Highest incidence of both is in tropics, where eggs survive more easily, and in children, who do more fecal–oral transmission
Ascariasis: fecal–oral spread, 2-wk incubation of eggs necessary outside body before infective
Trichuriasis: fecal–oral spread
Sx:
Ascariasis: only if abnormal site or so many that they block gi tract. After ingestion, migrate to lungs, then coughed up, reingested
Trichuriasis: imbed in superficial intestinal mucosa, mainly colon; no tissue reaction, hence occasionally diarrhea
Ascariasis: small bowel obstruction; perforated bowel; asphyxia due to aspiration; biliary obstruction; hepatic abscess
Trichuriasis: anemia, malnutrition; rectal prolapse; allergic pneumonitis (in 10%) (rx w steroids–Weinstein, 1987)
Lab:
Bact:Ascariasis: stool shows eggs, and adults
Trichuriasis: stool shows barrel-shaped eggs w mucus plug at both ends; adults, whip is head end, handle is tail end
Rx:
(Nejm 1996;334:1178)
Avoid reinfection; worms live <2 yr