Screwworm Fly Chrysomya Bezziana Research Articles

The bioefficacy of crude extracts of Azadirachta indica (Meliaceae) on the survival and development of myiasis-causing larvae of Chrysomya bezziana (Diptera: Calliphoridae).

Myiasis is a type of parasitosis originating from the invasion of tissues of live humans and other vertebrates by dipteran larvae. The Old World screwworm fly—Chrysomya bezziana—is known worldwide in the tropical regions for causing myiasis among man and domestic animals, thereby leading to health hazards and severe economic losses to the dairy farmers. Management techniques for controlling populations of the fly are needed to minimize these losses. Plant-derived materials have been increasingly evaluated these days in controlling the insects of medical and veterinary importance. This study evaluated the efficacy of crude extracts of the plant neem, Azadirachta indica, against C. bezziana. The dried leaves of the plant were extracted successively with four different solvents viz. petroleum ether, chloroform, ethyl acetate and methanol and were evaluated against the third instar larvae of C. bezziana using dipping method and thin film application technique. In the dipping method, larvae were dipped in four different concentrations of plant extracts for 30 s, whereas in the thin film application, they were exposed to a thin film of plant extracts. The results showed that all the extracts had toxic effect on the larvae in both the techniques. In the dipping method, the highest mortalities were recorded in methanol extract followed by chloroform, petroleum ether and ethyl acetate extracts with LC50 values 1.07 g/100 ml, 1.7 g/100 ml, 3.39 g/100 ml and 4.9 g/100 ml, respectively. In the thin film application method, methanol extract showed the highest mortalities followed by chloroform, ethyl acetate and petroleum ether with LC50 values 0.4 mg/cm2, 0.6 mg/cm2, 2.1 mg/cm2 and 2.5 mg/cm2. It is concluded that the crude extracts of A. indica can be used in controlling the larvae of C. bezziana by using the dipping as well as thin film application technique.

Enabling technologies to improve area‐wide integrated pest management programmes for the control of screwworms

The economic devastation caused in the past by the New World screwworm fly Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) to the livestock industry in the U.S.A., Mexico and the rest of Central America was staggering. The eradication of this major livestock pest from North and Central America using the sterile insect technique (SIT) as part of an area-wide integrated pest management (AW-IPM) programme was a phenomenal technical and managerial accomplishment with enormous economic implications. The area is maintained screwworm-free by the weekly release of 40 million sterile flies in the Darien Gap in Panama, which prevents migration from screwworm-infested areas in Columbia. However, the species is still a major pest in many areas of the Caribbean and South America and there is considerable interest in extending the eradication programme to these countries. Understanding New World screwworm fly populations in the Caribbean and South America, which represent a continuous threat to the screwworm-free areas of Central America and the U.S.A., is a prerequisite to any future eradication campaigns. The Old World screwworm fly Chrysomya bezziana Villeneuve (Diptera: Calliphoridae) has a very wide distribution ranging from Southern Africa to Papua New Guinea and, although its economic importance is assumed to be less than that of its New World counterpart, it is a serious pest in extensive livestock production and a constant threat to pest-free areas such as Australia. In the 1980s repeated introductions and an expansion of Old World screwworm populations were reported in the Middle East; in the 1990s it invaded Iraq and since late 2007 it has been reported in Yemen, where a severe outbreak of myiasis occurred in 2008. Small-scale field trials have shown the potential of integrating the SIT in the control of this pest and various international organizations are considering using the release of sterile insects as part of an AW-IPM approach on a much wider scale. Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is a screwworm of temperate regions, which, although of limited agricultural importance, has invaded several new locations in the past few years. This special issue reports on the results of a 6-year project funded by the Joint Food and Agriculture Organization of the United Nations/International Atomic Energy Agency (FAO/IAEA) Programme of Nuclear Techniques in Food and Agriculture entitled 'Enabling Technologies for the Expansion of the SIT for Old and New World Screwworm'. A major goal of the project was to better understand population genetic variation in screwworms as an aid to the identification of isolated populations. The project also addressed issues related to genetic sexing, cuticular hydrocarbons, population dynamics, genetic transformation and chromosome analysis.

Comparative efficacy of Moxidectin and Ivermectin in cattle naturally infected with old world screw worm larvae

Moxidectin is a second generation semi-synthetic Macrocyclic Lactone of the Milbemycins family, which have a broad spectrum of activity against external and internal parasite including Oestrus ovis and hypodermatosis. A trial was conducted to identify the efficacy of moxidectin against the natural infection of cattle with larvae of screw worm fly Chrysomya bezziana. A dose of 0.2 mg/ kg b.wt. (1 ml /50kg b. wt.) S.C . which was found to be very effective for more than 40 days? The trial shows the effect of Moxidectin is over that of Ivermectin in re-infection of the animal. No side effects & no abnormal behaviors, was noticed on the animals treated with Moxidectin during the trial.

VACCINATION TRIALS IN SHEEP AGAINST CHRYSOMYA BEZZIANA LARVAE USING THE RECOMBINANT PERITROPHIN ANTIGENS Cb15, Cb42 AND Cb48

Recombinant forms of a number of peritrophic membrane proteins from the screwworm fly Chrysomya bezziana have been assessed in vitro and in vivo for their efficacy as antigens in vaccination against the tissue-invasive, larval form of the parasite. The proteins included Cb15 and Cb42 expressed in Escherichia coli and Cb48 expressed in both Escherichia coli and Pichia pastoris . In all cases, the in vitro assays of larval growth on serum from vaccinated sheep failed to show inhibition of larval weight gain or any detrimental effect on larval survival relative to controls. Chrysomya bezziana Cb48 has a significant degree of sequence identity with the antigen PM48 from Lucilia cuprina. Feeding Lucilia cuprina larvae on antisera to Cb48 induced a small but statistically significant reduction in weight gain, as does feeding on antisera to PM48. In vivo , larvae feeding on sheep vaccinated with Escherichia coli -expressed Cb15 and Cb42 and Pichia pastoris -expressed Cb48 showed marginally greater weight gain and survival which was equal to or greater than that on non-vaccinated sheep. The significance of these observations is discussed. Key words: Chrysomya bezziana , recombinant antigen, peritrophin, vaccination

FRACTIONATION, IDENTIFICATION AND VACCINATION EFFICACY OF NATIVE ANTIGENS FROM THE SCREWWORM FLY, CHRYSOMYA BEZZIANA

sources of potential protective antigens from the sheep blowfly Lucilia cuprina . Their importance in the screwworm fly Chrysomya bezziana has now been investigated. Purified serine proteases from Chrysomya bezziana were tested for their potential as vaccine antigens in sheep, efficacy being assessed by in vitro and in vivo assays with larval Chrysomya bezziana . No effect of vaccination was observed by the in vitro assay. However, in the in vivo challenge, larval weights were diminished in the vaccinated sheep, although larval recoveries increased marginally. Vaccination with Chrysomya bezziana peritrophic membrane does induce an effective immune response against the parasite resulting in a significant reduction in larval growth and considerable larval mortality in the in vitro assay. Sequential fractionation of the peritrophic membrane with various surfactants and chaotrophic agents of increasing solubilisation capacity resulted in the separation of discrete groups of proteins. The groups of fractionated proteins were tested in a vaccination trial in sheep with vaccine efficacy assessed by in vitro assays. The urea extract, guanidine-HCl extract and SDS soluble fraction each induced significant levels of protection against Chrysomya bezziana larvae but the effects were poorer than those obtained from vaccination with whole, native peritrophic membrane. Several major proteins selected from the three most protective fractions were purified by SDS polyacrylamide gel electrophoresis. Since insufficient quantities of these proteins were available for vaccination trials, they were either sequenced directly from the N-terminus or subjected to endoproteinase Lys-C digestion, followed by peptide purification and amino acid sequencing. This gave the information necessary for the expression of several of these roteins as recombinants in a form suitable for vaccination studies. Key words: Chrysomya bezziana, peritrophic membrane, vaccination, amino acid sequence, serine protease

Establishment and maintenance of a colony of the Old World Screwworm fly Chrysomya bezziana at Balitvet in Bogor, West Java, Indonesia

A colony of the Old World Screwworm fly, Chrysomya bezziana , has been established and maintained at Balai Penelitian Veteriner, Bogor, West Java, Indonesia since 1994. Culture on a convenient, defined diet able to sustain long term reproducibility of insect performance is described. The long-term viability of the colony has been further assured with an effective and reliable culturing procedure, with the genetic diversity and robustness of the colony being maintained through regular infusions of wild-type field isolates. The colony has been a reliable source of larval material used for the isolation and identification of protective antigens in the ACIAR funded Screwworm Fly Vaccination Project. Larvae have been used in the development and routine application of assays employed to evaluate vaccine efficacy. The colony continues to be a valuable resource for both screwworm fly vaccine and other new research includi the evaluation of screwworm fly attractants and lures. Key words: Chrysomya bezziana , culture, colony, larvae, vaccination

An investigation of the feasibility of vaccinating against the Old World Screwworm fly Chrysomya bezziana

The problem of the Old World Screwworm fly Chrysomya bezziana and the limitations of current methods of control are discussed briefly. Any attempt to investigate the feasibility of vaccinating against the fly, as a novel control technology, demands the establishment of methods for fly culture, the production of sources of antigens and the development of assay techniques suitable for the assessment of vaccination effects. This must be coupled to a strategy for vaccine development. This strategy is described, as a prelude to a series of papers evaluating the feasibility of vaccination in detail. Key words: Chrysomya bezziana , screwworm fly, vaccine

Purification of recombinant peritrophic membrane proteins of the Old World Screwworm fly, Chrysomya bezziana

To evaluate the feasibility of vaccinating sheep against the Old World Screwworm fly Chrysomya bezziana several recombinant peritrophin proteins were expressed in either a denatured form in Escherichia coli or a native-like form in Pichia pastoris cultures. Purification of the hexaHis tagged proteins was achieved by immobilized metal affinity chromatography. Proteins purified under reducing conditions were refolded using a glutathione shuffle procedure. Purification of a glutathione-Stransferase fusion protein was attempted using glutathione affinity chromatography in conjunction with anion exchange chromatography. The authenticity of the expressed proteins was verified by amino terminal amino acid sequencing. Carbohydrate analysis using biotinylated lectins revealed that Cb-peritrophin-48 expressed in Pichia pastoris was glycosylated with high mannose-type sugars. Four of the purified recombinant proteins were used to evaluate their protective immunogenicity in sheep against Chrysomya bezziana strike. Key words: Screwworm fly, Chrysomya bezziana, recombinant proteins, immobilized metal affinity chromatography

Vaccination against Chrysomya bezziana: a summary of current knowledge

Methods for the culture of the Old World Screwworm Fly Chrysomya bezziana on a small laboratory scale, the production of life stages and tissues suitable for vaccine study, and the in vitro and in vivo assessment of vaccine effects have all been developed. These methods would be applicable to further studies on screwworm control by many alternative technologies. It has been shown to be possible to induce dramatic immunological effects on feeding larvae and to isolate and characterise individual antigens. However, a recombinant vaccine remains elusive. Current understanding of the effects of vaccination is discussed and suggestions made for possible future research directions. Key words: Chrysomya bezziana , Old World screwworm fly, vaccine, recombinant antigen, sheep

The development of an “in vivo assay technique” as a tool for measuring protective immune responses of vaccine against myiasis in sheep

An “ in vivo assay technique ” is urgently needed for measuring protective immune effects of a myiasis vaccine in sheep. Such a technique is being developed simultaneously with the development of a vaccine against myiasis caused by the screwworm fly Chrysomya bezziana under a collaborative project undertaken by Balitvet, ITB and CSIRO (Australia) and funded by ACIAR. Experiments were conducted in naive sheep. C. bezziana larvae were allowed to develop on abraded skin in aluminium rings which had been attached to the sheep by means of a glue (Aibon) on the day prior to infection. Rings were arranged on clipped areas close to the mid line of the sheep’s back, two rings on the right side and two rings on the left. Four trials were performed, involving studies on the effects of including wet sponges in the rings to maintain humidity (Trial 1); the effects of sponge and blended meat as counting and transferring media during infection (Trial 2); the effects of the repellants citronella, eucalyptus oil and neem extract in assisting the recovery of larvae (Trial 3); and the effects of the reducing the infective dose from 50 to 25 1st instar larvae/ring and using a fine brush for counting and transferring larvae instead of using a forceps as in the previous groups (Trial 4) on the larval recovery rates (LRR). The results indicated that the inclusion of wet sponges in the rings, the use of sponge and blended meat as counting and transferring media during infection, and the application of repellants all increased the LRR to some extent; however, variations among individual rings remained high. On the other hand, the reduction of infective dose of larvae from 50 to 25 1st instar larvae/ring and using a fine brush for counting and transferring larvae sharply increased the LRR while substantially decreasing the coefficient variations. Key words : Myiasis, Chrysomya bezziana , larval recovery rate

Cytogenetic variation in natural populations of the Old World screwworm fly Chrysomya bezziana (Diptera: Calliphoridae)

The existence of sibling species in the Old World screwworm fly Chrysomya bezziana would raise serious problems in eradicating this pest if it entered Australia. Cytogenetic variation in C. bezziana was investigated by analyzing pupal trichogen polytene chromosomes. Natural populations of C. bezziana spanning its range from southern Africa to Papua New Guinea were examined as well as hybrids between a New Guinea laboratory strain and natural populations. No evidence of sibling species was found. All populations exhibited the same basic banding pattern as the standard sequence established from a Papua New Guinea strain. Extensive asynapsis of chromosome homologues was found in some hybrid crosses and was therefore measured in all populations and hybrids to detect systematic variation. Asynapsis levels in most hybrids could not be statistically distinguished from those present in the parent populations except for crosses between populations at the ends of the range. This result does not permit asynapsis levels to be used in establishing the origin of introduced flies by estimating their distance from known populations. One inversion polymorphism and six band polymorphisms spread over three chromosomes were analyzed. Populations in each sampled region had characteristic combinations of band polymorphisms. This may offer a diagnostic method for determining the origin of flies accidentally introduced to Australia.

Report on a sterile insect release trial for the control of the Old World screw-worm fly Chrysomya bezziana in Papua New Guinea

Australian Veterinary JournalVolume 68, Issue 8 p. 277-279 Report on a sterile insect release trial for the control of the Old World screw-worm fly Chrysomya bezziana in Papua New Guinea GM CLARKE, GM CLARKE DPIE/CSIRO Screw-Worm Fly Unit, PO Box 6712, Boroko, Papua New Guinea *CSIRO Division of Entomology, PO Box 1700, Canberra City, Australian Capital Territory 2601Search for more papers by this author GM CLARKE, GM CLARKE DPIE/CSIRO Screw-Worm Fly Unit, PO Box 6712, Boroko, Papua New Guinea *CSIRO Division of Entomology, PO Box 1700, Canberra City, Australian Capital Territory 2601Search for more papers by this author First published: August 1991 https://doi.org/10.1111/j.1751-0813.1991.tb03243.xCitations: 3 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume68, Issue8August 1991Pages 277-279 RelatedInformation

Age-determination in the old-world screw-worm fly Chrysomya bezziana by pteridine fluorescence

Highly significant positive relationships were observed between pteridine fluorescence in the head and chronological age for both sexes of the old-world screw-worm fly Chrysomya bezziana Villeneuve in the laboratory and in field mark-release-recapture trials in Papua New Guinea. The relationships were multiplicative in form and, in most cases, age accounted for in excess of 80–90% of the variance in fluorescence. The rate of accumulation of pteridines with age was greater for males than females, was not affected by the absence or presence of protein in the diet, but was highly dependent on temperature. Pteridine levels appear to be a good indicator of age in this species and will enable the chronological age of wild flies to be determined with a relatively high degree of accuracy.

Occurrence of the Old World screw-worm fly Chrysomya bezziana on livestock vessels and commercial aircraft.

Occurrence of the Old World screw-worm fly Chrysomya bezziana on livestock vessels and commercial aircraft.