Protozoa (EXAM IV) Flashcards

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1
Q

Protozoa have typically been classified as:

A

Parasites

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2
Q

What is a parasite?

A

An organism that lives on or within another organism (the host) and benefits from the association while harming the host

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3
Q

Where does a parasite typically obtain its nutrients from?

A

Host

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4
Q

Types of parasites include:

A

Protozoa & Helminths

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5
Q

Protozoa can be described as a:

A

Diverse group of eukaryotic microbes

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6
Q

How are protozoa related?

A

Related only by their simple organization

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7
Q

The simple organization relating protozoa includes:

A

Unicellular or multicellular without specialized tissues

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8
Q

Most protozoa are ____ in ____ environments or on _____

A

free-living; aquatic; decaying organic matter

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9
Q

Some protozoa are considered _____

A

Parasitic

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10
Q

Many protozoa are capable of:

A

Encystation

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11
Q

Formation of a cyst:

A

Encystation

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12
Q

Formation of a cyst by protozoa involves a ______ state with:

A

resting state; with a wall & low metabolic activity

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13
Q

Describe the metabolic activity of protozoa during encystation:

A

Low metabolic activity

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14
Q

List the function of cysts: (3)

A
  1. Protection from changes in environment
  2. Sites for nuclear reorganization & cell division
  3. Transfer from one host to another
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15
Q

Escape from vegetative form from cyst:

A

Encystation

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16
Q

Encystation is usually triggered by:

A
  1. Return to favorable environment
  2. Entry into new host
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17
Q

What is the vegetative form released by parasitic species:

A

Trophozoite

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18
Q

Discuss the locomotion or protozoa:

A

Some are nonmotile some are motile

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19
Q

The motile species of protozoa use one of the following:

A

-Cilia
-Flagella
-Psuedopodia

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20
Q

Psuedopodia are:

A

Cytoplasmic extensions

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21
Q

Reproduction of protozoa may be:

A

Asexual or sexual

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22
Q

Asexual reproduction of protozoa typically occurs through:

A

Binary fission

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23
Q

Describe the binary fission:

A

Mitosis followed by cytokinesis

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24
Q

Sexual reproduction of protozoa typically occurs through:

A

Conjugation

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25
Q

Describe conjugation:

A

Exchange of gametic nuclei between paired protozoa of opposite mating types

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26
Q

Zooflagellates are motile due to:

A

One or more flagella

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27
Q

Species of protozoa that cause Giardiasis:

A

Giardia Lamblia

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28
Q

Giardiasis is a:

A

Gastrointestinal disorder

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29
Q

Species of protozoa that cause Trichomoniasis:

A

Trichomonas Vaginalis

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30
Q

Trichomoniasis is a:

A

Sexually transmitted disease

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31
Q

Hemoflagellates that are important blood pathogens:

A

Trypanosomes

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32
Q

Trypanosomes are:

A

Hemoflagellates (AKA blood parasites)

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33
Q

Give an example of a Trypanosome:

A

African sleeping sickness

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34
Q

Most common cause of epidemic waterborne diarrheal disease:

A

Giardiasis

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35
Q

Giardiasis is a _____ disorder

A

Gastrointestinal disorder

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36
Q

Giardia lamblia forms ____ & _____

A

Cysts & trophozoites

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37
Q

Giardia lamblia forms cysts & trophozoites. The trophozoites attach to _____ & interfere with ____

A

intestinal epithelium; nutrient absorption

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38
Q

Discuss the transmission of Giardia lamblia:

A

Cyst-contaminated water

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39
Q

Discuss the reservoirs of Giardia lamblia:

A

numerous animal reservoirs & asymptomatic carriers are common

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40
Q

The clinical manifestations of ________ include- severe diarrhea, epigastric pain, cramps, voluminous flatulence & anorexia:

A

Acute giardiasis

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41
Q

The clinical manifestations of _____ include- intermittent diarrhea with periodic appearance and remission of symptoms:

A

Chronic gastritis

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42
Q

What antiprotozoal agents are used for the treatment of giardiasis?

A

Metronidazole

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43
Q

How might one prevent contraction of giardiasis?

A

Avoiding contaminated water of puriy it by boiling or filtering (cysts are resistant to chlorine treatment)

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44
Q

The cysts formed in Giardia lamblia are resist to:

A

Chlorine treatment

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45
Q

One of the most common sexually transmitted diseases:

A

Trichomonas vaginalis

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46
Q

Trichomonas vaginalis is found in ____ % of women

A

15%

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47
Q

Trichomonas vaginalis lacks a ____ stage but does produce ____

A

Cyst stage; trophozoites

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48
Q

Discuss the clinical manifestations of Trichomoniasis:

A
  1. accumulation of leukocytes at site of infection
  2. In female, results in yellow purulent vaginal discharge and itching
  3. In males usual asymptomatic or burning urination
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49
Q

Discuss how we diagnose trichomonas vaginalis:

A

Observation of parasite in vaginal discharge, semen or urine

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50
Q

What is the treatment of trichomonas vaginalis:

A

Antiparasite therapy of metrodiazole

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51
Q

Resides in the mouth; usually associated with poor oral hygiene:

A

Trichomonas tenax

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52
Q

Trichomonas tenar aspiration is associated with:

A

Pneumonia

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53
Q

Hemoflagellate diseases are caused by:

A

flagellated protozoa

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54
Q

Two major groups of flagellated protozoa include:

A

Leishmanias & trypanosomes

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55
Q

Hemoflagellate diseases are transmitted by:

A

bites of infected arthropods

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56
Q

Hemoflagellate disease infect:

A

Blood & tissues of humans

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57
Q

Also called African sleeping sickness:

A

African trypanosomiasis

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58
Q

African trypanosomiasis is transmitted by:

A

Tsetse flies

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59
Q

The reservoirs of African trypanosomiasis include:

A

Domestic cattle & wild animals

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60
Q

African trypanosomiasis symptoms are characterized as:

A

Chronic bloodstream infections with bouts of parasitemia

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61
Q

what happens after months to years with African trypanosomiasis infection?

A

CNS invasion

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62
Q

The clinical manifestations of African trypanosomiasis include:

A

Interstitial inflammation and necrosis within lymph node and small blood vessels of brain & heart, leading to lethargy & death within 1 to 3 years

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63
Q

Disease characterized by interstitial inflammation & necrosis within lymph nodes and small blood vessels of brain & heart leading to lethargy & death in about 1 to 3 years:

A

African trypanosomiasis

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64
Q

Disease characterized by interstitial inflammation & necrosis within lymph nodes and small blood vessels of brain & heart leading to lethargy & death in about 1 to 3 years:

A

African trypanosomiasis

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65
Q

The causative agent of African trypanosomiasis is:

A

Trypanosoma Brucei

66
Q

How is African trypanosomiasis diagnosed?

A

observation of motile parasites in blood

67
Q

Treatment of African trypanosomiasis includes:

A

Drug therapy during systemic stage, but not as effective when CNS is involved

68
Q

Describe the vaccination for African trypanosomiasis:

A

Vaccine not useful due to antigenic variation

69
Q

Why is the vaccine for African trypanosomiasis not useful?

A

Due to antigenic variation due to genetic rearrangements

(multiple silent copeis & one expression locus)

70
Q

What is the intermediate host between animal reservoir and humans for African trypanosomiasis:

A

Tsetse fly

71
Q

What determines the disease range of African trypanosomiasis?

A

Tsetse fly

72
Q

American trypanosomiasis (Latin America; sporadic in southern USA)

A

Chagas disease

73
Q

Chagas disease is transmitted by:

A

Kissing bug (Reduviid bug)

74
Q

Reservoirs of Chagas disease include:

A

Domestic cattle & other animals

75
Q

In endemic regions, who is typically infected with chugs disease

A

Most people in population infected in childhood

76
Q

Describe the progression of chugs disease:

A

Early disease= mild; small % develop complications 10-20 years later

77
Q

When would individuals develop complications from chagas disease?

A

10-20 years later

78
Q

Chagas disease can result in heart disease and other disorder due to destruction of parasitize cells in the:

A

Liver, spleen, lymph nodes & CNS

79
Q

Chagas disease can result in heart disease & other disorders due to _____ in the liver, spleen, lymph nodes & CNS

A

Destruction of parasitized cells

80
Q

____ & ____ may occur in chagas disease due to damage to nerves in the GI tract

A

Megaesophagus & megacolon

81
Q

____ may occur in chagas disease due to damage to heart muscle

A

Cardiomyopathy

82
Q

Cardiomyopathy may occur in chagas disease due to damage to heart muscle, which may ultimately result in:

A

Sudden death from arrhythmia

83
Q

What is the treatment for Chagas disease?

A

No available for late complications; vaccines not useful due to antigenic variation

84
Q

Why are vaccines not useful against chagas disease?

A

Antigenic variation due to genetic switching

85
Q

What is causative agent of Chagas disease?

A

Trypanosoma cruzi

86
Q

Describe how the parasite is discharged in chagas disease:

A

Discharged in feces

87
Q

How does the vector enter the human body in chagas disease?

A

Enters the human body through bite wound

88
Q

Disease caused by Leishmania species (several, with different tissue tropisms):

A

Leishmaniasis

89
Q

Leishmaniasis is transmitted by:

A

Sandflies when they take a blood meal (usually tropical)

90
Q

What are the reservoirs for leishmania species?

A

Canines & rodents

91
Q

Leishmania survives & differentiated in:

A

Macrophages (superoxide dismnutase)

92
Q

The three forms of Leishmaniasis infection include:

A
  1. Mucocutaneous
  2. Cutaneous
  3. Visceral
93
Q

Form of leishmaniasis that involves lesions of the mouth, nose, throat & skin that cause extensive scarring & disfigurement:

A

Mucocutaneous leishmaniasis

94
Q

Form of leishmaniasis that involves papules that develop into crustated ulcers:

A

Cutaneous leishmaniasis

95
Q

Cutaneous leishmaniasis occurs with ____ & ____

A

Scarring & permanent immunity

96
Q

Form of leishmaniasis that involves tissue macrophage dysfunction with clinical manifestations of intermittent fever & enlargement of spleen or liver:

A

Visceral leishmaniasis

97
Q

Visceral leishmaniasis involves _____ dysfunction

A

Tissue macrophage

98
Q

Recovery from visceral leishmaniasis provides:

A

Permanent immunity

99
Q

Treatment of leishmaniasis includes:

A

Several types of drugs available including amphotericin B, the polyene antifungal agent

100
Q

What are ways to control contraction of leishmaniasis?

A

Vector & reservoir control along wit epidemiological surveillance

101
Q

Amoebiasis (Amoeboid protozoa) causes:

A

Amoebic dysentery

102
Q

The causative agent of Amoebiasis:

A

Entamoeba histolytica

103
Q

Transmission of Amoebiasis occurs through:

A

Ingestion of cysts

104
Q

The clinical manifestations of amoebiasis includes:

A

Asymptomatic to fulminating dysentery, exhaustive diarrhea, and abscesses of the liver, lungs & brain

105
Q

How is Amoebiasis diagnosed?

A

Observation of trophozoites in fresh warm stools or cysts in ordinary stools & serological tests

106
Q

What treatment may be used for Amoebiasis?

A

Metronidazole therapy

107
Q

Why is metronidazole therapy effective against Amoebiasis?

A

Because amoebas carry out anaerobic metabolism & the drug penetrates tissue well to destroy invasive pathogens

108
Q

What is one way to control the contraction of Amoebiasis?

A

Avoiding contaminated water & food and hyperchlorination/iodination of water supplies to destroy waterborne cysts

109
Q

Phylum Apicomplexa lack _____ except for ___ & ____

A

Locomotor organelles; male gamets & zygotes

110
Q

All Phylum Apicomplexa contain:

A

Apical complex

111
Q

Arrangement fibrils, tubules, vacuoles & other organelles at one end of the cell describe:

A

Apical complex of Phylum Apicomplexa

112
Q

The spirally arranged fibers:

A

Conoid

113
Q

Contains materials that are secreted and aid in penetration of host cell:

A

Rhoptry

114
Q

The life cycle of _____ invovles two different hosts, (usually mammal & mosquito)

A

Apicomplexan

115
Q

The apicomplexan life cycle involve both:

A

Sexual & asexual phases

116
Q

The asexual phase of the apicomplexan life cycle involving a rapid series of mitotic event producing infective organisms:

A

Schizogony

117
Q

What is produced during the sexual phase of apicomplexan life cycles?

A

Oocyst

118
Q

Describe the oocyst produced during the sexual phase of the apicomplexan life cycle:

A

Thick-walled diploid structure that undergoes meiosis to produce haploid spores

119
Q

Apicomplexan = ______

A

Sporozoan

120
Q

Important sporozoan (apicomplexan) generas include:

A
  1. Plasmodium
  2. Cryptosporidium
  3. Toxoplasma
121
Q

The important sporozoan (apicomplexan) responsible for malaria:

A

Plasmodium

122
Q

The important sporozoan (apicomplexan) responsible for cryptosporidiosis:

A

Cryptosporidium

123
Q

The important sporozoan (apicomplexan) responsible for Toxoplasmosis:

A

Toxoplasma

124
Q

Malaria is caused by four species of:

A

Plasmodium

125
Q

What species of plasmodium that causes malaria is most virulent?

A

Plasmodium falciparum

126
Q

What are the four species of plasmodium that cause malaria?

A
  1. P. Falciparum
  2. P. Vivax
  3. P. Malaria
  4. P. Ovale
127
Q

Malaria is transmitted by bite of an infected:

A

Female anopheles mosquito

128
Q

What is the reservoir of malaria?

A

Humans

129
Q

What is the intermediate host of malaria?

A

Humans- asexual reproduction

130
Q

What is the definitive host of malaria?

A

Mosquito sexual reproduction

131
Q

P. Vivax & P. Ovale form _____ which are the _____ forms within liver cells

A

Hypnozoites; dormant

132
Q

The hypnozoites formed by p. Vivax & P. Ovale within liver cells cause:

A

Recurrent malaria (months to years after initial disease)

133
Q

The clinical manifestations of malaria include:

A

Periodic attacks of chills & fever

134
Q

The periodic attacks of chills & fever seen with malaria coincide with:

A

RBC lysis and merozoite release, which stimulates cytokine production

135
Q

Describe the hepatocellular cycle involved in malaria infection:

A

8-14 Days; multiply asexually

136
Q

Describe the erythrocyte cycle involved in malaria infection:

A

2-3 days; multiple asexually

137
Q

In a malaria infection, a small number of merozoites develop into:

A

Gametocytes

138
Q

How is malaria diagnosed?

A

Demonstration of parasites within Wright- or Giemsa-stained red blood cells & serological tests

(But these are of little value in acutely ill patient)

139
Q

What is the treatment for malaria?

A

Antimalarial drugs

140
Q

What are the classic antimalarial drugs & how do they function?

A

Chloroquine & other quinine based drugs- these block heme detoxification in plasmodium food vacuole

141
Q

In treatment of malaria ____ resistance is widespread due to the drug being pumped out of the vacuole:

A

Chloroquine resistance

142
Q

What is the mechanism of Chloroquine resistance in malaria infections?

A

Drug pumped out of vacuole

143
Q

For individuals traveling to high endemic malaria areas what is recommended?

A
  1. Chemoprophylaxis
  2. Netting
  3. Insect repellants
144
Q

What is characteristic of early stages of malarial infection?

A

Early ring formation

145
Q

Endemic to the USA & transmitted by same Ixodes tick as Borrelia burgdorferi:

A

Babesia

146
Q

Babesia is caused by:

A

Babesia species

147
Q

Infections of Babesia range from______ & can be described as:

A

Subclinical to severe disease & “summer flu”

148
Q

Describe what happens when protozoa infect red blood cells & babesia:

A

Once protozoa infect red blood cells they cause fever upon release

149
Q

Babesia infection is similar to _____ but there is no ____

A

Malaria; no intermediate liver stage

150
Q

What is the reservoir for babesia?

A

The white-footed mouse (NOT HUMANS)

151
Q

Diagnosis of babesia is by:

A

Microscopy of Giemsa-stained blood samples & PCR

152
Q

What is the treatment of babesia?

A

Clindamycin + quinine (different from malaria)

153
Q

The causative agent of toxoplasmosis:

A

Toxoplasma gondii

154
Q

Transmission of toxoplasmosis occurs by:

A

Ingestion of undercooked meat, congenital transfer, blood transfusion, tissue transplant & ingestion of cat feces

155
Q

Toxoplasma gondii invade:

A

macrophages

156
Q

What is the definitive host of toxoplasma gondii?

A

Cats

157
Q

What are two common modes of transmission of Toxoplasmosisn for humans?

(list the most common1 mode first)

A
  1. Undercooked meat containing tissue cysts
  2. Humans handling kitty litter or soil
158
Q

The clinical manifestations of toxoplasmosis include:

A

-Usually asymptomatic (in greater than 99%) or resembles mono
-Can be fatal in immunocompromised hosts (mass lesions in the brain)
-congenital infections

159
Q

Treatment for toxoplasmosis include:

A

Antiparasite therapy for immunocompromised hosts

160
Q

Control of toxoplasmosis contraction includes:

A

-Minimizing exposure by avoidance of raw meat & eggs, washing hands after working in soil & cat-handling practices

-Women screened for anti toxoplasma antibody at marriage or very early in pregnancy, if positive, fetus is protected