Hepatitis viruses Flashcards
1
Q
What shape is the Hep A virus?
A
- Spherical
2
Q
Is the Hep A virus enveloped or non-enveloped and does it consist of RNA or DNA?
A
- Non-enveloped
- Single stranded RNA genome
3
Q
Is the Hep A virus stable?
A
- Yes
4
Q
How can the Hep A virus be transmitted? (4 points)
A
- Person to person
- Food-borne
- Water-borne
- Faecal-oral route
5
Q
Is the Hep A virus more prevalent in developed or developing countries?
A
- Developing
6
Q
What is the incubation period for the Hep A virus?
A
- 2-7 weeks
7
Q
What is an ‘incubation period’?
A
- The period between exposure to an infection and the app earace of the first symptoms
8
Q
What does Hep A usually cause on people in relation to infections?
A
- Usually sub clinical infection - don’t necessarily have any obvious signs or symptoms
9
Q
What is the mortality rate of Hep A?
A
- <0.2%
- People don’t usually die from Hep A
10
Q
Does Hep A have the ability to cause chronic infections?
A
- No
11
Q
How can you diagnose Hep A? (2 points)
A
- Demonstartion of HAV antigen in faeces
- Serology: detection of IgM anti-HAV
12
Q
What is meant by ACTIVE immunisation?
A
- Give an antigen and the body produces own antibodies
13
Q
What is meant by PASSIVE immunisation?
A
- Give a pre-formed antibody
14
Q
A person can be given human normal immunoglobulin for short-term protection against Hep A. How long does this protect you for?
A
- 4 months
15
Q
What is in the Vaccine for Hep A? (2 points)
A
- Formaldehyde-inactivated hep A virus
- Prepared from the GBM or HM 175 strain of hepatitis A virus
16
Q
How long does a single dose of the Hep A vaccine give a person antibodies for?
A
- 1 year
17
Q
If a person is given the Hep A vaccine and then given a booster dose 6-12 months later, how long should this give them immunity for?
A
- Immunity for 10 years
18
Q
Hoe many people globally are infected with the Hep B virus?
A
- 350 million (global problem)
19
Q
70% of new cases of Hep B occur among people between the ages of what?
A
- 15-39
occurs relatively young
20
Q
How much more infectious is Hep B than HIV?
A
- 100 times
only need a small amount of blood to transmit - very infectious
21
Q
Is there an effective vaccine available for Hep B?
A
- Yes
22
Q
Is there a curative treatment for Hep B?
A
- No, but new antivirals can suppress the viral loa d
23
Q
What is meant by ‘viral load’?
A
- The number of viral particles per ml of blood
24
Q
Is there DNA or RNA in the Hep B virus?
A
- Partially double stranded DNA virus
25
What is another name for the hepatitis DNA virus?
- Hepadnavirus
26
How many subtypes of HBV virus exist?
- 8
| - You are protected against all of them by the 1 vaccine
27
What is a Dane particle?
- A spherical particle found in the serum in the Hep B that is the virion of the causative double-stranded DNA virus
28
What is another name for the outer coat of a hep B particle?
- Hep B surface antigen
29
If a strand of Hep B has the Hep B core antigen what does this mean?
- The likelyhood of transmitting the infection is very high
30
What are the 2 different forms a Hep B virus particle can be?
- Long, cylindrical forms
| - Short, circular forms
31
What is the most common risk factor of getting infected with the Hep B virus?
- Heterosexual exposure
| - A big problem is that a lot of the patients that are infected with the virus will not know
32
What are the 3 main routes of transmission of the HBV virus?
- Bloodborne
- Sexual
- Perinatal
33
What categories of people have a higher risk of transmitting HBV? (7 points)
- IV drug users
- Sexually active hetero- and homosexuals
- Children of immigrants from disease-endemic areas
- Sexual/household contacts of infected people
- Infants born to infected mothers
- Healthcare workers
- Haemodialysis patients
34
What is the recovery rate of adults in non endemic areas with HBV?
- 95% recovery
35
What is the recovery rate of infants in endemic areas with HBV?
- 5-20% recovery
36
In non endemic countries, what percentage of adults have the inapparent disease of HBV and what percentage has acute hepatitis?
- 80% inapparent disease
| - 20% acute hepatitis
37
In endemic countries, do most infants with HBV have an inapparent or chronic hepatitis?
- Mostly inapparent disease
38
In people with chronic HBV what can this lead to the development in the long term? (2 points)
- Cirrhosis and liver cancer
39
What is the % risk of chronic HBV for neonates?
90%-100%
40
What is the % risk of chronic HBV for children?
20%-40%
41
What is the % risk of chronic HBV for the HIV positive (immunocompromised)?
21%
42
What is the % risk of chronic HBV for adults?
<5%
43
If the Hep B surface antigen is positive for more than 6 months, but the person has not developed an antigen to this, what are they?
- A carrier
44
In someone who is making a normal recovery from Hep B. If you look in the blood at an early stage what will be present? (2 points)
- The DNA of the virus
| - e antigen
45
As someone is recovering from Hep B what is the last antibody to develop?
- The antibody to the surface protein of Hep B (anti-HBs)
46
In someone who is recovering from Hep B, once the antibody is created to the Hep B e antigen what happens to the patient?
- The patient is now not nearly as infectious
47
What would you give a patient for passive immunisation against the Hep B virus?
- Hep B immunoglobulin
| - From pooled plasma
48
What is the main use for passive immunisation against Hep B and when should this be administered by?
- Main use: single acute exposure in non-immune individual
| - Administer within 48 hours
49
The HBV vaccine is highly immunogenic. What does this mean?
- It is very able to produce an immune response
50
Is a booster dose required for the HBV vaccine?
- no, no booster dose is required for persons who have responded to the HBV vaccine
51
In active immunisation against HBV what is in the vaccine?
- Hep B surface antigen (HBsAg) absorbed on aluminium hydroxide adjuvant
- Produced by recombinant DNA technology (perfectly safe)
52
In active immunisation against HBV how effective is the protection?
- Protection is good
53
In active immunisation against HBV how effective is the response against the virus?
- Not always good - need to check antibody levels
54
In active immunisation against HBV how is the vaccine administered?
- IM (intramuscular)
55
In active immunisation against HBV how many doses are required in the treatment and when?
Three doses
- Time zero
- One month
- 6 months
56
In active immunisation against HBV what has to be tested post immunisation?
- Test for antibody response 2-4 months after vaccination course complete
57
In active immunisation against HBV do vacc ine responders need any post exposure prophylaxis?
- None required
58
In active immunisation against HBV do vaccine non-responders need and post exposure prophylaxis?
- In the occupational setting, Hep B immune globulin (HBIG) provides an estimated 70%-75% protection from HBV infection
59
The average volume of blood inoculated during a needlestick injury with a 22 gauge needle is 1 microliter. How many infectious doses of HBV are can be contained in this?
- 100 doses
| - A non responder to the vaccine that gets a needlestick injury has a 1 in 3 chance of getting hep B
60
What is the goal of therapy of the HBV virus?
- Sustained viral supression
61
What are the 3 types of suppressant agents for the HBV virus?
Immunolodulatory agents
- interferon-alpha
- Pegylated interferon
Nucleoside analogues
- Lamivudine
- Telbivudine
- Entecavir
Nucleotide analogues
- Adefovir
- Tenofovir
- Don't cure but are very good suppressants
62
The Hep C virus was discovered in 1989. What was it previously called?
- Non-A, non-B hepatitis
63
What virus is the hep C virus?
- Flavivirus
64
How many genotypes are there for hep C?
- 1-6
| - All behave quite differently
65
How many people are affected with Hep C worldwide?
- 200 million people
66
What is the ratio of people who are infected with HIV compared to HCV?
- For every one person infected with HIV, Four are infected with HCV
67
Are there vaccines available for HCV?
- No
68
Are there treatments for HCV?
- Yes, treatments have been improved greatly but they are expensive
69
Is Hep C a DNA virus or an RNA virus?
- Enveloped RNA virus
70
Can the Hep C virus be grown in tissue culture?
- No
| - Therefore we rely on serology to make the diagnosis
71
What is the main risk factor of getting HCV in developed countries?
- Intravenous drug use
72
What are the tests available to use to detect HCV virus? (4 points)
- Anti-HCV test
- HCV-RNA test
- Viral load/quantitative HCV test
- Viral genotyping
73
How is the anti-HCV test used to diagnose HCV?
- Detects presence of antibodies - indicates exposure to HCV
74
How is the HCV-RNA test used to diagnose HCV?
- Identifies presence of virus in blood - indicates active infection
75
How is the vial load/ quantitative HCV test used to diagnose HCV?
- Measures the number of viral particles in peripheral blood
- More virus in the blood the more infectious the person is
76
How is the viral genotyping test used to diagnose HCV?
- Determines the type of HCV present
| - Certain genotypes respond better than others to different forms of medication
77
What is the mean incubation period for HCV?
- 6-12 weeks
78
What is a seroconversion period?
- The time period during which a specific antibody develops and becomes detectable in the blood
79
What is the mean seroconversion period for HCV?
- 15 weeks
80
What is an acute infection of HCV like?
- Clinically mild (may be subclinical)
| - A high number of these become chronic
81
What is a chronic infection of HCV like?
- High frequency: at least 60% of those infected
- Most are clinical inapparent infection
- Most patients unaware of their disease and infectivity
- Indolent and slowly progressive over 20+ years
- Progression from milk hepatitis to cirrosis
- Link with hepatocellular carcinoma
82
From exposure of the HCV virus, what percentage of people will develop the chronic version of the virus?
- 75%
83
Of the people with chronic HCV, what percentage will not be stable and will develop cirrhosis?
- 20%
84
Of the people with chronic HCV that develops into cirrhosis, what percentage will have a slowly progressive infection and what percentage will develop liver failure, HCC, need a transplant or result in death?
- Slowly progressive = 75%
| - Liver failure, HCC, transplant, death = 25%
85
As a treatment of chronic Hep C interferon alpha can be combined with other things. What are 2 examples of this?
- Ribavirin (combined with this makes the outcome much better)
- Plus boceprevir or telaprevir (HCV protease inhibitors) for genotype 1 (combined with this and ribavirin you get much better results)
86
What are 2 examples of second generation protease inhibitors that are used as a newer treatment for chronic Hep C and how do they work?
- Sofosbuvir
- Ledipasvir
- These drugs stop new viral particles from being produced
87
Is hep D a DNA virus or an RNA virus?
- RNA virus
88
Why an Hep D only replicate when the Hep B virus is present too?
- Delta agent relies on hep B to produce the outer protein coat for Hep D
- Could be co-infectant where both infect at the same time OR
- Super infection where hep B comes first then hep D comes after
89
What percentage of patients infected with hep D recover from a co-infection?
- 90-95%
90
What percentage of patients infected with a hep D co-infection suffer from a fulminant infection (severe or sudden infection)?
2%-20%
91
What percentage of patients infected with a hep D co-infection virus develop a chronic infection?
- 2%-7%
92
What percentage of patients infected with a hep D super infection develop fulminant (a severe or rapid onset infection)?
- 10%-20%
93
What percentage of patients infected with a hep D super infection recover?
- 5%-10%
94
What percentage of patients infected with a hep D super infection develop a chronic infection?
70%-95%
95
What percentage of patients infected with a hep D super-infection or co-infection that develop a chronic infection will develop cirrhosis?
70%-80%
- This can lead to a hepatocellular carcinoma
96
Is the Hep E virus an RNA or DNA virus?
- Single stranded RNA genome
97
How can the Hep E virus be transmitted
- Faecally contaminated drinking water
98
What is the incubation period for hep E?
Incubation period 2-9 weeks
99
What is the mortality rate for pregnant women with Hep E?
- up to 20% mortality
100
Can Hep E develop into a chronic form?
- No
