BackgroundThe nematodes Dirofilaria immitis and D. repens are enzootic in Greece. In the light of evidence of dirofilariosis spreading to new areas around the world, the aim of the present study was to update and enrich the current knowledge on the prevalence of Dirofilaria infections in dogs in Greece, to assess the risk factors of heartworm infection, and to initiate the drawing of the epizootiological map of canine dirofilariosis, investigating Dirofilaria infections in five locations along the north-south axis of the country, i.e. municipalities of Thessaloniki, Larissa, Achaia, Attica and Heraklion, associated with the five largest urban centres of Greece.MethodsBlood samples collected from 750 dogs in total, were examined by the modified Knott’s method and by serology. A questionnaire including information about each examined dog was filled in and statistical analysis of the results was performed using the Chi-square test and a Binary Multiple Univariate Generalized Linear Model.ResultsIn total, 31 (4.1 %) out of 750 examined animals were found positive for D. immitis by any of the tests applied (Knott’s method and serological examination). Moreover, microfilariae of D. repens and Acanthocheilonema reconditum were detected by the Knott’s method in 17 (2.3 %) and 10 (1.3 %) of the animals, respectively. At the municipality level, the prevalence of infection was 14, 7, 5.3, 0.7 and 0 % for D. immitis, 1, 2, 8.7, 0.3 and 0 % for D. repens, and 0, 3, 2.7, 0.7 and 1 % for A. reconditum in Thessaloniki, Larissa, Achaia, Attica and Heraklion, respectively. In addition, in three dogs (one each in Thessaloniki, Achaia and Attica) mixed D. immitis - D. repens infections were detected by the Knott’s method. The area of the country, dog’s usage and age were determined as risk factors for heartworm infection.ConclusionsNorthern areas of Greece have higher Dirofilaria prevalence and the prevalence in a western province (Achaia) is recorded for the first time. The mosquito population dynamics recorded in the past is likely to play an important role in the distribution of Dirofilaria infections in Greece, and needs further investigation. Similarly, the role of wild reservoirs of filarial parasites in different areas needs to be clarified. Promotion by veterinarians of preventive treatment and compliance by pet owners is essential in all parts of Greece, regardless of the recorded prevalence of infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1797-6) contains supplementary material, which is available to authorized users.

The present study investigated the presence of endo- and ecto-parasites, and vector-borne pathogens, in dogs from four islands of Greece. A total of 200 (123 owned and 77 sheltered) dogs were examined with different microscopic, serological and molecular methods. Of the examined dogs, 130 (65%) were positive for one or more parasites and/or vector-borne pathogens. The most common zoonotic intestinal helminths recorded were Ancylostomatidae (12.5%) and Toxocara canis (3.5%). Ninety-three dogs (46.5%) seroreacted to Rickettsia conorii . Twenty-two (11%) of them were also PCR positive and 7 (3.5%) showed corpuscles suggestive of Rickettsia spp. on the blood smears. Nineteen dogs (9.5%) were seropositive for Ehrlichia canis , three of them being also PCR positive. Dogs positive for Anaplasma phagocytophilum-Anaplasma platys (1%), Dirofilaria immitis (0.5%) and Babesia canis (0.5%) were also found. Fleas and ticks were recorded in 53 (26.5%) and 50 (25%) dogs, respectively, and all specimens were identified as Ctenocephalides felis felis and Rhipicephalus sanguineus sensu lato . Binary multiple univariate Generalized Linear Models were used to investigate factors and clinical signs related to the recorded positivity, while the association of specific signs with the pathogens was evaluated using tests of independence. Knowledge of occurrence and impact of zoonotic parasites and vector-borne pathogens in dog populations is crucial to prevent the infection in animals and people, and to control the risk of spreading of these pathogens in endemic and non-endemic areas.

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29The present study investigated the presence of endo-and ecto-parasites, and vector-borne pathogens, 30 in dogs from four islands of Greece. A total of 200 owned and sheltered dogs were examined with 31 different microscopic, serological and molecular methods. 32Of the examined dogs, 130 (65%) were positive for one or more parasites and/or vector-borne 33 pathogens. The most common zoonotic intestinal helminths recorded were Ancylostomatidae 34 (12.5%) and Toxocara canis (3.5%). Ninety-three dogs (46.5%) seroreacted to Rickettsia conorii. 35 Twenty-two (11%) of them were also PCR positive and 7 (3.5%) showed corpuscoles suggestive of 36 Rickettsia spp. on the blood smears. Nineteen dogs (9.5%) were seropositive for Ehrlichia canis, three 37 of them being also PCR positive. Dogs positive for Anaplasma phagocytophilum-Anaplasma platys 38 (1%), Dirofilaria immitis (0.5%) and Babesia canis (0.5%) were also found. Fleas and ticks were 39 recorded in 53 (26.5%) and 50 (25%) dogs and all specimens were identified as Ctenocephalides felis 40 felis and Rhipicephalus sanguineus sensu latu. Binary multiple univariate Generalized Linear Models 41 were used to investigate factors and clinical signs related to the recorded positivity, while the 42 association of specific signs with the pathogens was evaluated using tests of independence. 43 Knowledge of occurrence and impact of zoonotic parasites and vector-borne pathogens in dog 44 populations is crucial to prevent the infection in animals and people, and to control the risk of 45 spreading of these pathogens in endemic and non-endemic areas. 46 47 Author summary 48 Both owned and sheltered dogs can harbor a variety of intestinal and extra-intestinal endoparasites, 49as well as vector-borne pathogens and ectoparasites, of zoonotic concern. Dog shelters and stray dogs 50 are present in several touristic areas of Greece, including Sporades and Cyclades islands, where 51 tourists often bring their pets with them, likely travelling from non-endemic to endemic areas. The 52 present study has been carried out with the aim to evaluate the occurrence of the aforementioned 53 pathogens. Data obtained showed that they are present in canine populations of Greece, with 54 possibilities of infection for travelling dogs, which can also contribute to the spreading of zoonotic 55 vector-borne diseases, introducing new pathogens in previously non-endemic areas. For these 56 reasons, a constant monitoring of the epidemiological situation, improving control measures and 57 correct diagnostic approaches are of primary importance for the prevention of canine and human 58 infections, decreasing the spreading of potentially deadly pathogens. 59 60 61 62 65circulation of zoonotic infections are difficult to control. Because of a lifestyle that implies a low-66 grade of sanitary management, stray and free-roaming dogs are at high risk of becoming infected with 67 a wide range of pathogens. Consequently, they act as a permanent source of infection for vectors, 68 other animals an...