Fungal and Protozoan Diseases Flashcards Preview

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Flashcards in Fungal and Protozoan Diseases Deck (158):
1

What kind of organisms are fungi? 

Eukaryotic organisms 

2

What do fungi comprise? 

  • Yeasts
  • Moulds
  • Higher fungi 

 

3

What kind of organisms are yeasts? 

Single celled 

4

What are moulds? 

Filamentous fungi 

5

What are higher fungi? 

Mushrooms and toadstools

6

What survival advantage do fungi have? 

They can survive in an environment where nutrients are limited 

7

What are saprophytes? 

Organisms that live off dead organic matter in soil and water. 

Many fungi are saprophytes 

8

What are the main forms of fungal growth? 

  • Yeast like growth via simple budding
  • Mould-type growth

 

9

What does yeast like growth allow for? 

Growth in the simplest form 

10

What can some yeast form?

Pseudeohyphae 

11

How do yeasts that form pseudohyphae grow? 

Buds elongate to form filaments 

12

What happens in mould-type growth? 

Numerous microscopic, branching, filamentous hyphae are produced to form extensive arrangement of mycelia

13

What is the purpose of mycelia? 

They are used to gain nutrients and reproduce 

14

What do reproductive mycelia do? 

Produce spores 

15

How do reproductive mycelia produce spores? 

Either sexually or asexually 

16

What do the spores produced by mycelia do? 

Disseminate throughout the atmosphere and colonise new environments

17

What do mycelia look like? 

18

What is meant by dimorphic growth? 

It will invade a tissue in its yeast form, yet form a mould in the living environment 

Fungi can, and commonly do, grow in this manner 

19

What is the exception to the dimorphic growth of fungi? 

Candida spp. 

20

How does Candida spp. grow? 

It stays in its yeast form except for producing pseudohyphae 

21

On what basis can fungi be classified? 

  • Degree of tissue involvement 
  • Mode of entry into the host organisms 

 

22

What are the classifications of fungi? 

  • Superficial 
  • Subcutaneous 
  • Systemic
  • Opportunistic 

 

23

What is meant by superficial fungi? 

Localised to hair, skin, and nails 

24

How common are subcutaneous fungi? 

Rare 

25

What is meant by systemic fungi? 

Deep infections of internal organs 

26

When are opportunistic fungal infections seen? 

Only in immunocompromised individuals 

27

Give 5 examples of fungi that can be superficial 

  • Dermatophytes 
  • Candida 
  • Apergillus 
  • Cryptococcus
  • Pneymocystitis 

 

28

Give 4 examples of fungi that can be systemic

  • Candida
  • Apergillus 
  • Cryptococcus
  • Pneumocystitis 

29

Give 4 examples of fungi that can be opportunistic 

  • Candida
  • Apergillus 
  • Cryptococcus
  • Pneumocystitis 

30

How common are fungal infections in the UK?

Most fungal infections are uncommon to healthy individuals, except for candiasis or dermatophyte infections, which are quite common

31

What are dermatophytes? 

Superficial fungi that grow on keratin 

32

Where are dermatophytes mainly seen? 

On skin or hair 

33

How can infection from dermatophytes be acquired? 

From people, animals, or the environment, depending on the species 

34

What are the main species implicated in dermatophyte infection? 

  • Epidermophyton
  • Microsporum 
  • Trichophyton 

 

35

How do dermatophyte infections commonly present? 

Ringworm 

36

What is ringworm? 

Red scaly patches that spread out that are itchy, but rarely painful 

37

On what basis are dematophyte infections clinically labelled? 

By their sites of infection 

38

What are the clinical labels of dermatophyte infection? 

  • Tinea Capitis 
  • Tinea Corporis
  • Tinea Pedis 

 

39

Where does Tinea Capitis affect? 

Head and neck 

40

Where does Tinea Corporis affect? 

Trunk

41

What is Tinea Pedis? 

Athlete's foot

42

Where are candida species found?

Widely distributed in the environment 

43

What do the candida species form part of? 

The normal commensal population in the GI tract, skin, and female genital tract 

44

What is the result of candida species forming part of the normal commesnal population? 

Following the use of broad spectrum antibiotics, a fungal growth may develop 

45

Other than antibiotics, how else may a fungal growth develop? 

As a result of any immune deficiency 

46

What do yeast fungi contain? 

Pseudohyphae 

47

What are most fungal infections caused by? 

Candida Albicans 

48

What does candida cause? 

Oral and vaginal thrush 

49

What happens in oral and vaginal thrush? 

Creamy, curd-like plaques are produced 

50

What do the plaques in thrush cause? 

Pain and itching 

51

Who can develop a systemic infection from Candida spp.? 

Individuals who suffer from neutropenia 

52

Why can Candida infection not be diagnosed by growth on laboratory media? 

As they are part of the normal commensal flora, the growth on laboratory media can prove inconclusive 

53

How can Candida infection be viewed? 

Microscopy 

54

What should any results of Candida infection investigation be determined in relation to? 

The clinical picture 

55

Who is at risk of developing opportunistic fungal growth? 

  • Immunocompromised
  • Metabolic defects 
  • Undergone surgery

 

56

What fungi can grow opportunistically? 

  • Aspergillus spp. 
  • Cryptococcus
  • Pneumocystis jiroveci

 

57

When can candiasis develop systemically? 

  • In severely immunocompromised individuals
  • Following chemotherapy

58

What are aspergillus spp.? 

Ubiquitous saprophytic fungi 

59

What can aspiration of aspergillus spores give rise to? 

Type III hypersensitivity reaction (Farmers lung) 

60

What can become colonised by aspergillus? 

Healed old cavities or bronchiectasis 

61

What is caused when healed cavities or bronchiectasis are colonised by aspergillus? 

Aspergilloma 

62

What can happen in aspergillus infection in neutropenic patients? 

They begin in the lung, and can develop into disseminated systemic disease 

63

How can aspergillus infections be diagnosed? 

  • Broncholavage
  • Antibody detection 

 

64

How can aspergillus infections be treated? 

Using anti-fungals 

65

What is cryptococcus? 

A saprophyte that infects humans 

66

Where is cryptococcus commonly found? 

In pigeon faeces 

67

What is the main species of the cryptococcus genus?

Cryptococcus neoformans 

68

What is cryptococcus neoformans associated with? 

Subacute or chronic form of meningitis

69

What does meningitis caused by cryptococcus neoformans result from? 

Inhalation of the species 

70

In whom does pneumocystis jiroveci cause infection? 

Only patients with severe T-cell dysfunction

71

Why may someone have severe T-cell dysfunction? 

  • HIV
  • Malnutrition 
  • Primary immune deficiencies 
  • Immunosupressive drugs 

 

72

What kind of fungus is pneumocystis jiroveci? 

Yeast-like

73

How is pneumocystis jiroveci transmitted? 

Via the respiratory route 

74

How do patients with pnuemocystis jiroveci present? 

  • Progressive dyspnoea 
  • Unproductive, dry cough

 

75

What does pneumocystis jiroveci cause? 

Pneumocystsis pneumonia (PDP)

76

What happens in PCP?

  • Pulmonary consolidation 
  • Decreased pO2

 

77

How can pneumocystis jiroveci be diagnosed? 

  • Bronchiolavage
  • Immunoflourescence

78

What is the result of fungi being eukaryotes? 

They share a similar cellular structure to human cells 

79

What is the result of fungi sharing a similar cellular structure to human cells? 

Any anti-fungals used have the potential to cause damage to our own cells 

80

What are the main types of anti-fungals commonly used? 

  • Azoles 
  • Terbinafine 
  • Polyenes 
  • Echinocandins 

 

81

What do azoles do? 

Block the action of cytochrome C450

82

What does the type of azole given depend on? 

The fungus in question 

83

Give 4 types of azole

  • Fluconazole
  • Itraconazole
  • Vorixonazole
  • Flucystosine

 

84

What does terbinafine do? 

Inhibits squalene epoxidase with resultant accumulation of aberrant and toxic sterols in the cell wall

85

What do polyenes do? 

Forms a pore in the fungal membrane 

 

86

What do echinocandins do? 

Inhibit the synthesis of 1,3-ß-glucan

87

What is 1,3-ß-glucan? 

A molecule in the cell wall of pathogenic fungi 

88

What are protozoan? 

Single celled eukaryotes 

89

How do protozoan differ from fungi? 

In their cell walls and life cycle 

90

What are the main two protozoan worldwide? 

  • Toxoplasmosis
  • Malaria 

 

91

What is the prevalence of toxoplasmosis? 

1-2billion 

92

What is the prevalence of malaria? 

200-300million

93

How can the life cycles of protozoan be classified? 

  • Simple 
  • Complex

 

94

Give two examples of a protozoa with a simple life cycle

  • Entamoeba
  • Giardia

95

Give two examples of protozoa with complex life cycles 

  • Plasmodium 
  • Toxoplasma 

 

96

Draw a diagram illustrating the simple life cycle of a protozoa 

97

Draw a diagram illustrating the complex life cycle of a protozoa

98

What is a trophozoite? 

The active protozoa which is mitotically dividing constantly 

99

What is the cyst? 

The non-replicating, resistant form of the protozoa 

100

What are the eggs in the complex life cycle seen to be? 

The infectious form of the protozoa

101

What are the main groups of protozoa? 

  • Amoebae 
  • Flagellates 
  • Apicomplexa 

 

102

What are the simplest forms of protozoa? 

Amoebae 

103

What are amoebae characterised by? 

A feeding and dividing trophozoite 

104

How can amoebae survive in most environments? 

They can form a resistant cyst

105

What form do flagellates have? 

A trophozoite form with a flagella attached

106

What is the purpose of flagellates flagella?

Locomotion 

107

Give an example of a flagellate

Giardia 

108

What are apicomplexa?

Protozoa that are intracellular, and have a sexual and asexual reproduction life cycle 

109

Give two apicomplexa

  • Toxoplasmosis
  • Malaria 

 

110

Give 3 types of protozoa that affect humans to cause disease 

  • Entamoeba histolytica
  • Giardia lambia 
  • Cryptosporidium 

 

111

What does entamoeba histolytica infect? 

The large intestine 

112

How are entamoeba histolytica transmitted? 

By faeco-oral route 

113

How do entamoeba histolytica infect the large intestine? 

They adhere to the intestinal epithelium 

114

What can entamoeba histolytica lead to? 

  • Dysentry 
  • Brain or liver abscesses 

 

115

Is giardia lamblia common worldwide? 

Yes 

116

How is giardia lamblia transmitted? 

 In the water and food supplies 

117

What allows giadia lamblia to be transmitted in the food and water supplies? 

Poor sanitiation

118

What path do giardia lamblia take in the human body? 

They divide in the jejenum, then adhere to the intestinal walls 

119

How do giardia lamblia divide?

By binary fission

120

How do giardia lamblia adhere to the intestinal wall? 

By sucking discs 

121

What do giardia lamblia form that allows their transmission to the environment? 

Cysts in faeces 

122

What are the symptoms of giardia lamblia? 

  • Abdominal pain 
  • Flatus 
  • Bulky, fatty stools 

 

123

Why does giardia lamblia infection cause bulky, fatty stools? 

Due to poor fat absorption 

124

What kind of protozoa is cryptosporidium? 

Zoonotic 

125

How is cryptosporidium transmitted? 

By farm animal contact 

126

Who is cryptosporidium infection common in? 

Children and immunosuppressed individuals 

127

What are the symptoms of cryptosporidium infection?

Self-limiting watery diarrhoea with abdominal cramps 

128

How does cryptosporidium produce its symptoms? 

The protozoa interferes with the sodium pumps in the small intestine

129

What causes malaria? 

Four species of the genus plasmodium; 

  • P. Falciparum 
  • P. Vivax
  • P. Ovale 
  • P. Malarie 

 

130

How many people live under the treat of malaria? 

More than 1.5 billion people

131

How many children under the age of 5 years die in Africa each year from malaria? 

1 million 

132

How does malaria get into the body? 

The oocytes of plasmodium (sporozoa) are injected into the circulation of individuals by the female Anopheles bites

133

What happens to the malaria parasites once they are inside the body?

They multiply in the hepatocytes in the liver before invading the red blood cells and multiplying

134

How are the systemic features of malaria caused? 

The plasmodium provoke the release of cytokines from the red blood cells 

135

How are plasmodium spread to other cells from RBCs? 

They cause the lysis of the erythrocytes and so can spread to other cells, producing very large numbers 

136

What happens to the malaria infected erythrocytes? 

They can adhere to the endothelial wall, causing cerebral malaria 

137

How can malaria be transmitted from an infected individual? 

The plasmodium protozoa differentiate into the sexual stage and can be taken up by another biting female Anopheles, and develop in the mosquito gut before migrating to the mosquitos salivary glands 

138

Between that do the symptoms of malaria vary? 

  • Individuals 
  • Plasmodium species 

 

139

What are the symptoms of malaria? 

  • Shaking
  • Fever 
  • Anaemia 
  • Pre-hepatic jaundice 
  • Dark pigmented urine 

 

140

Why is dark pigmented urine a symptom of malaria? 

From erythrocyte destruction 

141

What secondary pathologies can malaria cause? 

  • Cerebral malaria
    Hepatospleenomegaly 

 

142

What is the most fatal malaria species? 

Plasmodium Falciparum 

143

What is the most common malaria species? 

Plasmodium Vivax

 

144

What is plasmodium Vivax known to do? 

Reoccur from latency 

145

What does treatment for malaria involve? 

  • Chemotherapy 
  • Quinine

146

What is the purpose of chemotherapy in malaria treatment? 

To destroy the parasites 

147

What is the best means to reduce malaria cases? 

Prevention 

148

How is malaria prevented? 

  • Use of mosquito nets while sleeping
  • Prophylaxis regularly taken 

149

Draw a diagram illustrating the cycle of malaria

150

What causes toxoplasmosis? 

The protozoan toxoplasmosis gondii 

151

Where does toxoplasmosis gondii have its life cycle? 

In cats

152

What can toxoplasmosis gondii infect? 

All warm blooded mammals 

153

How can humans become infected with toxoplasmosis gondii? 

  • Through ingestion of the oocytes from cat excrement contaminating food
  • Can spread vertically to foetus 

 

 

 

154

What does toxoplasmosis cause in the primary infection? 

Flu-like symptoms 

155

Who is toxoplasmosis a problem for? 

Immunocompromised individuals 

156

Why is toxoplasmosis a problem for immunocompromised individuals? 

Because toxoplasmosis gondii persists inside the host cell for very long periods, yet falling immunity can allow for reactivation 

 

157

Where can toxoplasmosis spread to? 

The brain 

158

What is the result of toxoplasmosis spreading to the brain? 

  • Cerebral abscesses 
  • Encephalitis