[Helminth Paraites in Ethiopian Wolves]

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ACKNOWLEDGEMENT

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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ACKNOWLEDGEMENT2

DECLARATION3

CHAPTER 1: INTRODUCTION5

Helminths Definition5

Tapeworms (Cestodes)7

Wolves-Ethiopian wolf11

Geographic Range11

Physical Description11

Reproduction12

Behavior13

CHAPTER 2: LITERATURE REVIEW16

Classical Examples of Parasitic 'Manipulation'18

Parasites of Veterinary Importance20

Dicrocoelium dendriticum20

Diplostomum spathaceum20

Echinococcus21

Toxoplasma gondii22

CHAPTER 3: MATERIALS AND METHODS29

Study Area29

Morphological analysis of parasite stages31

PCR and sequencing of parasite stages32

Statistical Analysis32

Study site33

Fecal sample collection and analysis33

CHAPTER 4: RESULTS35

CHAPTER 5: DISCUSSION40

Ecology and diversity of parasites detected in wolf feces40

Seasonal Patterns in Parasite Occurrence45

Spatial Patterns in Parasite Occurrence in Wolf Feces46

CHAPTER 6: CONCLUSION47

REFERENCES48

CHAPTER 1: INTRODUCTION

Helminths Definition

Helminth is a general term meaning worm. The helminths are invertebrates characterized by elongated, flat or round bodies. In medically oriented schemes the flatworms or platyhelminths (platy from the Greek root meaning “flat”) include flukes and tapeworms. Roundworms are nematodes (nemato from the Greek root meaning “thread”). These groups are subdivided for convenience according to the host organ in which they reside, e.g., lung flukes, extraintestinal tapeworms, and intestinal roundworms. Helminth is a general term for a parasitic worm. The helminths include the Platyhelminthes or flatworms (flukes and tapeworms) and the Nematoda or roundworms (Altizer, 2006, 467-484). All helminths are relatively large (> 1 mm long); some are very large (> 1 m long). All have well-developed organ systems and most are active feeders. The body is either flattened and covered with plasma membrane (flatworms) or cylindrical and covered with cuticle (roundworms). Some helminths are hermaphrodites; others have separate sexes.

Helminths are worldwide in distribution; infection is most common and most serious in poor countries. The distribution of these diseases is determined by climate, hygiene, diet, and exposure to vectors. The contributions of various stages to disease are listed in table below.

Table 1: Common Larval Forms of Helminths Found in Humans

Table 2: Stages of Helminths

Platyhelminths and nematodes that infect humans have similar anatomic features that reflect common physiologic requirements and functions. The outer covering of helminths is the cuticle or tegument. Prominent external structures of flukes and cestodes are acetabula (suckers) or bothria (false suckers). Male nematodes of several species possess accessory sex organs that are external modifications of the cuticle. Internally, the alimentary, excretory, and reproductive systems can be identified by an experienced observer (Altschul, 1990, 403-410).

The mode of transmission varies with the type of worm; it may involve ingestion of eggs or larvae, penetration by larvae, bite of vectors, or ingestion of stages in the meat of intermediate hosts. Worms are often long-lived. Many infections are asymptomatic; pathologic manifestations depend on the size, activity, and metabolism of the worms. Immune and inflammatory responses also cause pathology (Anderson, 2000).

Nonspecific defense mechanisms limit susceptibility. Antibody- and cell-mediated responses are important, as is ...