In vitro quantitation of Theileria parva sporozoites for use - TropMed ...

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Chapter 1: Quantitation of Theileria parva sporozoites: Review of literature 27 ______________________________________________________________________________________________ T. parva infected lymphoblasts (Morrison et al., 1987; Goddeeris et al., 1990; Taracha et al., 1992; Taracha et al., 1995). These CTL are parasite strain specific and restricted to the MHC class 1 markers (Goddeeris et al., 1986). 1.1.5. Epidemiology The disease is generally endemic in the eastern, central and southern regions of Africa within the geographic distribution of the tick vector (Figure 4). Tick numbers, tick infection and susceptibility of bovine hosts are the main determinants of risk of infection (Medley et al., 1993). Climatic factors, particularly rainfall, affecting tick distribution and survival have been found to play a major role in the occurrence and seasonality of the disease (Branagan, 1973a; Branagan, 1973b; Short et al., 1989; Berkvens et al., 1995; Mulumba et al., 2000; Mulumba et al., 2001; Fandamu et al., 2005). Transmission and occurrence of disease may be seasonal or not depending on the rainfall patterns that determine the tick instars and population densities on the host (Norval et al., 1991; Mulumba et al., 2000; Mulumba et al., 2001). The main bovine host factor complicating the epidemiology of the disease is the carrier state in recovered or immune animals (Neitz, 1964; Young et al., 1986; Dolan, 1986a; Bishop et al., 1992; Latif et al., 2001), which serve as infection sources for field ticks. Other bovine host factors include susceptibility to T. parva, resistance to ticks, breed and age (Fivaz et al., 1989; Koch et al., 1990; Latif et al., 1991; Ndungu et al., 2005). It has been shown recently that the mean volume of erythrocytes is correlated to the fatality of cases with smaller sizes predisposing the symptomatic animal to death (Fandamu et al., in press). The degree of disease establishment is broadly classified as epidemic or endemic. Endemic stability is a state in which all calves come in contact with the disease within a few months of age and morbidity is low (Moll et al., 1986). This situation is observed in East Africa where climatic conditions allow the all year round possibility of the tick to infect the bovine host and where innate resistance of the local cattle to the prevailing parasite stocks is known to occur (Moll et al., 1984). In contrast, Billiouw et al. (2002) have shown that this is not the case for eastern Zambia where the disease was introduced more recently, i.e. during the early 20 th century, and tick presence and therefore transmission pressure is seasonal.
28 Chapter 1: Quantitation of Theileria parva sporozoites: Review of literature ______________________________________________________________________________________________ Figure 4: Distribution range of Theileria parva (adapted from Norval et al., 1992e; Speybroeck et al., 1999 and Chaka, 2001) and the distribution of Rhipicephalus appendiculatus (adapted from Berkvens et al., 1998; Speybroeck et al., 1999; Walker et al., 2000 and Chaka, 2001). Some authors have graded the degrees of endemicity from very stable to very unstable (Norval et al., 1992c) depending on factors such as age at first contact of calves, sero-prevalence in the adult population and case fatalities. Billiouw (2005) suggests a reclassification of the states into epidemic, first level endemic stable, second level endemic stable and ultimate endemic stable states. The criterion is mostly based on stability of infection prevalence and age at first contact. As such, he classifies the state in eastern Zambia as first level endemic stability. 1.1.6. Diagnosis 1.1.6.1. Clinical signs Cattle undergoing a clinical manifestation of the disease present with a high fever, which may reach 42°C. They develop enlarged superficial lymph nodes especially the parotidian (ln.
Page 1 and 2: Victor Mbao In vitro quantitation o
Page 3 and 4: II Front cover photograph Copyright
Page 6 and 7: V ACKNOWLEDGEMENTS This work was ma
Page 8 and 9: VII TABLE OF CONTENTS ACKNOWLEDGEME
Page 10: IX APPENDIX I .....................
Page 14 and 15: General Introduction 13 ___________
Page 16 and 17: General Introduction 15 ___________
Page 18: Chapter 1 - Quantitation of Theiler
Page 21 and 22: 20 Chapter 1: Quantitation of Theil
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Page 44 and 45: Chapter 2: Objectives 43 __________
Page 46: Chapter 3 -Comparison of two Theile
Page 49 and 50: 48 Chapter 3: Theileria parva extra
Page 58 and 59: Chapter 4: Suspension media and mul
Page 68: Chapter 5 - Snap freezing of Theile
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Chapter 6: Storage of Theileria par
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Chapter 7: Lyophilisation of Theile
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Chapter 8: SNA and refinement of ti
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Chapter 9: General Discussion 119 _
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APPENDICES
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SUMMARY
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Curriculum Vitae
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List of Abbreviations 183 _________
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