Old World screwworm fly, Chrysomya bezziana, occurs as two geographical races

Abstract

A morphological and molecular analysis was undertaken with the objective of identifying markers for geographical populations of Old World screwworm flies, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae). The morphological analysis involved 192 adult flies from 14 countries, and the molecular analysis involved 45 larvae or adults from 14 populations in 11 countries. Principal components and cluster analysis of 10 morphological characters indicated that flies from Papua New Guinea (PNG) were a distinct group and most similar to flies from nearby Asian islands (Java, Sabah). There was poor resolution of other geographical regions, but some support for clustering of flies from Africa or India. Cladistic analysis of mitochondrial DNA sequences gave strong support for recognizing two races of Old World screwworm, one from sub-Saharan Africa and the other from the Gulf region and Asia. This latter race could be further divided into two lineages, i.e. one from mainland Asia (from Iraq to the Malay Peninsula) and the other from two islands of PNG.

Observations of the third instar larva and puparium of Chrysomya bezziana (Diptera: Calliphoridae)

“…Geographically, this fly is widely distributed in Africa, the Middle East, the Indian subcontinent, south-eastern Asia, and Australia (Mahon et al 2004) and was recently recorded as an insect involved in parasitic zoonoses in Papua New Guinea (Owen 2005). Morphological and molecular analyses of C. bezziana populations by Hall et al (2001) has revealed that there are two races of this fly species, one from sub-Saharan Africa and the other from the Gulf region and Asia.…”

Occurrence of Chrysomya bezziana in a buffalo in Jammu

“…Cutaneous myiasis caused by the Old World screw-worm fly, Chrysomya bezziana, is a wide spread infestation of domestic animals and man in Southeast Asian and African countries (Soulsby 1982;Hall et al 2001;Mahon et al 2004). Chrysomya bezziana is an obligatory parasite of warm blood animals, lays eggs in necrotic tissues and/or wounds caused by ticks and lice which offer a favourable environment for the development of their larvae.…”

Impact of Screwworm Eradication Programmes Using the Sterile Insect Technique

“…This screwworm species is also found in tropical and subtropical sub-Saharan Africa, and in several countries in the Middle East (Spradbery 2002). Kloft et al (1981) reported repeated "transit infestations" of the Old World screwworm from South-East Asia to the Middle East, and a recent (1996) infestation recorded in Iraq is assumed to have originated from South-East Asia (Hall et al 2001). …”

“…Before an eradication programme is planned, however, an essential preliminary phase is the collection of comprehensive baseline data, including ecological and genetic studies to delineate the relevance of the problem (Hall et al 2001 …”

“…Studies were conducted to determine the genetic variation of C. bezziana samples from as many localities as possible within its geographic range (Hall et al 2001), using a range of techniques including allozyme studies (Strong and Mahon 1991), some hybridization tests (J. P. Spradbery, unpublished data), cytogenetic studies (Bedo et al 1994), and biochemical profiles of the exoskeleton chitin analysed by gas chromatography (Brown et al 1998). …”