Trematoda Flashcards
What is the common name for Alaria spp.?
Intestinal flukes
What are the hosts for Alaria spp.?
Final hosts: dog, cat, fox, mink
Intermediate host: snails and tadpoles
Paratenic host: frogs, snakes, mice, rats, birds, reptiles, boars, humans. Zoonotic
What are the characteristic features of Alaria spp.?
Adults: pink or brown, 10mm
Eggs: oval, honey color, distinct operculum, up to 130 micrometers, larger than other helminths
What can you identify in this image?
Adult alaria spp.
What species of trematode eggs is this? What is the arrow pointing to?
Alaria spp. Arrow is pointint at operculum
Explain the life cycle of Alaria spp.
Final host passes eggs in feces, which hatch in water -> miracidia emerge, penetrate the snail (1st ih) and emerge as cercaria -> Cercariae encyst in frogs (2nd ih) as mesocercariae -> a paratenic host becomes infected after ingesting an infected frog with mesocercariae -> when dog or cat ingests the 2nd ih or paratenic host, mesocercariae is liberated, penetrates gut wall, migrates to lungs and develops to juvenile fluke -> juvenile fluke migrates up the trachea, swallowed, and matures in small intestine. PPP is 5 weeks
Where are the sites of infection for Alaria spp.?
Adults in small intestine and immature stages in lungs
What are the pathogenesis and lesions for Alaria spp.?
Heavy infection causes severe duodenitis. Lung migration causes clinical illness.
What are the clinical signs for Alaria spp.?
Usually not in final host
How is Alaria spp. diagnosed?
Fecal sedimentation for detection of eggs from final host
What are the treatment and prevention for Alaria spp.?
Though a trematode, cestocides work
What is the common name for Nanophyetus Salmincola?
Salmon poisoning fluke
What are the hosts of Nanophyetus Salmincola?
Final hosts: dogs, cats, minks, raccoons, fish-eating mammals. Intermediate hosts: snails and fish. Zoonotic
What are the characteristic features of Nanophyetus Salmincola?
Adults: ovoid and creamy white, up to 2 mm
Egg: oval, yellowish brown, thick shell, 80 micrometers
What species of trematode is shown in this image? What else can you depict from this image?
Adult Nanophyetus Salmincola. Oral and ventral suckers present
What is the species name of this egg and what is a unique feature about it?
Nanophyetus Salmincola egg. The operculum is very noticeable
Explain the life cycle of the Nanophyetus Salmincola
Final host passes eggs in feces that hatch in streams -> Miracidia emerg and penetrate the snail -> cercariae emerge from snal to penetrate the fish to form metacercariae in tissues -> When dog or cat ingests the intermediate host the juvenile fluke encysts and matures in small intestine. PPP 1 week
Where are the sites of infection for Nanophyetus Salmincola?
Adults in small intestine
What are the pathogenesis and lesions for Nanophyetus Salmincola?
Extremely pathogenic. Flukes are vectors for salmon poisoning in dog causing severe hemorrhagic enteritis
What are the clinical signs of Nanophyetus Salmincola infection?
Large number of flukes cause enteritis. Salmon poisoning causes: sudden fever, vomition, diarrhea, high mortality
How is Nanophyetus Salmincola diagnosed?
Fecal sedimentation for detection of eggs
What are the treatment and prevention for Nanophyetus Salmincola?
Appropriate trematocidal anthelmintics. Tetracycline therapy for rickettsia
What is the common name for Paragonimus Kellicotti?
Lung fluke
What are the hosts for Paragonimus Kellicotti?
Final hosts: dog, cat, carnivores
Intermediate hosts: snails, crayfish
Ten species infect humans
What are the characteristic features of the lung fluke?
Adult: ovoid, reddish brown, up to 16 mm
Eggs: oval, yellowish brown, distinct operculum, 110 micrometers
What species does this egg belong to?
Paragonimus Kellicotti
What are you viewing in this image?
Paragonimus Kellicotti
What is this image showing?
Eggs of Paragonimus Kellicotti in a lung biopsy
Explain the life cycle of Paragonimus Kellicotti
Eggs pass from a pulmonary cyst to a bronchiole and are swept up the trachebronchial tree, swallowed and passed out to feces -> when eggs reach water, miracidia develop and penetrate the snail -> Cercariae emerge from the snail, infect a crayfish and encyst as metacercariae. -> when a dog or cat ingests the crayfish, the juvenile cyst excysts in intestine, penetrates gut wall, migrates through the peritoneal cavity to the lungs to mature in lung parenchyma. PPP 4-10 weeks
Where are the sites of infection of Paragonimus Kellicotti?
In cysts in the lung parenchyma
What are the pathogenesis and lesions for Paragonimus Kellicotti?
Developing flukes cause formation of cyst
What are the clinical signs of Paragonimus Kellicotti?
Intermittent cough can occur. Heavy infections lead to severe cough, pneumonia, death
How is Paragonimus Kellicotti diagnosed?
Radiographs reveal cysts. Sedimentation method for eggs
What is the treatment and prevention for Paragonimus Kellicotti?
Praziquantel effective. Access to hosts is difficult to prevent
What is the common name for Platynosomum Fastosum?
Lizard poisoning
What are the hosts for Platynosomum Fastosum?
Final host is cat. Two intermediate host: snail and crustacean. Third host is obligate paratenic host: lizard, toad, geckos, skinks
What are the characteristic features of Platynosomum Fastosum?
Egg: oval, brownish, medium thick shell, operculate, up to 50 micrometers. Adult: 8 mm in length
What species does this parasitic egg belong to?
Platynosomum Fastosum
Explain the life cycle of Platynosomum Fastosum
Eggs pass in feces into water -> snails ingest eggs, develop to miracidia and then cercariae -> Cercariae emerge from snail which infect crustaceans, or snails ingested by crustaceans. Metacercariae encyst in crustaceans -> lizard, toad, gecko ingest crustacean with metacercariae -> cat becomes infected when it ingests these hosts. Develop to juvenile flukes, migrate to bile ducts to develop to adults. PPP 3 months
Where are the sites of infection for Platynosomum Fastosum?
Bile ducts
What is the pathogenesis or lesions for Platynosomum Fastosum?
Hyperplastic bile ducts
What are the clinical signs for Platynosomum Fastosum infection?
“lizard poisoning”, palpable liver, icterus, death
What parasite causes this?
Platynosomum Fastosum
How is Platynosomum Fastosum diagnosed?
Eggs on fecal sedimenation
How is Platynosomum Fastosum treated or prevented?
Praziquantel can be used, surgery is considered
