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Parasite Table Exam 3 (Nematodes Part 1).docx

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Department
Biology
Course
BIOL 2000
Professor
Gubbels
Semester
Fall

Description
Parasite Nematodes Type Intestinal Species Ascaris lumbricoides (roundworms) Trichuris (whipworms) Ancylostoma duodenale and Necator americanus (hookworms) Transmission -eat food contamination with fecal eggs ingest eggs Transmission from ground (make contact with larvae) Life Stage 1) fully embryonated eggs swallowed and L2 1) Embryonated eggs are ingested (infective stage) 1) adult worms live in small intestine hatches in stomach and penetrate stomach 2) larvae hatches in small intestine and penetrate 2) eggs passed in feces 2) larvae enter blood stream and leave through mucosa, adults in cecum 3) larvae develop outside body and molt twice alveoli into lung 3) unembryonated eggs pass in feces (diagnosis) 4) filariform (L3) move to surface in serach for host 3) Larvae molt several times in lungs, L3/L4 move 4) 2 cell stage 5) if contact host they penetrate skin, enter blood up and get swallowed 5) advanced cleavage vessels and leave the circulatory system in alveoli 4) 2-3 months after infection adult worms start 6) larvae move up trachea into esophagus, are swalled laying eggs and finally reach intestine, where molt twice more 5) eggs shed with feces and embryonate within 2-3 before reaching adult hood weeks Unique -anterior end of both sexes shows 3 lips -eggs hatch upon contact with bacteria -head slightly bent (hook) -fertilized eggs are shorter and rounder than -mouth carries teeth (anycylostoma) or plates unfertilized eggs (necator) -Necator found in southern US Diseases Symptoms -occasional pulmonary symptoms -less than 10 worms = asymptomatic -skin penetration can result in ground itch -intestinal phase asymptomatic -moderate to heavy infection = abdominal pain, -pulmonary phase is asymptomatic -dangerous complications in kid under 10 diarrhea, weight loss -intestinal phase: worms attach to mucosa and feed on -volvulus, mass of knotted worms in intestine -heavy infection in children = bloody diarrhea, cramps, blood, leave bite site causing bleeding -penetration of intestinal wall, followed by rectal prolapse --anemia and iron deficiensy peritonitis -adults can live for years Pathology -blood loss -with malnutrition can stunt growth in children Diagnosis -show eggs in feces -demonstration of characteristic eggs, champagne corks Diagnosis eggs in feces Treatment mebendazole mebendazole mebendazole Prevention -sanitary disposal of human feces Parasite Nematodes Type Blood (microfilaria = prelarvae), usually in blood/tissue Species Onchocerca volvulus Brugia malayi Wuchereria bancrofti Transmission Blackflies (larvae live in fast flowing oxygen rich water) Mosquito Mosquito -L1 in pool of blood in wound taken up, L3 can leave fly and go into wound Life Stage 1)Adult worms (macrofilaria) living in nodules under skin -L1 larvae swept into bloodstream and circulate, remain infective for several months of human host -diurnal rhythm, found in blood during night (increase chance to take up by vector?) 2) female releases microfilaria (L1) which migrate through -L1 (MF) taken up by mosquito and leave sheath in midgut, and migrate to flight muscle where they cutis molt twice 3) blackflies take up L1 through blood meal -L3 migrate through hemolymph until find labium, which penetrate when sense feeding and move into 4) worms develop to infectious L3 in fly thorax muscle wound Unique -unsheated -sheated -sheated -females produce L1 larvae still in egg membrane (sheath) Diseases Onchoceriacis (River Blindess) (subcutaneous tissue) Lymphatic Filariasis (lymphatics) Lymphatic Filariasis (lymphatics) -infection occur in proximity to fast moving water Symptoms -adult worms form nodules in cutis enclosed by host w/ -severe elephantiasis of legs, scrotum, arms (tends to effect arms) fibrotic granuloma (onchocercoma) -maturing larvae and adults provoke strong inflammatory response -lymphnode and lymphchannel swelling (with fever) -chronic disease can lead to widespread fibrosis and rupture and discharge of lymph into urinary system or scrotum
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