Fungal and Protozoan Diseases Flashcards Preview

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

What kind of organisms are fungi?

A

Eukaryotic organisms

2
Q

What do fungi comprise?

A
  • Yeasts
  • Moulds
  • Higher fungi
3
Q

What kind of organisms are yeasts?

A

Single celled

4
Q

What are moulds?

A

Filamentous fungi

5
Q

What are higher fungi?

A

Mushrooms and toadstools

6
Q

What survival advantage do fungi have?

A

They can survive in an environment where nutrients are limited

7
Q

What are saprophytes?

A

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

Many fungi are saprophytes

8
Q

What are the main forms of fungal growth?

A
  • Yeast like growth via simple budding
  • Mould-type growth
9
Q

What does yeast like growth allow for?

A

Growth in the simplest form

10
Q

What can some yeast form?

A

Pseudeohyphae

11
Q

How do yeasts that form pseudohyphae grow?

A

Buds elongate to form filaments

12
Q

What happens in mould-type growth?

A

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

13
Q

What is the purpose of mycelia?

A

They are used to gain nutrients and reproduce

14
Q

What do reproductive mycelia do?

A

Produce spores

15
Q

How do reproductive mycelia produce spores?

A

Either sexually or asexually

16
Q

What do the spores produced by mycelia do?

A

Disseminate throughout the atmosphere and colonise new environments

17
Q

What do mycelia look like?

A
18
Q

What is meant by dimorphic growth?

A

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
Q

What is the exception to the dimorphic growth of fungi?

A

Candida spp.

20
Q

How does Candida spp. grow?

A

It stays in its yeast form except for producing pseudohyphae

21
Q

On what basis can fungi be classified?

A
  • Degree of tissue involvement
  • Mode of entry into the host organisms
22
Q

What are the classifications of fungi?

A
  • Superficial
  • Subcutaneous
  • Systemic
  • Opportunistic
23
Q

What is meant by superficial fungi?

A

Localised to hair, skin, and nails

24
Q

How common are subcutaneous fungi?

A

Rare

25
Q

What is meant by systemic fungi?

A

Deep infections of internal organs

26
Q

When are opportunistic fungal infections seen?

A

Only in immunocompromised individuals

27
Q

Give 5 examples of fungi that can be superficial

A
  • Dermatophytes
  • Candida
  • Apergillus
  • Cryptococcus
  • Pneymocystitis
28
Q

Give 4 examples of fungi that can be systemic

A
  • Candida
  • Apergillus
  • Cryptococcus
  • Pneumocystitis
29
Q

Give 4 examples of fungi that can be opportunistic

A
  • Candida
  • Apergillus
  • Cryptococcus
  • Pneumocystitis
30
Q

How common are fungal infections in the UK?

A

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

31
Q

What are dermatophytes?

A

Superficial fungi that grow on keratin

32
Q

Where are dermatophytes mainly seen?

A

On skin or hair

33
Q

How can infection from dermatophytes be acquired?

A

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

34
Q

What are the main species implicated in dermatophyte infection?

A
  • Epidermophyton
  • Microsporum
  • Trichophyton
35
Q

How do dermatophyte infections commonly present?

A

Ringworm

36
Q

What is ringworm?

A

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

37
Q

On what basis are dematophyte infections clinically labelled?

A

By their sites of infection

38
Q

What are the clinical labels of dermatophyte infection?

A
  • Tinea Capitis
  • Tinea Corporis
  • Tinea Pedis
39
Q

Where does Tinea Capitis affect?

A

Head and neck

40
Q

Where does Tinea Corporis affect?

A

Trunk

41
Q

What is Tinea Pedis?

A

Athlete’s foot

42
Q

Where are candida species found?

A

Widely distributed in the environment

43
Q

What do the candida species form part of?

A

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

44
Q

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

A

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

45
Q

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

A

As a result of any immune deficiency

46
Q

What do yeast fungi contain?

A

Pseudohyphae

47
Q

What are most fungal infections caused by?

A

Candida Albicans

48
Q

What does candida cause?

A

Oral and vaginal thrush

49
Q

What happens in oral and vaginal thrush?

A

Creamy, curd-like plaques are produced

50
Q

What do the plaques in thrush cause?

A

Pain and itching

51
Q

Who can develop a systemic infection from Candida spp.?

A

Individuals who suffer from neutropenia

52
Q

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

A

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

53
Q

How can Candida infection be viewed?

A

Microscopy

54
Q

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

A

The clinical picture

55
Q

Who is at risk of developing opportunistic fungal growth?

A
  • Immunocompromised
  • Metabolic defects
  • Undergone surgery
56
Q

What fungi can grow opportunistically?

A
  • Aspergillus spp.
  • Cryptococcus
  • Pneumocystis jiroveci
57
Q

When can candiasis develop systemically?

A
  • In severely immunocompromised individuals
  • Following chemotherapy
58
Q

What are aspergillus spp.?

A

Ubiquitous saprophytic fungi

59
Q

What can aspiration of aspergillus spores give rise to?

A

Type III hypersensitivity reaction (Farmers lung)

60
Q

What can become colonised by aspergillus?

A

Healed old cavities or bronchiectasis

61
Q

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

A

Aspergilloma

62
Q

What can happen in aspergillus infection in neutropenic patients?

A

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

63
Q

How can aspergillus infections be diagnosed?

A
  • Broncholavage
  • Antibody detection
64
Q

How can aspergillus infections be treated?

A

Using anti-fungals

65
Q

What is cryptococcus?

A

A saprophyte that infects humans

66
Q

Where is cryptococcus commonly found?

A

In pigeon faeces

67
Q

What is the main species of the cryptococcus genus?

A

Cryptococcus neoformans

68
Q

What is cryptococcus neoformans associated with?

A

Subacute or chronic form of meningitis

69
Q

What does meningitis caused by cryptococcus neoformans result from?

A

Inhalation of the species

70
Q

In whom does pneumocystis jiroveci cause infection?

A

Only patients with severe T-cell dysfunction

71
Q

Why may someone have severe T-cell dysfunction?

A
  • HIV
  • Malnutrition
  • Primary immune deficiencies
  • Immunosupressive drugs
72
Q

What kind of fungus is pneumocystis jiroveci?

A

Yeast-like

73
Q

How is pneumocystis jiroveci transmitted?

A

Via the respiratory route

74
Q

How do patients with pnuemocystis jiroveci present?

A
  • Progressive dyspnoea
  • Unproductive, dry cough
75
Q

What does pneumocystis jiroveci cause?

A

Pneumocystsis pneumonia (PDP)

76
Q

What happens in PCP?

A
  • Pulmonary consolidation
  • Decreased pO2
77
Q

How can pneumocystis jiroveci be diagnosed?

A
  • Bronchiolavage
  • Immunoflourescence
78
Q

What is the result of fungi being eukaryotes?

A

They share a similar cellular structure to human cells

79
Q

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

A

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

80
Q

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

A
  • Azoles
  • Terbinafine
  • Polyenes
  • Echinocandins
81
Q

What do azoles do?

A

Block the action of cytochrome C450

82
Q

What does the type of azole given depend on?

A

The fungus in question

83
Q

Give 4 types of azole

A
  • Fluconazole
  • Itraconazole
  • Vorixonazole
  • Flucystosine
84
Q

What does terbinafine do?

A

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

85
Q

What do polyenes do?

A

Forms a pore in the fungal membrane

86
Q

What do echinocandins do?

A

Inhibit the synthesis of 1,3-ß-glucan

87
Q

What is 1,3-ß-glucan?

A

A molecule in the cell wall of pathogenic fungi

88
Q

What are protozoan?

A

Single celled eukaryotes

89
Q

How do protozoan differ from fungi?

A

In their cell walls and life cycle

90
Q

What are the main two protozoan worldwide?

A
  • Toxoplasmosis
  • Malaria
91
Q

What is the prevalence of toxoplasmosis?

A

1-2billion

92
Q

What is the prevalence of malaria?

A

200-300million

93
Q

How can the life cycles of protozoan be classified?

A
  • Simple
  • Complex
94
Q

Give two examples of a protozoa with a simple life cycle

A
  • Entamoeba
  • Giardia
95
Q

Give two examples of protozoa with complex life cycles

A
  • Plasmodium
  • Toxoplasma
96
Q

Draw a diagram illustrating the simple life cycle of a protozoa

A
97
Q

Draw a diagram illustrating the complex life cycle of a protozoa

A
98
Q

What is a trophozoite?

A

The active protozoa which is mitotically dividing constantly

99
Q

What is the cyst?

A

The non-replicating, resistant form of the protozoa

100
Q

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

A

The infectious form of the protozoa

101
Q

What are the main groups of protozoa?

A
  • Amoebae
  • Flagellates
  • Apicomplexa
102
Q

What are the simplest forms of protozoa?

A

Amoebae

103
Q

What are amoebae characterised by?

A

A feeding and dividing trophozoite

104
Q

How can amoebae survive in most environments?

A

They can form a resistant cyst

105
Q

What form do flagellates have?

A

A trophozoite form with a flagella attached

106
Q

What is the purpose of flagellates flagella?

A

Locomotion

107
Q

Give an example of a flagellate

A

Giardia

108
Q

What are apicomplexa?

A

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

109
Q

Give two apicomplexa

A
  • Toxoplasmosis
  • Malaria
110
Q

Give 3 types of protozoa that affect humans to cause disease

A
  • Entamoeba histolytica
  • Giardia lambia
  • Cryptosporidium
111
Q

What does entamoeba histolytica infect?

A

The large intestine

112
Q

How are entamoeba histolytica transmitted?

A

By faeco-oral route

113
Q

How do entamoeba histolytica infect the large intestine?

A

They adhere to the intestinal epithelium

114
Q

What can entamoeba histolytica lead to?

A
  • Dysentry
  • Brain or liver abscesses
115
Q

Is giardia lamblia common worldwide?

A

Yes

116
Q

How is giardia lamblia transmitted?

A

In the water and food supplies

117
Q

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

A

Poor sanitiation

118
Q

What path do giardia lamblia take in the human body?

A

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

119
Q

How do giardia lamblia divide?

A

By binary fission

120
Q

How do giardia lamblia adhere to the intestinal wall?

A

By sucking discs

121
Q

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

A

Cysts in faeces

122
Q

What are the symptoms of giardia lamblia?

A
  • Abdominal pain
  • Flatus
  • Bulky, fatty stools
123
Q

Why does giardia lamblia infection cause bulky, fatty stools?

A

Due to poor fat absorption

124
Q

What kind of protozoa is cryptosporidium?

A

Zoonotic

125
Q

How is cryptosporidium transmitted?

A

By farm animal contact

126
Q

Who is cryptosporidium infection common in?

A

Children and immunosuppressed individuals

127
Q

What are the symptoms of cryptosporidium infection?

A

Self-limiting watery diarrhoea with abdominal cramps

128
Q

How does cryptosporidium produce its symptoms?

A

The protozoa interferes with the sodium pumps in the small intestine

129
Q

What causes malaria?

A

Four species of the genus plasmodium;

  • P. Falciparum
  • P. Vivax
  • P. Ovale
  • P. Malarie
130
Q

How many people live under the treat of malaria?

A

More than 1.5 billion people

131
Q

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

A

1 million

132
Q

How does malaria get into the body?

A

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

133
Q

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

A

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

134
Q

How are the systemic features of malaria caused?

A

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

135
Q

How are plasmodium spread to other cells from RBCs?

A

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

136
Q

What happens to the malaria infected erythrocytes?

A

They can adhere to the endothelial wall, causing cerebral malaria

137
Q

How can malaria be transmitted from an infected individual?

A

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
Q

Between that do the symptoms of malaria vary?

A
  • Individuals
  • Plasmodium species
139
Q

What are the symptoms of malaria?

A
  • Shaking
  • Fever
  • Anaemia
  • Pre-hepatic jaundice
  • Dark pigmented urine
140
Q

Why is dark pigmented urine a symptom of malaria?

A

From erythrocyte destruction

141
Q

What secondary pathologies can malaria cause?

A
  • Cerebral malaria
    Hepatospleenomegaly
142
Q

What is the most fatal malaria species?

A

Plasmodium Falciparum

143
Q

What is the most common malaria species?

A

Plasmodium Vivax

144
Q

What is plasmodium Vivax known to do?

A

Reoccur from latency

145
Q

What does treatment for malaria involve?

A
  • Chemotherapy
  • Quinine
146
Q

What is the purpose of chemotherapy in malaria treatment?

A

To destroy the parasites

147
Q

What is the best means to reduce malaria cases?

A

Prevention

148
Q

How is malaria prevented?

A
  • Use of mosquito nets while sleeping
  • Prophylaxis regularly taken
149
Q

Draw a diagram illustrating the cycle of malaria

A
150
Q

What causes toxoplasmosis?

A

The protozoan toxoplasmosis gondii

151
Q

Where does toxoplasmosis gondii have its life cycle?

A

In cats

152
Q

What can toxoplasmosis gondii infect?

A

All warm blooded mammals

153
Q

How can humans become infected with toxoplasmosis gondii?

A
  • Through ingestion of the oocytes from cat excrement contaminating food
  • Can spread vertically to foetus
154
Q

What does toxoplasmosis cause in the primary infection?

A

Flu-like symptoms

155
Q

Who is toxoplasmosis a problem for?

A

Immunocompromised individuals

156
Q

Why is toxoplasmosis a problem for immunocompromised individuals?

A

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

157
Q

Where can toxoplasmosis spread to?

A

The brain

158
Q

What is the result of toxoplasmosis spreading to the brain?

A
  • Cerebral abscesses
  • Encephalitis