Trematodes of the Intestinal Tract

Apart of the Helminth GI Infection Notes

Epidemiology of Intestinal Trematodes

• geographical distribution

  • Asia, Oceania, Europe, America, and Africa (Genus specific)

  • Limited based on intermediate host (snail) range

• about different 76 species

  • four the most frequently described intestinal flukes will be reviewed her: Fasciolopsis buski, Heterophyes heterophyes, Metagonimus yokogawai, and Echinostoma species

Life Cycle of Foodborne Intestinal Flukes

• infection occurs upon consumption of metacercariae (second intermediate host) (infective stage)

• metacercariae excyst and attach in the intestines where they develop into the adult

• adult produces eggs that are passed in the stool (diagnostic stage)

• egg in the environment release miracidia which invade the snail (first intermediate host)

• cercariae are released from the snail and (invade) encyst as meta cercariae in the second intermediate host

Infective stage and diagnostic stage of foodborne intestinal flukes

• infective: Consumption of metacercariae

• diagnostic: eggs

First and second intermediate hosts of foodborne intestinal flukes

• first intermediate host: snail

• second intermediate host: metacercariae

Clinical Syndromes of Intestinal Trematodes

• most are asymptomatic

• heavy infections cause abdominal discomfort, diarrhea, weight loss can occur, bowl obstruction, or ulcers on the intestinal wall

Diagnosis of Intestinal Trematodes

eggs/adult fluke in stool or vomit

Treatment and prevention of intestinal trematodes

• praziquantel

• avoid raw, undercooked fish, snails, aquatic vegetation

• education and sanitation