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Flashcards in non-diarrheal invasive infestations Deck (58):
1

Ascaris lumbricoides

size

giant intestinal roundworm, "the wanderer"

adult female: 30 cm long, 5mm diameter
male: shorter, narrower, curved posterior with pair of copulatory spicules -yikes!

2

Ascaris adults live in the ?? where they do not ?? but rather ??

small intestine
don't hatch, but constantly move agains peristalsis

3

Ascaris female produces how many eggs/day

eggs are ??? until they are deposited in soil with poop

embryonization can take place in ?? or longer if unfav. conditions

200,000 eggs/day

fertilized, not embryonated

2-4 wks

4

when ingested, Ascaris larvae hatch in the ?? penetrate the ??and are carried via blood to ??

small intestine
lamina propria, carried to the liver, heart, then lungs

5

in the lungs, Ascaris larvae lodge in the ?? and break out into the ??

from there the larvae actively migrate ???

alveolar capillaries
alveolar spaces

up the bronchi into the trachea, across the epiglottis
are SWALLOWED, reaching the lumen of the small intestine

6

Ascaris lumbricoides larvae do what in the small intestine

grow and reach sexual maturity
cycle then begins again

7

whole Ascaris cycle takes ??
how long to the worms live ??

2-3 mos
1-2 yrs

8

Ascaris occurs where ??
host/reservoir?

S and SE US (need warm embryonation in soil)
humans are sole host/reservoir, 1-4 mill affected

Africa, Latin America, East Asia

9

light Ascaris infections are

asymptomatic (typ. of parasites: host-parasite homeostasis)

10

most intense reactions with Ascaris are caused by ??

what type of reaction occurs ??

migrating larvae, esp. if high numbers

Type 1 hypersensitivity rxn: cough, wheezing, urticaria, fever

11

other complications of Ascaris larvae migration

hepatic damage
lung damage, vermis pneumonitis
other organs

12

if moderately infected with Ascaris adult worms...

rarely symptomatic
vague abd pain, acute colicky pain (heavier infections)

13

Ascaris aka "the wanderer" may pass spontaneously via

vomiting, thru nares when adult worms wander up there

14

young kids with large Ascaris burden may ??

be malnourished or have nutr. deficiencies, stunted growth

15

Ascaris adult worm infection complications

bolus obstruction
perforation of intestine
blockage of bile duct
-others related to aberrant adult migration

16

this may irritate Ascaris adult worm and cause migration

tx for other nematode infections

17

dx Ascaris

migrating larvae, vermis pneumonitis
hx, CXR
*eosinophilia, Charcot-Leyden crystals* NO anemia
worms in stool, other sites
ova in stool (easily found due to so many produced)

18

Ascaris tx

mebendazole
pyrantel pamoate
good ppx

19

how to prevent Ascaris

sanitary disposal of feces
educating at risk pop
washing raw fruit/veggies in clean water

20

this 2 hookworms are very similar


but differ in ??

Necator americanus
Strongyloides stercoralis

different geography

21

Necator americanus



crazy estimate !!

New World hookworm
-tropical and subtropical regions of Africa, Asia, Central and South America
-US: S/SE (2-15% prevalence)
estimated 1/6th of world infected!

22

Ancylostoma duodenal

Old World hookworm
distribution overlaps Necator americanus

23

N. americanus morphology

female adults: 1 cm, males a bit shorter
buccal cavity has 2 cutting plates

ova: thin-shelled, early cleavage stage found in feces
larvae: Rhabditiform (non-inf) and Filariform (infective)

24

N. americanus adults live in ?? where the feed on ??

the small intestine, feed on the intestinal villi by their cutting plates (Necator) or teeth (Ancylostoma)

25

N. american eggs are embryonated ?? after pooped out and deposited in soil
the ?? will hatch w.in 48 hrs of deposition and will grow/dev. in soil into ??

immediately

rhabditiform larvae
filariform larvae

26

the N. american filariform larvae will seek out ?? in order to ??
then ??

a tall blade of grass, etc. to contact human skin

then actively penetrate subcutaneous tissue (hair follicle) and carried via blood

27

N. american filariform larvae are carried via blood to ??
where they ??


similar to ???

lungs
break out of alveolar capillaries, cruel up bronchi and trachea over the epiglottis and into pharynx and swallowed

Ascaris "the wanderer"

28

N. american larvae develop into adult worm in the ??

small intestine

29

N. americanus symps caused by ??
manifestations ?

penetration of larvae
ground or dew itch (allergic reaction): intense itching, burning erythema, edema, papular lesions-->vesicular if sensitized

30

N. american symps not typically caused by ??
unless ??

larval migration thru lung (inapparent)
unless heavy worm infestation-->vermis pneumonitis

31

N. american sypms from adults in sm. intestine

depends on ?? and ??

loss of blood

worm burden (need 200+)
host nutritional status (related to host Fe++ loss and replacement)

32

light N. american infection typically

no recog. symptoms

33

acute/heavy N. american infection

heartburn, flatulence, diarrhea, wl, +/- eosinophilia
GI symps disappear if become chronic

34

chronic N. american infection resembles ??



bad symps in kiddos?

iron deficiency anemia
fatigue, ha, numbness, tingling, dyspnea, anorexia, hd/ft edema, sexual dysfunction, pallor, tachy, enlarged heart

physical, mental dev. may be arrested

35

N. armerican dx

clinical suspicion +
labs: ova in feces, quant. counts for worm burden, CBC looks like infection/iron deficiency (hypochromic RBC, eosinophilia)

36

N. american tx

Mebendazole

37

N. american prevention

improve sanitary facilities, only poop in toilets!
don't use night soil
wear shoes
education
mass tx

38

Strongyloides stercoralis

roundworm
occurs in warms climates like hookworms (N. americanus)
also spread sporadically in temperate climates

39

signif reservoir of Strong ster

dogs

40

Strong ster has both a ??

free living phase and parasitic cycle

41

Strong free-living phase: larvae are ??
form of larvae ?? will ??

pooped out and deposited in soil (unlike hookworms)
rhabditiform larvae will grow and dev. into free-living adult worms

42

Strong free-living phase is

diecious, adults mate and female produces embryonated eggs that hatch and undergo similar cycle

43

if poor conditions, the Strong filariform larvae will ??

penetrate skin of host and begin parasitic infection

44

initial part of Strong parasitic life cycle:

similar to hookworms and Ascaris (spread to lungs, swallowed)
larvae develop into *female* adults in small intestine

45

Strong female adult is ?? and can live ??

weird brief appearance of ??

2 mm (small), lives w.in and among columnar epi cells of sm. intestine
male sex organs-->self-fertilization-->involution of male gonads
*no parasitic male per se*

46

Strong embryonated eggs hatch in ?? and proceed to ??
where they develop to ?? and are ??

sm. intestine-->colon
rhabditiform larvae, pooped into soil

47

if host is constipated, Strong rhabditiform larvae will ??

develop into filariform larvae and directly re-infect host by penetrating colon mucosa or perianal area

48

Strong ster: common?
found where ??

less prevalent than hookworm
SE USA, rural areas (0.4-4%)
mental institutions (40%)
veterans
immunocompromised pts

49

Strong ster symptoms due to penetration

little reaction observed in direct cycle, if auto infected may see creeping eruption at perianal region

50

Strong ster sypms from larval migration thru lungs..

few unless large infestation: pneumonitis, peripheral eosinophilia

51

Strong intestinal symps

invasion of mucosa, enteritis, tissue damage

52

manifestation of Strong ster infection

most asymptomatic
moderate: pain in epigastric region, diarrhea w. alternating constipation
eosinophilia
severe: malabsorption

53

autoinfections of Strong ster may lead to

sev. systemic infections, gen. abd pain, shock, fever, G- sepsis

54

Strong steer may cause ?? in immunocompromised host

hyperinfection

55

Strong ster dx

most difficult roundworm to dx
eosinophilia in 50-80%
look for larvae in feces (vs. ova in feces for hookworm)
serum IgG by ELISA
skin tests
larvae in sputum: agar test, look for worm tracks

56

Strong ster tx

Thiabendazole

57

Strong ster prevention

same as hookworm:
improve sanitary facilities, only poop in toilets!
don't use night soil
wear shoes
education
mass tx

58

Visceral and cutaneous larval migrans

"lost worms"
cut/subcut condition from skin penetration and transient migration of hookworm larvae form dogs, cats, etc

larvae die once in human host, but penetration/migration causes a "creeping eruption" inflamm. response in skin
-irritating and can become scratched and secondarily infected

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