Epidemiological and Pathological Studies of Fascioliasis in Goats in Sylhet Region of Bangladesh and investigation on Effects of Different Liver Tonic on Pathology of Fascioliasis

Abstract

An attempt was made to determine the prevalence, patho-surveillance and histopathology of caprine fascioliasis in five agro-ecologic zones in Sylhet region of Bangladesh. Goats were divided into young and adult groups. Rectal fecal samples from household live goats and livers from slaughtered goats were collected randomly and examined from July 2012 to June 2013. A survey was also conducted to determine the snail populations and to know the infection status of the developmental stages of F. gigantica in Lymnaea snails. In addition,, the effects of liver tonic, anthelmintic and their combination treatments on some indicator parameters were evaluated. Statistical comparisons, using SPSS analysis, Pearson’s correlation and ANOVA statistics, were made to determine the differences in prevalence among seasons, age, sex and different upazillas. A total of 1288 rectal fecal samples from household live goats and 2000 livers of slaughtered goats were examined. Four hundred five (31.75%) household live goats and 202 (10.10%) slaughtered goat livers were infected with Fasciola gigantica. The overall prevalence was 20.93%. The prevalence of fascioliasis in Biswanath (25.96%) was significantly (P<0.001) higher than Beanibazar (22.16%), Balaganj (20.23%), Jaintapur (19.45%) and Sylhet Sadar (16.84%). It was noticed that prevalence in household goats was higher than slaughtered goats. The infection rate in young household (39.05%) and slaughtered (15.58 %) goats was higher than adult household (23.22%) and slaughtered (9.59%) goats. The females showed high infection rate than male. The fascioliasis was more significantly recorded in females household (39.15%) and slaughtered (13.10%) goats than males (19.96% and 7.10%, respectively). Closer analysis of results indicated that there was statistically significant difference (p<0.001) in prevalence rates in different upazilla as well as between female and male goats. Seasonally, the highest prevalence (25.71%) was recorded during rainy season and the lowest (10.12%) was in summer season. The prevalence rate in rainy season was statistically significant (p<0.001) than winter and summer. Intermediate hosts for Fasciola gigantica, the L. auricularia var rufescens was found in all agro-ecological sites at five different upazilla of Sylhet region. A total of 1865 Lymnaea snails were collected and examined. Of which 56 (3%) Lymnaea snails were infected with different developmental stages of F. gigantica. The infected snail percentage was highest 4.08% in Biswanath followed by 3.16% in Beanibazar, 2.53% in Balaganj, 2.40% in Jaintapur and the lowest 1.83% in Sylhet Sadar. In month-wise data, the prevalence of snails infection was highest in May (5.06%) and August (5.61%) and the lowest in February (0.68%) and March (0.74%). No infection was observed in November to January. The larval stages of F. gigantica infection in Lymnaea snail’s was highest in rainy (4.63%) season followed by summer (1.92%) and the lowest in winter (0.76%). The study revealed that the infection level of the developmental stages of F. gigantica in snails population decreases from November to January and increases from February to October and highest in August and September. In gross examination, the infected livers were enlarged with rounded edges and thickened capsule. In acute cases, numerous hemorrhagic spots were observed on the parietal and visceral surfaces of the affected liver. In chronic form, liver was cirrhotic and reduced in size. The affected intra-hepatic bile ducts were protruded and engorged with flukes. Microscopically, migratory tracts were represented by the presence of hemorrhage, edema and infiltration of numerous eosinophil mixed with few lymphocytes. Fatty change, atrophy and necrosis of hepatocytes were recorded along with deposition of bile pigment in hepatic parenchyma and damage of portal tract area. The wall of bile ducts was thickened due to fibrosis and lining epithelia were hyperplastic. Cross sections of adult and immature flukes were found within the lumen of the thickened bile ducts and hepatic parenchyma respectively. The efficacy of the anthelmintic, liver tonic and anthelmintic along with liver tonic against F. gigantica infection in goats and its effect on hematological and biochemical parameters were determined. Thirty five goats (2.0 to 2.5 years old) were randomly selected and divided into seven groups (namely T0, Ti, and T1 to T5) based on fecal sample examination. The first group (T0) kept as non infected control (negative control) and the second group (Ti) was infected control (positive control). Blood samples were collected to assess the hemto-biochemical parameters. The efficacy of anthelmintic, liver tonic and their combination treatment was evaluated by counting faecal egg per gram (EPG) and comparing hematological and biochemical parameters with pretreatment values. On 7th, 14th, 21st and 28th days of treatment, a significantly (P<0.001) decreased EPG count was found in treated group of goats. The EPG count of positive control group (Ti) were significantly (P<0.001) increased. The packed cell volume (PCV), hemoglobin (Hb), total erythrocyte count (TEC) levels were gradually decreased significantly (P< 0.001) in goats of positive control group. Conversely, hematological values were increased in treated group of goats, except the total leukocyte count (TLC) which was decreased significantly (p<0.001). This result was the indication of effective treatments. The level of serum glutamate pyruvate transaminase/aspartate transaminase (SGPT/AST), serum glutamate oxaloacetate transaminase/alanine transaminase (SGOT/ALT) and alkaline phosphatase (ALP) were declined significantly (P<0.001) in treated groups (T1, T3, and T5) as compared to the infected control group (Ti). The current research generated data on the epidemiology of Fasciola gigantica, pathology (gross and microscopic) caused by the immature and mature stages of the parasite in goats at Sylhet region of Bangladesh. This study was also provided information about the developmental stages of this parasite in its intermediate host (Lymnaea auricularia var rufescens) which is very important to design effective control program. A combined approach of administration of anthelmintic and liver tonics was applied to investigate how helpful the liver tonic is in regeneration of liver tissue which was damaged by fluke. The results showed that the liver tonic might have great impact on regeneration of hepatocytes and recommence of functional activities of the liver. Taken together, the findings of the present study have significant values and might helpful in establishing an effective treatment, control and eradication programs of fascioliasis in goats in Sylhet region of Bangladesh and also in similar temperate agroecological zones around the world.