Protozoa Flashcards Preview

Parasitology > Protozoa > Flashcards

Flashcards in Protozoa Deck (222):
1

How are Protozoa classified?

Kingdom Protista - eukaryotic

2

What type of cell are Protozoa?

Single celled animals (unicellular).

3

Are all Protozoa pathogenic?

No. Most are free-living and non-pathogenic.

4

Are Protozoa parasitic?

They can be.

5

What is the anatomy of Protozoa?
-Nucleus

1. Membrane-bound nucleus (eukaryotic)

6

What is the anatomy of Protozoa?
-Locomotion

1. Pseudopodia
2. Cilia
3. Flagella

7

Pseudopodia

-False feet.
-Cells have NO definite shape.
-Amoeba

8

Cilia

-Tiny hair-like projections that cover the entire body, or just part (one side).
-Found ONLY in trophozoite stages.
-Ciliates

9

Flagella

-Long whip-like structures.
-May be one or several, ONLY found in trophozoite stages.
-Flagellates

10

Are Protozoa sexual or asexual?

May be either, or they may alternate between the two.

11

Asexual reproduction in Protozoa.

1. Sometimes by binary fission.
2. Sometimes by schizogony.

12

Schizogony
3 Stages

1. Multiple fission.
2. Undergoes multiple mitoses to form a multi-nucleated schizont.
3. Schizont bursts and releases multiple new organisms (merozoites).

13

What two things do most Protozoa have?

Most have two morphological forms.
-Trophozoite
-Cyst

14

Trophozoite

-This is the feeding and reproduction stage.
-Live and reproduce inside the host.

15

Cyst

-Dormant stage.
-Survives in the environment.
-Infective to new host (usually by ingestion)

16

Which morphological form of Protozoa are the diagnostic form?

Cysts
-They come out in the feces.

17

Which morphological form of Protozoa do we not usually see?

Trophozoite

18

What is the common life cycle of Protozoa?

1. Host ingests cyst.
2. In host, cyst undergoes excystment.
3. Develops into trophozoites in host body.
4. Usually, trophozoites encyst before leaving the host body.
5. Therefore, new cysts enter the environment and wait to infect a new host.
6. Some life cycles get more complicated.

19

What does excystment mean?

Organism comes out of, or EXITS, the cyst and starts to grow.

20

What does encystment mean?

Organism forms, or ENTERS into, a new cyst.

21

What are the 4 subphyla of Phylum Sarcomastigophora?

1. Sarcodina
2. Ciliaphora
3. Mastigophora
4. Apicomplexa

22

What are Sarcodina called?

Amoebas

23

What do Amoebas look like?

No defined shape.

24

How do Amoebas feed and move?

By pseudopodia.

25

Where are Amoebas common?

They are common in water and most soil. Most of them do NOT cause disease.

26

What are the 4 steps in the life cycle of Amoebas and Ciliates?

1. Cysts are ingested by drinking fecal contaminated water, or ingesting fecal contaminated material.
2. Excystment in intestines produces trophozoites.
3. Trophozoites reproduce by binary fission inside the host.
4. Trophozoites and cysts are shed in feces.

27

What happens to trophozoites and cysts after they have been shed in the feces?

-Trophozoites die very quickly in the environment.
-Cysts survive to infect another animal.

28

What disease to Amoebas cause?

Amebiasis

29

What is one example of an Amoeba that can infect animals?

Entamoeba spp.

30

What are Ciliaphora called?

Ciliates

31

What do Ciliates do in the trophozoite stage?

Use cilia for locomotion and/or feeding.

32

What is it rare to see in the feces with Ciliate infection?

Cysts

33

What is usually seen in the feces with Ciliate infection?

Trophozoites

34

How is Ciliate infection dx'ed?

Presence of trophozoites in the feces.

35

What do you have to do to see trophozoites when Ciliates are suspected?

-MUST use fresh stool sample since trophozoites die quickly.
-May have to use direct smears instead of fecal floatations.

36

What one example of a Ciliate that can cause infection in animals?

Balantidium coli

37

What are Mastigophora called?

Flagellates
-mastigophora means whip-bearer.

38

What do flagellates posses?

They are protozoa that posses at least one long flagellum.

39

What is the flagellum normally used for?

Movement

40

Are all flagellates alike?

No.
-They are highly variable in shape and life cycle.
-About the only thing they have in common is flagella.

41

What are the 2 types of parasitic flagellates?

1. Hemoflagellates
2. Mucosoflagellates

42

Where do Hemoflagellates live?

In the blood, lymph, and tissue fluid.

43

How are Hemoflagellates usually transmitted?

Blood-sucking insects.

44

Are Hemoflagellates important in veterinary medicine.

No

45

What do Trypanosomes cause in humans?

Sleeping sickness.

46

Where do Mucosoflagellates live?

Digestive or genital tract.

47

How are Mucosoflagellates transmitted?

Feces or genital fluid.

48

Are Mucosoflagellates zoonotic?

Yes

49

What is one example of Mucosoflagellates?

Giardia spp.

50

Infective forms of Apicomplexa are characterized by?

An ornate complex of organelles at their apical ends.

51

The most complex and diverse group of Protozoans is?

Apicomplexa

52

Do Apicomplexa have complex or simple life cycles?

They all have complex life cycles.

53

What is another name for Apicomplexa?

Sporozoa

54

What are sporozoites?

Nonmotile cyst-like shapes. They look like commas inside an oocyst.

55

What is the infective form in Apicomplexa?

Sporozoites

56

What are all Apicomplexa parasites of?

Animals

57

What are the most important veterinary parasites?

Coccidia

58

Where do Coccidia usually grown in the host?

The intestines.

59

Coccidia cause a form of enteritis called?

Coccidiosis

60

How is Coccidia transmitted?

Fecal-oral route.

61

What are 6 examples of Coccidia?
TBS ICE

T oxoplasma gondii
B abesia canis
S arcocystis spp.

I sospora spp.
C ryptosporidium spp.
E imeria spp.

62

TYPICAL COCCIDIA LIFE CYCLE
Where do the sporozoites live in the host?

The intestines.

63

TYPICAL COCCIDIA LIFE CYCLE
What does the sporozoite grown into? What does this form look like?

A trophozoite. These are amoeboid looking.

64

TYPICAL COCCIDIA LIFE CYCLE
How do trophozoites reproduce?

By schizogony to produce many merozoites.

65

TYPICAL COCCIDIA LIFE CYCLE
What is schizogony?

Multiple division within the cell. The cell bursts and releases many merozoites.

66

TYPICAL COCCIDIA LIFE CYCLE
What do merozoites look like?

Comma, or banana shaped.

67

TYPICAL COCCIDIA LIFE CYCLE
What do merozoites do?

Escape the host cell and enter other host cells in the intestines. They lyse the host cell in the process.

68

TYPICAL COCCIDIA LIFE CYCLE
After the merozoites invade a new cell, what do they do?

Divide more and form male and female gametocytes.

69

TYPICAL COCCIDIA LIFE CYCLE
What do the gametocytes do?

They fuse to form zygotes.

70

TYPICAL COCCIDIA LIFE CYCLE
What do the zygotes do after they have been formed by the gametocytes?

Produce sporozoite-filled oocysts.

71

TYPICAL COCCIDIA LIFE CYCLE
What happens to the oocysts after the zygotes produce them?

They are excreted from the host in the feces.

72

TYPICAL COCCIDIA LIFE CYCLE
After the oocysts have been excreted in the feces, what happens to them?

They are ingested by the new host.

73

TYPICAL COCCIDIA LIFE CYCLE
Do all coccidia complete their life cycle in one host?

No. Some require 2 hosts.

74

What is Entamoeba histolytica?

Coccidia that are Sarcodina (amoebas).

75

What does Entamoeba histolytica do?

Causes intestinal amebiasis (amebic dysentery). AKA: montezooma's revenge

76

What are the hosts in Entamoeba histolytica?

-Mainly dogs.
-Also infects cats, humans, and others.

77

In what host is Entamoeba histolytica the most serious?

In humans.

78

Are Entamoeba histolytica host specific.

No

79

Where is Entamoeba histolytica usually found?

In water (ponds, streams) and moist soil.

80

What does Entamoeba histolytica do to the host?

Damages intestines and causes ulcers in the colon.

81

What are the symptoms of Entamoeba histolytica?

Diarrhea with abdominal pain, blood in the stool.

82

Is Entamoeba histolytica zoonotic?

Occasionally. Most of the time dogs, and cats catch it from humans. Fecal-oral.

83

How is Entamoeba histolytica diagnosed?

By finding cysts or trophozoites in the feces (mostly cysts).

84

What may you need to do to find trophozoites in Entamoeba histolytica infection?

Use direct smear instead of fecal float, since they do not survive well outside the host.

85

What is Balantidium coli?

Coccidia that are Ciliaphora (ciliates).

86

What is the importance of Balantidium coli?

It is the only really important ciliate.

87

How big is Balantidium coli?

Very large, 30-150 micrometers.

88

What is the host for Balantidium coli?

-Humans
-Pigs
-Other animals

89

In what host is Balantidium coli the most serious?

In pigs. It infects their large intestine.

90

What are the symptoms of Balantidium coli?

Similar to Entamoeba spp. Diarrhea with abdominal pain, blood in the stool.

91

Is Balantidium coli zoonotic?

Possibly, however it seems that different strains often infect humans and pigs.

92

What is Giardia lamblia?

Coccidia that are Mastigophora (flagellates).

93

What is another name for Giardia lamblia?

Beaver fever.

94

What does Giardia lamblia cause?

Giardiasis in a wide variety of hosts.

95

What is Giardia lamblia more damaging than, and why?

Balantidium coli and Entamoeba histolytica. It is more damaging to the intestinal wall.

96

Is Giardia lamblia serious?

Yes. It can be a very severe infection.

97

Is Giardia lamblia chronic or acute, who is it common in?

It causes chronic disease that is common in dogs and cats.

98

What are the symptoms of Giardia lamblia?

The only symptom may be weight loss. However, it often cause chronic diarrhea.

99

What do the feces look like with Giardia lamblia infection?

Diarrhea - soft feces with mucus, not watery.

100

Is Giardia lamblia zoonotic?

Yes

101

How is Giardia lamblia transmitted?

Fecal-oral.

102

How is Giardia lamblia diagnosed?

There are both Elisa and snap tests.

103

What do Giardia lamblia trophozoites look like?

Very characteristic.
-Two nuclei look like eyes.
-Tear drop shaped.
-4 pairs of flagella.

104

What do you need to be able to see Giardia lamblia in the stool?

Fresh feces, direct smears.

105

Is is possible to see cysts in the feces with Giardia lamblia?

The cysts are only shed intermittently, and they are very hard to find.

106

What is Toxoplasma gondii?

Coccidia that are Apicomplexa (sporozoan).

107

What does Toxoplasma gondii do?

Causes enteric coccidiosis.

108

What are the hosts of Toxoplasma gondii?

Cats are the only known definitive hosts. They are the main reservoir in the environment.

109

Why is it important that Toxoplasma gondii is mainly present in cats?

They are the only ones it can undergo sexual stages in. Almost any animal can host the asexual stages.

110

Aside from cats, can other animals be infected with Toxoplasma gondii?

Most animals can be, including birds and humans.

111

What is the life cycle of Toxoplasma gondii in other animals?

1. Infective oocyst is ingested.
2. Oocysts rupture in host intestine and release sporozoites.
3. Sporozoites multiply in the intestines and spread to all tissues including brain, muscle, and liver.

112

Once Toxoplasma gondii has spread to tissue in animals, what happens?

It remains there for life embedded in the muscle as a cyst. They are infective if uncooked meat is eaten.

113

What is the life cycle of Toxoplasma gondii different in cats?

In cats, development continues. Sporozoites undergo sexual reproduction to form oocysts.

114

What happens to Toxoplasma gondii in cats once the oocysts have formed?

Cats shed the oocysts in their feces intermittently.

115

What are the symptoms in animals of Toxoplasma gondii?

Transient diarrhea.

116

Do humans infected with Toxoplasma gondii get sick?

-Most healthy humans have no symptoms.
-Some develop disease.

117

What are the symptoms of disease in humans infected with Toxoplasma gondii?

-Fever
-Symptoms of pneumonia, mono, hepatitis, or myocarditis.
-Usually self limiting.

118

When is Toxoplasma gondii dangerous to humans?

When a pregnant mother contracts it. It is very dangerous to the fetus.

119

What does Toxoplasma gondii do to a human fetus?

Causes death, congenital malformation, and mental retardation.

120

What percentage of humans test positive for Toxoplasma gondii?

About 60%.

121

In what two ways is Toxoplasma gondii transmitted?

1. Fecal-oral
2. Ingesting undercooked or raw meat.

122

How many Toxoplasma gondii oocysts can a cat excrete in a day?

Up to 10 million!

123

How long do Toxoplasma gondii oocysts survive outside the host?

May survive for many months in the environment.

124

How is Toxoplasma gondii diagnosed?

By the presence of oocysts in the feces (intermittent).

125

What is Babesia canis?

Coccidia that are Apicomplexa (sporozoan).

126

Babesia spp. is very?

Host specific.
-Canis infects dogs.
-There are species that infect just cows, and just horses as well.

127

Where does Babesia canis live?

In the red blood cells of the dog.

128

What is another name for Babesia canis?

-Canine piroplasm or piroplasmosis.
-Babesiosis

129

What is the host for Babesia canis?

The dog is the only host.

130

What is the intermediate host for Babesia canis?

The brown dog tick (Rhipicephalus spp.)

131

What is the life cycle of Babesia canis?

1. Dog is bitten by tick carrying it in salivary glands.
2. Tick injects Babesia canis into blood.
3. Trophozoites enter dogs rbc's and reproduce asexually to produce merozoites.
4. Infected rbc's burst and release organisms.
5. If another tick bites the dog, it can then pick up the organism and infect another dog.

132

The symptoms of Babesia canis vary in what way?

Symptoms can be subclinical, to mild, to very serious hemolytic crisis.

133

What is almost always seen in Babesia canis infection?

Some anemia.

134

What are the symptoms of Babesia canis in most cases?

-Weakness
-Hemolytic Anemia
-Hypochromic Anemia
-Pale mucus membranes (anemia)
-Fever
-Enlarged lymph nodes and spleen

135

What is hypochromic anemia?

Lower levels of hemoglobin in the RBC's.

136

Is Babesia canis infection fatal?

It can be.

137

In what two ways is Babesia canis transmitted?

1. Brown tick bite.
2. Transplacental transfer.

138

What does Babesia canis cause in puppies?

It is a cause of fading puppy disease.

139

How is Babesia canis diagnosed?

By seeing trophozoites in erythrocytes in stained blood smear.

140

How is Babesia canis treated?

With antiprotozoal drugs. This only decreases the symptoms.

141

Can Babesia canis be eliminated from an infected dog?

No, it can only be controlled. The disease can reoccur at any time in the dog's life.

142

Once a dog has been infected with Babesia canis what can you no longer use its blood for?

Transfusion

143

How is Babesia canis prevented?

Tick control.

144

Is there a vaccine for Babesia canis?

Yes (in the US), but it is not that effective.

145

Is Babesia canis zoonotic?

It is considered to be zoonotic by ticks.

146

Is Babesia infection serious in humans?

No

147

There are species of Babesia that?

Infects almost all animals. They are all host specific.

148

What is Sarcocystis cruzi?

Coccidia that are Apicomplexa (sporozoan).

149

How many hosts does Sarcocystis cruzi utilize?

It utilizes both a definitive and intermediate host.

150

What are the definitive hosts for Sarcocystis cruzi?

Always a carnivore.
-ex: dog, cat

151

What are the intermediate hosts for Sarcocystis cruzi?

Always an herbivore.
-ex: rodent, ruminant

152

What type of life cycle does Sarcocystis cruzi have?

An indirect since it uses both a definitive and intermediate host.

153

The life cycle for Sarcocystis cruzi is _____?

complicated

154

What is the life cycle (Intermediate host) for Sarcocystis cruzi?

1. Intermediate host ingests oocyst.
2. Schizogony takes place in host (bradyzoites released).
3. Cysts form in muscle and other tissue.

155

What is the life cycle (definitive host) for Sarcocystis cruzi?

1. Definitive host eats infected meat from intermediate host.
2. Reproduces and forms oocysts in intestine.
3. Host then excretes oocysts in feces.

156

What does an oocyst contain?

A sporocyst which contains sporozoites.

157

In addition to oocysts, what else can a definitive host infected with Sarcocystis cruzi shed in their feces?

Sporocysts, though oocysts are what is primarily shed.

158

What do you see with dogs and cats (definitive host) infected with Sarcocystis cruzi?

Usually no disease is seen.

159

What do you see with farm animals (intermediate host) infected with Sarcocystis cruzi?

-Infections are common.
-usually no disease, though it may cause abortions, fever, anorexia.

160

What happens to meat when Sarcocystis cruzi cysts are seen?

The meat is condemned.

161

What is the importance of Sarcocystis cruzi infection?

It has economic importance since the meat is condemned.

162

Is Sarcocystis cruzi zoonotic, if so, what does it do?

Yes, when humans ingest uncooked or undercooked infected meat they may develop an intestinal illness for about 48 hours.

163

How long after ingesting Sarcocystis cruzi contaminated meat does the definitive host begin producing oocysts in feces?

11 to 14 days.

164

How is Sarcocystis cruzi infection diagnosed in dogs and cats?

The presence of oocysts in feces.

165

How is Sarcocystis cruzi infection diagnosed in farm animals?

Usually by finding cysts in meat after slaughter.

166

How is Sarcocystis cruzi treated/prevented?

It is usually untreated. It can be prevented by not feeding raw flesh to dogs and cats.

167

What is Sarcocystis neurona?

Coccidia that are Apicomplexa (sporozoan).

168

What does Sarcocystis neurona cause?

Equine Protozoal Myelitis (or Myeloencephalitis) EPM

169

Sarcocystis neurona is the most important cause of?

Neurological disease in horses, and is the most common.

170

What can Sarcocystis neurona infect in horses?

The brain and spinal cord (CNS).

171

What is the only definitive host for Sarcocystis neurona?

The opossum.

172

What is the life cycle of Sarcocystis neurona?

1. Opossum sheds infective sporocysts in feces.
2. Intermediate host ingests (fecal-oral)
3. Cysts develop in muscle of intermediate host.
4. Opossum eats meat from intermediate host and becomes infected.

173

What are the intermediate hosts for Sarcocystis neurona?

-Cats
-Skunks
-Armadillos
-Beavers
-Others

174

How does a horse become infected with Sarcocystis neurona?

Most likely by ingestion of contaminated feed or water.

175

What type of host are horses infected with Sarcocystis neurona?

Accidental, dead end hosts (aberrant).

176

What must the Sarcocystis neurona organism do to cause disease in the horse?

It must migrate to the brain or spinal cord (CNS).

177

Do all Sarcocystis neurona infected horses become sick, why?

No, because it is not always able to migrate to the DNS. ~22%-65%

178

What is the major symptom of Sarcocystis neurona infection in horses?

Ataxia

179

What are the other symptoms of Sarcocystis neurona in horses?

-Muscle Loss
-Difficulty Swallowing
-Possible Blindness

180

How is Sarcocystis neurona diagnosed?

Definitive diagnosis is very difficult to do in a living horse, usually done at necropsy. It can be tentatively diagnosed based on symptoms.

181

What is the treatment for Sarcocystis neurona?

Drug therapy is effective, especially if started early.

182

What is the rate of relapse of Sarcocystis neurona?

It is high, about 25%.

183

What happens once a horse has been infected with Sarcocystis neurona?

They never seem to recover full function of muscles.

184

How is Sarcocystis neurona prevented?

Eliminate opossums from feed storage areas and stable areas.

185

Is there a vaccine for Sarcocystis neurona?

Yes, and it is effective.

186

What is Cryptosporidium spp.?

Coccidia that are Apicomplexa (sporozoans).

187

Is Cryptosporidium spp. host specific?

Much less so than the other Coccidians.

188

In what animal does Cryptosporidium spp. infect the epithelia?

-Mammals
-Birds
-Reptiles
-Fish

189

Cryptosporidium spp. is intestinal in?

Mammals

190

Cryptosporidium spp. can infect what in birds?

Bursa and respiratory tract.

191

What type of parasite is Cryptosporidium spp. to humans?

Opportunistic
-especially to young children and immunodeficient (AIDS).

192

Does Cryptosporidium spp. need more than one host to complete its life cycle?

No. Both sexual and asexual stages can be completed in one host (direct life cycle)

193

What is the life cycle of Cryptosporidium spp.?

1. Oocysts are ingested by host.
2. Sporozoites excyst and invade epithelial cells (of intestines or respiratory sys in birds).
3. Undergo schizogony to produce many merozoites.
4. Merozoites undergo sexual reproduction to produce oocysts.
5. Oocysts are shed in feces.

194

How long does the Cryptosporidium spp. life cycle take to complete in the host?

5 days.

195

What are the symptoms of Cryptosporidium spp.?

-Water diarrhea in most animals. This can cause dehydration and weight loss.
-May be respiratory in birds.

196

Is Cryptosporidium spp. zoonotic?

Yes. It causes severe diarrhea for 1-2 weeks in humans. Severe fluid and weight loss.

197

How is Cryptosporidium spp. transmitted?

Fecal-oral.

198

How is Cryptosporidium spp. diagnosed?

The presence of oocysts in feces.

199

How is Cryptosporidium spp. infection treated?

-Rehydration and supportive therapy.
-Anticoccidial drugs in some patients.

200

What is Isospora spp.?

Coccidia that are Apicomplexa (sporozoans).

201

In what hosts of Isospora spp. is disease less serious?

-Dogs
-Cats
-Horses
(almost all have it at lease once in life)

202

In what hosts of Isospora spp. is disease very serious?

-Cattle
-Sheep
-Goats
-Pigs
-Poultry
-Rabbits

203

What is the life cycle of Isospora spp.?

1. Oocysts are ingested.
2. Sporozoites invade intestinal mucosa.
3. Schizogony produces many merozoites.
4. Merozoites infect and destroy other intestinal cells.
5. Undergo sexual reproduction to form new oocysts.
6. Oocysts excreted in feces.

204

What type of life cycle does Isospora spp. have?

Usually direct. Some of them may use transport hosts.
-ex: mouse ingests oocyst, becomes a cyst in muscle tissue of mouse, eaten by dog or cat and they become infected.

205

What the are the symptoms of Isospora spp.?

-Diarrhea
-Fever
-Loss of appetite
-Weight loss
-Emaciation

206

What can Isospora spp. do in severe cases?

Hemorrhagic enteritis.
-especially in puppies.

207

Isospora spp. can be fatal in?

-Puppies
-Kittens
-Cattle
-Sheep
-Goats
-Poultry
-Rabbits

208

Is Isospora spp. zoonotic?

Yes

209

How is Isospora spp. treated?

-Rehydration and supportive care.
-Anticoccidial drugs in some cases.

210

Isospora spp. infection is usually?

Self limiting in a few weeks.

211

How is Isospora spp. prevented?

Hygiene to prevent fecal oral transmission.

212

What is Eimeria spp.?

Coccidia that are Apicomplexa (sporozoan).

213

What is Eimeria spp. similar to?

Isospora spp.

214

How is Eimeria spp. different from Isospora spp.?

It does not infect dogs and cats.

215

There is a species of Eimeria spp. to?

Infect any animal from fish, to poultry, to reptiles, to large animals, to humans.

216

Eimeria spp. is the most abundant coccidian with at least how many species?

1500

217

What does Eimeria spp. tend to have on the oocyst?

It tends to have a cap on the end.

218

Which species of Eimeria spp. is the most common?

Eimeria bovis. Pretty much every cow gets it once.

219

Are Eimeria spp. host specific?

Yes, they do tend to be.

220

Eimeria spp. can be very dangerous in which animal?

Chickens.

221

List the 7 Apicomplexa discussed in class.
BISECTS

-B abesia canis (in blood)
-I sospora spp.
-S arcocystis cruzi
-E imeria spp.
-C ryptosporidium spp.
-T oxoplasma gondii
-S arcocystis neurona

222

What are the 3 Protozoa that we discussed in class that are NOT Apicomplexa? Give name and subphylum.
BEG

-B alantidium coli (Ciliaphora / Ciliate)
-E ntamoeba histolytica (Sarcodina / Amoeba)
-G iardia lamblia (Mastigophora / Flagellate)