No chikungunya virus infections among Dutch long-term travellers to (sub)tropical countries: A prospective study 2008-2011

Background: Chikungunya is an arthropod-borne viral disease now identified in over 60 countries in Asia, Africa, Europe, and the Americas. Chikungunya virus (CHIKV) has spread in the last 15 years to many countries, causing large local outbreaks. CHIKV infection can be clinically misdiagnosed in areas where dengue and/or Zika infections occur. Prospective studies are necessary to calculate the true incidence rate of CHIKV infection in travellers. The aim of this study was to obtain the attack and incidence rates of CHIKV infection among long-term travellers and identify associated risk factors. Methods: A previously collected prospective cohort of Dutch long-term travellers (12-52 weeks) to subtropical and tropical countries was tested. From December 2008 to September 2011, participants were recruited at the travel clinic of the Public Health Service Amsterdam. A weekly diary was kept during travel in which participants recorded their itinerary, symptoms, and physician visits. On return, their pre- and post-travel blood samples were tested for the presence of IgG antibodies to CHIKV antigen. Seroconversions were confirmed by an in-house CHIKV neutralisation test. Results: The median age of 603 participants was 25 years (interquartile range [IQR]: 23-29); 35.7% were male; median travel duration was 20 weeks (IQR: 15-25), and purpose of travel was predominantly tourism (62%). The presence of anti-CHIKV IgG in the pre-travel sample, suggestive of previous CHIKV infection, was found for 3/603 participants (0.5%); all three had been previously travelling in either Africa or Asia. In one traveler who visited Latin America, a seroconversion was found (0.2%) but the CHIKV neutralisation test was negative, making the incidence rate 0. Conclusion: No chikungunya virus infections were found in this 2008-2011 prospective cohort of long-term travellers. We recommend the research be repeated, particularly as the sample size of our cohort might have been too small. Also, extensive spread of chikungunya virus has likely increased incidence rates among travellers since 2013

Hepatitis E in long-term travelers from the Netherlands to subtropical and tropical countries, 2008–2011

Hepatitis E virus (HEV) is a common cause of acute viral hepatitis. Virus genotypes 1 and 2 infect humans in developing countries by the fecal–oral route. To assess attack rates and disease incidence for travelers, we prospectively studied 604 long-term travelers to subtropical and tropical countries. Participants donated blood samples pretravel and posttravel and kept a diary. A total of 89/604 (15%) pretravel samples were positive for HEV IgG by ELISA, suggesting previous HEV infection. Seroconversion for HEV was found for 19/515 travelers (attack rate 3.7%, incidence 1.8 cases/1,000 person-weeks). We believe there is a substantial risk for acquiring HEV infection among long-term travelers. Although HEV infection does not seem to be a major problem in this healthy cohort, hygienic measures should be stressed in all pretravel health advice, particularly for pregnant women and immunocompromised travelers who are at risk for severe disease

Dutch Travel Health Nurses: Prepared to Prescribe?

Background. In travel medicine, as in other specialties, independent prescribing of medication has traditionally been the domain of practitioners like physicians, dentists, and midwives. However, a 2011 ruling in the Netherlands expands independent prescribing and introduces supplementary prescribing by nurses, with expected implementation over the next few years. As specialist nurses will not be eligible for independent prescribing, this study addresses supplementary prescribing, specifically by travel health nurses. Such nurses will work in partnership with an independent prescriber, usually a physician. After the physician evaluates a patient's condition and needs, the nurse may prescribe from an open or limited formulary. This supplementary approach seems appropriate in travel medicine, which is highly protocolized. A questionnaire survey was conducted to assess whether travel health nurses themselves aspire and feel competent to prescribe, and what training they might need. Methods. All travel health nurses in the Netherlands received a questionnaire seeking their anonymous response. Results. The response rate was 58%. Self-reported compliance with protocols and quality criteria was high; 82% of respondents aspire to prescribe and 77% feel competent to prescribe. Of the latter, 22% indicated that ongoing access to a doctor would remain important, and 14% preferred to prescribe under certain conditions like a restricted number of medicines. The reason most frequently given for not feeling competent was the need for additional education before obtaining prescribing rights (40%). Aspiration to prescribe was the only significant predictor for feeling competent to prescribe (odds ratios: 6.8; 95% confidence intervals: 3.5-13). Of all the responding nurses, 95% reported one or more educational needs related to prescribing, particularly in pharmacology. Conclusions. Most Dutch travel health nurses aspire to prescribe and feel competent for the supplementary approach, but require further education before the approach is implemented in travel medicin

Low incidence of helminth infections (schistosomiasis, strongyloidiasis, filariasis, toxocariasis) among Dutch long-term travelers: A prospective study, 2008-2011

<div><p>Background</p><p>Despite the considerable burden of helminth infections in developing countries and increasing international travel, little is known about the risks of infection for travelers.</p><p>Objective</p><p>We studied the attack and incidence rate of serology confirmed strongyloidiasis, filariasis, and toxocariasis among long-term travelers and associated factors. A second objective was to evaluate eosinophilia as a positive/negative predictive value (PPV/NPV) for a recent helminth infection.</p><p>Methods</p><p>From 2008 to 2011, clients of the Public Health Service travel clinic planning travel to (sub)tropical countries for 12–52 weeks were invited to participate in a prospective study. Participants kept a weekly diary, recording itinerary, symptoms, and physician visits during travel and completed a post-travel questionnaire. Pre- and post-travel blood samples were serologically tested for the presence of IgG antibodies against <i>Schistosoma</i> species, <i>Strongyloides stercoralis</i>, filarial species, and <i>Toxacara</i> species and were used for a blood cell count. Factors associated with recent infection were analyzed using Poisson regression. Differences among groups of travelers were studied using chi square tests.</p><p>Results</p><p>For the 604 participants, median age was 25 years (interquartile range [IQR]: 23–29), 36% were male, median travel duration was 20 weeks (IQR: 15–25), and travel purpose was predominantly tourism (62%). Destinations were Asia (45%), Africa (18%), and the Americas (37%).</p><p>Evidence of previous infection was found in 13/604 participants: antibodies against <i>Schistosoma</i> spp. in 5 (0.8%), against <i>S</i>.<i>stercoralis</i> in 3 (0.5%), against filarial species in 4 (0.7%), and against <i>Toxocara</i> spp. in 1 (0.2%). Ten recent infections were found in 9 participants (3, 1, 6, 0 cases, in the above order), making the attack rates 0.61, 0.17, 1.1 and 0, and the incidence rates per 1000 person-months 1.5, 0.34, 2.6 and 0. The overall PPV and NPV of eosinophila for recent infection were 0 and 98%, respectively.</p><p>Conclusions</p><p>The risk of the helminth infections under study in this cohort of long-term travelers was low. Routine screening for eosinophilia appeared not to be of diagnostic value.</p></div

Post-travel eosinophilia among long-term travelers during travel, including participants with evidence of infection with <i>Schistosoma</i> spp., <i>S</i>.<i>stercoralis</i> and/or filarial species.

<p>Post-travel eosinophilia among long-term travelers during travel, including participants with evidence of infection with <i>Schistosoma</i> spp., <i>S</i>.<i>stercoralis</i> and/or filarial species.</p

Characteristics, eosinophil counts, and risk behavior of participants with serologic evidence for infection with <i>Schistosoma</i> spp., <i>S</i>.<i>stercoralis</i>, filarial species, and/or <i>Toxocara</i> spp.

<p>Characteristics, eosinophil counts, and risk behavior of participants with serologic evidence for infection with <i>Schistosoma</i> spp., <i>S</i>.<i>stercoralis</i>, filarial species, and/or <i>Toxocara</i> spp.</p

Attack and incidence rates of infection with <i>Schistosoma</i> spp., <i>S</i>.<i>stercoralis</i>, filarial species, and/<i>or Toxocara</i> spp. among long-term travelers with evidence of seroconversion during travel.

<p>Attack and incidence rates of infection with <i>Schistosoma</i> spp., <i>S</i>.<i>stercoralis</i>, filarial species, and/<i>or Toxocara</i> spp. among long-term travelers with evidence of seroconversion during travel.</p

Dengue virus infection among long-term travelers from the Netherlands: A prospective study, 2008-2011

<div><p>Background</p><p>Dengue is increasing rapidly in endemic regions. Data on incidence among travelers to these areas are limited. Five prospective studies have been performed thus far, mainly among short-term travelers.</p><p>Objective</p><p>To obtain the attack and incidence rate (AR, IR) of dengue virus (DENV) infection among long-term travelers and identify associated risk factors.</p><p>Methods</p><p>A prospective study was performed among long-term travelers (12–52 weeks) attending the Public Health Service in Amsterdam. Clients planning to travel to (sub)tropical countries were invited to participate. Participants kept a travel diary, recording itinerary, symptoms, and physician visits. Pre- and post-travel blood samples were serologically tested for the presence of Anti-DENV IgG antibodies. Seroconversion was considered suggestive of a primary DENV infection. Anti-DENV IgG present in both corresponding samples in combination with a post-/pre-travel ratio of ≥4:1 was suggestive of a secondary infection. Risk factors for a DENV infection were studied using poisson regression.</p><p>Results</p><p>In total, 600 participants were included; median age was 25 years (IQR: 23–29), 35.5% were male, and median travel duration was 20 weeks (IQR: 15–25). In 39 of 600 participants (AR: 6.5%; 95% CI 4.5–8.5%) anti-DENV IgG test results were suggestive of a recent infection, yielding an IR of 13.9 per 1,000 person-months traveling (95%CI: 9.9–19.1). No secondary infections were found. IR for Asia, Africa, and America were comparable and 13.5, 15.8, and 13.6 per 1,000 person-months respectively. Of participants with a recent DENV infection, 51% did not report dengue-like illness (DLI) or fever, but 10% were hospitalized. In multivariable analysis, travelers who seroconverted were significantly more likely to be vaccinated with ≥2 flavivirus vaccines for the current trip or to have reported DLI in >1 consecutive weeks.</p><p>Conclusions</p><p>Long-term travelers are at substantial risk of DENV infection. Half of those with a DENV infection reported no symptoms, but 10% were hospitalized, demonstrating the importance of advising anti-mosquito measures during travel.</p></div

Characteristics of 600 long-term travelers attending a Dutch travel health clinic for pre-travel advice including prevalence and determinants of previous dengue infection, December 2008 –September 2011.

<p>Characteristics of 600 long-term travelers attending a Dutch travel health clinic for pre-travel advice including prevalence and determinants of previous dengue infection, December 2008 –September 2011.</p

Characteristics of 600 long-term travelers to dengue-endemic areas attending a Dutch travel health clinic for pre-travel advice including their incidence rates and risk factors of suggestive recent dengue virus infection, December 2008 –September 2011.

<p>Characteristics of 600 long-term travelers to dengue-endemic areas attending a Dutch travel health clinic for pre-travel advice including their incidence rates and risk factors of suggestive recent dengue virus infection, December 2008 –September 2011.</p