Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 5 2 2011 12 15 60 68 EN M Sharifdini Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran M Mohebali Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran H Keshavarz Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran M Hosseininejad Department of Veterinary Parasitology, Faculty of Veterinary Medicine and Research Institute of Zoonotic Diseases, University of Shahrekord, Shahrekord, Iran H Hajjaran Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran B Akhoundi Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran A Rahimi Foroushani Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Z Zarei Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran S Charehdar Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2015 10 03 Background: Mediterranean visceral leishmaniasis (MVL)is an infectious disease that affects both human and ani­mals. Domestic dogs (Canis familiaris) are principal reservoir hosts of MVL caused by Leishmania infantum. Dogs are definitive hosts for Neospora caninumand a risk factor for infecting intermediate hosts. The immunosuppression caused by visceral leishmaniasis (VL) can promote the occurrence of co-infections with other agents such as neosporo­sis. This study aimed to determine the frequency of co-infection of the both protozoan parasites in the en­demic areas of VL from Meshkin-Shahr District, north-west of Iran. Methods: Altogether, 171 serum samples were collected from domestic dogs of Meshkin- Shahr District by multistage cluster sampling from October 2008 to August 2009. The collected serum samples were tested for the detection of simultaneous infection of L. infantum and N. caninum using direct agglutination test (DAT) and indirect ELISA, respectively. Results: Of the 171 domestic dogs, 27 (15.8%) and 52 (30.4%) were showed antibodies against L. infantum and N. caninum, respectively. Simultaneous infections of N. caninum and L. infantum was found in 16 (9.4%) of the dogs. In VL-positive and VL-negative dogs, N. caninum infection was found in 59.3% and 25.0%, respectively. A statisti­cally significant difference was found between VL-positive and VL-negative dogs with N. caninum infection (P= 0.001). Conclusion: These findings indicate that Meshkin-Shahr District in northwestern Iran is an active focus of canine visceral leishmaniasis (CVL). Neospora caninum and L. infantum co-infection is prevalent in the area and infection by L. infantum seems to enhance susceptibility to N. caninum infection in domestic dogs. https://jad.tums.ac.ir/index.php/jad/article/view/92 https://jad.tums.ac.ir/index.php/jad/article/download/92/90