Incidence and seroprevalence of dengue virus infections in Australian travellers to Asia

Abstract

The purpose of this study was to estimate the incidence density and prevalence of dengue virus infection in Australian travellers to Asia. We conducted a multi-centre prospective cohort study of Australian travellers over a 32-month period. We recruited 467 travellers (≥ 16 years of age) from three travel clinics who intended to travel Asia, and 387 (82.9%) of those travellers completed questionnaires and provide samples pre- and post-travel for serological testing for dengue virus infection. Demographic data, destination countries and history of vaccinations and flavivirus infections were obtained. Serological testing for dengue IgG and IgM by enzyme-linked immunosorbent assay (ELISA) (PanBio assay) was performed. Acute seroconversion for dengue infection was demonstrated in 1.0% of travellers, representing an incidence of 3.4 infections per 10,000 days of travel (95% confidence interval [CI]: 0.9-8.7). The seroprevalence of dengue infection was 4.4% and a greater number of prior trips to Asia was a predictor for dengue seroprevalence (p = 0.019). All travellers experienced subclinical dengue infections and had travelled to India (n = 3) and China (n = 1). This significant attack rate of dengue infection can be used to advise prospective travellers to dengue-endemic countries.

Dengue Virus Seroconversion in Travelers to Dengue-Endemic Areas

“…Several other studies used similar methods to calculate DENV-Ab seroconversion in different populations of travelers and found similar results. [7][8][9][10][11] Cobelens and others studied travelers to Asia for 1-13 weeks, excluding samples whose DENV-Ab titers were exceeded by JE-Ab titers, and found 2.9% seroconversion with an IR of 30 per 1,000 personmonths. 8 Potasman and others studied travelers who stayed at least 3 months in tropical areas and found that 6.7% seroconverted.…”

“…We used information from previous prospective studies showing rates ranging from 1.1% to 6.7% to assume a rate of 5% DENV-Ab seroconversion. [7][8][9][10][11] A sample size of 1,166 participants would allow calculation of the proportion of travelers with DENV-Ab seroconversion with 1.25% margin of error, using a 95% confidence interval (CI). We aimed to enroll 240 participants at each site, but expiration of grant funding limited recruitment of the desired sample size.…”

“…Five prospective studies, two in Dutch, one in Israeli, one in Swiss, and one in Australian travelers, reported DENV seroconversion in 1.0-6.7% of adults traveling to dengue-endemic areas. [7][8][9][10][11] No prospective study of DENV antibody (DENV-Ab) seroconversion has been conducted in travelers from the United States. The objective of this study was to measure DENV-Ab seroconversion in travelers to dengue-endemic countries.…”

Identification of Concurrent Bacterial Infection in Adult Patients with Dengue

“…Like others, we used the IgM assay as one of our confirmatory tests for dengue. [9][10][11][12][13][14][15] The likelihood of cross-reactivity was low, because other flaviviruses (yellow fever, Japanese encephalitis, tick-borne encephalitis, and West Nile fever) are not endemic in our setting. Also, IgM antibodies are specific, even in Japanese encephalitis and yellow fever vaccinees.…”

Seroprevalencia en una zona de hiperendemia por dengue, en Barranquilla, Colombia

“…Resultados: a soroprevalência para IgG foi 88,2 % (IC 95 % =85,2-91,1) e para IgM de 11,8 % (IC 95%= 8,80-14,75). Constatouse associação estatística em idades de 30 a 49 e 50 a 69 anos (OR=7,09 [2,[6][7][8][9][10][11][12][13][14][15][16][17][18][19]3] e OR= 8,93 [2,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27],0] respectivamente), pertencer ao sistema de saúde subsidiado (OR=2,56 [1,53]) e ocupação do lar (OR= 3,38 [1,67]. Conclusões: a alta soroprevalência para IgG é explicada pela circulação dos quatro sorotipos no país, os surtos epidêmicos a cada dois ou três anos e os comportamentos e práticas desfavoráveis relacionados com o uso da água.…”