The risk of Japanese encephalitis (JE) in travelers is unknown. In this prospective study, we investigated the incidence of JE in 387 short-term Australian travelers visiting Asia over a 32-month period from August 2007 to February 2010 by performing pre- and post-travel antibody testing. No travelers were infected with JE virus during travel, indicating a low risk of infection for short-term travelers.

We analyzed paired pre- and post-travel sera in a cohort of Australian travelers to Asia and demonstrated the acquisition of hepatitis C virus (HCV) and hepatitis B virus (HBV) infection. The incidence density in nonimmune travelers for HCV infection was calculated as 1.8 infections per 10,000 traveler-days and for HBV infection 2.19 per 10,000 traveler-days.

Hepatitis B and C virus (HBV and HCV) cause significant morbidity and mortality worldwide. With the rise in international travel over the last three decades, many travelers are at risk of HBV and HCV infection.This review focuses on the epidemiology of HBV and HCV in international travelers, the modes of transmission, and the prevention of infection in travelers.The risk of HBV and HCV infection varies widely and depends on the prevalence of the destination country, the duration of travel, and the activities undertaken while abroad. Travelers commonly undertake high-risk activities that place them at risk of both HBV and HCV infection. Poor uptake of preventative health measures and poor adherence to health recommendations are also common. The monthly incidence of HBV infection for long-term travelers to endemic countries ranges from 25 to 420 per 100,000 travelers. HBV infection can be prevented through timely vaccination of travelers. HBV vaccination is safe and efficacious with protective levels of antibodies achieved in >90% of recipients. Information regarding the risk of HCV acquisition is scarce and until recently was limited to case reports following medical interventions.This review demonstrates international travelers are at risk of HBV and HCV infection and provides evidence-based information enabling health practitioners to provide more appropriate pre-travel advice. HBV vaccination should be considered in all travelers to countries with a moderate to high HBV prevalence (HBsAg ≥ 2%) and the risk and benefits discussed with the individuals in consultation with the health practitioner. There is no duration of travel without risk of HBV infection. However, it is apparent that those travelers with a longer duration of travel are at greatest risk of HBV infection (ie, expatriates). Travelers should also receive advice regarding the modes of transmission and the activities that place them at risk of both HBV and HCV infection.

Dengue virus ( DENV) nonstructural protein 1 ( NS1) has been used as a novel diagnostic marker during the early phase of DENV infection.Presence of NS1 antigen was examined using 336 serum samples obtained from 276 travelers returning to Japan from Asia, Central and South America, Pacific Islands, and Africa with dengue. Assay specificity was evaluated using 148 non-dengue samples.Positive rates among four DENV serotypes were 68%-89%. NS1 antigen positive rates were at similar levels between primary infection and secondary infection. NS1 antigen positive rates were 88%-96% on days 1-5, 75%-100% on days 6-10, and 36-60% on ≥day 11. Positive rates using real-time polymerase chain reaction (RT-PCR) were over 70% on days 1-5, but decreased thereafter.The results indicate that NS1 antigen positive rates were higher than those of RT-PCR during longer period of early phase in DENV infection. Thus, NS1 antigen ELISA is a useful tool for confirming DENV infection in international travelers, when it is used in combination with anti-DENV IgM ELISA.

International travelers were at risk of acquiring influenza A(H1N1)pdm09 (H1N1pdm09) virus infection during travel and importing the virus to their home or other countries.Characteristics of travelers reported to the GeoSentinel Surveillance Network who carried H1N1pdm09 influenza virus across international borders into a receiving country from April 1, 2009, through October 24, 2009, are described. The relationship between the detection of H1N1pdm09 in travelers and the level of H1N1pdm09 transmission in the exposure country as defined by pandemic intervals was examined using analysis of variance (anova).Among the 203 (189 confirmed; 14 probable) H1N1pdm09 case-travelers identified, 56% were male; a majority, 60%, traveled for tourism; and 20% traveled for business. Paralleling age profiles in population-based studies only 13% of H1N1pdm09 case-travelers were older than 45 years. H1N1pdm09 case-travelers sought pre-travel medical advice less often (8%) than travelers with non-H1N1pdm09 unspecified respiratory illnesses (24%), and less often than travelers with nonrespiratory illnesses (43%; p < 0.0001). The number of days from first official H1N1pdm09 case reported by a country to WHO and the first GeoSentinel site report of a H1N1pdm09-exported case in a traveler originated from that country was inversely associated with each country's assigned pandemic interval, or local level of transmission intensity.Detection of travel-related cases appeared to be a reliable indicator of sustained influenza transmission within the exposure country and may aid planning for targeted surveillance, interventions, and quarantine protocols.

The number of people, both adults and children, traveling abroad, is on the rise. Some seek counseling at travel medicine centers before departure.A prospective study was conducted among children <16 years visiting a travel medicine center in Marseille, France, from February 2010 to February 2011. Parents were contacted by telephone 4 weeks after their return, and asked about compliance with pre-travel advice.One hundred sixty-seven children were evaluated after their trip. Compliance with immunizations, malaria chemoprophylaxis, and food-borne disease prevention was 71, 66, and 31%, respectively. Compliance with malaria chemoprophylaxis varied significantly with destination, and was higher for African destinations. Significant features associated with poor compliance with chemoprophylaxis were a trip to Asia or the Indian Ocean, age <5 years, and a monoparental family. Compliance with prevention of food- and water-borne diseases was higher in children < 2 years of age.A ≥80% compliance with pre-travel counseling in children traveling overseas was achieved only for drinking bottled water, using repellents, a routine vaccine update, and yellow fever immunization.

Japanese encephalitis (JE) vaccine is recommended for travelers to Asia whose itineraries increase their risk of exposure to JE virus. The numbers of travelers with such itineraries and the proportion of those who receive JE vaccine are unknown. We performed a survey to estimate the proportion of US travelers to Asia who receive JE vaccine according to the Advisory Committee on Immunization Practices (ACIP) recommendations.We surveyed US residents ≥18 years old departing on 38 flights to Asia selected through a stratified random sample of all direct flights to JE-endemic countries from three US airports. We asked participants about planned itineraries and activities, sources of travel health information, JE vaccination status, and potential barriers to vaccination. Participants planning to spend ≥30 days in Asia or at least half of their time in rural areas were defined as "higher JE risk" travelers for whom vaccination should have been considered.Of 2,341 eligible travelers contacted, 1,691(72%) completed the survey. Among these 1,691 participants, 415 (25%) described itineraries for which JE vaccination should have been considered. Of these 415 higher JE risk travelers, only 47 (11%) reported receiving ≥1 dose of JE vaccine. Of the 164 unvaccinated higher JE risk travelers who visited a health care provider before their trip, 113 (69%) indicated that they had never heard of JE vaccine or their health care provider had not offered or recommended JE vaccine.A quarter of surveyed US travelers to Asia reported planned itineraries for which JE vaccination should have been considered. However, few of these at-risk travelers received JE vaccine.

Travelers to countries where rabies is endemic may be at risk of rabies exposure. We assessed rabies immunization of travelers attending a travel clinic in Thailand.The medical charts of international travelers who came for preexposure (PrEP) or postexposure (PEP) rabies prophylaxis at the Queen Saovabha Memorial Institute (QSMI), Bangkok, Thailand between 2001 and 2011 were retrospectively reviewed.A total of 782 travelers, including 188 patients who presented with mammal-associated injuries and possible rabies exposures and 594 persons who came requesting PrEP, were studied. Of the travelers who received PEP, only 27 (14.3%) had been previously immunized against rabies and 141 (75.0%) cases experienced high-risk WHO category III exposure. Most of the incidents were unprovoked. Although promptly seeking medical services after the injuries, 114 (60.7%) travelers did not undertake any first-aid care for their wounds. Of these travelers, 19 (10.3%) received intradermal rabies vaccination as they could complete the series here. Rabies immunoglobulin was given to 118 of 121 (97.5%) patients. About one fourth of recipients could accomplish the full schedule at QSMI. Among visitors who requested PrEP, 454 (76.4%) persons had just started their first dose. Among all visitors, 263 (44.3%) were Japanese. The number of Japanese asking for PrEP was higher in 2006, the year when cases of imported human rabies to Japan were reported. This trend has sustained since then. Two (0.3%) travelers were bitten by suspected rabid dogs before they completed their PrEP program.Rabies prophylaxis is an important decision for each traveler. It should be made before visiting endemic areas.