Intensity And Liver Histopathology In Cattle Fasciolasis At Portharcourt Abbatoir

INTENSITY AND LIVER HISTOPATHOLOGY IN CATTLE FASCIOLASIS AT PORTHARCOURT ABBATOIR

BY

BRIGGS ALEXANDRA ASI

G2014/PGD/AEB/FT/063

DEPARTMENT OF ANIMAL AND ENVIRONMENTAL BIOLOGY

FACULTY OF BIOLOGICAL SCIENCE

UNIVERSITY OF PORTHARCOURT

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF A DIPLOMA IN POST GRADUATE STUDIES (PGD) IN ANIMAL AND ENVIRONMENTAL BIOLOGY

CHAPTER ONE

INTRODUCTION

Fascioliasis is a zoonotic disease caused by two species of parasitic flatworms or trematodes that mainly affect the liver, (Mas-Coma, Bargues and Valero 2005). The two species of trematodes are Fasciola hepatica and Fasciola gigantica, which usually infect cattle, sheep, goats, and other domestic ruminants. Fascioliasis is a highly pathogenic (Valero et al; 2003) disease of clinical and Veterinary importance caused by Faciola hepatica and Fasciola gigantic (Talukder et al, 2010, Shaikh et al, 2004 and Ozung et al, 2011). Transmission of the fluke and the presence of its infection in any given population is dependent upon and exacerbated by some factors such as; the presence of a substantial reservoir of water parasite and potential host and the presence of the lymneae snail intermediate host. Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a parasitic flatworm of the class Trematoda, phylum Platyhelminthes that infects the livers of various mammals, including humans. The disease caused by the fluke is called Fascioliasis. F. hepatica is distributed worldwide, and causes great economic losses in sheep and cattle. It has been known as an important parasite of sheep and cattle for hundreds of years. The parasite lives in the liver and bile duct. These snail host which commonly measure about 10mm in size, usually occur in areas with high annual rainfall, large areas of poorly drained pastures and moist soil (Afrakhosravi, 2001 and Keiser et al, 2007). Other factors which enhance the spread of fascioliasis are opportunity for water source contamination by human and nonhuman hosts and dietary practices that includes the raw, untreated aquatic vegetation or foliage located around water reservoir. (Afrakhosravi, 2001, Keiser et al, 2007 and Valero et al, 2003).Fascioliasis is cosmopolitan infection. Incidence of the infection has been reported in many countries including Nigeria, Parkistan, China, United States of America and Iran. (Valero et al, 2010 and WHO, 2006). It is commonly reported in ruminants; cattle, goat and sheep. (Okaiyeto et al, 2012, Talukder et al, 2010 and Ozung et al,2011). Ruminant hosts become infected when forage with metacercarial cyst is ingested. They can also be infected when ingesting cysts suspended in soil and detritus while drinking water. Ingested parasite finds its way to intra hepatic billiary duct or hepatic parenchyma and later to the bile duct where it resides.

Humans are infected after ingestion of larval stages, called metacercariae, which, after development in lymnaeid intermediate hosts, attach to aquatic and semi-aquatic plants, ( Mailles, Capek, Ajana, Schepens, Ilef, Vaillant,2006). Interestingly, the role of humans as solely accidental hosts has recently been questioned, because, in some regions, human infection might play a significant role in the maintenance of the infectious cycle.

Originally a European disease, F. hepatica has spread to all continents, and is now the food-borne disease with the widest geographical distribution. An estimated 2.4–19 million people are infected, and 180 million are at risk, WHO (2007).

Hot spots are the South American highlands, the Nile delta, and the Caspian basin. Owing to its emerging nature and high endemicity in some developing countries, the WHO classified the disease as a neglected parasitic infection that merits international attention. Furthermore, fascioliasis has been recognized as an emerging infection in international travellers and migrants, causing significant diagnostic and therapeutic problems, (Behar, Winston, Borgstein, 2009).

STATEMENT OF PROBLEM

Cattle fasciolasis is distributed worldwide, and has been known as an important parasite of cattle for hundreds of years and causes great economic losses in cattle. Because of its economic importance, it has been the subject of many scientific investigations.

AIM OF STUDY

To investigate the intensity and liver histopathology in cattle fasciolasis

OBJECTIVES

To assess the intensity and prevalence of cattle fasciolasis

To assess liver histopathology on cattle

CHAPTER TWO

2.1 LITERATURE REVIEW

The prevalence of fasciolosis in cattle in many parts of the world has been reviewed [ Adedokun, Ayinmode, Fagbemi, 2008]. In Africa [Adedokun et al 2008] quoted prevalence rates of 37% in Sudan, 45% in Cameroon, 30–90% in Ethiopia, 16% in Uganda, 62% in the Central Africa Republic, and 50% in Rwanda [ Kithuka, Maingi, Njeruh, Ombui, 2002]. In Nigeria, prevalence of fascioliasis has been reported from different parts of the country. There are also several reports on the prevalence, regional incidence, and seasonal variation for bovine fasciolosis (Babalola and Schillhorn Van Veen, 1976). From slaughtered cattle in Maiduguri, (Biu et al.2006) reported a prevalence of 80%, from Zaria, Northwest, and a prevalence of 65.4% was also reported by [Schillhorn Van Veen, Foloranmi, Usman, Ishaya,1980]. A study was conducted to evaluate the number of cattle slaughtered, prevalence, seasonal variation, and socioeconomic consequence of bovine fasciolosis at the Ibadan municipal abattoir, Ibadan, Oyo State, Nigeria, between 1994 and 2004, based on retrospective abattoir meat inspection records and a perspective meat inspection survey (Oladele-Bukola and Odetokun 2014). Of the 1,640,095 cattle slaughtered in 11 years, 37,828 livers were condemned due to fasciolosis, translating into a prevalence of 2.31%. The incidence observed among males 172 (4.24%) was slightly higher than that noted for females 452 (3.73%) though significant at 0.05 level of error. Moreover, the prevalence recorded in the dry season (October–March) was 19,816 (2.58%) and 18,012 (2.07%) for the rainy season (April–September) with a fairly strong positive correlation (+0.76) occurring between the incidences of the disease in the seasons (Oladele-Bukola and Odetokun 2014). Another study was carried out between July and October 2012, aimed at determining the prevalence of fascioliasis and the economic loss of condemned liver due to Fasciola infection in cattle slaughtered at three abattoirs in Eket Urban, Akwa Ibom State, Nigeria [Usip, Ibanga, Edoho, Amadi, Utah,2014]. A total of 279 cattle consisting of 185 males and 94 females were examined. The livers were examined for the adult flukes while the faecal samples were examined for the eggs of Fasciola. The result of the investigation showed that 38 (13.62%) of the cattle were infected with fascioliasis. The prevalence rate recorded for female cattle was 17.02% compared to the male with prevalence rate of 11.89% [Usip et al, 2014]. Futhermore Fasciola gigantica in cattle slaughtered in Onitsha abattoir and three other abattoirs in Onitsha area of Anambra State, Nigeria was investigated from November to December 2004. The study involved actual post mortem inspection on the slaughtered cattle. The livers were examined for Fasciola by making length wise incision on the ventral side of the liver in such a way that the bile duct and gall bladder are cut o p en. All cases of Fasciola were detected from the liver. Afor-Igwe abattoir recorded the prevalence rate of 10. 8% while the prevalence rates of 7.0%, 7.7% and 13.4% were recorded at Nkwor-Ogidi abattoir, Oye Olisa abattoir and Onitsha main market abattoir respectively. Out of a total of 158 0 cattle examined, 166(10. 51%) were infected with F.gigantica. Of the 166 diseased liver, 26(15. 7%) had light worm load, 77(4 6 .4 %) medium worm load a n d 63(38%) had heavy worm load. The lowest number of worm recovered per liver was 3 while the highest was 88. The prevalence of fascioliasis in cattle slaughtered in the Sokoto metropolitan abattoir was investigated. Faeces and bile samples were collected and processed using formal ether concentration technique. Gross lesions from 224 out of 1,313 slaughtered cattle were randomly selected and examined. Out of the 224 cattle examined, 95(42.41%) were males and 129(57.59%) were females. Out of 95 male cattle examined, 27(28.42%) were infected and out of 129 females 35(27.13%) were infected. Based on breed, infection rates were 31(31.0%), and 31(25.2%) for breeds of Sokoto Gudaliand Red Bororo respectively. No infection was recorded in White Fulani breed. Lesions observed were more in males than in females and more in Red Bororo than in Sokoto Gudali. Overall, prevalence of infection with Fasciola was 27.68%. There was no statistically significant association between infection and breed and between infection and sex of the animals sampled (𝑃>0.05). Fasciolosis occurs worldwide. While animal fasciolosis is distributed in countries with high cattle and sheep production. Fasciolosis occurs only in areas where suitable conditions for intermediate hosts exist. Therefore Based on the accumulated material it is justifiable to consider liver fluke infection as an important regional threat to animal production in many countries. The infection should be controlled in herd health programs. In the absence of statistically sound epidemiological data, control programs based on common sense, field observations and liver condemnation statistics may prove useful in the initial stages of control implementation. In Kenya, a retrospective study covering a period of 10 years (1990–1999) was carried out using postmortem meat inspection records [Kithuka et al 2002]. A total of 5,421,188 cattle were slaughtered in the seven provinces of Kenya during the 10-year period and 427, 931 (8%) of these cattle were infected with Fasciola. The region with the highest prevalence of fasciolosis was Western Province (16%) followed, in descending order, by Eastern Province (11%), Nyanza Province (9%), Rift Valley Province (8%), Central Province (6%), Nairobi Province (4%), and Coast Province (3.5%). The total economic loss incurred by the country during the 10-year period as a result of condemnation of the infected livers was approximately US$2.6 million [Kithuka et al 2002]. This cross-sectional study was carried out to determine the prevalence of fascioliosis and dicrocoelioss in Slaughtered animals in Kashan,Isfahan Provience central Iran. A total of 267802 liver stock including 9066 cattle, 77912 sheep and 180824 goats and were slaughtered in the 2-year period were examined and overall 31954 (12%) livers were infected. Fascioliasis and dicrocoeliosis were responsible for 4.8% and 5.6% of total liver condemnations in this period, respectively. The infection rate of female sheep was more than males, but in female cattle and goats was lower than males. Liver condemnations due to fascioliasis and dicrocoeliosis were more prevalent in cattle slaughtered during spring. This survey provides baseline data for the future monitoring of these potentially important parasitic infections in this region. A total of 208 cattle were randomly selected among slaughter houses, household and livestock farms to determine the prevalence of fascioliasis. Infection rate was 51.42%, 27.69% and 21.91% in slaughtered, livestock farm and household cattle, respectively. Overall, the highest seasonal prevalence (45.19%) in all types of cattle was recorded during wet season while as only (24.40%) was recorded during the dry season. It was noticed that a higher infection rate was recorded in young cattle ages (0- 2 years) (40.02%) than in adult ones (28.04%) (3- 8 years). Moreover, the prevalence of infection in females was more (38.07%) than males (29.09%). It was also observed that the infection rate was high in comparatively low land areas (37.14%) as compared to high altitudes (30.09%). In addition, In Indonesia, however the incidence of F.gigantica in cattle seems to be higher compared to buffaloes. In a survey depending on carpological analysis 20% of cattle as opposed to 14% of buffaloes were found to be positive (01251) and in an abattoir survey the figures were 61% and 31% respectively.In Venezuela, infections are important in mountainous area. The number of sheep infected in the Andes is very high (80%) and it is estimated that the annual mortality of the flocks in the order of 15-25% (02745). The incidence in the sheep is also available for Rio Grande del Sol Brazil (70%; 03740). In colombia, (04288) and in the Altoplano Region of Boliva the prevalence of F.hepatica in cattle determined on faecal analysis is estimated the range between 40-49% infected cows are less fertile and suffer a high abortion rate. In south korea the prevalence of fasciolasis at the slaughterhouse and intradermal serological tests in 300,000 healthy cattle showed an infection rate of 36.5%. The average condemnation percentage due to F.hepatica in another survey was 45% and it was demonstrated that out of 80 distinguished areas only 8 were completely free from infection. Other intradermal test surveys were positive in 31% out of 170,000 cattle. Average loss of liver tissue per infected animal was 2.73kg. Fasciolasis infection in cattle are present in turkey though at a low incidence of 0.8%.In Iraq, prevalence are at the following levels, 4.8% in buffaloes, 3.3-11% in cattle, 0.7-9% in sheep and 0.1-22% in goats. Based on faecal analysis prevalence in cattle and goat in Sikkim are 83 and 81% respectively. Mortality have been described in buffaloes in the Nicobar Isles with erratic F.gigantica in lungs and spleens. In Kashmir prevalence are high running at 85.1% in cattle, 51.3% in sheep, and 14.8% in goats. In this province sheep were infected with F.hepatica as well. Human cases of F.hepatica infection have been described in Yeme and Iran.

HISTOPATHOLOGY OF FASCIOLA INFECTED LIVERS

Mophology

Fasciola hepatica is one of the largest flukes of the world, reaching a length of 30 mm and a width of 13 mm. It is leaf-shape, pointed at the end or posteriorly, and wide in the front or anteriorly, although the shape varies somewhat.These flatworms form seven different developmental stages: eggs, miracidia, sporocysts, rediae, cercariae, metacercariae, and adult flukes. The eggs are operculate (‘hatch’ at one end), brown and ovoid (130-150µm in length by 65-90µm in width). Miracidia are pyriform motile larval stages (150-200µm long) covered with cilia. Sporocysts are pleomorphic sac-like bodies (0.3-1.5mm in diameter) containing germinal cells which give rise to small rediae (embryos). Mature cercariae (~0.5mm long) are free-swimming gymnocephalous stages with simple elongate club-shaped tails, which are subsequently shed when they encyst on vegetation to form membrane-bound metacercariae (~ 0.2mm in diameter). Mature flukes are leaf-shaped (2.0-3.5cm long by 1.0-1.5cm wide) with a conical apex demarcated by wider ‘shoulders’. They are dorsoventrally flattened, the tegument is covered with scaly spines, and they have two suckers (distome arrangement with the oral sucker and acetabulum close together). They have a bifurcate blind gut and each worm is hermaphroditic, possessing both male and female reproductive organs. These worms (known as liver flukes) have soft flat leaf-like bodies with two ventral suckers and a blind gut (mouth but no anus). Adults possess both male and female reproductive organs (hermaphroditic) and they have digenetic life-cycles involving at least two hosts and several developmental stages. Miracidia are released from eggs into water where they infect snails (obligate intermediate hosts) and undergo massive asexual proliferation through sporocyst and redia stages eventually releasing cercariae into the water. Vertebrate (definitive) hosts become infected by the ingestion of encysted stages (metacercariae) on aquatic vegetation. Infected ruminant liver usually experience traumatic injury giving rise to diffusely hepatic parenchyma containing haemorrhagic streaks or foci. The animal may experience weight loss, anaemia and general depression. The liver may be enlarged and show abnormal functions. Blood leukocytosis with eosinophilia in response to Cathepsin B (cat 12) antigen secreted by juvenile fluke may be observed (Afrakhosravi, 2011).

Fig 3 Morphology of Fasciola Hepatica

LIFECYCLE

Fig 4 LIFE CYCLE OF FASCIOLA HEPATICA Source: www.cdc.gov.com

Fig 5 Snail (Lymnae) Source: www.animalia-life.com

To complete its life cycle, F. hepatica requires a freshwater snail as an intermediate host, such as Galba truncatula, in which the parasite can reproduce asexually. Species in the family of air-breathing freshwater snails, the Lymnaeidae that serve as naturally or experimentally intermediate hosts of Fasciola hepatica include: Austropeplea tomentosa. The metacercariae are ingested by the ruminant or, in some cases, by humans eating uncooked foods such as watercress or salad. Contact with low pH in the stomach causes the early immature juvenile to excyst. In the duodenum, the parasite breaks free of the metacercariae and burrows through the intestinal lining into the peritoneal cavity. The newly excysted juvenile does not feed at this stage, but, once it finds the liver parenchyma after a period of days, feeding will start. This immature stage in the liver tissue is the pathogenic stage, causing anaemia and clinical signs sometimes observed in infected animals or humans. The parasite browses on liver tissue, on the lining of biliary ducts, for a period of up to six weeks, and eventually finds its way to the large bile duct, where it matures into an adult. Adult hepatica lives in small passages of the liver of many kinds of mammals, especially ruminants and begins to produce eggs. Up to 25,000 eggs per day per fluke can be produced, and, in a light infection, up to 500,000 eggs per day can be deposited onto pasture by a single sheep

Geographical Distribution

This disease is widespread in many part of Africa, America, South and South-East Asian countries and Hawaii Islands. It requires a warmer and is associated with stagnant water bodies.

Epidemiology

The disease is globally socio-economically important in cattle and buffalo,however regional infection are important in goat, sheep, and donkeys, especially in the tropics. The prevalence of the disease in different endemic foci ranges from 30%-90%. Moreover many countries do not have adequate prevalence data of the disease, despite the fact that the infections of ruminants in Asia and Africa ranging from 80%-100%. The occurrence and distribution of lymnaea auricularia are determinant factors in the epidemiology of fasciola species. Usually rainfall is a major determinant in snail activity and parasite transmission. The disease exhibits diverse patterns of prevalence for different localities, the close contact of animals with water, particularly during dry season enhances parasite transmission and prevalence. Large areas of overlap in the endemicity of fasciola species are found in Africa and Asia.

CONTROL OF FASCIOLASIS

Control is to restrain, minimize or reduce the occurrence of infection or endemicity of disease in the host community so that the disease is no longer of public health importance. Control involves reducing the burden of infectious disease by reducing the disease incidence, prevalence, morbidity or mortality to locally acceptable levels.

Method of disease control: life cycles studies are important in designing disease control programs, 3 basic approaches include

Eliminaton of the source of infection

Reservoir host

Infected host

Interruption of the pathway of transmission and

Protection of the susceptible host

Efficient control of fascioliasis requires a well planned and executed, integrated control programme designed for each farm, area, country or region. The available strategies which can be used individually or in combination are:

· Strategic application of anthelminthics, eliminating the parasites from the host at the most appropriate time for effective prevention of pasture contamination.

· Reduction in the number of intermediate host snails by chemical or biological control.

· Reduction in the number of snails by drainage, fencing and other management practices.

· Reduction in the risk of infection by planned grazing management.

Chemical control of snails

The use of molluscicides for the control of snail intermediate hosts is a potential tool for the control of fluke infections. Before considering chemical control of snails it should be noted that:

· Many habitats are topographically unsuitable for the use of molluscicides and it is often very difficult to apply them effectively.

· They are toxic to the environment

· Cooperation between neighboring properties is required for effective cover

· regular (at least yearly) application is required because rapid repopulation of snails may occur

· they are not species-specific and may destroy edible snails highly valued as food in some communities.

· they are expensive

Biological methods of snail control

Reports from several parts of the world indicate that a number of plants have molluscicidal properties. Planting of these trees and shrubs along streams and irrigation channels can reduce the number of snails in a population. The efficacy of this method for control of flukes has not yet been assessed.

The introduction of large numbers of ducks into rice fields after harvest has been used to reduce the snail population. The ducks eat the snails and the fluke species specific to the ducks compete with the fluke species of ruminants in the infection of snails. It is reported that snails infected with duck flukes will not become infected with flukes of livestock.

The introduction of edible snail species unsuitable as intermediate hosts into the habitat of the host snails may prevent the flukes from completing their life cycle.

Managemental methods of snail control:

The important management methods of controlling fluke infections are:

(a) To prevent snail habitats from developing by regular clearing of drainage channels in vegetation that will provide suitable sites for snail development.Good drainage and the building of dams at appropriate sites in marshy and low lying areas may reduce the snail problem.

(b) To keep livestock away from pastures contaminated with metacercariae. This may only be possible when the number of animals involved is small.

(c) Provide proper watering facilities to prevent animals from drinking from lakes, ponds and streams.

ECONOMIC IMPORTANCE OF FASCIOLASIS

In Nigeria, the first incidence of fascioliasis was reported by Burke, (1939) when about 3000 goats died of the disease in the then Borno province, north-eastern Nigeria. In a South-Western State of Nigeria, a gross total liver loss of 8.292 kg was observed with about 75% loss of value in 29.952 kg of partially condemned liver tissues in a single abattoir over a three-year period (World Bank, 2006). Estimating that each of the 36 states and the Federal Capital Territory will record similar losses in at least one abattoir per state, this will translate to huge loss of resources (US$ 5,762,010) for the country. These enormous losses are especially important for a low-income food-deficient country (LIFDC) like Nigeria (World Bank, 2006). When cattle have worm burdens,damage to the liver is more severe and the cattle may develop chronic fasciolasis and classically show loss of weight, condition and develop anaemia. A lower fluke burden may result in sub clinical infection which affects growth rates, carcass composition, and fertility and in dairy cattle reduce milk production and changes in milk quality. Charlier et al (2008) suggest that a fluke burden of more than 10 flukes was associated with raised γ-GT and detectable liver damage. A recent study of 606 high yielding dairy herds in Britain, showed a significant (p˂0.001) negative association between F.hepatica exposure and milk yield at the herd level; herds with the highest levels of exposure had 15% lower yield compared to herds with low exposure. Moreover A study in Belgium showed that closantel treatment at drying off increased milk production by 303kg over a 305kg day lactation (Charlier et al 2012). The effect of fluke infection on milk quality and fertility well defined, several studies show differing effects, confounded by different farming systems. Economic impact of fasciolasis on livestock is enormous. Great loses are evident especially where farmers have little or no knowledge on the disease. (Ozung et al 2011) reported 7.35% and 96.65%, 18.58% and 81.42% and 5.77% and 94.23% condemned and partially condemned liver in Bovine,Caprine and Ovine species respectively. Loses are more encountered during the raining season when most stocks are exposed to fluke challenge. Reduction in milk and meat production, condemnation of liver, loss of draught power, reproduction and molality are some of the loses encountered (Talukder et al,2010 and Diawet et al, 1998). Ross (1970) stated that loss in productivity was about 8% in low grade infections (about 100 liver flukes present), 16% in moderate infections (about 250-300 liver flukes present), 23+% in heavy infections (about 500 or more liver flukes). In a study conducted at the Maiduguri abattoir of Borno State, Nigeria on slaughtered cattle, Biu et al., (2006) reported about 1, 290 kg condemnable weight of liver from 250 cattle valued at N451, 720.50k due to fascioliasis. Fasciolasis is one of the most important disease of livestock,especially of cattle and buffaloes ( Kendall, 1954). (sewell, 1966). (swamp and Pachauri, 1987) etc. However, most reports are anecdotal or faecal egg examination studies. With few exceptions, estimate of loss have been narrowly based usually on value of infected livers condemned at slaughter as unfit for human consumption (Hyera, 1984), or on the value of meat lost through lower carcaria weights of infected animals (sewell, 1966) (ollerenshaw and Graham, 1987). Most authors recognized the inadequacy of their estimates but lacked the information to make more comprehensive study of its type with F.gigantica so far, estimate the benefits risk cost ratios per cow unit at Zimbabire based on one of two anthel mantic doses. They took into account the consequent reduction in mortality and liver condemnation, improved weight gain and reproductive performance and the anticipated. Improvement in feed conversion efficiency and milk yield. Their assessment also included the influence of the quality of the diet and the presence of concurrent infection with gastro intestinal nematode. There are many parasitic infection of animal in Nigeria. Parasitic infection tends to lower the market nutritional economic values of animals infection (Ukoli, 1967). Furthermore Much of the research work done on veterinary parasitology in Nigeria is done with confirmed animals and they do not involve treatment or curative measures (Wilson, 1968). Most of the meat market in Nigeria has been found to be infected with fasciola gigantica because there no adequate control measures put in place for the animals. Economic impact of fascioliasis on livestock is enormous. Great loses are evident especially where farmers have little or no knowledge on the disease (Ozung et al; 2011 and Hammond and Sewell, 1990). In addition Loses are more encountered during raining season when most stocks are exposed to fluke challenge. Reduction in milk and meat production, condemnation of liver, loss of draught power, reproduction failure and mortality are some of the loses encountered (Talukder et al, 2010 and Diawet et al, 1998). Ozung et al (2011) reported 7.35% and 96.65%, 18.58% and 81.42% and 5.77% and 94.23% condemned and partially condemned liver in Bovine, Caprine and Ovine species respectively. The global losses in cattle productivity due to fascioliasis were estimated at over US$3.2 billion per annum during the last decade (Spithill et al., 1999).

CHAPTER THREE

MATERIALS AND METHODS

3.1 THE STUDY AREA AND SAMPLE COLLECTION

The area of study was in Port Harcourt south- south of Niger delta in Rivers State, Nigeria. It is located in tropical rain forest. Cattle are usually transported from Northern Nigeria to Rivers State, cattle are slaughtered at abattoirs located proximal to meat markets.

COLLECTION OF SAMPLES AND LIVER TISSUE INSPECTION

Each abattoir was visited during the weekend in the early hours of the morning between the hours of 5:30-6:00am before the cattle will be slaughtered. Collection of sample was done with the help of a qualified veterinary officer around after the cattle have being slaughtered. Inspection was done first by visual and palpation of the liver tissue, for better examination instrument were used a sharp knife and hook. Access was made to the duct of the liver by cleaving the liver with the hook and cutting through making an incision to thoroughly check for the presence of parasite. The fluke were seen rushing out of the duct in heavily and slightly infected tissue. At advance stage of infection the liver becomes whitish and hard with holes on it, while healthy liver tissue was red and fluffy. The degree of infestation was recorded and tissue samples for both infected and non-infected liver were collected for proper histopathological procedures. Heavily infected liver tissues were discarded and lightly infected liver tissue were trimmed off and discarded then the non-infected were cleared for sales to the consumer.

HISTOLOGICAL PREPARATION OF LIVER TISSUES

Infected liver of cattle were trimmed into sizes and fixed in formol saline solution for at least 24 hours, and washed in tap water. Fixed tissues were dehydrated in ascending grades of alcohol (70%, 95% and absolute concentration). Dehydrated tissues were cleared in zylene, infiltrated in liquid paraffin wax at 600C and embedded in clean wax to block. Blocked tissues were mounted in wood frames and cut into 5µ thick sections using rotary microtome. Cut sections were flattened on water bath at 400c and picked with clean albumenized slides. Sections were dewaxed in descending grades of alcohol (absolute concentration, 95% and 70%). Dewaxed sections were stained with haematoxylin and counter stained with eosin, dehydrated in alcohol, cleared in xylene and mounted with cover slip for examination. The photographs of the different slides of liver tissue were taken.

CHAPTER FOUR

RESULT

Table 1: Prevalence and intensity of fasciola and the number of infected liver examined at Trans-Amadi Abbatoir.

Table 2: Prevalence and intensity of fasciola and the number of infected liver examined at Choba Abbatoir.

Table 1 show the prevalence of fasciola spieces in Trans-amadi Abbatoir which was visited in the space of three (3) months. Out of 550 livers examined 30 (16.34%) was infected the rate of intensity was 21 low and 9 heavy.

Table 2 show the prevalence of of fasciola spieces in Choba Abbatoir which was visited in the space of 3 months. Out of 162 livers examined 8 (14.74%) was in infected the rate of intensity was 6 low and 2 heavy.

Histopathology of liver tissue.

Plate 1: Normal liver tissue structure showing normal hepatocytes with nuclei and cell wall with normal sinusoid

Magn: x100 Stain (H&E)

Plate 2 Infected liver tissue showing fluke migratory tract abnormal sinusoid

Plate 3 infected liver tissue: pale color with egg of fluke

Plate 4 A Healthy liver

Plate 5 Heavily Infected liver (pipe stem appearance)

Plate 5 infected liver with fasciola rushing out

Discussion

The present study was carried in two abbatoir in portharcourt for 3 months respectively to assess the intensity of cattle fasciolasis and the histopathology of the liver. The result for intensity of cattle fasciolasis in both abbatoirs did not show much significant difference this is because the study was carried out during the dry season, according to Mas-Coma (2005) in his work named Fascioliasis and other plant-borne trematode zoonoses, he reported that the prevalence of helminthes parasites in cattle is highest in the tropical rainforest as well as in the sub-tropical areas where annual rainfall very is high. This high rainfall is known to favour the proliferation of snail, Lymnacea natalensis and Lymnaea truncatula, which are intermediate host of liver flukes. The difference between prevalence and intensity of cattle fasciolasis may have to do with the location of the abbatoir and also with the season. The duration of this study is another factor have also influence the amount of data obtained. Since the rainy season favours the survival of the intermediate host, water snails (Lymnae species) and the parasite (Okon and Enyenihi, 1977; Suarez and Busetti, 1995). The intensity of this liver will result to the condemnation of heavily infected liver which will result to the loss of profit for the owner thereby affecting the market price of the healthy liver in other to recover the loss. Danbirni et al (2015) reported that a prevalence of 1.2% from 80 condemned livers out of 6,933 cattle examined and that the total weight of both partially and totally condemned liver tissue was 295.8kg which translated to a financial losses of ₦354.960 only,also a study conducted in Maidugari abbatoir by Biu et al (2006) reported about 1,290kg weight of condemned liver from 250 cattle valued at ₦451,720.50k due to fasciolasis. Histopathology of non-infected and infected liver was carried out. Microscopically the non-infected liver tissue cells, sinusoids, bile duct and portal tract were all normal. There were also no abnormal changes in the nucleus and the color of the tissue. But that of the infected liver tissue appeared pale in color, there was dilation in the central vein and accumulation of debris this indicates the obstruction of liver functions including protein synthesis (Talukder et al 2010), gross fibrosis of bile duct were as a result of migrating fluke in the liver tissue. Damage to the hepatic cells is as a result of feeding habit of the premature parasites and it’s the most common of bovine cirrhosis (Njoku-Tony and Okoli, 2011). Haroun et al. (1986) also reported the degenerative and necrotic changes in hepatocytes associated with haemorrhage, fibrosis, increased lobulation of the liver, mononuclear cell infiltration with haemosiderin deposition in fluke tracks and portal areas and the formation of granulomata around fluke eggs and fluke remnants in sheep naturally infected with F. gigantica. Also Odigie et al reported gross examination of infected livers and revealed that the capsule were enlarge, adult and young fluke were seen in the bile duct of 62 livers out of 540 cattle examined also liver cirrhosis was reported only in 3 cattle.

Conclusion

From the study, it can be concluded that the prevalence and rate of intensity of fasciolasis in cattle greatly affects the histology of the liver tissue, depending on the grade of intensity, histopathological changes in the livers of cattle infected with fasciolais reflects tissue damage, which can amount to significant economic losses in animals and great health problems to the uninformed populace. More attentions and care are required for the veterinary workers to ensure that heavily damaged livers are not sold for public consumption and also low infected livers are properly trimmed off before being sold because of the serious health risk problems.