The status of Linguatula serrata infection of stray dogs in Shiraz, Iran

Linguatula serrata is one of the parasitic zoonoses 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 lactophenol. 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.