Serum enzyme and hematological profile of Fasciola gigantica immunized and experimentally infected riverine buffaloes

Abstract

Sixteen male, yearling Murrah buffaloes were randomly assigned to four groups of four buffaloes each. Each animal in Gr-I and II were immunized, respectively, with 4.8 mg of excretory secretory antigen and 1,300µg Infection Specific Antigen, in three divided doses. Subsequently, each animal in Gr-I, II, and III was per os infected with 800 viable Fasciola gigantica metacercariae (bubaline origin) on week-6 after the start of the experiment, while animals in Gr-IV served as healthy controls. The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations progressively increased during the prepatency and respectively attained the highest levels during week-6 and 8 post-infection (PI). The alkaline phosphatase (AP) exhibited elevated trends from eighth week PI onward and continued to be higher until the end (p<0.05-0.01). With the cessation of traumatic activities of the diastomes, the AST and ALT levels declined yet were throughout significantly higher than the healthy controls (p<0.05-0.01). In the immunized animals (Gr-I and II), the fluctuation patterns were similar but the values were significantly lower than the non-immunized (Gr-III) animals (p<0.05-0.01). The elevated levels of the enzymes had positive correlation with depressed erythrocytic indices, leucocytosis, eosinophilia, necropsy worm recovery, and hepatic lesion score in the respective groups. The increased concentrations of the enzymes revealed two clearly demarcated stages: (a) remarkably elevated AST (40.8%) and ALT (140.0%) levels during the prepatency, signifying traumatic lesions inflicted by the F. gigantica adolescercariae and (b) the significant increase in AP (107.9%), suggestive of bile duct hyperplasia, cholangitis, periportal fibrosis, and biliary obstruction etc. from sixth week PI onward. None of healthy controls developed clinical signs and had normal hematological and serum enzyme profiles. Diagnostic significance of these marker enzymes in the disease forecasting and in time application of control strategies to combat tropical fasciolosis in buffaloes in the endemic areas has been discussed.

Epizootiology, pathogenesis and immunoprophylactic trends to control tropical bubaline fasciolosis: an overview

“…Grossly the carcasses were emaciated and had icteric appearance, extensive gelatinization of subcutaneous fat, hepatomegaly (1.5 times) and liver had rounded margins. The establishment of adult flukes in biliary network was associated with enlarged, thickened and mineralized and prominent bile ducts beneath the liver capsule and distended gall bladder (Yadav et al 1999b;Edith et al 2010a). A hepatic load of 368 ± 110 adult flukes could cause death in buffalo calves, aged above 6 months by Day 140 post-infection (pi).…”

“…The elevated serum enzyme concentrations in fasciolosis were exploited for early and semi quantitative diagnosis of the disease before the animal is coproscopically positive for the fluke eggs (Kumar et al 1982;Swarup and Pachauri 1987;Edith et al 2010a). The recent experimental findings on the liver specific enzyme concentrations, periodically refluxed by the damaged hepatic tissues in the circulation of F. gigantica infected buffalo yearlings, during the course of disease revealed that the elevated levels of serum Aspartate transaminase (AST) and Alanine transaminase (ALT) were suggestive of the hepatic tissue injury, whereas the elevated levels of alkaline phosphatase (AP) indicated establishment of adult flukes in the bile ducts.…”

“…In contrast to AST and ALT, the elevated levels of AP are ascribed to decreased biliary excretion of the enzyme or obstruction of bile flow stimulate de novo synthesis of the hepatic AP and synthesized enzyme is refluxed into the host circulation. Over 28% increase in AP concentration indicates obstructive hepato-biliary lesions and less than 8% increased AP concentration was suggestive of chronic form of the disease or post-patency immune carrier status of the host (Edith et al 2010a). …”

“…Quantitative examination of faeces and assessing hepatic fluke load at necropsy are also not sensitive enough to precisely predict severity of the disease (Garg et al 2009). However, it is possible to predict/suspect fasciolosis during early pre-patency (Day 40 pi onwards) by periodical monitoring the elevated levels of marker enzymes (AST and ALT) in the host circulation (Edith et al 2010a).…”

“…In the tropical and sub-tropical countries, including India, fasciolosis has been a major economic threat to the development of ruminants, especially buffaloes. High sensitivity to solar radiation and poorly evolved body thermoregulation in buffaloes are comforted by their wallowing nature in fresh water bodies that predisposes to snail borne metazoan infectious diseases, especially tropical fasciolosis mainly caused by Fasciola gigantica-an inhabitant of hepatobiliary system of domestic ruminants (Mehra et al 1999;Garg et al 2009;Edith et al 2010a). In recent past, global losses incidental to fasciolosis were estimated over US $3,200 million per annum.…”