Trematodes Flashcards
1
Q
Describe trematodes
A
- Morph:
- flat, solid-bodies, unsegmented
- oral sucker and acetabulum
- blind digestive tract
- Indirect life cycle
- First IH usually an snail
-
Hermaphrodites
- Asexual and sexual reproduction
- Operculated eggs - except schistosomes
2
Q
Describe the basic life cycle of trematodes
A
- The adult in present in the DH (sheep)
- operculated eggs released in feces
- Once the egg hits the water, a ciliated miracidium is released
- the IH (snail) ingests the miracidium, which develops into a sporocyst
- Within the snail, the sporocyst develops into the redia
- The redia develops into and releases a cercaria, which leaves the snail
- The cercaria develops into a metacercaria and is ingested by the DH (sheep)
3
Q
True or False: trematodes have evolved a system of ‘soldier’ and reproductive castes that prevent invasion of the IH by multiple trematodes
A
True
4
Q
Describe the life cycle of Platynosomum fastosum (lizard poisoning flukes)
A
- adults in bile ducts of cats
- eggs shed in feces, miracidium develops
- eggs ingested by terrestrial snail (1st IH)
- mother sporocyst —> daughter sporocysts —> cercariae
- cercariae encyst in Anolis lizards (2nd IH)
- also toads, geckos
- Lizards ingested by cats
- metacercariae excyst —> juvenile flukes entire bile duct/gallbladder and mature
5
Q
Describe Platynosomum Fastosum (lizard poisoning flukes)
A
- Distribution: Florida, other SE states, Hawaii
- Host: cats
- Habitat: Bile duct
- Morph: Adults are small, operculated eggs
6
Q
How do you diagnose P. Fastosum?
A
- eggs in fecal sedimentation
- necropsy: flukes in bile duct, hepatic lesions
7
Q
How do you treat P. fastosum?
A
-
No approved treatment
- High dose praziquantel
- Epsiprantel
- Fenbendazole
- Tx unrewarding in late stage disease - gets worse after flukes die off
- prevent predation
8
Q
Describe Paraginomus kellicotti (lung fluke)
A
- Distribution: North America
- DH: Dogs, cats, mink/muskrat (primary DH)
- Habitat: lungs - live in pairs in cysts
- Morph: adults - reddish brown, eggs - yellow brown, operculated, terminal spine
9
Q
What is the life cycle of P. Kellicotti?
A
- Adults in lungs
- eggs pass in bronchi —> trachea —> coughed up and swallowed —> exit in feces
- contact with water released miracidium —> enters stream snail (1st IH)
- cercarie leave snail and penetrate crayfish (2nd IH), encyst
- DH ingests the crayfish containing metacercariae
- Juvenile flukes penetrate the SI and the diaphragm, enter the lungs
10
Q
Describe the disease caused by P. Kellicotti
A
- Migrating immature flukes
- eosinophilic peritonitis, pleuritis, myositis, multifocal pleural hemorrhage
- Adult flukes
- chronic bronchitis, granulomatous pneumonia
- heavy infections or rupture cysts —> hemorrhage or pneumothorax
11
Q
What parasite are you looking at?
A
P. Kellicotti (lung fluke)
12
Q
How do you diagnose P. Kellicotti?
A
- Eggs in sedimentation or float
- sputum, feces, TTW
- thoracic rads might show pulmonary cysts
- frequently right caudal lung lobe
13
Q
How is P. Kellicotti treated?
A
- No approved treatment
- praziquantel
- epsiquantel
- fenbendazole
- prevent ingestion of uncooked crayfish
14
Q
Describe Nanophyetus salmonicola (salmon poisoning worm)
A
- Dist: Pacific NW
- DH: Dogs, cats, fish-eating mammals including humans
- Habitat: SI crypts
- Morph: eggs yellow brown, operculated
15
Q
Describe the life cycle of N. Salmonicola
A
- Adults in SI, eggs released in feces
- in water, miracidium released and penetrates aquatic snail (1st IH)
- cercarie leave and penetrate fish (2nd IH), encyst
- trout and salmon most susceptible
- metacercariae most abundant in kidneys, fins, muscle
- DH ingests fish
- Flukes excyst, mature in SI
17
Q
How do you diagnose N. Salmonicola?
A
- History of eating fish in last 5-7 days
- clincal signs
- eggs in fecal sedimentation (PPP = 4-5 d)
19
Q
Describe Heterbilharzia americana (canine blood fluke)
A
- Dist: Gulf Coast, south Atlantic coast, as far north as Kansas and Indiana
- Host: dogs, raccoons (natural DH), bobcat, horses
- Morph: Adults - dioecious, egg - non-operculated, contains miracidium
21
Q
Describe the disease caused by H. Americana
A
- Usually asyptomatic
- Cercarial penetrations —> possible rash with pustular eruptions
- Zoonosis: cercarial dermatitis
- Eggs in tissue - granulomatous dermatitis, calcification
- Possible clinical signs: lethargy, weight loss, inappetence, diarrhea
22
Q
How do you diagnose H. Americana?
A
- Eggs in feces
- sedimentation best - 0.9% saline, not water!
- Fecal PCR
- Histopath
24
Q
Describe Alaria spp.
A
- Dist: North America
- Host: Dogs, cats
- Habitat: SI
- Morph: eggs light brown, operculated
25
Q
Describe the life cycle of Alaria spp.
A
- Adults in SI, passed in feces
- in water, miracidium released —> penetrates freshwater snail (1st IH)
- Cercaria leave snail, penetrate tadpole (2nd IH)
- remain as mesocercariae
- DH ingests tadpole or paratenic host (frog, snake, bird, small mammal)
- Mesocercariae penetrate diaphragm, migrate to lungs, develop into metacercariae
- Metacercariae carried up thru trachea, swallowed, matures in SI
- If lactating queen ingests mesocercariae —> migrate to mammary glands and develop in kittens, some remain in queen to infect future litters
26
Q
Describe the disease caused by Alaria spp.
A
- Adults usually non pathogenic
- migrating flukes can cause pulmonary hemorrhage
27
Q
How do you diagnose and treat Alaria spp?
A
- Dx: eggs in fecal sedimentation
- Tx: No approved treatment - Epsiquantel, Praziquantel, Fenbendazole
- Prevention predation
28
Q
Describe the disease caused by P. Fastosum
A
- Disease: normally not severe (inappetence)
- Chronic infection — biliary hyperplasia —> fibrosis, cholestasis, hepatic failure
- Severe infections — V/D, anorexia, lethargy, depression, fever, jaundice
