**1. Introduction**

Leishmaniasis is a disease that affects humans, as well as wild and domestic animals. They are caused by parasites of the genus *Leishmania* (protozoa, trypanosomatidae) and are transmitted by Phlebotominae flies (Diptera, Psychodidae). Not all species of *Leishmania* parasites are of

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

medical importance; over 20 of them are considered pathogenic for humans and 10 have been isolated from dogs, including *L. infantum* (Syn. *L. chagasi*), *L. donovani*, *L. tropica*, *L. major*, *L. arabica*, *L. amazonensis*, *L. mexicana*, *L. braziliensis*, *L. peruviana*, and *L. colombiensis*[1]. *L. donovani* is the one that causes human visceral leishmaniasis (VL) with more than 90% of the cases occurring in India, Sudan, Bangladesh, and Brazil [2]. This species is involved in anthroponotic epidemiological cycle with anthropophilic vector and humans act as the reservoir of the disease. *L. tropica* causes anthropophilic cutaneous leishmaniasis (CL). Unique proven vector *Phlebotomus sergenti* is present mainly in urban areas, often at the periphery of old towns and cities, and in poor suburbs where low sanitary conditions facilitate breeding sites for this species. Zoophilic CL epidemics seem to be related to the fluctuations of the rodent popula‐ tions and the accumulations of nonimmune people. This disease is found mainly in rural areas. The responsible parasite for zoonotic CL is *L. major* and the proven vectorin the Mediterranean basin is *Phlebotomus papatasii* [3, 4]. *L. infantum* is involved in zoonotic epidemiological cycle with zoophilic vectors serving dogs as the reservoir of the disease [5] and is currently the predominant causative agent of VL in humans and dogs in the Mediterranean region. Majority of both suspected and proven vectors of this pathogen belongs to the *Larroussius* subgenus. With so many species of human‐infective parasites, different reservoir and vector species in a wide range of topographically different foci, the ecology, and epidemiology of leishmaniases are without doubt the most diverse of all vector‐borne diseases.

At the beginning of the twentieth century in Europe only sporadic human visceral leishma‐ niasis cases had been reported. The spread of the disease happened after 1975 and many of the European Union (EU) countries developed surveillance system around that time. The in‐ creased incidence of leishmaniasis in the Mediterranean region is due to several reasons including the influx of nonimmune population into the natural foci of transmission, changes in ecology of vectors and reservoir hosts, reduction in the use of residual insecticides for the control of mosquito populations, improvements in the diagnostic methods, and reporting of positive cases.

Human VL has long been considered a disease of young children but epidemiology of the disease after 1975 has changed with the increase of incidence in adults. This correlated to the emergence of HIV. However, in the last decade, numbers of VL infections in adults in many EU countries decreased. This can be attributed, among other measures, also to the use of a novel, highly active antiretroviral therapies (HAART) [6].

We are observing also changes of epidemiology of canine leishmaniasis (CanL). While foci of CanL including insecticide nontreated dogs of predisposed breeds traditionally were settled in the coastal districts, recent studies show that there are various risk factors for CanL, such as age 2 years or more, sleeping mostly outdoors, season of sampling (spring to autumn), and geographical origin [7, 8]. Today, leishmaniasis is endemic in all the countries of Southern Europe, with an incidence rate of 0.21 per 100,000 inhabitants and more than 750 autochtho‐ nous human cases reported each year [6, 9]. In the Mediterranean region, leishmaniasis is generally associated with *Leishmania infantum*, but other species autochthonous in Asia, the Middle East, and Africa, such as *L. donovani* and *L. tropica*, may colonize European Phleboto‐ mine fly vectors as well.

Slovenia is one of the smallest member countries of the European Union neighboring to Austria, Italy, and Croatia. Despite an area count of only 16,423 square kilometers, it has diverse landscape. The northern part of the country is composed of Alpine and the southern part is composed of Mediterranean landscape. Being the bridge between eastern and western part of the Mediterranean, this region hosts unknown *Leishmania* species and some of the most important Phlebotomine fly vectors.

From 2004 to 2011 a questionnaire‐based multinational survey on canine leishmaniasis has been conducted in Europe. Slovenian veterinary clinics were among the 12,546 subjects that have been questioned. Reply rate of Slovenian veterinarians was satisfying (46.7%) and the survey had shown no endemic CanL case recognized in Slovenia up to that time [10, 11]. In spite of its vicinity to Italy and Croatia, both well‐known endemic countries, all infected dogs were found to be imported to Slovenia or have previously traveled to one of the endemic regions. Autochthonous cases of both canine and human leishmaniasis in Slovenia were not reported until recently. There may be two main reasons: unrecognizing and underreporting of potential cases.

In January 2014, the first endemic CanL case was reported in Slovenia the same year when the first specimens of Phlebotomine flies were collected. During the survey in the Istrian peninsula, both Slovenian and Croatian side, five Phlebotomine fly species were identified, including *P. neglectus* and *P. perniciosus*, some of the most important vectors of *Leishmania* parasites [12]. Although only one CanL autochthonous case and one suspected autochthonous human case (data not published) have been reported [13], recent information indicates increase in the number of infected dogs settled in Slovenia.

Registration of CanL cases in certain region is of great epidemiological importance for prevalence of disease in people as well.
