Primary experimental infection of riverine buffaloes with Fasciola gigantica

The clinical course of the primary experimental Fasciola gigantica infectio n was investigated in riverine buffalo calves of the Murrah breed. Nine mal e calves aged 12-15 months were randomly assigned to two groups of five (Cr oup I) and four (Group II) animals. Each animal in Group I, was orally infe cted with 1000 metacercariae (mc) of F gigantica, whereas Group II animals did not receive any infection dose and served as uninfected controls. No cl inical signs of fasciolosis were observed until the sixth week post-infecti on (PI). Group I animals, however, developed recognised symptoms of acute f asciolosis, comprising apyrexic inappetance, anemia, poor weight gain, diar rhoea and sub-mandibular and facial oedema, respectively, from 5, 6, 8, 16 and 17 weeks PI. The signs were intermittent in nature and of variable dura tion. The prepatent period was of 92-97 days (mean 95.2 +/- 3.1). One of th e five infected animals died on Day 147 PI. Al necropsy, 36.8 +/- 11.0% of the infection dose was recovered as adult fluke population. The gross lesio ns were primarily biliary in nature. Group II, the uninfected controls, thr oughout the study period of 165 days PI, did not show any symptom and were negative for K gigantica. The study demonstrated that the onset of adverse effects of F: gigantica on the growth and health of the infected host was m ainly noted during late prepatency much before coprological prediction and diagnosis. The significance of preventive therapy against fasciolosis durin g prepatency has been stressed in endemic areas. (C) 1999 Elsevier Science B.V. All rights reserved.