• ascariasis (caused by roundworm)
• trichuriasis (caused by whipworm)
• hookworm infection

• physical growth retardation
• intellectual and cognitive delays

• benzimidazoles (albendazole is the best one for STH's because one of it is absorbed outside the GI tract)
• mechanism- bind to unusual invetebrate tubulin that is present in all helminthes

1. unembryonated eggs passed in stool
2. eggs develop and embryonate in soil
3. ingestion of soil contaminated foods
   • fresh feces are NOT infective
4. eggs hatch in GI tract
5. larval worms emerge to establish selves in colon
   • ONLY STH that lives in colon
6. larvae enter columnar epithelium of colon
7. as they grow, worms attenuated end remains intracellular while its fat posterior end remains in the lumen
   • in order to do this, they will secrete unique ampipathic pore forming proteins
8. adults are sexually differentiated, and females oviposit at two months post infection

• trichruis dysentery syndrome
• trichuris colitis
• rectal prolapse

• IBS- worms at the attachment site cause inflammation

• fecal examination
  • football shaped eggs with two polar plugs

1. eggs ingested
2. fertile eggs embryonate and develop with adequate moisture and shade
3. larvae hatch in small intestines
   • live in low oxygen environment
     • has Hb that H bonds oxygen
4. enter blood stream and go to liver
5. they will migrate to heart
6. reach the lung capillaries
7. reach alveolar spaces
8. migrate up the trachea via cough, then they are swallowed
9. adults mature in small intestines

Maturation into adults takes 2-3 months

• Loeffler's syndrome
• impaired nutrition
• growth retardation
• acute intestinal obstruction (kids)
• biliary tract obstruction (adults)
  • panceratitis
  • cholangitis
  • hepatitis
• major cause of "surgical abdomen"

• fecal examination looking for characteristic eggs
• adult worms pass through nasopharynx and rectum

1. animals eat embryonated eggs
2. acquires adult worms
3. eggs pass in feces and embryonate soil
4. eggs are ingested
5. larvae hatch in the small intestines and penetrate the wall
6. larvae migrate to all organs via blood stream
   1. CNS
   2. eye
   3. liver

Do not develop into adult worms while in humans

• visceral larva migrans (1-3 yr old)
• ocular larvae migrans (older than five)
• covert toxocariasis

• pneumonitis
• hepatitis
• eosinophilia
• hypergammaglobulinemia
• anti RBC Ag's
• cerebritis

Necator americanus

Ancylostoma duodenale

1. infect when third stage larvae penetrate skin through feet, hands, abdomen, buttocks, legs, arms
2. larvae resume development after host entry
3. enter small lymphatics and venules
4. get to heart
5. get to lung parenchyma where they are swallowed
6. mature in small intestines
7. rupture capillaries and arterioles
8. ingest extravasted blood

• blood loss leads to
  • iron deficiency anemia microcytic hypochromic anemia
  • protein malnutrition
• impaired cognition
• lassitude and fatigue

Germ of laziness

• ID eggs on fecal exam
• direct relationship between egg counts and hookworm blood loss

• women and children due to low iron stores
• in children:
  • growth retardation
  • cognitive defects
  • mental retardation
• in women of childbearing age
  • puberty
  • menstration
  • pregnancy (adverse fetal outcomes)

• Atlantic Seaboard
• Gulf coast
• Puerto Rico
• Carribean

1. ingest eggs
2. larvae hatch in small intestines
3. adults mature in colon
4. gravid adults migrate nocturnally out of naus and oviposit while crawling on skin in perianal area (sticky eggs)
5. larvae develop within eggs
6. infection when eggs swallowed by hand mouth contact or when eggs aerosolized and deposited on contaminated surfaces

• pruritus ani which can become secondarily infected
• in female UG tract, cause vulvogagnitis
• anorexia
• irritability
• abdominal pain

often asympotomatic

• apply piece of tape to perianal area in morning before child has bowel movement
• examine microscopically

in US, we use swube tubes

• Appalacia
• immigrants from SE Asia, Latin America

• only STH to amplify within the host
• female worms are the only ones to parasitize the human intestines
• patients with strongyloidiasis produce larvae, NOT eggs
• phenomenon of autoinfection
• heterogenic life cycle (free living) and parasitic (homogenic) life cycle

• when larvae (L1), it can molt twice to L3 stages while they are still in the intestines
• L3 penetrate intestinal mucosa and then cycle through lungs and develop into mature female worms in the small intestines

• dysregulation of autoinfection (esp. in patients on high doses of steroids)
• thousands of adult female worms accumulate in intestines
• results in thousands of L3 penetrate intestinal mucosa, leading to bacteremia and menigitis (HALLMARKS OF HYPERINFECTION)

• steroid dependency
• hematological malignancy
• malnutrition (esp. if under 10 yrs old)
• HTLV-1 infection

HIV DOES NOT PUT AT RISK

• Loeffler's pneumonitis (if migrates to lung)
• often asymp.
• diarrhea (HALLMARK)
• urticarial rash called larva migrans (resmble cutaneous larva migrans)
• often eosinophilia
• hyperinfection (FATAL)
  • sever diarrhea
  • abdominal pain
  • distension
  • intestinal perforation
  • shock, sepsis
  • secondary bacterial complications like bacteremia, meningitis (gram negative type)

• must examine multiple stool samples (only few L1 produced by each female worm each day)
• duodenal fluid sampled via string test
• place fecal sample on blood agar plate and inspect for tracks of bacteria that trail advancing L2
  • place on charcoal to amplify throughout heterogenic life cycle

myalgias

edema

eosinophilia

• zoonosis
• acquired by consuming
  • uncooked pork
  • bear
  • walrus, seal (Inuit tribes in Alaska, Canada)

• intestinal phase
  • diarrhea
  • abdominal pain
  • vomitting
• muscle phase
  • pain
  • periorbital and facila edema
  • eosinophilia

If invades heart, FATAL MYOSITIS!!!!

• CPK and LDH elevated
• need high clinical suspicion and dietary history
• muscle biopsy and/or Ab detection by ELISA for confirmation
• if confirmed outbreak setting, clinical manifestation sufficient for dx