They were compatible to Echinostoma revolutum or Echinostoma jurini, with only minor differences. As the adults were recovered from both. Echinostoma ‘revolutum’ (Digenea: Echinostomatidae) species complex revisited: species delimitation based on novel molecular and. To determine the prevalence of helminthic infections in Pursat Province, Cambodia, we tested fecal specimens from children, 10–14 years of age, in June.
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Trematodes in the genus, Echinostoma.
Echinostoma revolutum Infection in Children, Pursat Province, Cambodia
The genus is worldwide, and about ten species have been recorded in humans, including E. Many animals may serve as definitive hosts for various echinostome species, including aquatic birds, carnivores, rodents and humans. Unembryonated eggs are passed in feces and develop in the water. The miracidium takes on average 10 days to mature before hatching and penetrating the first intermediate host, a snail.
Several genera of snails may serve as the first intermediate host. The intramolluscan stages include a sporocystone or two generations of rediaeand cercariae.
The cercariae may encyst as metacercariae within the same first intermediate host or leave the host and penetrate a new ecjinostoma intermediate host. Depending on the species, several animals may serve as the second intermediate host, including other ecuinostoma, bivalves, fish, and tadpoles. The definitive host becomes infected after eating infected second intermediate hosts.
Metacercariae excyst in the duodenum and adults reside in the small intestine. Worldwide, but human cases are seen most-frequently in southeast Asia and in areas where undercooked or raw freshwater snails, clams and fish are eaten.
Catarrhal inflammation often occurs due to the penetration of the sharp-spined collar into the intestinal mucosa. In heavy infections, nausea, vomiting, diarrhea, fever and abdominal pain may occur.
Egg of Echinostoma sp. Image taken at x magnification. Structures illustrated in this figure include: This species has been recorded from humans in Taiwan. Higher magnification of the anterior end of the specimen in Figure A.
Notice the acetabulum ventral sucker, AC. Higher magnification of the posterior end of the specimen in Figure A. Notice the vitelline glands VT and lobed testes TE. Higher magnification of the specimen in Figures A-C.
Shown here are eggs EG within the size range for Echinostoma spp. This snail genus has been recorded as a second intermediate host for E.
This snail genus has been recorded as a first intermediate host for E. This snail genus has been recorded as an intermediate host for E. This bivalve genus has been recorded as a second intermediate host for E.
Microscopic identification of eggs in the stool. Because the eggs are large, careful measurements must be taken to avoid confusion with the eggs of Fasciola or Fasciolopsis. Species-level identification cannot be done based on egg morphology and adults are needed for revoluhum definitive diagnosis.
DPDx is evhinostoma education resource designed for health professionals and laboratory scientists. For an overview including prevention and control visit www.
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Enter Email Address What’s this? Recommend on Facebook Tweet Share Compartir. Life Cycle Many animals may serve as definitive hosts for various echinostome species, including aquatic birds, carnivores, rodents and humans. Geographic Distribution Worldwide, but human cases are seen most-frequently in southeast Asia and in areas where undercooked or raw freshwater snails, clams and fish are eaten. Image Gallery Echinostoma spp.
Eggs of Echinostoma spp. They have an inconspicuous operculum and the abopercular end is often thickened. The larger eggs are very similar to Fasciola and Fasciolopsis.
Eggs are passed unembryonated in feces. Adults of Echinostoma spp. The oral sucker is surrounded by a collar of spines, the number of which varies among species. The oral and ventral suckers are located fairly close to one another. A single ovary is situated near the large, paired testes.
Adults reside in the small intestine of the definitive host. The following images were taken from an adult echinostome removed from a colon polyp during routine colonscopy.
Intermediate hosts of Echinostoma spp. Like all trematodes, Echinostoma spp.
The second intermediate host may also be a snail, sometimes the same individual snail that served as the first intermediate host. Due to the large geographic distribution of echinostomes, and the many species present, there are many species of snails that may serve as first or second intermediate hosts. Other second intermediate echionstoma include bivalves, fish and tadpoles. Laboratory Diagnosis Laboratory Diagnosis Microscopic identification of eggs in the stool.
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