| intestinal nematodes | Trichinella spiralis | Trichuris trichiura (whip worm) (trichocephalus trichiurus) | Hook worms (Ancylostoma doudenale and Necator americanus) | Ascaris lumbricoides | Enterobius vermicularis (pinworm ,threadworm ,seatworm) | Strongyloides stercoralis (Dwarf threadworm) | ||
| shape | male 1.5mm length ,female 3.4 mm (very small after strongyloides) | whip shape | D larger ,mouth e hooks while N >mouth e plates **ova is oval or oblong but in N larger (ova tend to stick to glass) | largest nematode )male 15-20cm ,female :20-40cm)infect human intestine ,pale pink | sharply pointed tail ,male :3-5mm ,female :10mm | smallest (male :0.7mm ,female 2.2mm ) egg :oval shape ,thin shell ,transparent col | ||
| source | *undercooked pork meat *polar bear meat (parasite show unique tolerance for cold) | worldwide | world | swallowing water or raw vegetables polluted e eggs contain infective stg | over the world | |||
| life history | pork contain encysted larva is eaten >cyst capsule digested >larva to S.I (where become mature adult) >after copulatn male die ,female invade mucous memb >1000-1500 larva >larva migrate to circulatn >encysted in muscle | adult in cecum >egg in feces >2 cell stg >embryonated egg (infective stg) >ingested >larva hatch to intestine >penetrate & develop in mucosa | adult in intestine ><eggs in feces (diagnostic stage) >rhabditiform larva >Filariform larva (infective stg) >penetrate skin {dermatitis "ground itch") >circulatn >lung >trachea >pharynx >swallowed | adult (S.I) >fertilized egg in feces (Diag. Stg) >feces >rhabditiform larva >embryonated egg (2nd stg larva) {infective stg} >ingested >larva hatch to intestine >circulatn >lung >trachea >pharynx >swallowed | adult female worm migrate through anus and deposit their eggs e fully developed larva on perianal region (diagnostic stg) >autoinfectn (swallow eggs) >infective stg egg (embryonated) >ingested >larva hatches >adult in intestine | see graph ,,, 2-pecularities 1)adult can live in soil 2-some rhabditiform larvae while passing down the lumen of intestine >moult twice into infective stg (filariform) >they penetrate mucosa (internal auto infectn) or perianal skin (external auto infectn) and repeat the cycle >persistant infectn | ||
| infective stg | encysted larva in meat | embryonated egg | Filariform larva | embryonated egg | embryonated egg | flariform larva or autoinfection | ||
| pathogenisis | Trichinosis | Ascarasis | Enterobiasis | strongyloidosis | ||||
| pathogenisis | intestinal disturbance | irritatn & ulceratn of intestine 2-2ry bacterial infectn may occur 3-diarrhea ,bloody stool | tear the tissue to get small b.v from w bl is pumped to their intestine >anemia | 1-during migratn stg :haeg ,pneumonitis ,allergic manifestatn (as asthma ,oedema) ,fever ,cough ,oesinophilia ,larva emboli 2-intestinal stg :obstruction ,peritonitis 3-toxic effects :alergic manifestatn ,nervous irritability or loss of appetite and wt (see details) | 1-pruritis it may causing fatigue and insomnia 2-children may suffer from nervous irritability and enuresis 3-appendicitis 4-may migrate to vagina ,uterus ,tubes and even urinary bladder leading to irritatn anf inflammatn | skin lesion >dermatitis & itching ,larva may remain in skin >cutaneous larva migrans lung lesion >hge intestinal lesion >enteritis,congestion,hge *light >asymptomatic heavy ::epigastric pain ,tenderness ,nausea,vomiting ****Disseminated strongyloidiasis (very imp >details | ||
| lab diagnosis | 1-adult worm in stool 2-larva in blood or muscle (muscle biopsy by compressing () slides )3-serological test (Bachman's test) is hypersensitivity test by ID injectn of antigen from larva +ve >wheal ein 20 m ,CFT <haemoagglutinatn ,fluorescent Ab | eggs in stool (tray shape) ,adult may also present | 1-finding eggs in feces (diagnostic stage) w contain clear space () yolk & shell ,conc by floatatn increase chance for detectn (using sat'd soln of NacL) *for ancylostoma & H.nana2-clinical pic of anemia | 1-eggs (e brownish shell) 2-during pulmonary phase there may be eosinophilia and larva may be found in sputum *** if one male ascaris (no eggs) >diagnose :Levamisole Hcl (Ketrax) >to separate adults (stool contain male ascaris) | 1-eggs e fully developed larva are seldom found in feces 2-adult worms may be found in stool 3-eggs are best obtained by swabbing the peri-anal region (using scotch adhesive tape swab) to pick any ova nearby perianal region >examine on slide | 1-clinical 2-laboratory :*stool exam for rhabditiform larvae & ova (less common) *culture (from environment) :larvae develop into free-living adults *duodenal aspiration shows the larvae *eosinophilia 40% *serological tests (ELISA) | ||
| ttt | 1-adult worms expelled from intestine by purgatives 2-anthelmintics as *piperazine*-tetrachloroethylene *diethylcarbamazine 3- *Thiabendazole and Mebendazole | Mebendazole (vermox) | 1-pyrantel pamoate (combantrin) 2-Bephenium hydroxynaphthoate (Alcopar) 3-tetrachloroethylene ***supportive ttt :iron ,vit and high protein diet (fro he & anemia {proper ttt}) | 1-piperazine citrate 2-pyrantel pamoate (combantrin) 3-Levamisole HCl (Ketrax) >3 tb for adults 4--hexylresorcinol | 1-piperazine 2-pyridinium pamaote 3-pyrantel pamoate *** proper ttt :mercurial ointment is applied to perianal region esp at night >relive itching ,kills females coming out to lay eggs and prevent dispersal of eggs | 1-thiabendazole (Mintezol) 2-Mebendazole (vermox) | ||