Project topics and materials
Get Complete Project Material File(s) Now! »
Introduction
Myiasis is the infestation of live vertebrate animals with blowfly larvae which, at least for a certain period, feed on the host’s dead or living tissue, liquid body substances, or ingested food (Zumpt, 1965). These larvae, known as maggots, use the mentioned body fluids or exudates as their food source for their growth and development, and in the process cause severe tissue damage resulting in discomfort, loss in production, reproduction problems, blindness, lameness and even death (Farkas et al., 1997; Snoep et al., 2002). Although myiasis has been recognised as a major disease from ancient times (Sherman et al., 2000) the disease is still poorly controlled in the animal production industry of many countries in modern times, leading to severe economic losses. Losses that have resulted include abortions, decreased milk production, losses in weight and fertility, poor hide quality, muscle damage and even death from toxicity or secondary infections (Heath et al., 1987). In South Africa the direct losses to blowfly attacks and associated treatment is not quantified. One manufacturer of traps estimated an annual loss of R40 million in lost productivity (Anonymous, 2009a).
Species of flies in the families Calliphoridae, Sarcophagidae and Muscidae are the main cause of cutaneous myiasis (Hall, 1991). Of these, the old world screwworm Chrysomya bezziana of the Calliphoridae family is the major obligate agent of wound myiasis in most mammals in tropical Africa. In South Africa the parasite is most prevalent in the eastern coastal area, while in Zimbabwe the parasite is distributed across the entire country (Baker et al., 1968; Hall, 1991). Lucilia cuprina, also of the Calliphoridae family, is the other predominant species inducing ovine cutaneous myiasis (sheep-strike) in many countries worldwide including Australia, New Zealand and South Africa (Dalwitz et al., 1984; Heath, 1994; Norris, 1990; Fourie and Horak, 2000).
The control of the myiasis-causing flies relies heavily on the use of pharmaceutical chemicals such as the organophosphates, pyrethroids or insect growth regulators under first world conditions (Phillips, 2009). Unfortunately these chemical compounds are characterised by a low safety index with high potential to cause human or animal toxicity as well as being contaminants of the environment (Colwell and Dorchies, 2004; Wardhaugh, 2005). Their continued use has also promoted the development of resistance (Hemingway and Ranson, 2000), with the result that newer products need to be developed.
One source of these compounds could be the flora of Africa, in a similar manner in which pyrethrins were identified from the chrysanthemum flower (Chrysanthemum cinerariaefolium and C. coccineum) (Casida, 1980). To date numerous plants have been identified in numerous surveys for use in the treatment of myiasis. They include: Aloe marlothii A. Berger (Van der Merwe et al., 2001), Aloe zebrina Baker (Luseba and Van der Merwe, 2006), Calpurnia aurea (Aiton) Benth (Hutchings et al., 1996), Psydrax livida (Hiern) Bridson (Canthium huillense), Clausena anisata (Willd) Hook (Chavunduka, 1976), Erythrina lysistemon Hutch (Van Wyk et al., 1997), and Spirostachys africana Sond (Hutchings et al., 1996). It was believed that these plants could therefore lead to the discovery of novel structures or the development of active plant extracts for use to protect animals.
CHAPTER 1.
1.1 Introduction.
1.2 Hypothesis.
1.3 Aim and Objectives
CHAPTER 2 Literature Review .
2.1 Livestock agriculture .
2.2 Ethnoveterinary medicine .
2.3 Myiasis
2.4 Plants selected for the study.
2.5 Conclusion .
2.6 References
CHAPTER 3. In vitro antibacterial activity of seven plants used traditionally to treat wound myiasis in animals in southern Africa
3.1 Introduction.
3.2 Materials and methods
3.3 Results.
3.4 Discussion.
3.5 Conclusion.
3.6 Acknowledgements.
3.7 References .
CHAPTER 4 Evaluation of plant species used traditionally to treat myiasis for activity on the survival and development of Lucilia cuprina and Chrysomya marginalis (Diptera: Calliphoridae)
4.1 Introduction.
4.2 Materials and methods.
4.3 Results.
4.5 Conclusion
4.6 Acknowledgements
4.7 References
CHAPTER 5. Extracts of four plant species used traditionally to treat myiasis influence pupation rate, pupal mass and adult blowfly emergence of Lucilia cuprina and Chrysomya marginalis (Diptera: Calliphoridae)
CHAPTER 6 Field evaluation of acetone extracts of Clausena anisata (Rutaceae) as a blowfly population control product for management of myiasis in livestock
CHAPTER 7 Isolation of seselin from Clausena anisata (Rubiaceae) leaves and its effects on the feeding and development of blowfly larvae may explain its use in ethnoveterinary medicine
CHAPTER 8 General Discussion Conclusions and Future Research
CHAPTER 9 References
