Phlebovirus seroprevalence in Austrian Army personnel returning from missions abroad

Edwin Kniha,Julia Walochnik,Adelheid G Obwaller,Gerhard Dobler,Wolfgang Poeppl,Gerhard Mooseder

doi:10.1186/s13071-019-3674-6

Abstract

BackgroundPhleboviruses are mainly transmitted by sand flies and infections can result in various symptoms, including meningitis and meningoencephalitis. In endemic regions, seroprevalences in humans and animals are high. Military personnel on missions in endemic areas are at increased risk of infection, however, for soldiers from central European countries, data are scarce. The aims of this study were to determine the exposure to phleboviruses of Austrian soldiers returning from missions abroad and to assess potential risk factors. A retrospective serological study was performed with sera of 753 healthy Austrian soldiers returning from missions in Bosnia and Herzegovina (BIH, n = 61), Kosovo (n = 261), Syria (n = 101) and Lebanon (n = 63) and of soldiers prior to their missions (n = 267).ResultsAltogether, 119 sera (15.8%, 119/753) were positive for anti-Phlebovirus IgG antibodies, with highest seroprevalences found in soldiers returning from Kosovo (20.69%, 54/261), followed by Syria (17.82%, 18/101), Lebanon (14.29%, 9/63) and BIH (11.48%, 7/61). Of the soldiers tested prior to their missions 11.61% (31/267) were positive. Of the 119 seropositive individuals, 30 (25.2%, 30/119) also had anti-Phlebovirus IgM antibodies. Phlebovirus seropositivity significantly correlated with symptoms of febrile illness during the respective mission (OR: 1.9, 95% CI: 1.1–3.4, P = 0.03) and with Leishmania seropositivity (OR: 2.7, 95% CI: 1.2–5.8, P = 0.009). Also, the outdoor activity “running” during the mission showed a strong trend towards an association with Phlebovirus seropositivity (OR: 1.9, 95% CI: 0.9–4.4, P = 0.08), and seropositivity generally increased with the duration of a mission (OR: 2.5, 95% CI: 0.9–7.5, P = 0.07).ConclusionsThis study indicates that soldiers are exposed to sand flies and at significant risk for Phlebovirus infection during missions in the Mediterranean area and the Middle East. Adequate prevention measures should be applied particularly during vespertine outdoor activities.

Highlights

Phleboviruses are mainly transmitted by sand flies and infections can result in various symptoms, including meningitis and meningoencephalitis
No significant difference was observed between professional soldiers and militiamen (OR: 1.2, 95% confidence intervals (CI): 0.8–1.8%, P = 0.48)
Soldiers tested after their missions showed a significantly higher seroprevalence (18.1%, 88/486), than soldiers tested prior to their missions (11.6%, 31/267; Odds ratios (OR): 1.7, 95% CI: 1.1– 2.8%, P = 0.02)

Summary

Introduction

Phleboviruses are mainly transmitted by sand flies and infections can result in various symptoms, including meningitis and meningoencephalitis. Military personnel on missions in endemic areas are at increased risk of infection, for soldiers from central European countries, data are scarce. The aims of this study were to determine the exposure to phleboviruses of Austrian soldiers returning from missions abroad and to assess potential risk factors. Sand fly fever has been known to be of considerable medical importance in military personnel for decades [8], when large numbers of immunologically naïve soldiers are introduced to Phlebovirus-endemic regions [9]. UK military personnel was shown to be exposed to sand flies and phleboviruses in Afghanistan and high numbers of sand fly fever virus infections were reported from military personnel deployed in Iran [13, 14]

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