Miasis cutáneas en pequeños rumiantes

Abstract

Cutaneous myiasis in small ruminants is a parasitic disease of significant importance to animal health. Although it is widely recognized by veterinary professionals and livestock farmers, its evident clinical presentation, non-contagious nature and seasonal occurrence often lead to its harmful effects being underestimated. In Spain, the main causative agent of myiasis is Wohlfahrtia magnifica, an obligate parasite capable of causing lesions without any prior damage. This disease results in a range of both direct and indirect losses that are difficult to quantify. Numerous antiparasitic drugs have been marketed for both preventive and curative purposes, but their effectiveness and widespread use remain very limited. Moreover, most studies focus on ovine pathology, with considerably less information available regarding caprine cases. This study aims to gain a more precise understanding of the disease's dynamics, as well as the best techniques for its prevention and treatment. For this purpose, questionnaires were distributed to people involved in small ruminant farming, and a longitudinal follow-up was conducted over several months at a goat farm. On the one hand, the study sought to gather opinions regarding the characteristics of the disease in animals. On the other hand, it aimed to collect data in order to identify possible risk factors and to gain deeper insight into the biology of myiasis-causing dipterans. Based on the 123 questionnaire responses, it was concluded that cutaneous myiasis is a widely distributed disease across Spain, affecting a broad range of hosts and showing a trend to concentrate its incidence during the summer months. Treatment is necessary for cure, as recurrences are frequent. Data from the monitored goat farm indicated that the flight season of these dipterans tended to lengthen between 2011 and 2024. Additionally, the disease affected males more than females, particularly in the prepuce. The main species responsible for the cases was Wohlfahrtia magnifica, whose larvae are capable of undergoing diapause to maintain a viable population through unfavorable winter conditions. In conclusion, cutaneous myiasis is a pathological condition of significant sanitary and economic importance, with a trend towards both temporal and territorial expansion. Effective prevention and treatment must take into account both environmental factors and the biological characteristics of the animals.