Occurrence of Cochliomyia hominivorax in cattle in Maranhão, Brazil

Abstract

Cattle breeding has great importance in the Brazilian economy, however, diseases affect production, causing economic losses, such as myiasis. The causative agent is Cochliomyia hominivorax, the screwworm fly. They are suitable for tropical and subtropical regions in Brazil, and exhibit parasitic resistance to drugs. The objective of this study was to verify the occurrence of Cochliomyia hominivorax in cattle in the state of Maranhão, Brazil. In the first stage, 19 dairy and beef cattle properties were chosen, distributed in 11 municipalities in Maranhão. Questionnaires asked about the management, the drugs used and the cost of prevention related to the disease. The cattle were examined by inspection, collecting the larvae found on the body surface. The number of larvae per bovine, location of lesions, origin and complications were observed. Then, the collected specimens were placed in individual flasks, per sampled host, containing alcohol at 70°Gl. In the second stage, the fly larvae were identified in the laboratory, examined under a stereomicroscope and identified by their morphology and analysis of peritrematic plaques and respiratory spiracles. It was found that 60% of the properties had parasitized cattle. Among the 4,509 animals observed, 0.57% were infected with C. hominivorax larvae. Lesions were found on the navel (50%), as well as on the neck plate (42%), vulva (4%), horn (4%). It is concluded that there was a low prevalence of myiasis caused by C. hominivorax in cattle in the state of Maranhão, but prevention and health care should always be adopted by livestock farmers.