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

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.

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.

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).

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.