parasitic infestations: roundworms/nematodes

Question 1

Enterobius vermicularis

adult size?

egg size?

Answer 1

human pinworm (“seatworm”)

10 mm, 0,4 mm across, backside tapers to a point, male is about half female size

fully embryonated, infective-stage ova are elongated-ovoid, flattened on one side, and average 55 by 25 nm (small!)

Question 2

enterobius vermicularis adult pinworm lives freely in the ??

after copulation, adult female contains about 10^4 ??
she migrates thru ?? onto ?? where her uterus ?? and ??

Answer 2

transverse and desc. colon and rectum

fertilized but nonembryonated eggs
the anus onto perianal skin, prolapses and she releases her eggs and dies
larvae have been know to migrate back up anus

Question 3

after release, the Entero vermi eggs embryonate and take how long to become infective ??
eggs are resistant to ?? and easily spread how ??

Answer 3

6 hrs

desiccation, easily spread under clothing, bed sheets (“fluffing”), and fecal/oral route

Question 4

release of Entero vermi worm Ag often causes ??

not good to ?? bc ??

Answer 4

Type 1 hypersensitivity reaction, pruritis

scratch, eggs go under fingernails

Question 5

when Entero vermi eggs ingested the hatch upon reaching ?? where they also develop into an adult and migrate to the ??

Answer 5

the small intestine

large intestine

Question 6

pinworms(Entero vermi) live for

Answer 6

90 days

Question 7

pinworms typ. infect who ??

Answer 7

day care, school children (4-15)

most common intestinal nematode

Question 8

mode of Enterobius vermicularis transmission ??

Answer 8

anus-mouth via fingers (“thumb-suckers”)
airborne ova may be ingested/inhaled
parents of infected kiddos from close contact, changing clothes/bed sheets, hygiene

Question 9

majority of enterobius vermicularis (pinworm) inf. are

Answer 9

asymptomatic

Question 10

pinworm inf. symptoms

assoc. with ??

Answer 10

pruritis ani and vulvae (itchy butt/vagina), vaginal discharge (losing worms)

appendicitis, PID, granuloma formation

Question 11

other complications of pinworms

Answer 11

behavior changes, loss of sleep (itchy butt), grinding teeth

Question 12

ddx pinworms

Answer 12

ADHD, behavioral distrubances, H. nana infection

Question 13

dx pinworms: 1st consider ??

good simple test ??

Answer 13

pt age, hx, clinical observations

scotch tape test; may reveal ova in 50% of cases, 3 tests: 90%

Question 14

pinworm tx

Answer 14

Pyrantel pamoate: deworming for hookworms/roundworms, depolarizing NM blocker, causes worm to lose grip on intestinal wall and be pooped out

Mebendazole: all worms; inhib. synthesis of microtubles in parasitic worms

repeat both 2-3 wks later to kill hatched eggs (not egg-cidal)

Question 15

pinworm (entero vermi)

high probability of infection/reinfection due to ??

Answer 15

persistence of eggs and ease of transmission

so poor hygiene is NOT necessarily a factor

Question 16

Trichuris trichiura

morphology

Answer 16

diecious nematode (roundworm)
human whipworm

thin front, thick back, barrel-shaped with bipolar prominences (“plugs”)

Question 17

Trich adults live in ?? with ?? embedded w.in the epithelium and ?? protruding in lumen, so considered ??

Answer 17

transverse and desc. colon, the ant. portion

the posterior, minimally invasive

Question 18

Trich female produces ?? ova /day which are pooped out and must ?? for how long ?? to become infections
environmental requirements ??

Answer 18

3-5 x 10^3
undergo embryonation for 18-25 days
high humidity and warm temps

Question 19

become infected with Trich via ??
eggs hatch in ??? where it ??
moves on to ??
whole cycle time length ??

Answer 19

eating eggs
small intestine, attaches, matures
colon where it mates and the cycle begins again
totaling 90 days

Question 20

Trich worms can live for ??

Answer 20

1-5 yrs

Question 21

Trich is found where ??

who most affected?

Answer 21

poor hygiene/latrine facilities in warm/moist climates (for embryonation)
SE US and developing countries
800 mil inf. ww,
kiddos>adults

Question 22

Trich spread from ??

Answer 22

“night soil”: feces in fertilizer, imported

Question 23

Trichuriasis presentation: light vs heavy infection

Answer 23

light: asymptomatic

heavy: dysentery, “trichuris dysentery syndrome”
abd. pain, distention, bloody or mucoid diarrhea
- don’t rule out co-infection

Question 24

other complications of heavy Trich infection

Answer 24

appendicitis

rectal prolapse

Question 25

Trichuriasis may spread ??

if heavy worm burden in kiddos this may occur ??

Answer 25

systemically

blood loss–>anemia (confounding: previously malnourished)

Question 26

Trich lab dx: demonstrate worms via

Answer 26

1. proctoscopic exam
2. find ova (bipolar plugs) in poop
   - can also find Charcot-Leyden crystals
   - eosinphilia in heavily infected individuals

Question 27

Trich tx

Answer 27

Mebendazole for sympt. cases

90% cure rate! good px

Question 28

Trich ppx

Answer 28

sanitary disposal of poop
wash hands and raw fruits/veggies
don’t use “night soil”