Chapter 48 - Blood and Tissue Protozoa Flashcards
(53 cards)
1
Q
Plasmodium spp.
- what disease are they responsible for?
- what are the 5 species?
A
Malaria
- P. vivax (80% of infections)
- P. falciparum
- P. malariae
- P. ovale
- P. knowlesi
2
Q
Plasmodium spp.
- what is the vector?
A
- female anopheline mosquito
3
Q
Life Cycle of Plasmodium
- First 2 steps
- how does the illness enter the host?
- what organ is affected?
A
- Vector bites you, releasing sporozites into the puncture wound.
- Within an hour carried to the liver.
4
Q
Life Cycle of Plasmodium
- What step is the Preerythrocye?
- describe the steps in this cycle.
A
Preerythrocye or primary exoerythrocytic cycle
- Divide (Schizogony)
- Schizont—Is a trophozoite with dividing nuclei
- Mature schizont—Contains merozoites that invade RBCs.
- Exoerythrocytic merozoites
- Merozoite—Is the young trophozoite
5
Q
Life Cycle of Plasmodium: Erythrocytic Cycle
- Describe the two steps to this cycle.
- What part of the Plasmodium life cycle does this make up?
A
- Merozoites leave the liver and invade RBC and feed on hemoglobin
- mosquito then takes a blood meal of infected RBCs
- Last two steps
6
Q
Life Cycle of Plasmodium:
- define schizont
- what is a mature schizont?
- what are gametocytes?
A
- Schizont—Is a trophozoite with dividing nuclei.
- Mature schizont—Contains merozoites that invade RBCs.
- Gametocytes—Includes mature male or female merozoites
7
Q
Plasmodium vivax
- primary disease?
- where is the most common geographic location(s) for this disease?
A
- Causes benign tertian malaria.
- Is widely distributed in the tropics, subtropics, and temperate zones.
8
Q
Plasmodium vivax
- what are the main morphologic characteristics of this disease organism?
A
- Infection of young cells
- Enlargement of RBCs (one to two times the normal size)
- Schüffner dots
- Delicate ring
- Very amoeboid trophozoites
- Schizont containing 12 to 24 merozoites
9
Q
Plasmodium vivax
- can a patient relapse?
- what are paroxysms and how often to they occur?
- define hypnozoites.
A
- Relapses occur.
- Paroxysms are when the clinical signs manifest themselves in a patient.
- Paroxysms may cycle every 48 hours.
- Resting stages are called hypnozoites
10
Q
Plasmodium vivax
- what triggers the paroxysms?
A
- Occur when the schizont releases the merozoites
11
Q
Plasmodium vivax
- how often does the pathogen cycle through?
- what does that correspond with?
A
- Cycle 44-48 hrs.
- Corresponds with cycles of paroxysms
12
Q
Plasmodium vivax
- what are the cell stages of the life cycle?
A
- Early trophozite – ring form
- Schuffner dots-in all except very early.
- Trophozoite ameboid
- Schizont with TWELVE -
TWENTY-FOUR merozoites - Macro and microgametes
13
Q
Plasmodium ovale
- geographic range?
A
Geographic range is confined to central West Africa and some South Pacific islands
14
Q
Plasmodium ovale
- how does this change the morphology of the cells it infects/what does it look like under a microscope?
A
- Infection of young cells
- Enlargement of RBCs with fimbriated edges (oval)
- Early appearance of Schüffner dots
Smaller ring than P. vivax - Schizont containing EIGHT merozoites
15
Q
Plasmodium ovale
- relapses?
- paroxysm cycles?
A
- Relapses are possible but with spontaneous recovery.
- Paroxysms cycle every 48 hours
16
Q
Plasmodium ovale
- describe the morphology of the infected erythrocytes
- size
- edges
- shape
A
- 1.25x enlarged
- fimbriated
- oval
17
Q
Plasmodium ovale
- what do the trophs look like?
- describe the schizonts
- how many merozoites?
- color of pigment?
- pattern of schizonts?
- what shape are the gametocytes?
A
Trophs: compact
Schizonts:
- 6-14 merozoites
- dark pigment
- rosettes
- gametocytes are round-oval
18
Q
Plasmodium malariae
- type of malaria caused?
- geographic distribution?
A
- Causes quartan malaria
- associated with nephrotic syndrome
- Is sporadically distributed
19
Q
Plasmodium malariae
- infected RBC characteristics?
A
- Infection of older cells
- Normal-size RBCs
- No stippling
- Thick ring, large nucleus
- TROPHS that form “BANDS” across the cell
- Schizont containing 6 to 12 merozoites
20
Q
Plasmodium malariae
- relapses?
- define recrudescence
- how frequent are the paroxysm cycles?
A
- No relapses occur, but recrudescence is recognized.
- a new outbreak after a period of abatement or inactivity
- every 72 hours
21
Q
Plasmodium falciparum
- type of malaria caused?
- geographic distribution?
A
- Causes malignant tertian malaria.
- Is confined to tropical areas
22
Q
Plasmodium falciparum
- characteristics of infected cells?
A
- Invasion of all stages of RBCs (heavy parasitemia)
- Comma-like red dots (Maurer dots)
- Multiple ring forms, some appliqué forms
- Crescent-shaped gametocytes
23
Q
Plasmodium falciparum
- how often do fever cycles occur?
- relapses?
A
- Fever cycles every 36 to 48 hours.
- No relapses occur.
24
Q
Plasmodium falciparum
- where does schizogony occur?
- what happens to the organs infected?
A
- Schizogony occurs in spleen, liver, and bone marrow.
- Vessels of organs become plugged, causing fatal complications (e.g., black water fever).
25
Plasmodium falciparum
- describe the rings in the infected RBCs
- trophs - how often seen in peripheral smears
- rings are double chromatin dots, accole then forms, which allows for multiple infections in the same cell
- trophs are compact and rarely seen in peripheral blood
26
Plasmodium falciparum
- Gametocytes
- - two different forms?
- which is seen in peripheral blood?
- how many merozoites in a schizont?
- how often seen in peripheral blood?
- Gametocytes: mature form and immature form
- immature form rarely seen in peripheral blood
- 8-24 merozoites in a schizont
- - rarely seen in peripheral blood
27
Plasmodium knowlesi
- geographic location?
- what is the best way to detect?
- Is associated with forested areas of Southeast Asia.
| - Higher detection rate with PCR
28
Plasmodium knowlesi
- characteristics?
- - what do the early stages resemble?
- - what do the later stages resemble?
- stippling?
- chromatin?
- unique characteristic of the trophs?
- how many merozoites
- Early stages resemble P. falciparum and
- later/mature stages resemble P. malariae
- RBC’s are all sizes, no true stippling
- Multiple rings, with 2 to dots of chromatin
- Band forms with trophozytes
- Schizonts with 16 merozoites
29
Plasmodium knowlesi
- what is the gold standard for diagnosis?
- what type of specimen is preferred?
- how is it diagnosed in the field?
- Thick and thin blood films
- - 200 and 300 oil immersion fields are examined
- Giemsa or Wright stain is acceptable.
- EDTA
- Rapid malaria tests are now available (dipstick, cartridge).
30
Plasmodium knowlesi
- why is it hard to detect with automated instruments?
- what non-smear test is used?
- Automated instruments are not designed to detect intracellular parasites.
- Polymerase chain reaction (PCR) with specific deoxyribonucleic acid (DNA) probes is used
31
Plasmodium knowlesi
- treatment
- - drugs
- - what phase is being treated?
- why is it so hard to treat?
- Schizonticides, gametocytocides, and sporonticides are directed against relapses.
- Chloroquine-resistant P. falciparum is present in most endemic areas.
32
Babesia spp.
- mode of transmission
- what other protozoa life cycle does it mimic?
- what is the main difference?
- Is transmitted by ticks. Genus Ixodes.
- Has a life cycle similar to Plasmodium
- no exoerythrocytic stage
33
Babesia spp.
- how do trophs reproduce?
- what makes the ring forms unique?
- what makes the chromatin unique?
- Trophs reproduce by binary fission.
- Ring forms are pleomorphic. Can be outside erythrocytes.
- Maltese cross tetrads may be present
34
Babesia spp.
- what disease does it mimic?
- how is it diagnosed?
- Similar clinically to malaria
| - Diagnosis with thick and thin blood smears
35
Babesia vs. Plasmodium
- transmission
- hosts
- geographic locations
Babesia
- Is transmitted by ticks. Genus Ixodes.
- Infect wild and domestic animals
- Worldwide, US outbreaks around Cape Cod, LI, east coast Islands
Plasmodium
- Is transmitted by Anopheles mosquito
- Infects humans
- Tropics and subtropics, some temperate
36
Babesia vs. Plasmodium
- life cycle stages
- troph reproduction
- troph size
Babesia
- Has a lifecycle similar to Plasmodium spp., but no exoerythrocytic stage.
- Trophs reproduce by binary fission.
- Trophozoites are smaller than P. falciparum
Plasmodium
- Has an exo and endoerythrocytic stage.
- Troph reproduce by schizogony
37
Babesia vs. Plasmodium
- ring forms
- ring form location
- # of species
Babesia
- Ring forms are pleomorphic.
- Can be outside erythrocytes.
- Maltese cross tetrads may be present
- About 100 species
Plasmodium
- Inside the cell.
- Ringforms are uniform.
- 5 species
38
Babesia vs. Plasmodium
- symptoms
- diagnosis
Babesia & Plasmodium (same for both)
- Fever, chills, malaise, anemia, hepatosplenomegaly.
- Diagnosis with thick and thin blood smears
39
Trypanosoma spp.
- what type of protozoa are they?
- what is the common name for the diseases it causes?
- - how many types/what names are the subgroups of the diseases?
Hemoflagellate protozoa
Trypanosomiasis
- African sleeping sickness
- - East African
- - West African
- Chagas’ disease
- - American
- - Trypanosoma cruzi
40
Trypanosoma spp.
| - what are the three main features in an amastigote?
- nucmeus
- basal body
- kinetoplast
41
Trypanosoma spp.
| - what are the two additional features that a mature trypomastigote possesses?
- an undulating membrane
| - a flagellum
42
African sickness - East vs West:
- organism
- vector
- reservoir
East
- Trypanosoma brucei rhodesiense
- tsetse fly (morsitans)
- animals
West
- Trypanosoma brucei gambiense
- tsetse fly (palpalis)
- humans
43
African sickness - East vs West:
- illness time frame
- lymphadenopathy
East
- acute w/early CNS invasion, less than 9 months
- minimal
West
- chronic w/late CNS invasion, months to years
- prominent
44
African sickness - East vs West:
- parasitemia
- epidemiology
East
- high
- anthropozoonosis, game park
West
- low
- anthropozoonosis, rural populations
45
African sickness - East vs West:
- diagnostic stage
- recommended specimens
East and West (same for both)
- Trypomastigote
- chancre aspirate, lymph node aspirate, blood, CSF
46
African Trypanosomiasis
| - what is a unique feature that makes this challenging to treat?
- Unique feature is that they can change the antigenic surface coat of the outer membrane.
47
American Trypanosomiasis (Chagas’ Disease): T. cruzi vs T. rangell
- vector
- reservoir
T. cruzi
- reduviid bug
- opossums, dogs, cats, wild rodents
T. rangell
- reduviid bug
- wild rodents
48
American Trypanosomiasis (Chagas’ Disease): T. cruzi vs T. rangell
- symptomatic?
- recommended specimens?
T. cruzi
- symptomatic, can be acute or chronic
- blood, lymph node, aspirate, chagoma
T. rangell
- asymptomatic
- blood
49
```
American Trypanosomiasis (Chagas’ Disease): T. cruzi vs T. rangell
- diagnostic stage
```
T. cruzi
- blood:
- - Trypomastigote
- tissue:
- - amastigote
T. rangell
- blood:
- - Trypomastigote
- tissue:
- - none
50
Trypanosomiasis
| - what are the three stages?
- Amastigotes
- Trypomastigotes
- Epimastigotes
51
Leishmania spp.
| - Disease spectrum:
- Cutaneous lesions (flattened plaque or ulcer)
- Mucocutaneous infections
- Visceral involvement
52
Leishmania spp.
| Two phases:
- Amastigote—Intracellular parasite in humans
| - Promastigote—Form found in vector
53
Leishmania spp.
| - what are some common hospital and in-the-field diagnostic tests?
- Exudate from the lesion is smeared and stained.
| - A rapid dipstick test is also available for the detection of anti-Leishmania antibodies.
