Characterization of Trypanosomes Isolated from Bovine and Canine Using Polymerase Chain Reaction.


Trypanosomiasis is a vector-borne parasitic disease, transmitted to animals by tsetse fly (Glossina genus) bites. The human type causes sleeping sickness in man while animal type causes nagana in animals. The aim of this study is to characterize trypanosomes isolated from dogs and cattle in Jos South Abattoir.

Isolated trypanosomes were subjected to polymerase chain reaction using kin primers targeting internal transcribed spacer 1 (ITS1) of ribosomal deoxyribonucleic acids.

The PCR allowed detection of three trypanosome livestock species namely T. vivax sub-species (150bp, 250bps); T. congolense (750bp) and T. brucei (540bp).

The samples from dogs all showed T. vivax sub-species and one sample showed mixed infection of T. vivax sub-species and T. congolense.

The samples from cattle showed mostly mixed infections of brucei and T. congolense. The most significant finding is the observation that more than one sub-species of T.vivax is circulating in the Jos area.


Contents Pages
Title Page i
Certification ii
Dedication iii
Acknowledgements iv
Abstract v
Table of Contents vi
List of Tables x
List of Figures xi


1.0 Introduction 1
1.1 African Animal Trypanosomiasis 1
1.2 Statement of Problem 3
1.3 Justification of the Study 3
1.4 Aim and Objectives of the Study 4


2.0 Literature Review 5
2.1 Pre-History 5
2.2 Early History 6
2.3 Geographical Distribution 8
2.4 Classification of Trypanosomes 9
2.4.1 Classification of Trypanosomes of Economic, Medicinal and
Veterinary Importance 11
2.5 Trypanosome Life Cycle 12
2.5.1 Life Cycle of the Vector 15
2.5.2 Forms of Human African Trypanosomiasis 16
2.5.3 Animal Trypanosomiasis 16
2.5.4 Host range 17
2.6 Prevention 18
2.6.1 Transmission 18
2.6.2 Pathogenesis 19
2.6.3Clinical Signs 21
2.6.4 Epidemiology 23
2.7 Molecular Biology of Trypanosomes 25
2.7.1 Nucleus 25
2.7.2 Kinetoplast DNA 26
2.7.3 Maxicircles 27
2.7.4 Minicircles 27
2.7.5 Genotyping of Trypanosome Parasites 27
2.8 Diagnosis of Animal Trypanosomiasis 29
2.8.1 Diagnosis 29
2.8.2 Clinical 30
2.8.3 Microscopic Diagnosis 30
2.8.4 Serological Diagnosis 31
2.8.5 Molecular Diagnosis 32
2.9 Control Measure of the Vectors 34


3.0 Materials and Methods 36
3.1 Study Site 36
3.2 Sample Site 36
3.3 Collection of Blood Sample 36
3.4 Preparation of Buffy Coat 37
3.4.1 PCV Measurement 38
3.5 Preparation of Thin Blood Smears 38
3.6 Preparation of Buffers 39
3.6.1 Preparation of Buffer AL 39
3.6.2 Preparation of Buffer AW1 39
3.6.3 Preparation of Buffer AW2 39
3.6.4 Buffer AE 39
3.7 DNA Extraction 39
3.8 PCR Analysis of the Genomic DNA 41
3.9 PCR Amplification 43
3.9.1 Agarose Gel Electrophoresis 43


4.0 Results 45
4.1 Buffy Coat Examination 45
4.2 Thin Blood Smear Examination 45
4.3 Blood Parameters 45
4.4 Identification of Trypanosomes 46


Discussion and Conclusion 48
References 51


1.1 African Animal Trypanosomiasis

African animal trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease. The parasites concerned are protozoa belonging to the Trypanosoma genus.

They are transmitted to humans by tsetse fly (Glossina genus) bites which have acquired their infection from human beings or from animals harbouring the human pathogenic parasite (WHO, 2014)

Tsetse flies are found just in sub-Saharan Africa though only certain species transmit the disease. For reasons that are so far unexplained, there are many regions where tsetse flies are found, but sleeping sickness does not exist.

Rural populations living in regions where transmission occurs and which depend on agriculture, fishing, animal husbandry or hunting is the most exposed to the tsetse fly and therefore to the disease. The disease develops in areas ranging from a single village to an entire region.

Within an infected area, the intensity of the disease can vary from one village to the other.The tsetse fly is about the same size as a honeybee. They are quite aggressive and the bite hurts (WHO, 2014).

African animal trypanosomiasis is a complex debilitating protozoan disease of animals ranked among the top 10 cattle diseases. (Perry et al., 2002).This group of diseases caused by protozoa of the genus Trypanosoma affects all domestic animals.


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