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Trichuris Trichiura Superfamily: Trichinelloidea

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Trichuris Trichiura Superfamily: Trichinelloidea > TRICHURIS > TRICHINELLA > DRACUNCULUS Trichuris Trichiura Superfamily: Trichinelloidea Family: Trichuridae Genus: Trichuris Species: T. trichiura Trichuris Trichiura Common Name;Whip worm Distribution; World wide, common in tropical regions having high humidity like tropical Africa, South America and South East Asia. Habitat Adult worms are found in the caecum & less commonly in appendix & colon. Eggs are passed in faeces, not infective when freshly passed, infective larvae develop in the eggs in the soil Morphology Adult worms have a shape like a whip, anterior 3/5th is hair like (lash) and posterior 2/5th the stout portion (stock or handle) The worms lives in large intestine with whole of its anterior portion embedded in mucus membrane. Female •It measures 5cm in length & 2mm in breadth •Posterior part has a uterus tightly packed with eggs •Anterior part is occupied by a long oesophagus Male •The male measures 3-4cm X 2mm •Posterior end is coiled & has a spicule Eggs •Measuring 50 X 25μm, brown in color (bile stained) •Barrel shaped, wide in the middle with a mucus plug at each pole •When freshly passed contain unsegmented ovum Life History •Man is the only definitive host •Eggs when passed in faeces are not infective •Further development takes place slowly in damp soil •Rhabditiform larvae develop in 3-4 weeks •Man gets infected by swallowing fertile eggs in contaminated food, water or soiled fingers (children) •Eggs hatch in small intestine, larvae emerge through the pole, move down to caecum •Larvae develop directly to adults •Adults become sexually mature in about 3 months •Fertilization occurs •Gravid female starts laying eggs Pathogenicity Disease; Trichuriasis •Commonly found in children •Usually asymptomatic in light infections •In heavy infections diarrhoea, dysentery and rectal prolapse occurs Abdominal pain, weight loss and anemia can occur Worms entering appendix can result in Ac. appendicitis Diagnosis •By finding typical barrel shaped eggs in faeces •Sigmoidoscopy to see worms attached to rectal mucosa Trichinella Spiralis: Superfamily: Trichinelloidea Family: Trichinellidae Genus: Trichinella Species: T. spiralis Geographical Distribution •Pork eating races, prevalent in USA & Europe Habitat •Adult worms specially female is found embedded in the mucosa of duodenum and jejunum •No eggs are passed in faeces •Larvae are librated into lymph and blood •Larvae get encysted in skeletal muscles. •Most commonly the muscles affected are deltoid, thigh muscles, diaphragm, tongue, thorax & eye muscles Morphology: Male worm is rarely found Size1.5mm x 40µm Posterior end has a pair of conical papillae Female size 3-4mm x 60µm Uterus is a coiled tube, viviparous Larva size 100µm x 6µm. Life History: Parasite of rat & pig Pig is the reservoir host Man can also get infected Rat to rat, pig to rat, pig to pig & pig to man transmission occurs In humans infection is dead end Pig gets infected by eating pig / rat flesh Rat gets infected by eating other rats. Man gets infected by eating undercooked pig meat which contains encysted larvae Gastric juices digest the cyst After digestion of cyst the larvae get liberated & quickly grow into adult male & female After fertilization the male dies soon & female burrows into villi of small intestine A large number of larvae are discharged into blood and lymph Larvae get distributed to all parts of body These survive only in striated muscles Within muscles fibers larvae grow to a size of 1mm in 3 weeks These coil up in the muscles A capsule is formed by the host Cyst is produced Encysted larvae remain infective Can get calcified Pathogenicity: Disease is called Trichiniasis or Trichinosis. Majority of infections are asymptomatic Stages of disease 1) Invasion, 2) Migration, 3) Encystment Invasion In this stage following gastrointestinal symptoms are observed Irritation, nausea, vomiting, colic & diarrhoea During migration stage there is fever, myalgia, orbital edema, eosinophilia & albuminuria Encystment produces muscular pain, difficulty in breathing & mastication, muscular paralysis, severe toxemia, edema & weakness Diagnosis: Biopsy of effected muscles Adult worms or larvae can be seen in faeces In acute cases enzymes like CPK & LDH are raised Serological tests like CF, precipitation, latex agglutination, ELISA can be performed..
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