Micro444: Flagellates

Front 1

Giardia lamblia flagellate form

Back 1

9-21um long
horshoe crab looking thing
binucleate
8 flagella

Front 2

Symptoms of acute giardiasis?

Back 2

explosive watery diarrhea
dissemination very rare: non-invasive
inflammation of duodenum/small intestine
damage to villi --> malabsorption, fatty stools
temporary lactose intolerance
trophs in stool

Front 3

Geographic distribution of giardiasis?

Back 3

worldwide; #1 parasitic disease in USA

poor sanitation conditions: fecal contamination of water

St. Petersburg

Front 4

What populations are frequently affected by giardiasis?

Back 4

problems w/toilet hygiene:

daycare centers
nursing homes
mental wards
jails

St. Petersburg/Leningrad/places with old sewer + water lines

Front 5

Symptoms of chronic/recurring giardiasis?

Back 5

malnutrition/wasting
chronic fat absorption problems due to damaged small intestine
lactose intolerance
deficiency in fat-soluble vitamins (B12)
vitamin D deficiency --> Rickets
cysts in stool

Front 6

How is giardiasis diagnosed?

Back 6

similar to amoebiasis

3x stool examination (periodic cyst shedding)
trophs in stool (acute case)
cysts in stool (chronic case)
duodenal string test
biopsies (overkill)

Front 7

Why is it sometimes hard to dx giardiasis via stool examination?

Back 7

Flagellate has sucker disc and attaches itself to lining of intestine --> sometimes doesn't come out in stool

Front 8

What are the symptoms of Trichomoniasis?

Back 8

stinky/foamy vaginal discharge
UTI's

males asymptomatic

Front 9

How is trichomoniasis usually diagnosed?

Back 9

most reliable way: fluorescent antibody or anaerobic culture methods

not so reliable: wet mount, stains

Front 10

Morphology of flagellate form of Trichomonas vaginalis?

Back 10

7-15um pear shaped
axostyle starting near nucleus, curves through middle of cell (stem on pear)
bean shaped nucleus
anterior tuft of flagella
undulating membrane along 1/2 of cell

Front 11

What are the natural reservoirs of giardia lamblia?

Back 11

humans, mostly

sometimes dogs, beavers

Front 12

Describe the cysts of Giardia lamblia.

Back 12

oval cyst
5-15um
4 nuclei
axostyle along length of cyst
parabasal bodies

Front 13

Describe the morphology of Chilomastix mesnili flagellate form.

Back 13

10-20um pear shape
peanut shaped cytostome (mouth)
flagella at anterior end near nucleus
nucleus w/margination of chromatin + central karyosome

Front 14

Describe the cysts of Chilomastix mesnili.

Back 14

lemon-shaped w/a small "knob" on one end
round
one nucleus w/eccentric karyosome

Front 15

Describe symptoms of West African Trypanosomiasis.

Back 15

T. brucei gambiense: MILDER

chronic disease, trypomastigotes SPARSE in blood

fever, then invasion of brain tissue --> encephalitis --> coma, death

also invasion of heart tissue

Front 16

Describe symptoms of East African Trypanosomiasis.

Back 16

T. brucei rhodesiense: ACUTE

aggressive infection: 2-3 weeks til death due to encephalitis

trypomastigotes PLENTIFUL in blood and CSF

invasion of heart muscle

Front 17

How is West African Trypanosomiasis diagnosed?

Back 17

thick and thin blood smears (often not conclusive because trypomastigotes sparse in blood)

examination of BUFFY COAT

Front 18

How is East African Trypanosomiasis diagnosed?

Back 18

thick and thin blood smears: trypos plentiful in blood

examination of buffy coat

see trypos in wet mount of CSF!!

Front 19

Describe symptoms of Acute American Trypanosomiasis (Chagas disease)

Back 19

trypanosomes in blood, amastigotes intracellularly

acute myocarditis --> aneurysm, invasion of heart by lymphocytes in attempt to control

swollen eyelids

Front 20

Describe symptoms of Chronic American Trypanosomiasis (Chagas disease)

Back 20

Chronic myocarditis

trypomastigotes not plentiful in blood b/c soon enter amastigote stage

intracellular amastigotes --> megacolon, swollen espohagus, inability to pass stool

swollen lymph nodes and spleen

Front 21

How is acute Chagas diagnosed?

Back 21

thick/thin blood smear in the first 3 months.

examination of buffy coat

Front 22

How is chronic Chagas diagnosed?

Back 22

serology/antibody detection because blood parasites rare (blood smear useless)

Xenodiagnosis with clean Reduviid bugs: if parasite enters bug, it'll multiply like crazy

Front 23

How does one obtain Chagas disease?

Back 23

fecal inoculation: scratch Reduviid bug feces into bug bites

Front 24

Why is superinfection with chronic Chagas impossible?

Back 24

humoral immunity prevents superinfection.

parasite only found in blood for first couple of months because gets immunologically suppressed.

Front 25

When does chronic Chagas enter acute phase?

Back 25

Loss of immunity: AIDS pts with chronic Chagas often get acute Chagas.

AIDS pts can also get superinfection: if they have chronic they can get bitten again and get acute Chagas

Front 26

What percentage of chronic Chagas infections are clinically obvious?

Back 26

~3 to 4%

most asymptomatic until much later stages.

Front 27

Where is Chagas disease most prevalent?

Back 27

Central and South America

Texas!

Front 28

How is Chagas spread?

Back 28

-main route = Reduviid bug feces
-oral transmission (sugar cane/acai juice)
-blood transfusion w/contaminated blood
-organ transplant/immunosppression
-congenital mother to child transmission

Front 29

Morphology of epimastigote?

Back 29

anterior flagellum/undulating membrane 1/2 of body

kinetoplast just posterior to nucleus

central nucleus

volutin granules

Front 30

Morphology of trypomastigote?

Back 30

anterior flagellum, undulating membrane along whole body

kinetoplast at posterior end

central nucleus

20-30um long

volutin granules

Front 31

Morphology of promastigote?

Back 31

anterior flagellum and kinetoplast

no undulating membrane

central nucleus

volutin granules

Front 32

Morphology of amastigote?

Back 32

no undulating membrane or flagellum

2-5um round cell

"dot dash" nucleus + kinetoplast

Front 33

Which Trypanosoma species has the smaller, more delicate kinetoplast?

Back 33

T. cruzi

Front 34

What is the characteristic shape trypomastigotes of T. cruzi under the microscope?

Back 34

trypomastigotes curved into a "C" shape

(T. brucei more serpentine)

Front 35

What is one possible reason for decreased virulence in T. brucei gambiense?

Back 35

It has evolved to be an *anthropophilic* parasite.

good parasite doesn't kill host!

Front 36

What is the difference between T. brucei gambiense and rhodesiense presence in the blood?

Back 36

gambiense: sparse (no dx by blood smear)

rhodisiense: very abundant

Front 37

Recommendations for control of African Trypanosomiasis?

Back 37

-clear bushes away from streams to remove tsetse fly breeding grounds
-spray insecticides
-bed netting
-wear thick clothing + repellents

Front 38

What are the major targets for intracellular tissue invasion by T. cruzi amastigotes?

Back 38

liver and heart

Front 39

What are the major reasons we do not see major outbreaks of Chagas in the United States?

Back 39

-US homes--no place for reduviid to next
-local reduviid has delayed defecation --> reduced inoculation.

Front 40

Both Leishmaniasis and chronic Chagas are characterized by intracellular amastigotes. How to tell them apart?

Back 40

Leishmaniases: ONLY in macrophages!

Chagas: amastigotes may be in tissue cells, not just macrophages.

Front 41

What determines whether one gets cutaneous, mucocutaneous, or visceral Leishmaniasis?

Back 41

Immune system status.

cutaneous: intact immune system.

no immune system --> progresses to other forms

Front 42

What infections have been associated so far with immune suppression?

Back 42

Kala Azar (visceral Leishmaniasis)

Acute Chagas

Recurring Giardiasis

Front 43

What is the major morphological difference between Trypanosoma cruzi and Rangeli?

Back 43

T. rangeli: kinetoplast less apical than T. cruzi

Front 44

What harmless commensal overlaps geographically with and appears similar to T. cruzi?

Back 44

T. rangeli

cross-reacts serologically as well.

Front 45

Why have we not observed leishmaniasis outbreaks in the USA?

Back 45

USA phlebotomine (sand fly) is zoophilic. doesn't bite humans much.

Front 46

Describe symptoms of cutaneous leishmaniasis. When does cutaneous form occur?

Back 46

painless, well-demarcated ulcers w/small "satellite" papules

secondary bacterial infections sometimes

occurs when immune system is intact.

Front 47

Describe symptoms of mucocutaneous leishmaniasis. When does mucocutaneous form occur?

Back 47

hematogeneous spread of cutaneous form due to immune suppression

migrates to and colonizes cooler extremities of face, moves downward into chest

tapir nose = destroys cartilage
eats hole in roof of mouth (palate)
advanced stage: destroy larynx, fibrous tumors in pharyngeal (throat) area, invade bronchioles

Front 48

Describe symptoms of visceral leishmaniasis (kala-azar). When does visceral form occur?

Back 48

NO cellular immune response to Leishmania spp.

invade all macrophage systems: liver, spleen, bone marrow --> hepatomegaly, splenomegaly

severe muscle wasting, distended abdomen due to enlarged organs

100% mortality

Front 49

How to dx leishmaniasis?

Back 49

cutaneous: skin scrapings, biopsy, culture

mucocutaneous/visceral: bone marrow aspirates, serology (ELISA)

Front 50

Suggestions for control of leishmaniasis?

Back 50

CANNOT eradicate b/c too many animal reservoirs

AVOID GOING OUT AT NIGHT! Sand Flies active at night!

plant high grass around house
use bed nets
35% DEET insect repellent

Front 51

Reservoirs of Leishmania spp?

Back 51

humans (India)
dogs (Mediterranean)
wild canines (France)
tons of other stuff (S. America)