Parasitology 4 Flashcards
1
Q
gametogony
A
process by which gametes are produced in protozoa; occurs when
merzoites entering red blood cells transform into gametocytes
2
Q
Macrogametocyte (female)
A
cell that gives rise to macrogametes
3
Q
Microgametocyte (male)
A
cell that gives rise to microgametes
4
Q
what type of cell fertilizes macrogametocyte?
A
Microgametocyte
5
Q
Sporozoite
A
daughter cell resulting from sporogony
6
Q
Trophozoite:
A
active, feeding stage of a protozoan, in contrast to a cyst
7
Q
Schizogony:
A
form of asexual reproduction in which multiple mitoses occur,
followed by simultaneous cytokinesis, resulting in many daughter cells at once
8
Q
Schizont:
A
in schizogony when nuclear divisions have occurred but not cytokinesis
9
Q
Meront:
A
asexual stage where protozoan undergoes schizogony to form
merozoites
10
Q
Merozoite:
A
daughter cell resulting from schizogony
11
Q
Ookinete:
A
motile, elongated zygote
12
Q
Sporogony:
A
multiple fission of a zygote
13
Q
When does Sprogonous phase begins?
A
when ookinete begins to develop
14
Q
Oocyst:
A
cystic form resulting from sporogony
▪ Gives rise to many sporozoites
15
Q
Which of the following stages in the Plasmodium life cyctle is associated with sporogony?
a. merozoite
b. oocyst
c. none of the above
d. trophozoite
e. hypnozoite
A
Oocyst
16
Q
What is the vector of Plasmodium spp.?
A
Female Anopheles mosquito
17
Q
what does RBC contain if they are infected with the Plasmodium spp,?
A
RBC contain male and female gametocytes; as temp falls both gametocytes mature
- 1) microgametocyte produces numerous microgametes; exflagellation
- 2) macrogametocyte matures to macrogamete that can be fertilized by
microgamete
18
Q
exoerythrocytic schizogony
A
Sporozoites invade parenchymal cells of liver
19
Q
Quotidian malaria:
A
24 hour fever cycle (erythrocytic cycle); overlapping infections
20
Q
Tertian malaria:
A
48 hour fever cycle
21
Q
Quartan malaria:
A
72 hour fever cycle
22
Q
Febrile:
A
having or showing signs of fever
23
Q
Paroxysms:
A
rapid onset or return of symptoms or increased intensity of symptoms
24
Q
Recrudescence:
A
reappearance of the disease after it has been quiescent
25
Parasitemia:
presence of parasites in the circulating blood
26
where (geography) are mostly P. Vivax found?
in Asia; common in North Africa, but drops off in tropical Africa
27
what group P. vivax invades?
young erythrocytes with Duffy blood groups; 2 codominant alleles and a third
- No Duffy blood group receptors on RBC, no infection
28
How many sporozoites can the P. Vivax oocyst can produce?
- Oocyst produces up to 10,000 sporozoites
- 10,000 merozoites released from liver cell
- Erythrocytic schizogony yields on average 16 merozoites
29
2) Which of the following confers resistance to Plasmodium vivax?
a. recrudescence
b. Sickle cell trait
c. presence of Duffy blood group
d. absence of Duffy blood group
e. none of the above
d. absence of Duffy blood group
30
5) Which of the following is a characteristic of Plasmodium falciparum?
a. Sickle cell trait confers resistance
b. accounts for 50% of all malaria
cases
c. sequestration occurs along
endothelium
d. 4 different pathways to invade RBCs
e. all of the above
e. all of the above
31
how do humans get infected with Plasmodium spp.
Blood meal mosquito
32
what type of malaria does P. vivax has?
benign tertian malaria - 48 hour fever cycle
33
what type of malaria does P. falciparum has?
(malignant tertian malaria): 48 hour fever cycle
34
Which plasmodium is the most virulent ?
P. falciparum
35
How much % of all malaria cases does P. falciparum represent?
> 50%
36
Which parasite does sickle cells trait (heterozygote) is resistant to ?
P. falciparum
37
Which parasite can invade RBCs by at least 4 different pathways?
P. falciparum
38
what is considered high level of parasitemia? which parasite is concerned?
more than 65% of RBCs, P. falciparum
39
what does P. falciparum trophozoite produce?
proteins, then get deposited on RBC surface, causes
| sequestration
40
where does sequestration occurs ? P. falciparum
along venular endothelium and other RBCs (cerebral
| malaria)
41
how many merozoites does P. falciparum can produce?
- 30,000 merozoites released from liver cell
| - Erythrocytic schizogony yields on average 20 to 24 merozoites
42
How long P. falciparum can recrudescence can be up to ?
3 years
43
what type of malaria is P. malariae?
(quartan malaria): 72 hour fever cycle
44
how many % of cases are P. malariae?
7%
45
which parasite can only invade aging RBCs (soon to be removed from circulation) ?
P. malaria
46
How long P. malariae can recrudescence can be up to ?
53 years
47
how can one be infected with P. malariae?
by blood transfusion
48
What is the rarest malaria parasite to humans?
P. ovale
49
How rare is P. ovale?
> 1%
50
What type of malaria is P. ovale?
(mild tertian malaria): 48 hour fever cycle
51
Why is P. ovale hard to dignose?
because of similarity to P. vivax
52
What are two general factors leading to most major clinical manifestation?
1) host inflammatory response producing characteristic chills and fever,
etc.
▪ Single acute day of fever requires approx.. 5,000 calories = 2 days
hard manual labor
- 2) anemia, arising from the enormous destruction of RBCs (iron bound in
hemozoin)
53
Timing of paroxysms of fever follows maturation of each generation of merozoites
- 1) typical attack begins with feeling of intense cold as hypothalamus is
activated
- 2) temperature rises rapidly to 104F to 106F
- 3) teeth chatter and intense shivering; nausea and vomiting are usual
- 4) hot stage begins 30 min to 1 hour later, with intense heating and
headache
- 5) often a mild delirium stage lasts for several hours
- 6) copious perspiration signals the end of the hot stage
- 7) temp drops back to normal in 2 to 3 hours
- 8) entire paroxysm is 8 to 12 hours
- 9) patient sleeps well until next episode
54
What are reservoir host for Plasmodium spp.?
tolerant individuals and primates
55
what is the transmission for Plasmodium?
- blood transfusion or sharing needles
| - Rare, infection of newborn from an infected mother
56
when does Babesia microti peaks in infecterion and where?
it happens in northeast and upper midwest, it peaks during warm months
57
what is the definitive host of Babesia microti?
black legged tick (Ixodes scapularis
58
what is the intermediate host of Babesia microti?
primarily white-footed mouse; zoonosis
59
How do you get primary kinete?
when a male and female gametes forms a zygote
60
What are symptoms of Babesia microti?
- -Healthy people are usually asymptomatic; some experience “flu-like symptoms”
- Babesiosis can result in severe pathogenicity in the following people:
- Splenectomized
- Compromised immune system (ex. Cancer, lymphoma, or AIDS)
- Elderly
- Complications include severe hemolytic anemia (hemolysis)
61
how to avoid being infected with Babesia microti?
- Avoiding exposure to tick infested habitats
- Use repellent on skin and clothing
- Limit the amount of skin exposure
- Walk in the center of trails
62
what type of infection is Cryptosporidium parvum?
worldwide distribution; opportunistic infection
63
what is the infectious stage of Cryptosporidium parvum?
oocysts containing 4 sporozoites
64
what type reproduction does Cryptosporidium parvum has?
asexual
65
how is Cryptosporidium parvum involved in autoinfection?
Thick walled oocyst excreted in feces; thin-walled oocyst involved in autoinfection
66
What is Cryptosporidium parvum target organs?
GI tact or respiratory tract
67
What are symptoms of Cryptosporidium parvum?
-The most common symptom of cryptosporidiosis is watery diarrhea
-Other symptoms include:
-Stomach cramps or pain
-Dehydration
-Nausea
-Vomiting
-Fever
-weight loss
-AIDS patients: Bowel Movement frequency 6-25; maximal stool volume 1-17 liters
-Lasts a few days to 4 or more weeks in immunocompetent individuals
Epidemiology:
-Swallowing contaminated recreational water (water park, public pool,
68
cryptosporidiosis
diarrheal disease from Cryptosporidium parvum
69
how do you get infected with Cryptosporidium parvum?
- Swallowing contaminated recreational water (water park, public pool, etc.)
- Eating contaminated uncooked food
- Touching surfaces contaminated by stools from an infected person
- Can be found in swimming pools
- people with decreased immunity are most at risk for severe disease
- Occurs in young children both immunocompetent and immunodeficient
70
how many cases of cryptosporidiosis occurs each year in US?
748,000 cases
71
What type of people does Toxoplasma gondii affect?
pregnant women
72
What the definitive host of Toxoplasma gondii ?
Felidae (domestic cats)
73
how long does oocysts of Toxoplasma gondii take fore being infectious?
takes 1-5 days to sporulate (infective)
74
what is the intermediate host of Toxoplasma gondii?
commonly include birds and rodents
75
tachyzoites in Toxoplasma gondii
Rapidly undergoes endodyogeny to form merozoites
76
bradyzoites in Toxoplasma gondii
Tachyzoites localize in neural and muscle tissue to form tissue cyst
77
how does the defenitive host get infected with Toxoplasma gondii?
- eating meat containing bradyzoites
- Eating food or water contaminated with tissue cysts
- Transplacentally from mother to fetus
- Blood transfusion or organ transplantation
78
Congenital toxoplasmosis
occurs when a pregnant woman becomes newly infected
-damage is more severe the earlier the transmission
May result in: miscarriage, stillborn child, abnormal development
79
symptoms of Toxoplasma gondii
Widely prevalent in human worldwide, but clinical toxoplasmosis is less common
- Healthy people usually asymptomatic; some experience “flu-like” symptoms
- Serious opportunistic infection of AIDS patients; continuous tachyzoite multiplication
80
What is the % of world population of being infected with Toxoplasma gondii?
-Estimated that over 25% of world population is infected; CDC approx. 60 million in US
81
what are the 3 stage of Naegleria Flowleri
trophozite, ameboid, and flagellate
82
how do you get infected with Naegleria flowleri?
Nasal passage, ameba's migrate along olfactory nerve into cranium
- drinking water can not infect human, even if the water is infected
83
What are the environmental condition for Naegleria flowleri?
warm fresh water
84
Where can Naegleria flowleri be found?
```
o Freshwater
o Soil
o Ponds, canals, and lakes
o Freshwater aquariums
o Sewage
```
85
what are the % fatality of Naegleria flowleri?
98% only 3 survivor out of 128 cases in U.S
86
What does Naegleria flowleri causes to human
primary amebic meningoencephalitis (PAM), acute, fatal diseases
- PAM is an acute, fulminant, and rapidly fatal diseases
87
What are Naegleria flowleri sensitive to ?
chlorine
