Leishmania infections in Austrian soldiers returning from military missions abroad: a cross-sectional study.

OBJECTIVES: The incidence of leishmaniasis is known to increase in conflict areas. The aims of this study were to determine the exposure to Leishmania species in Austrian soldiers returning from missions abroad and to assess possible risk factors. METHODS: A retrospective explorative cross-sectional serologic study was conducted in 225 healthy Austrian soldiers returning from UN or EU peacekeeping missions in Syria, Lebanon and Bosnia and Herzegovina (BIH). Sera were tested for anti-Leishmania antibodies using a commercial enzyme-linked immunosorbent assay. All positive individuals were screened for Leishmania DNA by PCR targeting the ITS1 region using EDTA blood samples. RESULTS: In total, 13.3% (30/225) of the individuals tested were either positive (8%, 18/225) or borderline (5.3%, 12/225) in the enzyme-linked immunosorbent assay, with the highest seroprevalence in soldiers returning from Syria (17.8%, 18/101; 12 positive, six borderline), second from Lebanon (11.1%, 7/63; four positive, three borderline) and lowest from BIH (8.2%, 5/61; two positive, three borderline). Ten soldiers returning from Syria and one from BIH were also positive for Leishmania DNA. Six of these were identified as Leishmania donovani/infantum complex, two as L. tropica and another three as mixed infections by DNA sequencing. Epidemiologic data were collected via a questionnaire, and seropositivity was correlated with a history of insect bites that took a long time to heal (odds ratio, 5.33; 95% confidence interval, 1.23-23.04; p 0.025). CONCLUSIONS: Although pretravel serologic data were not available in this study, the exposure of soldiers to Leishmania spp. during their missions can be assumed to be considerable. Because even asymptomatic infections may resurge in case of emerging immunodeficiencies, adequate prevention measures seem important.

Exposure to Echinococcus multilocularis, Toxocara canis, and Toxocara cati in Austria: a nationwide cross-sectional seroprevalence study.

Despite emerging risks for the spread of zoonotic diseases, data on human exposure to Echinococcus multilocularis and Toxocara spp., the causative parasites of the two most important helminthozoonoses in Central Europe, are limited. To investigate risk factors and exposure, we conducted a nationwide, cross-sectional serological study in 1046 healthy individuals, of which 425 were soldiers and 621 were civilians. Serum samples and information on possible risk factors for exposure, including previous foreign military assignments, residential area, animal contact, and regular outdoor activities, were obtained. Immunoglobulin G antibodies against Echinococcus multilocularis and Toxocara spp. were examined with an enzyme-linked immunosorbent assay (ELISA). Samples reactive in the ELISA for antibodies against Echinococcus multilocularis were considered positive only after confirmation by western blot. Overall, 66 (6.3%) individuals tested positive in the serologic screening for Toxocara spp. Occupational animal contact was the only risk factor significantly associated with a higher risk for being seropositive. None of the individuals were positive for antibodies against Echinococcus multilocularis. In conclusion, the present study demonstrates that exposure to Toxocara spp. is widespread in Austria and occupational animal contact is a risk factor for seropositivity.

High prevalence of antibodies against Leptospira spp. in male Austrian adults: a cross-sectional survey, April to June 2009.

To assess the distribution of specific antibodies against Leptospira spp. in Austrian adults, we conducted an explorative nationwide cross-sectional serological study in 400 healthy individuals. Antibody titres against Leptospira spp. were determined in a microscopic agglutination test using a panel of 14 serovar cultures. Sera of 18 participants were excluded because the samples were unsuitable for testing; the remaining 382 participants comprised 166 professional soldiers and 216 civilians. Overall, 88 (23%) individuals tested positive in serological screening. The subjects' sera reacted most frequently with serovars Canicola (16.5%) and Hardjo (11.8%). Epidemiological information was obtained from a questionnaire: no correlation was found for area of residence, travel abroad, regular outdoor activities, occupational animal contact, or ownership of companion animals. The proportion of seropositive samples was significantly lower among professional soldiers (15.7%) than among civilians (28.7%) (p=0.003). Our data demonstrate serological evidence of a high rate of exposure to Leptospira spp. among the Austrian population. No increased risk of exposure to Leptospira spp. was detected in military personnel.

Seroprevalence and asymptomatic carriage of Leishmania spp. in Austria, a non-endemic European country.

Leishmaniasis is a rare disease in Central Europe and is diagnosed almost exclusively in travellers or migrants coming from tropical or subtropical countries. We conducted an explorative cross-sectional serological study, using a commercial ELISA, in 1048 healthy Austrian individuals to assess the distribution of specific antibodies against Leishmania spp. in humans in Austria. Overall, 47 individuals (4.5%) tested positive, and an additional 32 (3.1%) showed borderline results. After 12 months, sera from 42 of the 79 individuals who had initially tested seropositive/borderline were tested by ELISA a second time: 18 were persistently positive, nine were borderline. Those whose sera were persistently positive/borderline were then screened for potential carrier status using a commercial oligochromatographic PCR test to detect parasite DNA. Four samples were PCR positive and were subjected to a second PCR allowing parasite identification after DNA sequencing: two samples were identified as Leishmania donovani/infantum complex and Leishmania (Viannia) guyanensis, respectively. Epidemiological information was obtained with a questionnaire: no correlation was found for the number of holiday trips within the previous 6 months, but a significant risk of exposure to Leishmania spp. was found for travel to the New World, particularly to the Caribbean. Our data demonstrate that Leishmania spp. seroprevalence in non-endemic countries has been considerably underestimated.

Pre- and post-pandemic prevalence of antibodies to the 2009 pandemic influenza A (H1N1) virus in Austrian adults.

Antibody prevalence to the 2009 pandemic influenza A (H1N1) virus was determined in a sample of the Austrian population to assess the post-pandemic seropositivity rate, the infection attack rate, and the proportion of subclinical infections during the 2009/2010 influenza pandemic in Austrian adults. A total of 480 sera from individuals aged between 18 and 57 years from all nine federal states of Austria were collected between April and June 2010. Information on demographic characteristics, vaccination history, and history of suspected or verified influenza virus infection was ascertained. Antibodies were determined using a commercial ELISA and compared with 80 age-matched adult sera collected before the pandemic began. The overall seropositivity rate was 28% and was highest among young adults aged 18-29 years, followed by adults aged 50-57 years. Among seropositive unvaccinated individuals, infection was asymptomatic in more than 80%. Extrapolation to the overall Austrian adult population indicates that more than 1.3 million persons aged 18-57 years became infected in 2009. Compared with the pre-pandemic seropositivity rate, the infection rate was highest among young adults but low in those aged 30-57 years. Among 69 individuals previously vaccinated with the 2009 pandemic influenza A (H1N1) virus, 71% had specific antibodies. The study demonstrates that infection rates based on surveillance of clinical cases considerably underestimated the infection attack rate during the 2009 H1N1 pandemic in Austria and that vaccination against this virus elicited long-lasting seropositivity in more than 70% of adults.

Seroprevalence of anti-Yersinia antibodies in healthy Austrians.

Yersiniosis is caused by Y. enterocolitica and Y. pseudotuberculosis mostly presenting as intestinal infection. The infection is usually acquired from contaminated food. The aim of this study was to determine the seroprevalence of anti-Yersinia antibodies in Austrians. Sera of 750 healthy Austrians from all nine states were tested for anti-Yersinia IgG antibodies using the recomBlot Yersinia Westernblot kit. Overall seroprevalence was 29.7%. Seroprevalence increased significantly with age from 24.7% in the group of the 19 to 24 year olds to 38.5% in the group of persons older than 44 years. The seroprevalence of anti-Yersinia antibodies varied within the states between 18% and 43.5%. The high seroprevalence of anti-Yersinia antibodies in contrast to only approximately 100 reported yersiniosis cases per year points to the fact that the majority of infections is either subclinical or mild.