The screw worm, Cochliomyia hominivorax (Diptera: Calliphoridae), a problem in animal and human health

Abstract

The New World Screwworm (NWS) continues being a veterinarian and human problem in South America and part of the Caribbean. In order to update this matter based on the research of the last six years, the wealth of existing information was reviewed, and some results of the authors of this paper were compared and discussed with those results found in this framework. Studies on the agent have been focused on its biology, epidemiology, zoonotic role, the control and insecticide resistance. In this subject, studies have been carried out on the differences in the wings of the agent and some related bugs as a good identification marker; the development of a key for the identification of the ectoparasite first stage larvae; obtaining of evidence about the migration of insect populations from north to south in the Americas at the end of the last glacial maximum and then in the transition between the Pleistocene and the Holocene; the assessment of economic losses caused by the insect, in billions of dollars ($ 0.34) in Brazil; the polymorphisms (intraspecific) shown by three different primers for samples from Mexico, Costa Rica, Panama, Jamaica, and Brazil; the use of two other primers (CR92A1 and J1A2) which allowed to discriminate successfully between Cochliomyiahominivorax and C. macellaria; the association between Rhipicephalus microplusy charge and the occurrence of screwworm myiasis by C. hominivorax, with a relative risk of screwworm in cattle with a high tick load of 3.85; new cases of human myiasis (in head, associated with Pediculus humanuscapitis, maxillary, and in other anatomical locations) in different places of the areas where the agent abounds; evidences of ivermectin and abamectin ineffectiveness in preventing bull scrotal myiasis; the presence of E3 gene mutations associated with insecticide resistance, different types of diets and methods of genetic control.

Key words: Cochliomyia hominivorax; New World screw-worm, myiasis.