV-4 (33%), DENV-2 (16%) and DENV-3 (8%). Interestingly, DENV detection in mosquito pools was positive in both of dengue patients’ houses (71%) and DENV negative patients’ houses (93%). The matching of DENV serotype in dengue patients and mosquito pools collected from their houses and surrounding area were 57% whereas unmatching DENV serotype was found in 43% of dengue patients and mosquito pools. Most of these patients were students (70%) and workers (29%) who spend day time outside their houses. Conclusion: The circulation of DENV was found in mosquitoes at patients’ houses and surrounding area and also from DENV negative patients’ houses. From the correlation of matching DENV serotype result might suggest that the source of DENV transmission is not only from mosquitoes in patient's house but also from others regions.