Download - CESTODES
CESTODES
GEN. CHARACTERISTICS1. MORPHOLOGY
A. head and scolex- For attachment to
intestinal mucosa B. neck
- Region of growthC. proglottids or segments
- No alimentary and vascular system
- Have nervous system- In gravid segments:
male and female organs seen(hermaphroditic)
- Series of segments = STROBILA
- Eggs are non-operculated EXCEPT for Diphyllobothrium latum
• 2. LIFE CYCLE– Requires 1 intermediate host EXCEPT for
Diphyllobothrium latum (2 I.H) and Hymenolepis nana (no I.H)
3. TRANSMISSIONAlways accomplished by the oral routeUsually only 1 worm per person infected
ORDER PSEUDOPHYLLIDEA• Diphyllobothrium latum
– Broad or fish tapeworm– Disease: fish tapeworm infection– Largest tapeworm in man (3-10
meters)– Habitat: intestinal mucosa (ileum)– Morphology:
• Bothria or sucking groove• Spatulate scolex
• LIFE CYCLE
• CLINICAL MANIFESTATIONS:– Epigastic pain, abdominal cramps, vomiting,
weight loss, anemiaDIAGNOSIS:
Stool exam – recovery of proglottid or eggTREATMENT:
NiclosamidePREVENTION:Thorough cooking of freshwater fish
ORDER CYCLOPHYLLIDEAN• 1. Dipyllidium caninum
dog tapewormDISEASE: dipylidiasis or dog tapeworm infectionCLINICAL MANIFESTATIONS:- Indigestion, loss of appetite
- Passage of progllotids in feces
• LIFE CYCLE
• DIAGNOSIS: stool exam• TREATMENT: -Niclosamide -Quinacrine PREVENTION: Insecticide dusting of dogs
• 2. Hymenolepis nana• -dwarf tapeworm• Smallest tapeworm (25-40
mm)• No I.H• TRANSMISSION:
– Ingestion of contaminated food and drinks
– Internal obstruction
LIFE CYCLE
• CLINICAL MANIFESTATIONS:• Periodic diarrhea• DIAGNOSIS:• - stool exam• TREATMENT:• Niclosamide• PREVENTION:• -personal hygiene
3. Taenia saginata• Beef tapeworm• Scolex has 4 suckers• Size: 4-6 meters long,
12 mm wide• Man is the only definite
host• Habitat: small intestine
(duodenojejunal area)
• LIFE CYCLE
• CLINICAL MANIFESTATIONS:• - Relatively benign compared to T.solium• - Epigastric pain, diarrhea, nausea,
irritability, weight loss• DIAGNOSIS:• - stool exam• TREATMENT: - Niclosamide, ParomomycinPREVENTION:• - thorough cooking of beef
Taenia solium• Pork tapeworm• Smaller than beef
tapeworm• Has circular row
of hooks(rostellum)
• Man- only definitive host
• Habitat: small intestine (jejunum)
• LIFE CYCLE
• CLINICAL MANIFESTATION:– Cysticercosis - larval migration to organs - brain: epilepsy, disordered behavior - eyes : failing vision: blindness- Upon death of parasite: fever, muscle pain,
eosinophilia- Intestinal obstructionDIAGNOSIS:
- Stool exam- Biopsy
• TREATMENT: – Niclosamide– Praziquantel– Mebendazole
PREVENTION:- thorough cooking of pork- personal hygiene
- general sanitary measures
TREMATODES (FLUKES)
GEN. CHARACTERISTICS• 1. All trematodes are dorsoventrally
flattened EXCEPT Schistosomes (cylindrical)
• 2. have 2 suckers– Oral and ventral suckers– For attachmentLIFE CYCLEa. Egg
-all TREMATODES lay an operculated ova except for Schistosomes(non-operculated)
• b. larva– Miracidium sporocyst redia cercaria
metacercaria
• C. adult• 4. Definitive host: man
– Harbors the adult worm– Infective stage: metacercaria except
Schistosoma(cercaria)
• 5. I. Host– Harbors the larval worm– All trematodes require 2 I.H except
Schistosomes(1)– 1st I.H: ALWAYS a snail
• Infective stage: miracidium• 2nd I.H.• Infective stage: metacercaria• Aquatic vegetation: Fasciola hepatica, Fasciolopsis
buski• Freshwater fish: Clonorchis sinensis• Clams or crabs: Paragonimus westermani
• 6. Manner of Transmission– Ingestion of metacercaria– Skin penetration of fork-tailed cercaria
LIVER FLUKES• 1. Fasciola hepatica
– Sheep liver fluke– Habitat: liver– Transmission: ingestion of
contaminated aquatic vegetation
– Clinical Manifestations:Colic, obstructive jaundice,
cough, vomitting
Life cycle
• DIAGNOSIS:– Stool exam– Bachman intradermal test– Complement fixation testTREATMENT:
Bithionol (drug of choice)Emetine hydrochloride
PraziquantelPREVENTION:
-Molluscides - Sanitary protection of waterbeds
2. Chlonorchis sinensis(Opistorchis sinensis)
• Chinese liver fluke• Size: 16x4 mm• Habitat: liver• Transmission: ingestion of raw or
inadequately cooked freshwater fish• Clinical Manifestations:
– Mild– Progressive – irregular appetite, fullness of
abdomen, diarrhea, edema, hepatomegaly– Severe – cirrhosis, portal hypertension
Immersion of vegetables in boiling water or thorough washing
- Avoid water chestnut in infected waters
LUNG FLUKE: Paragonimus westermani
• Oriental lung fluke• Habitat: lung• Disease:
Paragonimiasis• Transmission: eating
freshwater crabs
LIFE CYCLE:
• CLINICAL MANIFESTATION:– Productive cough occasionally blood-streaked
(hemoptysis)– Chest pain,night sweats, abdominal pain,
diarrhea, epilepsyDIAGNOSIS:
- Chest X-ray- Sputum exam- stool exam
TREATMENT: - Praziquantel