Parasitic Diseases

Fascioliasis

It is a liverfluke infestation characterized by hepatic insufficiency, bile duct obstruction, and poor production performance.

Etiology: The liverfluke includes fascioloides and dicrocoelium. Hepatic fascioliosis is primarily referred to the disease caused by Fasciola species. It occurs mainly in cows, buffaloes and sheep.

Pathogenesis: Acute disease is caused by immature flukes. The chronic disease develops due to adult flukes which cause bile duct obstruction, hepatic damage, fibrosis and anaemia. There is continuous leakage of plasma proteins into gut causing deficiency of albumin in circulation.

Clinical signs: In acute cases, animals are dull and depressed, emaciated and feel pain on palpation over liver area. They also suffer from anorexia, pale mucus membrane and passage of blood mixed faeces. Such animals usually die within 3-5 days. However, in bovines, chronic fascioliasis is common which occurs due to ingestion of small number of metacercariae over a long period. The animals suffer from weight loss, anaemia, submandibular edema, pale mucus membrane, loss of milk yield and chronic diarrhoea.

Diagnosis: It is diagnosed by clinical signs and confirmed by faecal examination for the presence of liverfluke eggs. Blood examination reveals anaemia and low level of albumin while activity of liver specific enzymes is highly increased. In acute disease, eggs are not seen in faeces but on blood analysis normochromic anaemia, eosinophilia and low albumin level with high activity of liver enzymes were observed.

Treatment: Large number of drugs is available against the liverflukes. Some of these are active only against mature flukes while others are effective against both mature and immature flukes. Triclabendazole given @ 12 mg/kg/dose body weight orally is highly effective against both the stages. Rafoxanide or closantel are also very effective and can be used @ 7.5 mg/kg/dose body weight. Oxyclozanide and albendazole have somewhat low efficacy against immature flukes but are effective against mature flukes when used @ 10 mg/kg/dose body weight. Supportive treatment is given in the form of liver tonics and good nutritious diet help in early recovery. Occurrence of the disease can be reduced by controlling the snail population and regular deworming of the animals at least twice in a year with broad-spectrum anthelmintics. Under-dosing and repeated use of same anthelminitic should be avoided.