CASE REPORT A Case Report of Human Infection with Dioctophyma Renale from Iran Roghayeh Norouzi 1*, Arman Manochehri 2, Mustafa Hanifi3 Keywords: Dioctophyma renale; human infection; Iran. A 75-year-old man from Kurdistan province, western part of Iran was diagnosed with a mass in the right kidney by ultrasound and computed tomography. In operation, a parasitic helminth, 30 cm long and 1.2 cm in diameter con- sistent with D. renale was found in the right kidney. Microscopic examination revealed that the male Dioctophyma renale. Following removal of worm, the symptoms completely resolved within a few hours. Generally, parasitism by D. renale in human is a necropsy finding, nevertheless imaging techniques as ultrasound and computed tomog- raphy have been proven to be important tool to achieve diagnosis. 1 Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran. 2 MSc of Veterinary Parasitology, Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz ,Tabriz, Iran. 3 MSc of Microbiology, Shahid Ghazi hospital, Kurdistan, Iran. *Correspondence: Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran. Tel: +98 4136378743. Fax: +98 4136378743. E-mail: r.norouzi@tabrizu.ac.ir. Received October 2016 & Accepted January 2017 INTRODUCTION Dioctophyma renale (giant kidney worm), parasitic roundworm, has been reported in many mammalian spe-cies, including canines, mink, wolves, foxes, jackals, coyotes, skunks, ferrets, weasels, rats, raccoons, wol- verines, pumas, cats, seals, pigs, horses and humans, al¬though only rarely.(1,2,3) In its evolutionary cycle, the inter- mediary is an aquatic oligochaete annelid (Lumbriculus variegatus) that ingests eggs of the first stage containing larvae of the parasite and the primary host is infected by ingesting the infected annelid or paratenic host, which can be a fish or frog.(2) It inhabits temperate regions worldwide, particularly areas with freshwater streams and lakes. In these cases, worms were found in various body parts such as the kidneys, scrotum, breasts, thoracic cavity, perito- neal cavity, bladder, and subcutaneous layer.(4,5) Female worms can be over 100 cm long and male worms 35 cm, although their size may vary according to the affected species.(1) Male worms have a bell-shaped copulatory bursa that does not present rays and has one spicule, but adult female worm that does not present copulatory bursa.(1) Humans can also be definitive accidental hosts, and dioctophymatosis is a zoonotic disease, but in the case of hu- mans, locations outside the kidney are frequent.(6,7) Although animal infection with this parasite occurs in Iran, but human infection rarely in this country. Dioctophy- matosis has been reported from Iran(8) and other parts of the world.(4,6,7,9,10,11) In this study, we report a case of human infection with D.renale in an old man from the Bijar city of Kurdistan Province, Western part of Iran. Figure 1. Adult male Dioctophyme renale (30 cm long) removed from in the right kidney of a 75-year-old man Vol 14 No 02 March-April 2017 3043 Human infection with Dioctophyma renale- Norouzi et al. CASE REPORT A 75-year-old man from Bijar city, Kurdistan province, Iran, with hematuria and a specific intermittent pain in the right kidney area that persisted for 10 days, present- ed to the Imam Hassan hospital, Kurdistan, Iran on May 2015. He had always lived in an urban habitat, and there was suspicion of ingestion of dirty water. Clinical signs suggested nonspecific symptoms including hematuria, nephritis and intermittent pain in the right kidney.The complementary studies, including urine analysis, blood analysis, abdominal X-ray films, and abdominal ultra- sonography were carried out. In the urine sample many red blood cells and white blood cells were observed but no eggs were not found in the urinary sediment. The he- mogram showed leukocytosis by neutrophilia with left shift toxic granulation neutrophils, lymphopenia, eo- sinophilia and basophilia. In ultrasound and computed tomography, a mass in the right kidney was demonstrat- ed. In operation, a parasitic helminth, 30 cm long and 1.2 cm in diameter was found in the right kidney. The parasite was placed in a 10% formalin solution. The worm was identified using microscopic examination as the male Dioctophyma renale (Figure 1). The adult male worm had a bell-shaped copulatory bursa that did not present rays and had one spicule (Figure 2). Following removal of worm, the symptoms completely resolved within a few hours and remained asymptomat- ic two week later. DISCUSSION Dioctophyma renale, the giant kidney worm, is the larg- est known parasitic nematode.(12) In its evolutionary cy- cle, the intermediary is an aquatic oligochaete annelid (Lumbriculus variegatus) that ingests eggs of the first stage containing larvae of the parasite and the primary host is infected by ingesting the infected annelid or pa- ratenic host, which can be a fish or frog.(13,14) Human infections by D. renale have been very rare, and seem to have occurred accidentally. No more than 20 confirmed human cases have been reported worldwide, in which worms were found in various body parts, e.g. the kidneys and peritoneal cavity. These include 4 cas- es of dioctophymatid larvae found in the subcutaneous nodules. In the case reported here, the patient was a 75- year- old man who lived in a small village, near a lake that was used for daily activities, such as bathing, washing clothes, and defecation (both humans and cattle). The etiology of this case was not clear, but it was suspected that he became infected by drinking water. In the con- text of this zoonosis, several factors in this location pose a risk to the health of the inhabitants: high prevalence of infected canines, high level of surface contamination, and use of the river as a means of transport, recreation and fishing for food (fish, frogs and eels). The continu- ation of the life cycle of D. renale is directly related to water temperature and egg embryonation.(12) Other studies state that this parasitic infection is not very frequent infection in humans, considered to be ac- cidental hosts of the parasite(4). However, according to Le Bailly et al.(15), parasite has been found in archaeo- logical material dating from 3384 to 3370 BC. Although animal infection with this parasite occurs in Iran, but human infection rarely in this country. Dioc- tophymatosis has been reported from Iran(8) and other parts of the world.(4,6,7,9,10,11) Figure 2. A bell-shaped copulatory bursa of adult male worm Figure 3. MR urogram showing worm in right kidney of a 75-year-old man Case Report 3044 The latest publication the parasitism of a domestic dog by D. renale in Hamedan, Iran reported by Zolhavarieh et al.(16) While the nematode has been mainly reported from tem- perate regions of other parts of the world, the presence of dioctophymatosis in human Kurdistan province as a cold region is unusual but the parasitism of a domestic dog by D. renale is very frequent in Iran and Kurdistan. Therefore high prevalence of infected canines and use of the river as a means of transport are several factors in this location pose a risk to the health of the inhabitants. CONCLUSIONS D. renale infestation in canine and other mammals is high prevalence and transmission of the parasite to hu- man is easy, especially urban region, veterinarians and physicians should consider D. renale infestation in the differential diagnosis of urological disorders and un- known abdominal cystic masses regardless of ecolog- ical condition. CONFLICT ON INTEREST The authors declare that there is no conflict of interest. REFERENCES 1. Kumar V, Vercruysse J, Vandesteene R. Studies on two cases of Dioctophyma renale (Goeze, 1782) infection in Chrysocyon brachyurus (Illiger). Acta zool pathol Antwerp. 1972; 56: 83-98. 2. Samuel WM, Kocan AA, Pybus MJ, Davis JW, Ed. Parasitic Diseases of Wild Mammals, Iowa State. 2008; 357-364. 3. Tokiwa T, Harunari T, Tanikawa T, Akao N, Ohta N: Dioctophyma renale (Nematoda: Dioctophymatoidea) in the abdominal cavity of Rattus norvegicus in Japan. Parasitol Int. 2011; 60: 324-6. 4. Ignjatovic I, Stojkovic I, Kutlesic C, Tasic S. 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