Balantidium & Cryptosporidium Flashcards

1
Q

first recognized in two humans with dysentery in 1857

A

Balantidium coli

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2
Q

only ciliated protozoan known to infect humans

A

B. coli

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3
Q

largets protozoan infecting humans and non-human primates

A

Balantidium

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4
Q

vehicle of Balantidium for most cases

A

water

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5
Q

T or F. Balantidiosis is a zoonotic disease

A

T

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6
Q

definite host of Balantidium

A

porcein
- asymptomatic in pigs and humans
- can be found wherever pigs are found
- human to human may occur but RARE

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7
Q

biology and life cycle of B. coli

A
  • unicellular trophs covered in cilia (longitudinal wavelike motion); 30 to 150 um by 25-120um
    > vestibule is anterior portion of mouth
    > cytostome is the mouth
    > cytophage = anus where waste is discharged
    > macronucleus = shaped like large sausage; non-reproductive functions like feeding and metabolism
    > micronucleus = small organ that sits below macronucleus; genetics and cell division
  • cyst
    > transmissive stage (40 to 60 um in diameter)
    > tough membrane (formed as trophs move down intestines
    > can survive dessication & environmental stage
    > survives best in human surroundings protected from sunlight
    > bacteria and food particles and RBCs main food source
    > no nuclear/cytoplasmic division
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8
Q

T or GF. Micronucleus of B. coli is easily seen on the microscope

A

F

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9
Q

where can B. coli cysts be seen?

A

in formed stool; macronucleus = thick double wall; transmittive stage

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10
Q

how does B. coli reproduce?

A

asexual = transverse fission; occurs for most ciliates

sexual = conjugation followed by binary fission
> role of macro- and micronucleus here
> during binary fission= exchange of micronuclear material; macro will disintegrate during conjugation; new one formed by micronucleus => binary fission will then occur
- two sizes of trophs (large and small) are formed during conjugation; never bw same sizes

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11
Q

simple life cycle of B. coli

A
  • ingestion of contaminated food or water
  • hatching of parasite
  • gut invasion of parasite
  • encystation of trophs
  • excretion of cysts
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12
Q

B. coli = lesions formed due to ulcers in colon

A

forms flask shaped lesions in submucosa
= form clusters which are referred to as nides or nes

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13
Q

lumen dwellers

A

B. coli
- cecum and colon

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14
Q

gut wall invasion of B. coli produces this enzyme

A

hyaluronidase
- degrades intestinal tissue & digests hyaluronic acid = glue that holds mucosal epi cells together
- during invasion = bacterial and inflammatory rxn occur
- mucosa ulcers and subsurface abscesses form
- mucosa and submucosa are damaged
- muscular layer also affected =hemorrhage and necrosis

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15
Q

extraintestinal invasion of B. coli

A
  • may include appendix
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16
Q

T or F. B. coli produces many toxins that help with pathogenesis

A

F! does not produce any known toxins

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17
Q

symptomatology of B. coli

A
  • asymptomatic in humans and pigs
  • diarrhea -> dysentery (nausea, vomiting, or headache)
  • rarely appendicitis , UTI, vaginitis/cervicitis, peritonitis
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18
Q

B. coli reservoir

A

zoonotic disease
normal host (75% pigs)
also monkey, dog, cattle, sheep, rat
- high prevalence in poor rural areas such as Latin America, Philippines, etc.

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19
Q

how are humans affected by . coli

A
  • fecal oral-route
  • sewage sludge (human waste as fertilizer)

risk factors: pig farmers, slaughterhouse workers, vets, poor nutritional status, intestinal flora not normal, and also dependent on parasitic load, alcoholics, etc.

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20
Q

epidemics of B. coli

A

mental hospitals and prisons

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21
Q

B. coli diagnosis

A

stool microscopy (trophs more prominent than cysts (maybe difficult to ID; can be confused by other helminths))

tissue biopsy of colon

cultivation (grow between 20C to 40C)

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22
Q

prevention of B. coli

A

improved sanitation and hygiene for water and food supply

chlorine not effective against thick wall of B. coli cysts

prevent contamination of water source by pigs/human feces

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23
Q

treatment for B. coli

A

tetracycline
or metronidazole flagyl

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24
Q

minute coccidian parasite

A

Cryptosporidum
12 separate species
> 2 important for humans: C. hominis and C. parvum
> worldwide in distribution
> molecular characterization distinguishes human and domestic animal species

25
humans and monkeys Crypto
C. hominis
26
humans and cattle Crypto
C. parvum
27
two forms of Cryptosporidium
cyst stage - infective stage = oocyst = 4 sporozoites > thick and thin walled variety > thick = survive in stool > thin = burst in gut and infect internally troph stage - transitional stage (uninuclear) = sporozoites and merozoites to multinucleate meront
28
two types of meronts
type I = first asexual generation type II = develop from Type I produce micro- and macrogamonts (male and female --> goes o to produce zygote (pregnant cell)) > develop thick and thin walled oocyst => thin wall = other infection; thick => exit in feces)
29
where do Crypto cysts rest in the intestine?
villi
30
modified Kinyon stain
used for Crypto cysts
31
complicated life cycle of rypto
transmission = inhalation or containated water oocysts = 4 sporos = infective stage after ingestion = excystation = release of sporos leads to formation of trophs then first asexual cycle = meront type I = contains 6-8 meros type II = 4 merozoites => sexual cycle formation of gamonts = fertilization of macrogamont by the microgamonts (males) = zygote sporulating oocysts produced after zygote > thin walled = autoinfection > thick walled = exit host in feces
32
Cryptosporidium hosts
no one is safe! can be seen as zoonotic and "gum to bum" disease fish and snakes birds mice, rats rabbits, guinea pigs cats, dogs squirrels calves horses pigs sheep goats monkeys humans
33
pathology and pathogenesis of Crypto
- located in GI tract of epithelium and crypts of small intestine histological changes: - blunting/loss of villi - lengthening of crypts => cellular infiltration (plasma cells, neuts, macs and lymphs => development of diarrhea and cause infection
34
less common sites of infection of Crypto
stomach appendix colon rectum gall bladder pancreatic duct ?? pulmonary tree = certainty of disease/contam is not always clear > diarrhea with large fluid loss dehydration malabsorption in some patients
35
T or F. Crypto can be seen in sputum
T!
36
two syndromes of Crypto
1. immunocompetent host > children are the majority > incubation period = 1d to 1wk (or 30 d) > watery diarrhea > abdominal pain/bloating/gas/vomiting > low grade fever > duration is 1-2 wks or 1-2 months spontaneous resolution shedding of oocysts 8-50 days 2. immunocompromised *same as above** but more severe massive (8-20L/day) fluid loss malabsorption > duration is many months to years ; reversible as immunosuppression 3. pulmonary infection 4. other areas of G = cholangitis, pancreatitis, hepatitis
37
public health concern for Crypto
daycares and food handlers
38
geographical distribution of Crypto
- 5 continents - urban and rural - developing > develop countries newer molecular surveys = higher prevalence - Crypto seen more in non-breastfed infants - exposure vs asymptomatic excretion and immunity - seroprevalence studies = 15-90%
39
age distribution of Crypto
3 days to 95 yrs highest prevalence = <2yrs **daycare outbreaks**
40
sex distribution of Crypto
males less likely to get sick (based on relation to children; women care for kids more in general)
41
special groups high risk to Crypto
AIDS = high distribution no seasonality or may see higher % during spring esp. in climate like Canada that goes from winter to spring where you have runoff from melting of snow which can lead to contamination of water system
42
transmission of Crypto
- ingestion of oocysts (10 to 3000) > zoonotic > person to person (includes b/w sexual partners) > contaminated water (including swimming pools), food
43
number 1 source of transmitting Crypto
water = esp swimming pools
44
prevention of Crypto
ubiquitous so oocyst inactivation > exposure to temp below )c and above 65C for 30 mins > filtering driving water > 10% formol saline and 5% ammonia OR commerical bleach **no treatment can guarantee removal of oocyst**
45
diagnosis of Crypto
intestinal biopsy material = EM; could reveal meronts containing merozoites (asexual) OR gamonts containing micro and macrogametes (sexual stage)
46
specimen for Crypto
preserved stool = oocysts can be detected using special stains like mod acid-fast
47
duodenal string test
enterotest for Crypto > recovers oocysts
48
how to recover oocysts after enterotest
flotation and sedimentation - H&E to stain organisms lightly = appear as small round bodies on the mucosal surface - safranin-methylene blue - Giemsa - Auramine - Acridine orange (fluorescence)
49
what does mod. acid-fast stain crypto?
oocysts appear red
50
these are being used more routinely to diagnosis Crypto, but mainly for research purposes
PCR
51
flotation
parasites found at top of tube
52
sedimentation
formalin ethyl acetate sedimentation method = parasites found at bottom = bc sedimented and 3 other layers on top = ethyl acetate, debris, then formalin all three top layers removed only bottom layer where parasites should be is kept
53
T or F. Stool processing method used here is Flotation
F! We use formalin ethyl acetate sedimentation method
54
disadvantages of sedimentation
- some parasites can't withstand centrifugation > developmental and reproductive stages of protozoa - some parasites require longer/faster centrifugation ex: Cryptosporidia
55
purpose of sedimentation
to separate parasites from bulk of feces (undigested food) - concentrate parasites so less specimen needed for analysis
56
stain used for Crypto
modified Kinyon stain
57
T or F. Treatment is available for immunocompetent patients with Crypto
T! AIDS patients have no effective treatment for Crypto and must treat underlying HIV infection
58