4%) were lost to follow-up, 4 had missing sera and 18 were later excluded as they no longer fulfilled the inclusion criteria (travel to non-Asian destinations and/or did not return during the study period), leaving 387 travelers. The demographic characteristics of the 387 travelers in the study cohort have been described previously. A majority of travelers (75.5%) had traveled to Asia on a previous
occasion. There were no travelers infected with JE virus during travel to Asia as assessed by JE IgG seroconversion or clinical disease. As a result, the incidence density was zero cases of JE infection per 10,000 traveler-days this website (95% CI 0–3.9). During a 1-year period (2007–2008) of the study, JE vaccine was unavailable in Australia. Only 35 travelers (9%) were given JE vaccine prior to travel and they were excluded from the incidence-density analysis. The potential risk factors for JE infection were considered. Twenty-seven percent of travelers had a trip duration of 30 days or more and 55% (n = 214) reported one or more overnight stays in rural destinations. Peak travel periods
generally coincided with the rainy season for several Southeast Asian (SEA) countries (May to October). Of all the traveler-days in the study (n = 11,840), only 16% of the traveler-days were spent doing outdoor activities (hiking, camping, rock climbing, fishing, water skiing, and diving), 55% of Selleck TSA HDAC travelers stayed overnight in a rural location, Thiamet G and 1% reported camping outdoors. Adherence with mosquito repellent use was reported in 298 (81%) travelers, and 231 (61%) used either one or more of mosquito coils, nets, and long-sleeved clothing. Approximately 15% used no preventive measures. Of the travelers who completed the follow-up consultation, 363 travelers had no evidence of immunity to JE (post-travel antibodies ≤10). Low to moderate positive stationary (pre and post) antibody titers for JE (titers 40–80) were observed in 11 travelers of whom one had
pre- and post-travel antibody titer levels of 80. Two of these 11 travelers recalled past vaccination for JE prior to travel. Nonspecific levels of antibodies (>10–20) were observed in 13 travelers of whom 8 recalled past JE vaccination. There were no seroconversions for JE infection or clinical illnesses consistent with JE infection reported in this prospective cohort of Australian travelers. Interpretation of the 95% CIs around the estimate of zero cases of JE per 10,000 traveler-days should be done with care. Travelers have been infected in the past, so the true population risk is not zero. However, the upper bound of 3.9/10,000 traveler-days calculated is best thought of as indicative only, as it is affected by the sample size and the method of calculation. In addition, the CI is difficult to compare with the previous World Health Organization (WHO) crude estimate of one JE infection per million travelers as the latter estimate does not account for duration of exposure.