| Summary: | <p>Abstract</p> <p>Background</p> <p><it>Hyalomma aegyptium</it> is a hard-tick with a typical three-host life cycle. The main hosts are Palearctic tortoises of genus <it>Testudo</it>. However, other hosts can be used by immature ticks for feeding in natural conditions. Given this complex ecology and multiple host use, the circulation of pathogens by <it>H. aegyptium</it> between various hosts can be important from epidemiological point of view. The aim of this study was to evaluate the role of <it>H. aegyptium</it> as natural carrier of four important zoonotic pathogens.</p> <p>Methods</p> <p>From 2008 to 2011, 448 <it>H. aegyptium</it> ticks were collected from 45 Spur-thighed tortoises, <it>Testudo graeca</it> in Romania. DNA was extracted individually from each tick using a commercial kit. DNA was examined for the presence of specific sequences of <it>Borrelia burgdorferi</it> s.l<it>., Anaplasma phagocytophilum, Ehrlichia canis</it> and <it>Coxiella burnetii</it> by PCR, according to previously described protocols.</p> <p>Results</p> <p>PCR analysis of <it>H. aegyptium</it> revealed the presence of <it>A. phagocytophilum</it> (18.8%)<it>, E. canis</it> (14.1%) and <it>C. burnetii</it> (10%). 32.4% of the ticks were infected with at least one pathogen and 9.8% had co-infections. The stages most frequently infected were nymphs (50%) followed by males (33.9%) and females (27%). The number of tortoises which harboured infected ticks was 27/45 examined (60%). From all tested <it>T. graeca</it>, 40% harboured ticks infected with <it>A. phagocytophilum</it>, 46.7% had ticks infected with <it>E. canis</it> and 33.3% had ticks with <it>C. burnetii</it>. This study reports for the first time the presence of <it>A. phagocytophilum</it> and <it>E. canis</it> in <it>H. aegyptium.</it></p> <p>Conclusions</p> <p>The presence and relatively high prevalence of three important zoonotic pathogens in <it>H. aegyptium</it> raises the question of their epidemiologic importance in disease ecology. As tortoises are unlikely to be reservoir hosts for <it>A. phagocytophilum</it> and <it>E. canis</it> and both these pathogens are common in <it>H. aegyptium</it>, this is an important indication for (1) a possible increased host-switching behaviour of these ticks to competent reservoir hosts (i.e. hedgehogs) and (2) transstadial transmission. Furthermore, if we consider also the presence of <it>C. burnetii</it>, we conclude that <it>T. graeca</it> and its ticks should be evaluated more seriously when assessing the eco-epidemiology of zoonotic diseases.</p>
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