Determination of viral etiology of Dengue, Zika and Chikungunya on the suspected cases in the surveillance in Ha Noi and Nam Dinh, 2017-2018

Abstract

The retrospective cross-sectional study was conducted in Hanoi and Nam Dinh from January 2017 to July 2018 to determine the etiology of Dengue, Chikungunya and Zika virus on the suspected cases. A total of 463 suspected cases in the survey in Hanoi (200 cases) and Nam Dinh (263 cases) were selected for the study. The prevalence of Dengue infection was 51.5% (103/200) in Hanoi and 32.7% (86/263) in Nam Dinh. The rates of Dengue RNA detection in seropositive groups were 5.8% and 9.3% in Hanoi and Nam Dinh, respectively. On both study sites, only Dengue serotype 1 was detected. In Dengue-seronegative groups, the serology testing showed that anti-Zika IgM positive rate was 2.1% in Hanoi (2/97) and 0.6% in Nam Dinh (1/177). Among Dengue and Zika-seronegative cases, the antiChikungunya IgM positive rate was 0% (0/95) in Hanoi and 3.4% (6/176) in Nam Dinh. RNA Zika and Chikungunya were not detected in sero-positive cases. Thus, Degue virus is still the predominant etiology in the suspected cases for dengue fever (40.8%, 189/463). Zika and Chikungunya etiologies just covered a very low rate among the cases without Dengue infection. Further studies to investigate the viral etiology in the suspected cases not infected by Dengue virus should be conducted.