Fasiola

fascioliasis

1. Fascioliasis Liver Fluke, Bottle Jaw, liver rot SUBMITTED TO DR G AMBICA ASST PROFESSOR, DEPT OF MEDICINE PREPARED BY DR THOTA SRINIVAS RAO RVM/18-41

2. Definition It is an acute or chronic disease of ruminants mainly, caused by fasciola spp .,characterized by sudden death, bottle jaw, emaciation and chronic digestive disturbance.

3. ECONOMIC aspects of the disease

4. Sheep Apart from Death of the sheep , Reduced production and quality of wool Reduced lambing percentages Poor growth rate of lambs Increased costs for replacement stock Cattle Reduced production and quality of milk Lower growth rates and lower feed conversion rates in fattening cattle.

5. Overview Organism Transmission Epidemiology Pathogenesis Disease in Animals Prevention and Control

6. Etiology Fasciola hepatica:  Mostly found in temperate and cooler area of high altitude in tropical and subtropical countries Fasciola gigantica :  Mostly in tropical countries Broad Leaf shaped worms large enough to be visible to the naked eye (adult  F. hepatica  measuring 20–30 mm x 13 mm; adult  F. gigantica  measure 25–75 mm x 12 mm)

7. CAUSATIVE ORGANISM

8. Predisposing factors Common in low lying swampy areas In areas subjected to frequent flood-irrigation Stress factors as pregnancy and parturition

9. epidemiology

10. Disease is widely distributed in many countries

11. Epidemiology Animal Susceptible : It is primary disease of ruminants but may be affect others as horse, camel, deer, pigs, rabbits, human, dog and cat Seasonal incidence: Intermediate host snails is Lymnaea spp Fasciola hepatica: Lymnaea truncatula Fasciola gigantica L. auricularia L. acuminata & L.rufescens   (India & Pakistan)

12. Snail Optimum temperature for breeding: 10 – 28°C Increasing in environmental temperature: Mortality of snail occurs (Infectivity falls) Size of snail: Size directly related with release of Metacercariae Moist and warm condition (mud) grow well Under unfavorable condition goes to Hibernation Ecology of Lymnea Permanent habitat – poorly drained soils, ditches, area of seepage & spring Temporary habitat – Hoof marking of animals (clay soil) pH- slight acid pH favour growth

13. Disease transmission

14. Life cycle Sporocyst Redia cercaria Live in pasture for upto 6-12m Ingestion Larvae free from cyst and penetrate duodenum and wandering through abdominal cavity into liver and change to adult after 8-10 w Prenatal infection may occurs where migrating immature larvae infect fetus in uterus and adult fluke may be recovered from calves less than 6 w age

15. The egg production of adult flukes is responsible for the degree of pasture contamination. Fluke survive for many years in the liver of infected sheep; the adult fluke lays between 20,000 and 50,000 eggs a day, and over a long period. In cattle, the egg production declines as the animal develops a natural resistance to chronic infections. The fluke eggs are passed in the faeces into wet areas. Here they hatch, when mean temperatures increase to above 10°C (mostly from mid September to May).

16. In summer, the eggs take approximately 21 days to develop into miracidia ; in the spring and autumn, hatching can take up to 90 days. The larva ( miracidium ) invades the snail, where it develops and multiplies. One single miracidium hatching from a fluke egg can produce up to 4000 infective cysts ( metacercariae ). Actively swimming cercariae released from the snail attach to substrates, especially vegetation. The tail is shed and the cercaria forms a resistant cyst stage ( metacercaria ). In the presence of sufficient moisture the metacercariae will remain alive for many weeks, depending on the temperature. They survive longer at below 20°C; higher temperatures and desiccation will destroy the metacercariae in a short time.

17. The snails, acting as intermediate hosts, produce eggs throughout the year. These eggs hatch when the temperature is right. There is a marked increase in reproduction from spring to late autumn. Snails may produce 3000 eggs a month and one generation of snails from egg to egg takes only about one month under optimum conditions. Lymnaea spps survives in dry mud for at least one year, and tolerates low temperatures. The snail can move with and against the water current for long distances.

18. The epidemiology of the disease is influenced by the grazing habits of animals. Cattle often graze in the wet marshy areas favoured by the fluke snail, so the eggs are deposited in a suitable environment. If food is available elsewhere, sheep and goats prefer to graze away from marshy pastures. Long wet seasons are usually associated with a higher infection rate but sheep are more likely to ingest large numbers of cysts during dry periods after a wet season, when the animals are forced to graze in swampy areas, resulting in heavy infection.

19. pathogenesis

20. Pathogenesis Acute hepatic Fascioliasis in Sheep Sudden death due to massive invasion of liver by young fluke with acute hepatic insufficiency and hemorrhage in peritoneal cavity Morbidity & Mortality High 6 – 8 weeks old sheep are highly affected Severity of disease is directly related to No. of metacercariae ingested (10,000) Traumatic hepatitis – migration of immature fluke aided by suckers Extensive destruction of liver parenchyma & marked haemorrhage If No. of immature flukes entered in to liver is so high – rupture of liver capsule - haemorrhage falls into peritoneal cavity

21. Pathogenesis Sub Acute form Develop slowly due to mature liver fluke in bile duct which cause cholangitis, biliary obstruction, destruction of hepatic tissue, fibrosis and hemorrhagic anemia If No. of metacercariae ingested is less (<10,000) Liver is covered by migratory tracts – infiltration of inflammatory cells Inflammatory cells mount immune response (not upto protective level) Early fibrosis Majority of fluke reaches bile ducts and become mature fluke – Cholangitis Anaerobic condition created by migratory flukes favours multiplication of  Clostridium novyi  –  Black disease

22. Pathogenesis Chronic form Most common form (ingestion of few metacercariae ) Morbidity – 30 % and Mortality – 10 %

23. Disease in animals COMPARISION OF AFFECTED LIVER WITH NORMAL Normal liver Effected liver

24. Clinical signs Acute form: It is rare in cattle and buffaloes and occurs in young ruminants (sheep and calves) especially well fattened one Decrease of appetite, dullness and weakness Pale mucous membranes and edema in conjunctiva, enlargement in liver and ascites Recumbence and sudden death within 48 h with blood stain discharge passage from nostril and anus (mimics Anthrax)

25. Sub Acute / Chronic form: It is more prolonged due to ingestion of few number of cercaria Sheep Decrease appetite, loss weight, submandibular edema (bottle jaw), pale and icteric mm Diarrhea and wool shedding Anemia and hepatic malfunction

26. In Cattle and buffaloes Anorexia and reduce growth rate, loss of weight and milk production Chronic diarrhea or faeces may be normal/ hard Bottle jaw, jugular pulsation and icteric mm Fascioliasis/ Ostertagiasis complex Diarrhoea is not feature of fascioliasis unless it is complicated by the presence of  Ostertagia  larva

27. Postmortem lesions Acute form Blood stained exudate – stained & rule out for Anthrax Liver enlarged in size, pale, friable & fibrinous clot observed on surface Congested, swollen and damaged liver While incision extensive - haemorrhage tracts with immature flukes Small liver fluke can be seen on slicing a piece of liver Liver capsule showed perforation with subcapsular hemorrhage If liver capsule is ruptured the blood clots observed in the abdominal cavity

28. Chronic form In Sheep – Liver - Large leaf liver flukes present in bile duct and protruded above liver surface Calcification of bile ducts wall Liver parenchyma is extensively fibrosed In Cattle - Lungs – Hazel-nut sized cysts containing brownish gelatinous material in which a live/dead & calcified flukes are observed

29. Diagnosis History Field diagnosis based on emaciation, diarrhea, bottle jaw, sudden death and fasciolin (antigen Fh8) test. Postmortem lesion Laboratory diagnosis Samples: faeces , liver, blood and serum Fecal examination by direct and sedimentation Oval, operculated greenish yellow in color and embryonic cell well demarcated

30. Diagnosis Serum biochemical changes: Hypoproteinemia due to increase protein leakage into the gut Hematological changes: PCV, Hb and RBCs may be decrease with severe normochromic anemia, and hypochromic anemia in chronic form with eosinophilia Histopathology of liver to detect liver degenerative changes Slicing a piece of liver thinly and put in water with shaking then permitting the fluke to settle to the bottom, naked exam. Showed immature worms of ¼ inch length

31. Differential diagnosis Acute form : all diseases cause sudden death as anthrax, enterotoxaemia and acute pasturellosis Chronic form : it is confused with all affection characterized with anemia and diarrhea as John's disease, Paramphistomiasis , intestinal helminthes and nutritional deficiency (as copper and cobalt)

32. Prevention & Control

33. Immunity & Immunization Natural immunity Cattle - Reinfection of  F. hepatica  - moderate to high immunity Sheep - fails to develop protective immunity Active immunity Cattle – Three doses of irradiated metacercariae of  F. hepatica Age - 6 – 9 months Sheep – Not effective

34. Control Due to the great biotic potential of Fasciola hepatica and their intermediate host snails, only a continuous and coordinated strategic application of all available measures can provide economic control of the disease.

35. Control Control should be on a preventive rather than a curative basis. For effective control: use strategic antihelminthic treatment, to reduce the number of fluke in the host and the number of fluke eggs in pasture; reduce the number of intermediate host snails; manage fluke-prone areas, to reduce exposure to infection.

36. Control Treatment of infected animals Hygienic measurements Infected pastures should not use for grazing Wet pasture or floody areas are avoided Regular removing of manure Avoid grazing near pond area Prevent access of natural water resources – fencing of water resources Provide wholesome water supply at convenient places Drainage of water pools & swampy areas 3. Snail control 4. Prophylactic deworming

37. Snails control Physical – Improving drainages Chemical - Applying molluscicides Copper sulphate - 1 in 1,00,000 solution for water reservoir Copper sulphate powder - 10 – 35 kg / hectare Applied along with sand for easy apply and Sheep are not allowed to graze until rainfall occurs Biological – rearing of ducks, geese and frog - infected water sources

38. Deworming schedule Deworming schedule for sheep in endemic areas to reduce pasture contamination late April/May – adult sheep – treated for adult & late immature flukes ( Triclabendazole ) – Pre- mansoon October – entire flock with triclabendazole / Closantel – Post mansoon January – entire flock drug off mature flukes ( Albendazole ) In Cattle Every December and May to prevent pasture contamination on spring and winter

39. OXYCLOZANIDE Cattle – 10 to 15 mg / kg (mature -100%) Sheep – mature - 15 to 20 mg / kg & Immature - 45 mg /kg

40. RAFOXANIDE Sheep & Cattle – 7.5 mg / kg Mature - more than 90 % & Immature – 50 to 90%

41. TRICLABENDAZOLE Sheep & Cattle – 10 mg / kg Highly effective against immature flukes Sheep – single dose remove all stages (over one week old) Cattle – two doses remove over 4 weeks aged flukes The best prevention and control can be achieved with triclabendazole , which is effective against early immature and adult fluke.

42. NITROXYNIL Sheep & Cattle Mature (100% effective)- 10 mg / kg & Immature (90% effective) – 15 mg / kg

43. CLOSANTEL Sheep & Cattle – 7.5 mg / kg

44. THANK YOU