Occurrence and anatomical distribution of myiasis caused by Cochliomyia hominivorax (Diptera: Calliphoridae) in swine.

Abstract

Cochliomyia hominivorax (Diptera: Calliphoridae) has been considered the most important cause of myiasis in animals in the South America with most cases being recorded in cattle. In Brazil, the risk of myiasis in swine population is underestimated, leading to difficulties in the implementation of preventive measures. The aim of this study was to report the occurrence of myiasis infesting a swine population over a one-year period and to evaluate the anatomical distribution of these larvae on the animal's body. From May 2019 to April 2020, a total of 2038 inspections were carried out on pigs reared in two farms located in the state of Pernambuco, Northeastern Brazil. Fly larvae retrieved were morphologically identified and the anatomical distribution of myiasis was graphically represented by a heat map indicating its frequency in swine based on the interpolation of data. Cochliomyia hominivorax larvae (n=78) of second (n=29) and third (n=49) developmental stages were recovered in 13 animals (0.64%) out of 2038 inspections performed. The occurrence of myiasis was detected in eight anatomical sites, with higher concentration on the forehead region and on ears. Data herein obtained provide valuable information on the epidemiology and biological aspects of C. hominivorax affecting pigs. In addition, it indicates that the forehead and ears are important sites of parasitism most likely due the high frequency of skin lesions in these areas.