Introduction: Dogs harbour zoonotic parasites that cause serious infections in humans, such as visceral larva migrans, ocular larva migrans, cystic echinococcosis, and alveolar echinococcosis. Studies on dogs’ gastrointestinal parasites in different geographical locations are required to increase knowledge of the risk of canine zoonoses in human populations.Material and Methods: The presence of parasites was examined in 450 faecal samples collected from eight zones of Zanjan province, northwest Iran from June to November 2015. The samples were examined using the sedimentation concentration method and modified Ziehl-Neelsen staining.Results: Gastrointestinal parasites were found in 86 (19.1%) faecal samples. Sarcocystis spp. (7.3%), Taenia/Echinococcus spp. (5.6%), Toxocara spp. (1.8%), and Cystoisospora spp. (1.6%) were the most common parasites observed. The other detected parasites consisted of Dicrocoelium dendriticum (0.7%), Eimeria spp. (0.7%), Cryptosporidium spp. (0.4%), Physaloptera spp. (0.4%), Giardia spp. (1.3%), and Spirocerca lupi (1.3%). The lowest parasite infection rates belonged to Trichuris vulpis and Acanthocephalans (0.2% each).Conclusion: This study provides current information on the infection rates in dog populations in Zanjan Province. Furthermore, the study shows a high prevalence of gastrointestinal parasitic infections, including zoonotic ones and particularly Taenia/Echinococcus spp., potentially transmissible to humans and thus relevant to public health.

Infectious diseases of swine, particularly zoonoses, have had a significant influence on nutritional safety and availability of pig meat as high-energy protein product since the time that pigs were domesticated back in the 7ᵗʰ century BC. The main sources of swine infectious diseases include the so-called primary sources (direct infection, i.e. through contact with infected and sick animals) and secondary sources (contaminated meat products, slaughter products, and vectors, including ticks). At present, the most serious epidemiological and economic threat to swine breeding in Europe is African swine fever (ASF). This disease, originally coming from Africa, is incurable and causes death of infected pigs and wild boars during 7−10 days after infection. Among the various factors that influence the spread of ASF, important role is played by ticks from the genus Ornithodoros, mainly from the species Ornithodoros moubata. Research on the ASF indicates that other species of ticks can also transmit the virus to healthy pigs in laboratory conditions. Sylvatic and domestic cycles of ASF virus transmission, which have been described so far, require further studies and updating in order to point the potential new vectors in the Caucasus and Eastern Europe affected by the ASF. Effective methods of control and biosecurity may significantly slow down the spread of ASF, which undoubtedly is a major threat to world pig production and international swine trade.