ORIGINAL ARTICLE The status of Linguatula serrata infection of stray dogs in Shiraz, Iran A. Oryan & S. M. Sadjjadi & D. Mehrabani & M. Rezaei Received: 4 August 2007 / Accepted: 19 October 2007 # Springer-Verlag London Limited 2007 Abstract Linguatula serrata is one of the parasitic zoo- noses causing visceral and nasopharyngeal linguatulosis in human beings. Recently, L. serrata found a more public health importance, and new cases of human infection is reported from different parts of Iran including the Fars Province. Infected vegetables, fruits, and water resources with eggs of the mature parasite excreted via carnivores’ (especially stray dogs) nasopharyngeal secretions or feces is the main source of infecting human beings. However, consumption of infected improperly cooked viscera of the intermediate hosts including sheep, goats, cattle, or other herbivores containing the larval stages of this parasite is the other potential source of infection of human beings. Therefore, the present study was undertaken to investigate the prevalence of this parasite in stray dogs of Shiraz, the capital city of the Fars Province in Southern part of Iran. In a cross-sectional study, 85 stray dogs including 48 males and 37 females were captured at different parts of Shiraz city and the nasopharyngeal area, nasal turbinates, sinuses, eusthasian tubes, and brain were examined for L. serrata. The adult parasites were collected and fixed, cleared, and stained using formalin, alcohol, azocarmine, and lacto- phenol. A total of 65 (76.5%) dogs were infected with L. serrata. Age, sex, weight, and geographical locations did not have significant effects in the prevalence rate of this parasite. The number of parasites recovered from each dog ranged from 1 to 19 with an average of 4.06 per infected dog. The maximum length and width of the mature Linguatula were 80 and 10 mm for female parasites and 20 and 3 mm for the male ones, respectively. From the above results, it could be concluded that the rate of infection in dogs and possibly other carnivores, herbivores, and man is high in this locality, and strict control measures should be conducted to overcome the risk of infection with this zoonotic disease. Keywords Linguatula serrata . Stray dogs . Shiraz Introduction Linguatulosis poses veterinary and public health impor- tance in the world including Iran. Adult Linguatula serrata firmly attaches to the mucous membrane of the nasal passages, turbinates, and frontal sinuses of dogs and other canides by its four hooks where it produces large numbers of eggs. The eggs, which contain fully developed larvae, passed in the nasal secretions or feces of dogs are ingested by a wide range of intermediate hosts including ruminants, rats, and human beings. The four rudimentary-legged larvae that hatch from these eggs penetrate the gut wall and migrate to the lymph nodes, liver, lungs, rarely eyes, and other tissues (Schmidt and Roberts 1989). In these areas, the larvae develop into nymphs and are encapsulated within a granulomatous lesion of host tissue reaction. The cycle is repeated if the offal of the infected intermediate hosts is eaten by the carnivores as the definitive hosts. Comp Clin Pathol DOI 10.1007/s00580-007-0707-x A. Oryan : M. Rezaei Pathology Department, Veterinary School, Shiraz University, Shiraz, Iran S. M. Sadjjadi (*) Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran e-mail: smsadjjadi@sums.ac.ir D. Mehrabani Shiraz Branch, Razi Insitute, Shiraz, Iran