16 Journal of Camel Health. March 1, 2020, issue 2:16-21. https://camel.health/ Article Gastrointestinal nematodiasis in dromedary camels at Qassim region, Saudi Arabia: prevalence, hematology and treatment outcomes Salama A. Osman 1,2 1 Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, Saudi Arabia. P.O Box 51452, Saudi Arabia. 2 Department of Animal Medicine, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh 33516, Egypt. Abstract Correspondence to: Salama A. Osman Salama2068@yahoo.com A cross-sectional study was carried out in Qassim region, central of Saudi Arabia to determine the prevalence of gastrointestinal nematodes in dromedary camels, estimate the hematological changes associated with such infestation in addition to study the efficiency of albendazole and ivermectin in the treatment of infested animals. Among 1195 examined camels, the prevalence of gastrointestinal nematodes was 7.28%%. Gender had no significant effect on the disease prevalence where the prevalence was 7.53% in females and 5.88% in males. On the other hand, age had a significant (p = 0.0001) effect on the prevalence where lower prevalence was recorded in camels under three years (3.18%) compared to those over three years (9.94%). Camels infested with gastrointestinal nematodes showed observable signs only in young camels while adult animals appeared clinically normal and rarely showed clinical signs. The signs observed in young camels were in the form of emaciation in spite of good appetite, pale mucous membranes and weakness. Hematological examination revealed a significant decrease in the erythrocyte counts (p = 0.0001) and hemoglobin concentration (p = 0.001) in infested camels compared with the healthy controls. Concerning the treatment outcomes, albendazole either alone or in combination with ivermectin twice with 2 weeks interval gave 100% cure rate both clinically and parasitologically. However, treatment-using ivermectin alone gave only 93.33% parasitological cure. It can be concluded that the prevalence of gastrointestinal nematodiasis is less prevalent in Qassim region, Saudi Arabia and the age factor has a significant effect on the prevalence but the sex factor has no effect. In addition, albendazole either alone or in combination with ivermectin is the drug of choice in the treatment of gastrointestinal nematodiasis in dromedary camels in this region. Received: 10 December 2019 Accepted: 29 January 2020 Key words: Camels, Nematodes, Prevalence, Hematology, Treatment. 1. Introduction In tropical and subtropical countries, parasitic infestation represents a major constraint for livestock production where, it directly or indirectly affects the production by reducing animal fertility and work capacity, decreasing food consumption, and decreasing body weight gain and milk produc- tion, and lead to mortality in heavily parasitized animals [1]. Adverse and difficult environmental conditions in the areas where camels are raised especially in dry seasons lead to decrease the availability of food for these animals and subsequently resulted in lower their resistance and make them easily vulnerable to diseases [2, 3]. Among the parasites that infesting dromedary camels, nematodes are found to be the most prevalent [4, 5, 6]. Camels can be infested by