Overview

Brief Summary

Taxonomy

The species was first named in the literature by Schiner (1862) as Sarcophila magnifica. However, its larvae had previously been figured (but not named) in 1770 by a German physician, Dr J.A. Wohlfahrt, who removed some larvae from the eye of a patient.Portschinsky, who knew of Wohlfahrt’s paper but not of Schiner’s, named the fly Sarcophila wohlfahrti in 1875. The genus Wohlfahrtia was created by Brauer and Bergenstamm in 1889. A comprehensive description of the morphological characteristics of the taxon are given by Povolný and Verves (1997).

Morphology
Adults of W. magnifica are handsome fleshflies, with a striped greyish thorax and an abdomen whose dorsal surface is bright white with a series of contrasting dark black spots, three per tergite, with the central spots elongated and tending to merge at their anterior edge with the one above.

Molecular biology
Recent studies show that there are at least two main lineages of this species, based on analysis of the Cytochrome-b gene (mitochondrial DNA). These are western and eastern Mediterranean lineages, probably relics of ice-age refugia.Continental refugia await discovery. There is a strong geographical signal from the mt-DNA analysis which can help to show where invasions have or have not originated (Hall et al., 2009).

Evolution
Wohlfahrtia magnifica is the only obligate parasite in the genus and, therefore, likely to be one of the most recently derived taxa, evolving from carrion breeding species.
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Introduction

Wohlfahrtia magnifica is a parasitic species of flesh fly. The fly lays its first stage (instar) larvae on living warm-blooded animals and they immediately begin to feed on the underlying flesh. The wounds they cause are an example of an infestation known as traumatic myiasis and are a source of considerable pain and suffering to the host animal, which can die if untreated. Wohlfahrtia magnifica is a major animal welfare and economic concern to the livestock industry, but it can also affect humans.
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Comprehensive Description

Biology

Size
The body length of adults is in the order of 8-14mm.Larvae range from only 1.5-2.0mm when deposited up to about 15-18mm when mature.

Growth
Larvae mature in host wounds within about 5-7 days. The rate of growth is determined by the temperature where they are feeding which, for these parasites, is dependent on the host body temperature. Larvae of W. magnifica will feed only on live hosts, never on carrion.

Feeding strategy
Adult Wohlfahrtia magnifica are flower feeders, but females will feed on protein at animal wounds. Larvae are obligatory parasites of living mammal or bird tissuesThe rate of development of pupae is determined by environmental temperatures, therefore it becomes slower at low temperatures. When temperatures drop and daylight shortens in the autumn the species enters pupal diapause (Ternovoy 1978).Adult flies emerge in the following spring, when the soil warms and the days lengthen.

Life expectancy
Unknown, adults in captivity can live for 1-2 months.
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Distribution

Distribution and habitat

Distribution
Wohlfahrtia magnifica is widely distributed throughout the warmer, southern parts of the Palaearctic region, from the Mediterranean basin, through central and eastern Europe to northern and central Asia, Mongolia, China and Afghanistan (Hall and Farkas, 2000).

Habitat
The adults are thermophilic and inhabit hot and arid environments, usually being observed in flight only on sunny days in the summer, from May to October in the northern hemisphere to which they are restricted.Typical environments are forest-steppes and the steppes or semi-deserts of Russia where Portschinsky (1884, 1916) made his studies.

Dispersal
Adults of Wohlfahrtia magnifica are strong fliers, but no estimates of their flight range have been made.They colonised the whole island of Crete within about 5 five years, but the major potential agents for their dispersal are shipments of infested livestock.

Population biology
There is little information on population biology but, like other obligate myiasis-causing parasites, the adult density is low compared to related carrion-breeding species.There is little information on population biology but, like other obligate myiasis-causing parasites, the adult density is low compared to related carrion-breeding species.
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Physical Description

Look Alikes

Lookalikes

Other flies in the genus Wohlfahrtia (there are 26 in total) are very similar in appearance and correct identification requires microscopic identification by an experienced entomologist, looking especially at features of the antennae and the abdominal spots.In medical and veterinary myiasis cases, the larvae can be most easily confused with those of either the New World screwworm fly (Cochliomyia hominivorax) or the Old World screwworm fly (Chrysomya bezziana), both blowflies (Diptera: Calliphoridae). Larvae of all three species cause the same deeply penetrating wounds on hosts. Wohlfahrtia magnifica differs from the other two species by having a typical sarcophagid posterior end, with the posterior spiracles set in a cavity rather than being exposed on a flat surface. The mature larvae of these species can be discriminated in this Museum website article.
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Ecology

Diseases and Parasites

Disease

While adults of W. magnifica are harmless, their larvae are obligate parasites of warm-blooded vertebrates including humans.Portschinsky (1916) described many human cases in Russia and warned people not to sleep outside between the hours of 10.00 and 16.00, when the adult flies are active, because of the danger of infestations of the oral cavity as the mouth drops open in sleep, allowing the fly in to lay its larvae.Deposited by females directly onto the tissues of their hosts, the larvae feed and develop rapidly, moulting twice before reaching maturity, at which point they leave the wound they have created, dropping to the ground to pupate.The wounds they cause are an example of what is known as traumatic myiasis and they are a source of considerable pain and suffering to hosts, which can die if untreated. Even if the hosts do not die, this parasite is a major animal welfare concern to the livestock industry, affecting:
  • Sheep
  • Goats
  • Cattle
  • Pigs
  • Horses
  • Camels
  • Geese
  • Wildlife can also suffer
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Life History and Behavior

Behavior

Behaviour

Wohlfahrtia magnifica is a species for which, with regard to its behaviour in the field, we know relatively little. Adult males will sit on raised objects in the environment, called mating stations (for example, large stones and logs), from where they will fly out to mate with passing females. They will actually intercept almost any passing fly of approximately the same size as a female, but will only actively engage with those of the right sex and species, recognised by cuticular pheromones.Very little is known of female behaviour other than their activity around potential host animals. They can be attracted to even healthy hosts, depositing live larvae at the body orifices, especially genitalia, but already infested hosts are most attractive (Hall et al., 1995).

Migration
There is no known regular migration of this species but it is subject to range extensions either naturally or through the assistance of humans, for example with movements of infested livestock.In 1999 it reached Crete, Greece, for the first time and has now spread throughout the island (Sotiraki et al, 2003)
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Life Cycle

Lifecycle

Like most sarcophagids, adult females of W. magnifica deposit live larvae, each laying up to about 160.The larvae moult twice as they mature. When mature they stop feeding and leave the wound, falling onto the substrate into which they try to bury. The outer larval skin hardens and darkens into a lozenge-shaped puparium. This is actually the cuticle of the last larval instar and, within its protection, the pupa forms.The adult emerges from the pupa within about one week if not in diapause.
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Conservation

Conservation Status

Conservation

Conservation status
It is remarkable that this species manages to keep sufficient population numbers to maintain its distribution in spite of major efforts made by the livestock industry to reduce its numbers by repeated use of insecticide prophylaxis or treatments throughout the summer period.

Trends
Populations are probably stable, but there is considerable potential for long term expansion of this thermophilic species within central and northern Europe if even the conservative trends for global warming are realised.

Procedures
There are a number of prophylactic applications or treatments for this species (Hall and Farkas, 2000; Sotiraki et al., 2003, 2005ab)

Threats
The major threat to this species is anthropogenic in the form of a battery of insecticides that are applied to host animals to kill larvae.

Legislation
None presently, but there is potential for future inclusion of W. magnifica as a Category B pest in the International Office of Epizootiology’s Animal Health Code, which would necessitate livestock trading countries following advised procedures for control of its movement.
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Wikipedia

Wohlfahrtia magnifica

Wohlfahrtia magnifica, the spotted flesh fly, or sometimes called the screwworm fly, though species of flies from other families go by this name. It is a species of fly belonging to the family Sarcophagidae . The adults are about 6–10 mm in length,[1] 3 instar larvae are 5-7mm in length.

Myiasis[edit]

Wohlfahrtia magnifica larvae cause myiasis in mammals, mainly in sheep, but also in cattle, goat, horses and rarely in human. In sheep, larvae chiefly infest genitalia or open wounds. In human W. magnifica larvae may infest the ear, eye, mouth[2] or nose, damaging living tissues.[1] they may also infest open wounds, including post surgery.

Distribution[edit]

W. magnifica is found in southern Europe, Asiatic Russia, the Middle East, North Africa and China.[3] Their range is increasing, believed to because of spread of intensive sheep rearing.

Similar species[edit]

The larvae of the North American species, Wohlfahrtia vigil and Wohlfahrtia opaca, are incapable of penetrating adult skin; infestation occurs only in infants.[1]

References[edit]

  1. ^ a b c West, Anna M. "Myiasis". Retrieved 2009-03-29. 
  2. ^ BÜYÜKKURT, Mustafa Cemil , MD. et al. (2008). "Oral Myiasis in A Child Due to Wohlfahrtia Magnifica" (PDF). Turkiye Klinikleri J Med Sci 28: 782–785. Retrieved 2009-03-30. 
  3. ^ Ruis Martinz, I. Leclercq, M (1994). "Data on distribution of screwworm fly Wohlfahrtia magnifica (Schiner) in Southwestern Europe (Diptera:Sarcophagidae)" (PDF). Notes fauniques de Gemblous 28: 53–60. Retrieved 2009-03-30. 
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