Fascioliasis Dr. Gamal Allam

Learning outcomes By the end of the lecture, you should be able to: 1- Mention Causal Agent of Fascioliasis. 2- Mention systematic position of Fasciola spp. 3- Mention geographic distribution of Fascioliasis. 4- Enumerate Intermediate, Definitive and Reservoir hosts of Fasciola spp. 6- Explain life cycle of Fasciola spp. 7- Mention habitat of Fasciola spp. 8- Mention mode of infection by Fasciola spp. 9- Mention pathology and clinical features of Fascioliasis. 10- Diagnose Fascioliasis. 11- Enumerate disease control strategies Dr. Gamal Allam

Suggested Reading http://www.dpd.cdc.gov/dpdx/HTML/Fascioliasis.htm Dr. Gamal Allam

Causal Agents Fascioliasis is a parasitic disease caused by Fasciola hepatica and Fasciola gigantica, parasites of herbivores that can infect humans accidentally. Dr. Gamal Allam

Systematic position Phylum: Platyhelminthes Class: Termatoda Genus: Fasciola 3 species of can infect human: Fasciola hepatica Fasciola gigantica Fasciola buski (live in small intestine) Dr. Gamal Allam

Geographic Distribution Fascioliasis occurs worldwide in Europe, the Middle East, and Asia. Human infections with Fasciola are found in areas where sheep and cattle are raised.  Dr. Gamal Allam

Geographic Distribution…… cont. Dr. Gamal Allam

Morphology of the adult The adult is leaf-like, about 60 x 15 mm. It has an oral sucker and a larger ventral sucker Male reproductive system begins with two branched testes in the middle of the body The ovary is a branched organ Dr. Gamal Allam

Shape: Operculated, oval in shape. Colour: Yellow in colour. The ovum is: Size: about 150 x 80 . Shape: Operculated, oval in shape. Colour: Yellow in colour. Content: Contains immature embryo. Dr. Gamal Allam

Life cycle The parasite lives in the bile ducts of man and herbivorous animals which are the definitive hosts. The ova pass with bile to the intestine to come out with faeces. In water, the ovum needs two weeks to mature and a miracidium come out. It swims in water until it finds the snail intermediate host Lymnaea cailliaudi. Inside the snail it metamorphoses into sporocyst then rediae and finally cercariae in about 6 weeks. Dr. Gamal Allam

The cercariae swim in water and within 2 hours they settle on grass and water plants and even in water where they encyst forming encysted metacercariae )the infective stage). The encysted metacercaria can keep alive for about 6 months. The definitive host is infected by ingestion of vegetables or water containing the metacercariae. The cyst dissolves in the intestine and the metacercaria finds its way to the liver through the peritoneal cavity and reaches the bile ducts in about 6-8 week. Dr. Gamal Allam

Life cycle Dr. Gamal Allam

Life Cycle

Important points Definitive host: man Reservoir host: herbivorous animals Intermediate host: snail Lymnaea cailliaudi Infective stage: encysted metacercaria Diagnostic stage: eggs in stool Mode of infection: ingestion of encysted metacercaria in water or plants Dr. Gamal Allam

Clinical Features During the acute phase (caused by the migration of the immature fluke through the hepatic parenchyma), manifestations include: abdominal pain, hepatomegaly, fever, vomiting, diarrhea, eosinophilia, and can last for months. In the chronic phase (caused by the adult fluke within the bile ducts), the symptoms are: biliary obstruction, inflammation, liver Rot.  Dr. Gamal Allam

Liver Rot Dr. Gamal Allam

Halzoun syndrome (Pharyngeal fascioliasis): It is a disease characterized by pharyngitis and laryngeal oedema. It is limited to the Middle and Far East. The disease occurs due to adult Fasciola adhering to the posterior pharyngeal wall. The condition is caused by consumption of raw, infected sheep liver Dr. Gamal Allam

Mode of infection Humans can become infected by ingesting metacercariae-containing freshwater plants or metacercariae-contaminated water. Pharyngeal fascioliasis occur by eating raw infected liver. Dr. Gamal Allam

Laboratory Diagnosis Microscopic identification of eggs is useful in the chronic (adult) stage. Eggs can be recovered in the stools or in material obtained by duodenal or biliary drainage.  Dr. Gamal Allam

Laboratory Diagnosis….cont. Dr. Gamal Allam

Disease Control Treatment of infected animals. Snail control. Avoid eating raw vegetables before washing them. Avoid drinking infected water. Avoid eating raw liver to prevent halzoun syndrome

1- One of the following parasites belongs to Trematodes: Fasciola hepatica 2- Operculated egg is present in: 3- Encysted metacercaria is the infective stage of: Dr. Gamal Allam

4- Halzon occur in: Fasciola hepatica 5- Lymnaea snail is the intermediate host of: Dr. Gamal Allam

Thank You Dr. Gamal Allam