Blood Bourne Viruses Flashcards Preview

[ ESA 3- Infection and Immunity > Blood Bourne Viruses > Flashcards

Flashcards in Blood Bourne Viruses Deck (187):
1

What are viruses?

Obligate intracellular parasites without cellular structure

2

What do viruses consist of?

Molecule(s) of either DNA or RNA (but not both) surrounded by a protein coat

3

Do viruses have an envelope?

They may or may not

4

Where is the envelope of a virus derived from?

The plasma membrane of the host cell from which it is released

5

How do viruses reproduce?

They hijack the host's mechanism for creating mRNA and production of proteins

6

What happens once viruses have reproduced in the host cells?

They can be released from the cell to infect other cells

7

How can new viruses be released from the original cell?

Can often occur by death of the infected cell

8

How can viruses be classified?

In a variety of ways, based on their structure

9

Give 7 examples of key viral classifications

Single-stranded, non-enveloped DNA viruses
Double-stranded, non-enveloped DNA viruses
Double-stranded, enveloped DNA viruses
Single-stranded, positive stand, icosahedral, non-enveloped RNA viruses
Single-stranded, positive strand, icosahedral or helical, enveloped RNA viruses
Single-stranded, negative strand, helical, enveloped RNA viruses
Double-stranded, icosahedral, non-enveloped RNA viruses

10

How many people does HIV infect per year around the world?

~2 million

11

How many new cases of HIV are there per year in the UK?

~6,000

12

How many people in the world have HIV?

37million

13

What happens if HIV is left untreated?

Most cases of HIV will progress to AIDS

14

How many deaths worldwide did HIV cause in 2014?

1.2million deaths

15

How many deaths did HIV cause in the UK in 2014?

320

16

How many people with HIV are there in the UK?

103,000

17

What % of those infected with HIV in the UK are men?

67%

18

What is the HIV prevalence in Leicester, compared to the UK?

3.8/1,000 in Leicester, compared to 1.9/1000 in the UK

19

What % of those infected with HIV are heterosexuals?

57%

20

What has happened regarding new diagnoses of HIV in heterosexuals since 2005?

It has decreased by 50%

21

How does the stage of diagnosis of HIV differ between heterosexuals and homosexuals?

>50% of heterosexuals are diagnosed at a later stage

22

What is the result of heterosexuals being diagnosed with HIV at a later stage?

Worse outcome

23

What % of those with HIV in the UK are black African?

50-60%

24

What is the prevalence of HIV in IVDUs in the UK?

2/1000

25

What % of sexual transmissions of HIV in the UK do MSM account for?

57%

26

What is happening to the rate of sexual transmission of HIV by MSM?

It is increasing, whilst a decrease has been seen in every other group

27

What % of people living with HIV in the UK don't know they have it?

17%

28

What is HIV?

A retrovirus

29

What does HIV do?

Infects and replicates within cells of the immune system, particularly CD4+ cells

30

How does HIV gain access to CD4 cells?

It binds to the receptors on the CD4 cells, and fuses with them to deposit their contents into them

31

What happens once HIV has deposited it's contents into CD4 cells?

Single strands of viral RNA are then converted to double stranded DNA by reverse transcriptase

32

What happens once double stranded DNA has been produced from HIV RNA?

The viral DNA is combine with the cell's down DNA by the integrase enzyme

33

What is the result of the combination of HIV DNA and the cells own DNA?

When the infected cell divides, the viral DNA is read and long chains of proteins are made

34

What happens to the proteins produced as a result of HIV DNA integration?

Sets of these viral proteins come together and push out of the cell, taking some membrane with it to form an immature virus

35

What happens to the immature HIV virus?

It breaks free of the cell and matures to form a working virus that can infect more cells

36

What is the result of the use of CD4 cells as a host by HIV?

Causes death of CD4 cells and damages the immune system

37

What is the result of the damage to the immune system caused by HIV?

Patients present with opportunistic infections

38

Give 3 examples of opportunistic infections a patient with HIV might present with

Oral candidiasis
Kaposis's sarcoma
PCP (pneumocystis pneumonia)

39

What infections are HIV patients prone to in particular?

Infections from yeast, moulds, and protozoa

40

What happens to the levels of CD4 cells present when infected with HIV?

It alters the levels present, and this changes over time

41

What is the result of the altered levels of CD4 found in HIV?

Leads to altered states of health

42

What are the stages in a HIV infection?

Stage 1 - acute infection/seroconversion
Stage 2 - Latent infection
Stage 3 - Symptomatic infection
Stage 4 - Severe infection/AIDS

43

What happens in the acute infection/seroconversion state of HIV?

The body mounts an unsuccessful immune response and causes a brief fall in CD4 count

44

When does phase 1 of HIV infection occur?

2-3 months after exposure

45

What happens in the latent infection stage of HIV?

CD4 count remains high and the viral load is now

46

How long does the latent infection stage of HIV last?

Can last from 2 to 10 years, with some individuals never progressing from this stage

47

When do symptoms start to show in HIV?

If the CD4 count falls below viral load

48

What is the CD4 count in stage I HIV?

>500

49

What is the CD4 count in stage II HIV?

<500

50

What is the CD4 count in stage III HIV?

<350

51

What is the CD4 count in stage IV HIV?

<200

52

Where do the symptoms of an acute HIV infection affect?

Systemic
Central
Mouth and throat
Nose
Muscles
Liver and spleen
Lymph nodes
Skin
Gastric

53

What are the systemic symptoms of an acute HIV infection?

Fever
Weight loss

54

What are the mouth and throat symptoms of an acute HIV infection?

Pharyngitis
Sores
Thrush

55

What are the oesophageal symptoms of an acute HIV infection?

Sores

56

What are the muscular symptoms of an acute HIV infection?

Myalgia

57

What are the liver and spleen symptoms of an acute HIV infection?

Enlargement

58

What are the central symptoms of an acute HIV infection?

Malaise
Headache
Neuropathy

59

What are the lymph node symptoms of acute HIV infection?

Lymphadenopathy

60

What are the skin symptoms of an acute HIV infection?

Rash

61

What are the gastric symptoms of an acute HIV infection?

Nausea
Vomiting

62

Where do the symptoms of later HIV/AIDS affect?

Brain
Eyes
Mouth and throat
Blood
Lungs
Bone
Heart
Liver
Stomach
Reproductive system
Body

63

What are the brain symptoms of later HIV/AIDS?

Cryptococcal meningitis
Toxo (toxoplasmosis)
AIDS dementia complex

64

What are the eye symptoms for later HIV/AIDS?

CMV (cytomegalovirus)

65

What are the mouth and throat symptoms for later HIV/AIDS?

Cold sores and ulcers
Thrush (oral candidiasis)

66

What are the blood symptoms for later HIV/AIDS?

Hyperglycaemia
Dyslipidaemia

67

What is dyslipidaemia?

Abnormal amount of fat in blood

68

What are the lung symptoms of later HIV/AIDS?

Histoplasmosis
PCP
TB

69

What are the bone symptoms of later HIV/AIDS?

Osteoporosis

70

What are the heart symptoms of later HIV/AIDS?

Heart disease
Stroke

71

What are the liver symptoms of later HIV/AIDS?

HCV (Hep C virus)

72

What are the stomach symptoms of later HIV/AIDS?

CMV
Crypto (cryptosporidiosis)
MAC (mycobacterium avium complex)

73

What are the reproductive system symptoms of later HIV/AIDS?

Genital ulcers
HPV (human papillomavirus) and cervical cancer
Menstrual problems
PID (Pelvic inflammatory disease)
Vaginal yeast infections

74

What are the body symptoms of later HIV/AIDS?

HIV wasting syndrome

75

What is the cure for HIV?

There is none

76

What is the prognosis of HIV?

Can be treated, and leads to a life of chronic infection

77

How do the life expectancy and quality of life of someone with HIV differ from person without?

Very good- if detected early, is treated adherently and with a healthy lifestyle, life expectancy can be equal to those without disease

78

What is the result of a late detection of HIV?

Worse prognosis

79

How is HIV transmitted?

Sexual transmission
Sharing of injecting equipment
Vertical transmission
Medical procedures

80

What are the methods of sexual transmission of HIV?

Vaginal
Anal
Oral

81

How can HIV be transmitted vertically?

In utero
During childbirth
Breastfeeding

82

What medical procedures can lead to HIV infection?

Using blood/blood-products
Skin grafts
Organ donation

83

What is transmission of HIV affected by?

Type of exposure
Viral level
Other STIs
Condom use
Breaks in skin or mucosa

84

What is the risk of HIV transmission if the source is HIV positive with a one unit blood transfusion?

90-100%

85

What is the risk of HIV transmission if the source is HIV positive with receptive anal intercourse?

1/90 (1.11%)

86

What is the risk of HIV transmission if the source is HIV positive with sharing injecting equipment?

1/149 (0.67%)

87

What is the risk of HIV transmission if the source is HIV positive with mucous membrane exposure?

1/159

88

What is the risk of HIV transmission if the source is HIV positive with needlestick injury?

1/333

89

What is the risk of HIV transmission if the source is HIV positive with receptive vaginal intercourse?

1/1000

90

What is the risk of HIV transmission if the source is HIV positive with insertive vaginal intercourse?

1/1220

91

What is the risk of HIV transmission if the source is HIV positive with insertive anal intercourse?

1/1667

92

What are the diagnostic tests for HIV?

Blood tests
'Rapid' tests

93

What is looked for in blood tests for HIV?

HIV antigen
HIV antibody

94

Is the HIV antigen or antibody used in the current standard test for HIV?

Both

95

How long after infection will blood tests be positive for HIV?

4-6 weeks

96

How long does it take to get a result of a HIV blood test?

Same day

97

Can you get a false negative result with HIV blood tests?

Yes

98

What is the advantage of rapid HIV tests?

Low cost
<1 hr

99

What are the types of rapid HIV tests?

Blood test (finger-prick)
Oral (saliva)

100

How can rapid HIV tests be administered?

In-home tests
Postal testing

101

How accurate are 'rapid' HIV blood tests?

If negative, very accurate
May get false positives

102

Who should be tested for HIV?

Everyone, but some groups have additional need

103

What respiratory conditions would indicate a need for HIV testing?

Bacterial pneumonia
TB

104

What neurological conditions would indicate a need for HIV testing?

Aseptic meningitis
Dementia
Neuropathy

105

What dermatological conditions would indicate a need for HIV testing?

Severe psorasis
Seborrhoeic dematitis
Recurrent/multi-dermal shingles

106

What GI conditions would indicate a need for HIV testing?

Chronic diarrhoea
Weight loss with unknown cause
Salmonella
Shigella
Campylobacter

107

What haemotological conditions would indicate a need for HIV testing?

Any unexplained blood dyscrasia
LN

108

What oncological conditions would indicate a need for HIV testing?

Lymphoma
Anal cancer
Head and neck

109

What gynaecological conditions would indicate a need for HIV testing?

CIN2+
VIN
Any STI/Hep B/ Hep C

110

What is the treatment for HIV?

Anti-retroviral treatment

111

When should antiretroviral treatment be started in HIV patients?

As soon as possible, regardless of CD4

112

Why should antiretroviral treatment be started ASAP in HIV patients?

To increase outlook on morbidity and mortality

113

What is the aim of anti-retroviral treatment?

Prevent viral replication

114

How does anti-retroviral treatment prevent viral replication?

Inhibits reverse transcriptase
Inhibits integrase
Inhibits protease

115

How many drugs are used in combination to treat HIV?

3

116

Why are 3 drugs used in combination to treat HIV?

To combat resistance

117

Why must resistance be combated in HIV?

Over a million viruses are made each day, so it mutates quickly

118

What is the result of the treatment of HIV involving 3 viruses used in combination?

Makes it difficult for the virus to develop resistance to all of them

119

What does HIV treatment aim to do?

Create an undue table viral load
Reconstitute the immune system
Normalise lifespan
Reduce risk of infection

120

How many people does HBV infect around the world each year?

4 million

121

How many new cases of HBV are reported in the UK per year?

500

122

How many people in the world have the HBV virus?

400million (5-8% of population)

123

How many deaths did HBV cause worldwide in 2014?

~1 million

124

What is the prevalence of HBV in the UK?

1/1,000

125

What can HBV lead to if untreated?

Liver cirrhosis and hepatocellular carcinoma

126

What % of HBV cases lead to liver cirrhosis?

10%

127

How is hepatitis B transmitted

Blood
Sexual transmission
Vertically
Long term household contacts

128

How can HBV be transmitted in blood?

IVDU
HCW with needle stick injury

129

What is the risk of a HCW contracting HBV if they get a needlestick injury with a contaminated needle?

1:3

130

How can HBV be transmitted vertically?

Mother to child
Perinatal transmission in patients from high endemic areas

131

What is the incubation period of HBV?

6 weeks to 6 months

132

What can HBV progress too?

Chronic infection

133

What are the symptoms of acute hepatitis B?

Jaundice
Fatigue
Abdominal pain
Anorexia
Nausea
Vomiting
Arthralgia

134

What is athralgia?

Pain in joints

135

At what level is AST/ALTs in acute hepatitis B?

1000s

136

What % of hepatitis B patients present with no/vague symptoms?

50%

137

How long does it take for some people to clear the infection?

Within 6 months

138

What may result from acute hepatitis B?

Fulminant hepatic failure
Becomes chronic

139

In what % of acute hepatitis B cases result in fulminant hepatic failure?

1%

140

What % of acute hepatitis B cases become chronic?

6-10% of adults (more if from infancy)

141

What is classified as chronic hepatitis B?

Persistence of HBsAg after 6 months

142

What may result from chronic hepatitis B?

Cirrhosis
Hepatocellular carcinoma

143

What % of chronic hepatitis B infections lead to cirrhosis?

25%

144

What % of chronic hepatitis B infections lead to hepatocellular carcinoma?

~5%

145

How is hepatitis B diagnosed?

Serology

146

What is detected for in serology diagnosing hepatitis B?

Antigens and antibodies

147

When will surface antigen (HbsAg) be found in hepatitis B?

Acute infection
Chronic infection

148

When will surface antigen not be found in hepatitis B infection?

Past (cleared) infection
Never infected, vaccinated

149

When will core antibody (HbcAb) be found in hepatitis B infection?

Acute infection
Past (cleared) infection
Chronic infection

150

What core antibody will be found in acute hepatitis B infection?

IgM

151

What core antibody will be found in past (cleared) hepatitis B infection?

IgG

152

What core antibody will be found in chronic hepatitis B infection?

IgG

153

When will core antibody not be found in hepatitis B infection?

Never infected, vaccinated

154

When will surface antigen (HbsAb) be found in hepatitis B infection?

May or may not be in acute infection
Past (cleared) infection
Never infected, vaccinated

155

When will surface antibody (HbsAb) not be found in hepatitis B infection?

Chronic infection

156

What is the cure for hepatitis B?

None

157

What is the treatment for hepatitis B?

Life-long anti-virals to suppress viral replication

158

Are life-long antivirals required for everyone with hepatitis B?

No

159

Who will not require life-long antiviral treatment for hepatitis B?

'Inactive' carrier

160

How is someone determined to be an inactive carrier of hepatitis B?

Low viral load
Normal LFTs
Mild fibrosis

161

What is the vaccine for hepatitis B?

Genetically engineered surface antigen

162

How is the hepatitis B vaccine given? /

3 doses + boosters if required

163

How effective is the hepatitis B vaccination?

Effective in most people

164

How does the hepatitis B vaccine convey protection?

Produces surface antibody response

165

What surface antibody response is adequate to provide protecting in hepatitis B?

>10

166

What surface antibody response provides long-term protection in hepatitis B?

>100

167

How many people are infected with HCV per year around the world?

Unknown

168

Why is the number of people infected with HCV around the world unknown?

Many are not tested

169

How many people in the world have the HCV virus?

Around 200 million (3% of the population)

170

What is the prevalence of HCV in the UK population?

1 in 200 (most of them untested)

171

How many deaths from HCV were there in the UK in 2014?

424

172

What can HCV lead to if untreated?

Liver cirrhosis and hepatocellular carcinoma

173

In what % of untreated HCV infections does liver cirrhosis result?

80% of cases

174

Who is at risk of HCV infection?

IVDU/crack or heroin smokers
Blood transfusion patients prior to 1991
Infants born to HCV positive mothers
Sexual contact
Needle stick injuries to HCW

175

How is the risk of getting HCV from sexual contact increased?

If HIV infected

176

What is the risk of healthcare workers getting HCV from a needlestick injury with a contaminated needle?

1:30

177

What % of patients with HCV become chronically infected?

80%

178

What does chronic liver disease and cirrhosis in patients who develop it as a result of HCV result in?

Decompensated liver disease
Hepatoma
Transplant
Death

179

What % of people with HCV have no symptoms?

80%

180

What are the symptoms of HCV?

Fatigue
Anorexia
Dark urine
Nausea
Abdominal pain

181

Can hepatitis C be cured?

Yes

182

What is the cure for hepatitis C?

Directly acting antiviral drug combination

183

How long is the course of treatment for hepatitis C?

8-12 weeks

184

What is the chance of cure for hepatitis C?

>90%

185

How much does a course of hepatitis B treatment cost?

£50,000-£80,000

186

Can someone treated and cured of hepatitis C get reinfected?

Yes

187

Is there a vaccine for hepatitis C?

No