Clinico-Pathological Effects of Experimental Ascaris Suum Infection in Yankasa Lambs

Clinico-Pathological Effects of Experimental Ascaris Suum Infection in Yankasa Lambs.

ABSTRACT  

The effects of Ascaris suum infection in Yankasa lambs were investigated. Twenty-four Yankasa lambs aged 6-8 months were purchased and randomly allocated into two groups (G1 and G2).

The lambs in G1, consisting of 16 animals, were orally infected with 1500 infective A. suum eggs daily for seven days while G2, consisting of 8 animals served as the uninfected control.

All the experimental animals were closely monitored for 10 weeks, during which faecal samples were collected and analysed; haematological and biochemical parameters were evaluated.

A total of seven animals (six from the infected and one from the control group) were sacrificed on days 7, 14, 28 and 56 post-infection (p.i) for larval/worm recovery, pathological and histopathological examinations.

Clinical signs observed in the infected group were cough and dyspnoea. Significant differences (P<0.05) between the mean respiratory and pulse rates of the infected (28.03 and 83.78 beats/min).

There were significant differences in the counts of white blood cells, neutrophils, lymphocytes and monocytes at various weeks of the experiment between the infected group and the control.

TABLE OF CONTENTS

TITLE PAGE……………………..ii
DECLARATION…………………iii
CERTIFICATION……………iv
ACKNOWLEDGEMENTS ………v
ABSTRACT…………..vi
TABLE OF CONTENTS ………..viii
List of Figures………….x
List of Plates…………….xi
List of Tables…………xii
List of Appendices………xiii
ABBREVIATIONS, GLOSSARY AND SYMBOLS………xiv

CHAPTER ONE
1.0 INTRODUCTION………………..1
1.1 Background of the Study…………..1
1.3 Justification of the Study…………..2
1.4 Aim and Objectives of the Study ………….3
1.5 Research Questions………..4

CHAPTER TWO
2.0 LITERATURE REVIEW …….5
2.1 Introduction………….5
2.2 Life cycle of Ascaris suum…………6
2.3 Epidemiology of Ascariosis ………….7
2.4 Clinical Manifestations of Ascariosis ……….11
2.5 Pathology and Economic Importance of Ascariosis……..11
2.6 The Hepato-Tracheal Migration in Ascariosis……..13
2.7 Ascaris suum in Lambs and Kids………..16
2.8 Ascaris suum in Cattle ………..17
2.9 Diagnosis………18
2.9.2 Diagnosis in the laboratory ………..21
2.10 Control Strategies …………24
2.10.1 Chemotherapy…………..25
2.10.2 Alternative control measures ………26
2.11 Management Practices…………27
2.12 Vaccination Studies……….30

CHAPTER THREE
3.0 MATERIALS AND METHODS ………….32
3.1 Experimental Animals and Management ……….32
3.2 Experimental Design……….32
3.3 Isolation of Infective Eggs ………….32
3.4 Inoculation………….33
3.4 Clinical Observations………33
3.5 Examination for Lesions and Larval Recovery……….34
3.6 Larval Recovery…………….34
3.7 Faecal Egg Examination…………35
3.8 Haematological Examination………35
3.9 Data Analysis………36

CHAPTER FOUR
4.0 RESULTS ………..37
4.1 Egg Recovery and Culture ………….37
4.2 Clinical Signs…………..37
4.2.1 Vital Parameters………..39
4.2.2 Live Weight Changes……………43
4.3 Haematological Findings…………45
4.4 Biochemical Parameters…………54
4.5 Pathological Findings…………62
4.5.1 Gross pathology ………….62
4.5.2 Histopathology……………67
4.6 Larval Recovery……..72

CHAPTER FIVE
5.0 DISCUSSION…………75

CHAPTER SIX
6.0 CONCLUSIONS AND RECOMMENDATIONS……………79
6.1 Conclusions………………79
6.2 Recommendations……..79

REFERENCES……….80
APPENDICES….94

INTRODUCTION  

The large round worm of pigs, Ascaris suum, is reported to migrate in the tissues of a wide range of animals, including sheep (Fitzgerald, 1962; Johnson, 1963; McDonald and Chevis, 1965; Vassilev, 1960). 

Ascariosis is the most important internal macro-parasitism present in farmed pigs worldwide (Stewart and Hoyt, 2006).

In abattoirs, the presence of milk spots in the livers of affected animals represents considerable losses due to offal condemnations (Barker et al., 1993).

Milk spot liver is a well-established terminology used to denote the whitish healing foci occurring in the liver stroma when Ascaris suum larvae are immobilized by the host‟s inflammatory reaction (Kelly, 1993).

Estimates of daily Ascaris female egg production generally are in the range of 200,000 eggs (Sinniah, 1982) but the number of eggs a female produces decreases with worm load (Sinniah and Subramaniam, 2009).

In Nigeria, pigs and sheep are mostly reared on extensive and semi-intensive systems of management (Ajala and Osuhor, 2004) and Ascaris suum is a very fecund parasite producing eggs that are resistant.

So, the chances of sheep acquiring the infection through contaminated pasture are high. In view of this, it was considered worthwhile to evaluate the possible infectivity and pathogenicity of Ascaris suum in sheep. 

REFERENCES

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Aitken, M. M. and Sanford, J. (1968). Experimentally induced anaphylaxis in cattle.
Veterinary Record, 82: 418-419.

Ajala, M.K. and Osuhor, C.U. (2004). Economic analysis of returns and cost structure in
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Allen, G.W. (1961). Acute atypical bovine pneumonia caused by Ascaris lumbricoides.
Canadian Journal of Comparative Medicine, 26: 241-3.

Andersen, S. (1976). The influence of Ascaris suum infection upon growth rates in pigs.
Nordisk veterinaermedicin, 28: 322-330.

Andersen, S., Jorgensen, R.J, Nansen, P. and Nielsen, K. (1973). Experimental Ascaris suum
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