• Amornphat Kitro, Hisham Ahmed Imad, Phimphan Pisutsan, Wasin Matsee, Wachiranun Sirikul, Ratana Sapbamrer, Erica Rapheal, Stefan Fernandez, Thomas S Cotrone, Aaron R Farmer, Taweewun Hunsawong, Udomsak Silachamroon, Lapakorn Chatapat, Jutarmas Olanwijitwong, Parichat Salee, Kathryn B Anderson, and Watcharapong Piyaphanee.
• Department of Community Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
• J Travel Med. 2024 Mar 1; 31 (2).

BackgroundTravel to Southeast Asia increases the likelihood of acquiring mosquito-borne Flavivirus infections such as dengue (DENV), Japanese encephalitis (JEV) and Zika viruses (ZIKV). Expatriates are long-term travellers who have a higher risk of mosquito-borne illness at their destination country. The purpose of this study was to evaluate the seroprevalence of DENV, JEV and ZIKV infections and the determinants contributing to seropositivity among expatriates living in Thailand.MethodsA cross-sectional study was performed from December 2017 to February 2020. Expatriates from non-Flavivirus endemic countries were recruited. 5 mL of blood was collected for DENV 1-4, JEV and ZIKV antibody testing by plaque reduction neutralization test (PRNT50). Individuals with vaccination histories or diagnoses for dengue, Japanese encephalitis, yellow fever and tick-borne encephalitis were excluded.ResultsAmong 254 participants, most participants (83.1%) were male, the mean age was 65 years and the median duration of stay in Thailand was 6 years. Seroprevalence rate of any Flavivirus, non-specific DENV, DENV1-4, JEV and ZIKV were 34.3, 30.7, 20.5, 18.1, 18.9, 10.6, 4.7 and 2.8%, respectively. The presence of neutralizing antibodies against DENV1-4 positively correlates with the duration of stay in Thailand. DENV seropositivity was associated with living in urban areas (aOR 2.75, 95% CI 1.36-5.57). Expatriates were unlikely to have detectable anti-JEV antibodies regardless of time spent in a JEV-endemic area. No risk factors were identified that were significantly associated with JEV or ZIKV seropositivity. Only 48.4% received pre-travel counselling services, while only 18.9% visited a travel medicine specialist.ConclusionsA high proportion (34.3%) of long-term expatriates living in Thailand were seropositive for flavivirus, mainly from dengue (30.7%). To minimize risk, travel medicine practitioners should provide adequate pre-travel health risk information on mosquito-borne flavivirus infection and offer advice on mosquito bite prevention strategies. Dengue vaccine might be considered in high-risk travellers such as long-term expatriate.© International Society of Travel Medicine 2024. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

25 keywords...

hide…