UNIVERSITI PUTRA MALAYSIA

MORPHOLOGY OF A SANGUINICOLID BLOOD FLUKE, SANGUINICOLA ARMATA, IN GRASS CARP

(CTENOPHARYNGODON IDELLA C. V.) FINGERLINGS AND ITS PREVALENCE

ONG BEE LEE

FPSS 1994 2

MORPHOLOGY OF A SANGUINICOLID BLOOD FLUKE, SANGUINICOLA ARMATA, IN GRASS CARP (CTENOPHARYNGODON

IDELLA C. V.) FINGERLINGS AND ITS PREVALENCE.

ONG BEE LEE

MASTER OF SCIENCE UNIVERSITI PERTANIAN MALAYSIA

1994

MORPHOLOGY OF A SANGUINICOLID BLOOD FLUKE, SANGUINICOLA ARMATA, IN GRASS CARP (CTENOPHARYNGODON

IDELLA C. V.) FINGERLINGS AND ITS PREVALENCE.

By

ONG BEE LEE

Thesis submitted in partial fulfilment of the requirement for the Degree of Master of Science in the Faculty of Fisheries and Marine Science,

universiti Pertanian Malaysia

November 1994

ACKNOWLEDGEMENTS

I am immensely grateful to my supervisors, Dr. Faizah Shaharom,

Associate Professor Dr. Rehana Abdullah Sani and Professor Dr. Mohamed

Shariff bin Mohamed Din for their valuable and continuing supervision and

advice. It is my pleasure to extend a special token of appreciation to Dr. Faizah

Shaharom, the chairman of the supervisory committee for her encouragement,

support and untiring guidance throughout the project.

My sincere thanks also to Professor J. W. Lewis of Royal Holloway,

University of London, Professor Jiang Yulin of Institute of Hydrobiology,

People Republic of China, and Dr. B. W. Herbert of Department of Primary

Industries, Australia for giving some of the literatures needed for review.

Special thanks to Professor Y. L. Song and Dr. C. Y. Chien of National Taiwan

University, Taiwan for their efforts to cite literature of sangunicolid blood

flukes in Taiwan.

My appreciation to Professor Bjohn Berland of Institute of Zoology,

University of Bergen, Norway and Marcella, fiancee of Dr. Paul Van Mele of

Faculty of Veterinary Medicine, Universiti Pertanian Malaysia for translating

some of the literatures in German.

ii

I am also indebted to Dr. Nadzri Salim, Faculty of Veterinary Medicine

and Dr. Japar Sidek Bujang, Faculty of Fisheries and Marine Science for their

advice and guidance on the use of epidemiological terms and statistical

analysis respectively.

I greatly appreciate the assistance of Mr. C. C. Lee of the Faculty of

Veterinary Medicine, Universiti Pertanian Malaysia, Mr. M. Krishnasamy of

Institute Medical Research, Kuala Lumpur and Miss Si Si Hla Bu of School of

Biological Sciences, Universiti Sains Malaysia for providing me some of the

stains and staining procedures.

Thanks also to Puan Aminah Jusoh and Mr O. K. Ho from the Faculty

of Veterinary Medicine for their technical assistance in Scanning Electron

Microscopy and photography and to Encik Kadir bin Alias, the artist of

Faculty of Fisheries and Marine Science for his final touch on the composite

drawing of the adult fluke.

I thank the International Development Research Centre of Canada

(IDRC) for financing the theory and research components of the masters

programme. My sincere gratitute go to the Department of Veterinary Service,

Ministry of Agriculture, Malaysia for granting me the opportunity to

undertake this study at Universiti Pertanian Malaysia.

iii

I thank all my friends and colleagues at the Universiti Pertanian

Malaysia who helped me in various ways during the project.

Finally, I thank my husband Ramon Teo, my son Eng Chuan and my

daughter Wen-jing from the bottom of my heart, for their unselfish sacrifices,

patience and reassurance which made this endeavour a success.

iv

TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . ii

LIST OF TABLES . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

LIST OF PLATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

LIST OF ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

ABSTRAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

CHAPTER

I GENERAL INTRODUCTION

Background ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Significance of Grass Carp ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objectives .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

II REVIEW OF LITERATURE

1 3 5

Introduction ..... . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Classification and Taxonomy ... . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Morphology of Adult Fluke ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Scanning Electron Microscopy -Surface Morphology and Tegument .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 World Distribution, Host Specificity and Habitats.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Life-cycle .. . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 23 Prevalence and Seasonal Dynamics of Infection .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

v

Pathology ............. . . ................. . ........... . . ... ............... ............... .. 31 Control ..................................................................................... 35

III PREVALENCE AND INTENSITY OF INFECTION OF A SANGUINICOLID BLOOD FLUKE IN GRASS CARP FINGERLINFS ON A FARM

Introduction .............................................. .............................. 37 Ma terials and Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Source of Fish . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . 38 Description of the Farm .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Maintenance of Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Recovery of Blood Fluke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Results . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Discussion .................. ............................................................. 44

IV DESCRIPTION OF A FRESHWATER BLOOD FLUKE, SANGUINICOLA ARMATA (DIGENEA : SANGUINICOLIDAE) FROM LOCALLY PRODUCED GRASS CARP (CTENOPHARYNGODON IDELLA CUVIER AND VALENCIENNES 1884) FINGERLINGS

Introduction .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Study of live Fluke .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Study of Whole Mount Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Measurement of Morphological Characters . . . . . . . . . . . . . . . . . . . . Description of Parasite . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . .

Identification of Parasite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Results . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Observation of Live Flukes Under Dissecting Stereoscope .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Observation of Live Fluke Under Nomarski Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Description of Adult Fluke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... ..

Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .

Discussion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vi

53 56 56 57 59 60 60 62

62

63 64 69 75

V A SCANNING ELECTRON MICROSCOPIC STUDY ON SURFACE MORPHOLOGY OF SANGUINICOLA ARMATA PLEHN, 1905 (DIGENEA: SANGUINICOLIDAE) FROM GRASS CARP (CTENOPHARYNGODON IDELLA) FINGERLINGS

Introduction ................................................................................. . 81 Materials and Methods ................................................................ 83 Results ............................................................................. . ............ 83

Anterior and Mid-body Regions ............................................. 84 Tegumental Spines ............................. ...................................... 85 Posterior Region .............................................. ... ..... ................. 86

Discussion ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

VI GENERAL DISCUSSION AND CONCLUSION ............. 101

BIBLIOGRAPHY ...................... ................................................................ 110

APPENDIX ................................................................................................ 125

BIOGRAPHICAL SKETCH ................................................................... 127

vii

LIST OF TABLES

Table Page

1 Morphological Features of Members of the Genus Sanguinicola. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14

2 Habitats of Sanguinicola in Definitive Hosts and Their World Distribution ...... .................................... 21-22

3 Life-cycles of the Genus Sanguinicola . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4 Morphological Measurements of Adult Fluke . . . . . . ... . . . ..... . .......... 66

5 Prevalence and Intensity of Infection of Fluke and Length of Fish ........................................................................ 125-126

viii

LIST OF FIGURES

Figure

1 Map of Peninsular Malaysia Showing the Location of the Farm - * Salak

Page

South Baru, Selangor...... . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

2 Correlation Between Length of Fish and Intensity of Infection.. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

3 Sites of Recovery of Flukes and Its Distribution in the Heart. .. . . . . ... . . . . . ... . . ............. . . . . . ........ 43

4 Diagrammatic Presentation of the Morphological Measurement of (a) Adult (b) Spine.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5 A Composite Drawing of Sanguinicola armata.......................... 65

6 Spination and Denticulation of (a) S. armata (b) s. intermedin (c) s. inermis (Adapted from Bykhovskaya-Pavlovskaya et al., 1964). Scale Bar = 10 pm.......................................................................... 76

7 Spination and Denticulation of S. lungensis. (Adapted from Tang and Ling et al., 1975). Scale Bar = 1 0 pm........................................................................... 77

ix

LIST OF PLATES

1 Anterior Region of Live Fluke with Protrusible Proboscis (pp) and Single Column of Marginal Spines (ms) (Nomarski Optics). Scale ijar = 2011m... . . . . . . . . . . . . . . . . . . 70

2 Higher Magnification of Anterior Region of Live Fluke Showing First Five Anterior Spines which are Stouter and Closer Together than those Distal to Them (Nomarski Optics). Scale Bar = 1 Ollm... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

3 Mid-Body Region of Live Fluke Showing Tranverse Nerve Commissure (Arrowhead) Joining Two Longitudinal Nerve Cords and Distribution of Vitellariaon the Body (Nomarski Optics). Scale Bar = 20JIm.. . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

4 Higher Magnification of the Mid-Body Region of Live Fluke Showing Membranous Web-Like Structures (Arrowhead) Joining the Evenly Spaced Marginal Spines (Nomarski Optics). Scale Bar = 10JIm... . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5 Posterior Region of Live Fluke Showing Excretory Vesicle (ev) and One of the Genital Pores (gp) (Nomarski Optics). Scale Bar = 20JIm .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6 Higher Magnification of the Posterior Region of Live Fluke Showing Excretory Vesicle (ev) and the Lack of Marginal Spines at the Posterior Region (Arrowhead) (Nomarski Optics). Scale Bar = 10JIm .. . . . . . . . . . . . . . . . . . . . . . . . . 72

7 A Very Muscular Seminal Vesicles (sv) and Cirrus Pouch (cp) (Nomarski Optics). Scale Bar = 10JIm .. . . . . . . . . . . . . . . . . 73

x

8 Whole Mount of Fluke (Semichon's Acetocarmine). Scale Bar = 4011m ........................................................................................ 73

9 Anterior Region of Fluke Showing Muscular Organ (mo); Oesophagus (oe); and Marginal Spines (ms) (Semichon's Acetocarmine). Scale Bar = I011m ............... 74

10 Posterior Region of Fluke Showing Male and Female Genital Pores (mgp & fgp); Ootype (00) and Excretory Vesicle (ev) (Semichon's Acetocarmine). Scale Bar = 1 Ollm ........................................................................................ 74

11 Sanguinicola armata - WholeFluke ................................................ 87

12 Terminal Mouth Opening (TMO) and Minute Blunt Spines (BS) at the Posterior Part of Proboscis. Anterior Lateral Tegumental Spines (TS) which have a Curved End towards the Ventral Surface ................................. 87

13 Proboscis: Minute Blunt Spines (BS) at the Posterior Parts of Proboscis and Teminal Mouth Opening (TMO) .............................................................................. 88

14 Proboscis: Terminal Mouth Opening (TMO) Showing Smoother Surface without any Spination .............................. 88

15 Anterior and Mid-Body Region of the Fluke Showing Lateral Tegumental Spines (TS) and Proboscis (P) on the Dorsal Surface ........................................................ 89

16 High Magnification of the Mid-Region Dorsal Surface Showing Folding of Tegument into Lattice-Like Longitudinal Ridges with Cres ts and Troughs ..................................................................................... 89

17 Anterior Ventral Surface Showing Tegument of Coral-Like Arrangement and Circular Papillae (Arrowheads) with a Doughnut-Shaped Appearance ........................................ . 90

xi

18 Mid-Body of Fluke Showing Membranous Web-Like or Fin-Like Structure Joining the Regularly Spaced Tegumental Spines with Curved Ends ............... .............. ...................... 90

19 Posterior Region of the Fluke Showing Posteriorly Directed Tiny Spines (Arrowheads) with Curved Ends and Spaced Further Apart.. ......... ............................ 91

20 Posterior Extremity of Fluke Showing Cilium-Like Structures or Bristles (B) and Circular Papillae (CP) ........................... 91

21 Higher Magnification of the Posterior Extremity of the Fluke Showing Cilium-Like Structures or Bristles (B) and Circular Papillae (CP) ........................... 92

22 Separate Genital Pores (Arrowheads) on the Dorsal Median Surface of Fluke at the Posterior Region .................... 92

23 Protrusion of Separate Genital Pores (Arrowheads) on the Dorsal Surface of Fluke at the Posterior Region ...................... 93

24 Excretory Pore (EP) on the Ventral Surface of Posterior Region of the Fluke .............................................................. 93

25 Higher Magnification of the Excretory Pore (EP) ...................................................................................................... 94

xii

LIST OF ABBREVIATIONS

B - Bristles

BL - Body Length

BS - Blunt Spines

BW - Body Width

c - Caeca

cm - centimeter

cp - Cirrus Pouch

CP - Circular Papillae

EL - Length of Oesophagus

EP - Excretory Pore

ev - Excretory Vesicle

fgp - Female Genital Pore

gp - Genital Pore

h - Hour

Km - Kilometer

mgp - Male Genital Pore

MMC - Melano-macrophage centre.

mo - Muscular Organ

MOL - Length of Muscular Organ

MOW - Width of Muscular Organ

xiii

ms - Marginal Spines

mt - metric tonne

0- Ovary

oe - Oesophagus

od - Oviduct

OL - Length of Ovary

00 - Ootype

OoD - Distance of Ootype

ov - oviduct

OW - Width of Ovary

P - Proboscis

pp - Protrusible Proboscis

SEM - Scanning Electron Microscopy

SL - Length of Spine

sv - Seminal Vesicle

SW - Width of Spine

t - Testis

TL - Length of Testis

TMO - Terminal Mouth Opening

TS - Tegumental Spines

um - Micrometer

v - Vitellaria

vd - Vitelline duct

xiv

Abstract of thesis submitted to the Senate of Universiti Pertanian Malaysia in partial fulfilment of the requirement for the degree of Master of Science.

MORPHOLOGY OF A SANGUINICOLID BLOOD FLUKE, SANGUINICOLA ARMATA, IN GRASS CARP (CTENOPHARYNGODON

IDELLA C. V.) FINGERLINGS AND ITS PREVALENCE.

BY

ONG BEE LEE

November 1994

Chairman: Dr. Faizah Shaharom

Faculty: Fisheries and Marine Science

Sanguinicola armata Plehn, 1905 is redescribed under light and Nomarski

microscopy and SEM (Scanning Electron Microscopy). It is a lanceolate

sanguinicolid with a single column of heavy lateral marginal spines; extensive

vitellaria; long oesophagus and an X-shaped intestine with five-lobed caeca.

There are 9-10 pairs of testes; median; post intestinal caeca and a single

butterfly-shaped ovary. Male and female genital pores lie adjacent to each

other, near to the posterior extremity. The uterus is short, post ovarian and

contains only one egg.

xv

SEM study revealed minute, blunt spines at the posterior part of the

proboscis and tiny posteriorly directed marginal spines at the posterior end

which were not visible under the ordinary light and Nomarski microscopy.

This had added extra taxonomical features to S. armata.

Surface morphology of S. armata under SEM also showed many

tegumental folds with ridges and crest, cilium-like structure and sensory

papillae which may be related to their nutritional, sensory, excretory, secretory,

osmoregulatory and immunological functions. Protrusion of the genital pores

viewed under SEM helps to understand the fact that cross-fertilisation as being

a rule in the trematodes' reproduction.

The prevalence rate of infection of S. armata was found to be high

(66.7%) in the locally produced grass carp (Ctenopharygodon idella) fingerlings

in the farm under the present study. This was attributed to the abundance of

aquatic snails which act as intermediate hosts of the fluke. However, the

intensity of infection was low due to the host (immunological), environmental

(stocking density and water chemistry) and parasite (reproductive biology)

factors.

Since the distribution of S. armata was highest (87.8%) in the bulbous

arteriosus, it should be examined first for quick diagnosis of the fluke.

XVl

Abstrak tesis yang dikemukakan kepada Senat Universiti Pertanian Malaysia, sebagai memenuhi sebahagian daripada keperluan ·untuk mendapat Ijazah

Master Sains.

MORFOLOGI FLUK DARAH SANGUINICOLID, SANGUINICOLA ARMATA DALAM ANAK IKAN KAP RUMPUT (CTENOPHARYNGODON

!DELLA C. V.) DAN PREV ALENS PARAS IT.

Oleh

ONG BEE LEE

November 1994

Pengerusi: Dr. Faizah Shaharom

Fakulti: Perikanan dan Sains Samudera

Morfologi Sanguinicola armata Plehn, 1905 dihuraikan semula dengan

bantuan kompaun mikroskop menggunakan lensa biasa dan Nomarski serta

SEM (Elektron Mikroskop Pembiadas). Ia adalah fluk darah sanguinicolid yang

berbentuk daun dengan satu deretan spina yang tebal di bahagian pinggiran

ventral; mempunyai vitellaria yang meluas; esofagus yang panjang dan usus

yang berbentuk silang dengan lima lobus seka. Ia juga mempunyai 9-10

pasang testis, terletak di median, di bahagian belekang kepada lobus seka dan

mempunyai satu ovari yang berbentuk macam kupu-kupu. Liang-liang genital

jantan dan betina adalah bersebelahan antara satu sarna lain, di bahagian

belakang badan. Rahimnya pendek, terletak di belakang ovari dan

mengandungi sebiji telur sahaja.

xvii

Kajian SEM membolehkan spina halus dan tumpul, kelihatan di

bahagian posterior probosis dan spina keeil menghadapi posterior di bahagian

belakang fluk yang tidak dilihat dengan mikroskop kompaun lensa biasa dan

Nomarski. lni menambahkan ciri taxonomi kepada fluk darah S. armata.

Morfologi permukaan S. armata di bawah SEM juga menunjukkan

lipatan tegumen dengan rabung dan krista, struktur semaeam silium dan

papilla deria yang boleh dikaitkan dengan fungsi pemakanan, deria,

perkumuhan, rembesan, osmokawalaturan dan imunologi. Liang-liang genital

yang tersembul dari permukaan tegumen fluk membantu kami memahami

bahawa persenyawaan silang adalah fenomena kebiasaan fluk.

Prevalens S. armata pada anak ikan kap rumput tempatan adalah

didapati tinggi (66.7%) dalam kajian ini. lni boleh dikaitkan dengan kehadiran

banyak siput air di kolam sebagai perumah perantaraan fluk. Walau

bagaimanapun pengamatan jangkitan adalah rendah dan ini mungkin

disebabkan oleh faktor-faktor perumah (kesan imunologi), persekitaran (kadar

pelepasan dan kimia air) dan parasit (biologi pembiakan).

Oleh kerana taburan S. armata adalah tertinggi (87.8%) di bulbus

arteriosus, organ ini patut dipemeriksa dahulu untuk membuat diagnosa

segera fluk ini.

xviii

CHAPTER I

GENERAL INTRODUCTION

Background

Aquaculture plays an important role in contributing towards our

protein food supply and will become increasingly important as a response to

increasing demand for fish and declining fish catches from natural resources.

In Malaysia, though aquaculture is a relatively young industry, it has

developed rapidly in recent years. The total aquaculture production was 80,000

mt valued at RM 207 million in 1992 (Malaysia, 1993). This was about a 50%

increase compared to the 1990 production.

Topping the list of production was cockle (Anadara granosa) followed by

freshwater fishes. The major species produced were tilapia (Oreochromis

niloticus) 4,631 mt; Javanese carp (Puntius gonionotus) 2,505 mt; common carp

(Cyprinus carpio) 1,703 mt; bighead carp (Aristichthys nobilis) 1,222 mt; grass

carp (Ctenopharyngodon idella) 913 mt; walking catfish (Clarias spp.) 904 mt;

marble goby (Oxyleotrix marmoratus) 115 mt and the latest addition, eel

(Anguilla japonica) 1,572 mt (Malaysia,1993).

1

2

Rapid development and intensification of aquaculture practices together

with the degradation of the aquatic environment has resulted in increased

incidences of fish disease. Economic losses due to disease can be reduced

through adequate fish health management. However, in order to apply proper

health management and disease contol measures, identification of pathogens

and a clear knowledge of their biology are essential and must not be neglected.

Parasites play a major role among the pathogens which causes fish

diseases in Malaysian aquaculture. The parasitic diseases that have been

reported were ichthyophthiriasis; chilodonellosis; lernaeosis; argulosis (Shariff

1980; 1984), gold rust (Shaharom et a1., 1990) and myxosporiodiosis (Shariff,

1982).

Sanguinicoliasis caused by sangunicolid blood flukes have been

reported from many parts of the world causing high mortalities in hatcheries

and farms. Severe epizootics in cultured fish due to Sanguinicola have

demonstrated the importance of this parasite. There is no treatment indicated

and control of the disease is by interrupting the parasite's life-cycle.

Sanguinicolids are blood flukes which live and reproduce within the

circulatory system of fish. They are the only digeneans in which the adults are

of economic importance to fish culture (Smith, 1972; Bauer et a1., 1973). Most

adult digeneans live in organs which have a direct connection to the outside,

allowing eggs to pass out with minimal or no effect on the host. As blood

3

flukes live and deposit eggs in the circulatory system, the eggs ultimately

settle and lodge in tissues, often causing severe pathological responses in host

tissues. Hence, host-parasite relationships involving blood flukes usually differ

from those of the majority of digeneans which live and deposit eggs in their

host's alimentary tract and elicit little response.

The importance of fish parasites is related to the importance of the fish that

they may affect. Sanguinicolids are very important parasites in the culture of

many fish species world-wide including cyprinids in Europe, Asia and USSR;

salmonids on the west coast of North America and siluroids in Africa.

However, very little is known about their presence in fish from the Southeast

Asian region probably because their presence is often overlooked as they are

very small and not easily differentiated from the host tissues. Sanguinicola

armata was first reported in bighead carp and grass carp fingerlings imported

into Malaysia from Taiwan (Anderson and Shaharom-Harrison, 1986).

However no work has been conducted to identify and to examine the

prevalence of this parasite in fingerlings produced from Malaysia.

Significance of Grass Carp

Grass carp, Ctenopharyngodon idella Cuvier and Valenciennes 1884, was

the fish species chosen for the present study. It is the most cultivated species

in the Southeast Asian region (Pillay, 1976) and it fetches a high price in the

market (Shireman and Smith, 1983). It has been the subject of considerable

4

research in recent years because of its ability to consume aquatic vegetation

(Shireman et al., 1977; Riley, 1978 and Meske, 1985). Grass carp is susceptible

to diseases and according to Wu (1971), fish farmers in Taiwan had their

profits reduced each year due to high mortalities in cultured grass carp. A

sanguinicolid blood fluke, Sanguinicola magnus was identified by Hu et al.

(1965) causing high mortalities of grass carp fingerlings in China. However,

there is no report of blood flukes from Taiwan and other Southeast Asian

countries besides the report by Anderson and Shaharom-Harrison (1986) in the

imported carp fingerlings in Malaysia.

In Malaysia grass carp is one of the major Chinese carps introduced in

the 1800's (We1comme, 1981). The introduction was associated with the

immigration of Southern Chinese who brought along the techniques of culture

(Ang et al., 1989). This fish has since become the mainstay of the local

freshwater aquaculture and can be induced to breed in captivity. They are

cultured in earthen ponds, mostly by small scale operators using polyculture

and integrated farming system. They contributed significantly to the total

freshwater aquaculture production in Malaysia. Percentage contributions from

the major Chinese carps remained above 70% in the early eighties

accumulating to a peak of 90% in 1984. However, their dominance is gradually

being overtaken by tilapias in the nineties (Ismail, 1994).

5

Objectives

Culture of fish provides an ideal opportunity for the transmission of

parasites due to the density of potential host and their confinement in a

restricted area. Blood flukes are of no exception. Although the normal levels

of infection as experienced in natural habitats do not appear to detrimentally

affect the host, high levels of infection can result in reduced production and

mass mortalities in farms. Outbreak of sanguinicoliasis in fish propagating

ponds resulting in adverse effects on growth and survival have been reported

in many parts of the world (Iqbal and Sommerville, 1986). Therefore, blood

flukes is a cause of concern for freshwater aquaculture as it has not been

particularly identified in locally produced carp fingerlings. Hence, there is a

clear need to investigate this blood fluke to determine its effects on carp

culture in Malaysia and the objectives of this study are as follows:

(i) to study the prevalence and intensity of infection of this parasite in locally

produced grass carp fingerlings,

(ii) to describe and to identify the blood fluke, and

(iii) to study its surface morphology by scanning electron microscopy.