Measles, Mumps and Rubell Flashcards Preview

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Flashcards in Measles, Mumps and Rubell Deck (50)
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1
Q

What type of genes cause Measles?

A

Morbillivirus genes

2
Q

Describe the genome of Morbillivirus (Measles)

A
  • Single stranded, non-segmented, negative sense RNA genome (cannot immediately be replicated into proteins because it is complementary to mRNA. Requires transcription into mRNA before it can be translated into protein).
3
Q

What is meant by a negative sense RNA genome?

A

Cannot immediately be replicated into proteins because it is complementary to mRNA. Requires transcription into mRNA before it can be translated into protein

4
Q

Where does Morbillivirus replicate?

A

In the cytoplasm of epithelial cells in the respiratory tract and mucosae.

5
Q

How is Morbillivirus (Measles) transmitted?

A
Aerosol droplets (but only over short distances).  
Contact with an infected person.
6
Q

What therapy is available to treat Measles?

A

None - only supportive care.

7
Q

What organisms does Measles affect?

A

Both humans and animals

8
Q

How long do viral measles particles remain infectious for?

A

Several hours

9
Q

What areas does the Morbillivirus (measles) infect?

A

Epithelial cells of the respiratory tract and mucosae. And the lymphoid tissues and bone marrow.

10
Q

How is the morbillivirus pathogenic - how does it cause damage?

A

Damage due to viral invasion, cytopathic changes and host immune response

11
Q

Outline some of the symptoms of Measles.

A
  • 9-11 days after exposure to the virus a fever of around 38.3 degrees Celsius is likely
  • Coryza (runny nose)
  • Cough (due to virus attacking the respiratory tract)
  • Koplik’s spots (virus attacks mucosa)
    o Occurs 1-3 days after respiratory symptoms
  • Maculopapular rash
    o
  • Lymphadenopathy (immune suppression)
12
Q

What causes Maculopapular rash in people with measles and when does this symptom occur.

A

o Virus antigens and pathogens are in the tissues and attack the epithelial cells
o Develops a day after Kopilk’s spots
o Develops over 2-3 days then fades

13
Q

What is the immune response to Maculopapular rash in people with Measles?

A

o Immune response = T-cells targeting infected endothelial cells in the small blood vessels

14
Q

What is meant by the term lymphadenopathy ?

A

Swelling of the lymph nodes.

15
Q

Outline how diagnosis of Measles can be confirmed.

A
  • Koplik’s spots – small greyish white lesions in the mouth that fade once the rash has appeared.
  • Virus isolation
    o From onset of symptoms and about 2-3 days of the rash
    o Expensive and slow technique
    o Serodiagnosis – use of haemagglutination inhibition or ELISA to measure antibodies.
16
Q

Describe some of the complications that may occur in patients with Measles.

A
  • Superinfection of middle ear (otitis media, 8% cases)
  • Superinfection of lung (viral/ bacterial pneumonia in 6% of cases)
  • Secondary infections such as varicella-zoster and influenza viral infections
  • Diarrhoea in 8% of cases
  • Neurological complications
    o Meningoencephalitis in 1/1000 cases which causes deafness, mental retardation and seizures
    o Subacute sclerosing pan encephalitis (1 in 100,000 cases). Develops 1-10 years after the disease. Progressive results are coma and death.
     Incidence decreased since vaccination.
17
Q

In developing countries, why is contracting a disease more likely?

A

Malnutrition leads to immunosuppression.

18
Q

In developing countries, why are diseases often more severe?

A

Infections become complicated by bacteria and diarrhoea.

19
Q

What type of vaccine is the MMR vaccine and where is it stable?

A

Live attenuated vaccine

Stable under refrigeration

20
Q

What does the MMR vaccine contain and how does work?

A

o Contain live measles, mumps and rubella viruses that have been weakened.
o These stimulate the immune system but do not cause disease in healthy people

21
Q

What type of people shouldn’t be given the MMR vaccine?

A

 Shouldn’t be given to people who are clinically immunosuppressed due to drug treatment or underlying illnesses.

22
Q

When are the 1st and 2nd doses of the MMR vaccine given?

A

1st dose in the first year after birth, 2nd dose at 2 years 4 months.

23
Q

What % protection does the MMR vaccine give against measles and rubella?

A

99%

24
Q

What % protection does the MMR vaccine give against mumps?

A

88%

25
Q

Outline some of the side effects of the MMR vaccine, when these are likely to occur and how common they are.

A
-	Redness, pain and or swelling at the infection site
o	Very common
-	Raised temperature, loss of appetite, measles like rash
Common
6-10 days after vaccination
Lasts 2-3 days
-	Mumps like symptoms (raised temperature, swollen glands in the neck, cheek or under the jaw). 
o	About 3 weeks after vaccination
o	Common
-	Inflammation in the joints 
o	Rare in children but common in adults
o	Lasts approx. 3 days 
o	Common
-	Fits
o	Occur in every 1 in 1000 doses of the vaccine
o	As a result of the measles infection
o	Rare
-	Idiopathic thrombocytopenic purpura (A skin rash of small, bruise-like spots develops)
o	Very rare
o	Up to 6 weeks after vaccination
26
Q

What may happen if a person is allergic to the MMR vaccine?

A

Anaphylaxis - this causes life-threatening breathing and/or circulatory issues.

27
Q

How is anaphylaxis due to the MMR vaccine treated?

A

Medically with adrenaline.

28
Q

What strategy is used to eliminate the measles virus?

A

Having a high MMR vaccine coverage / uptake.

29
Q

What virus causes mumps?

A

Paramyxovirus

30
Q

What is the reservoir for Paramyxovirus (mumps)?

A

Humans

31
Q

Where does Paramyxovirus (mumps) replicate and spread to?

A

Replicates in the upper respiratory tract (specifically the nasopharynx) and then spreads to the lymph nodes. It can then cause viremia (virus in the blood) and spread to multiple tissues.

32
Q

What is inflammation of the salivary glands known as?

A

Parotitis

33
Q

What is caused when Paramyxovirus (mumps) infects the meninges?

A

Aseptic meningitis

34
Q

What is it called when the testes become infected by Paramyxovirus (mumps) and inflamed?

A

Orchitis

35
Q

How is Paramyxovirus (mumps) transmitted?

A
  • Aerosol transmission over a short distance

- Transmitted through direct contact with saliva or respiratory droplets

36
Q

How long do Paramyxovirus particles (mumps) remain infectious for?

A

Several hours

37
Q

How long is a person infectious for after parotitis onset in mumps?

A
  • Person is infectious from 2 days prior to 5 days after parotitis onset
38
Q

Outline the symptoms of mumps

A
  • Fever
  • Headaches
  • Muscles aches
  • Parotitis
  • Meningitis
39
Q

What is Parotitis?

A

Inflammation of the salivary glands.

40
Q

Name some of the complications caused by contracting mumps.

A
  • More severe in adults
  • Deafness
  • Orchitis (testicular inflammation)
  • Pancreatitis
  • Myocarditis
  • Inflammation of the ovaries (oophoritis) and breasts (mastitis) in females who have reached puberty
  • Encephalitis (inflammation of the brain)
  • Meningitis (inflammation of the lining of the brain and spinal cord).
41
Q

What virus causes Rubella?

A

Rubivirus genes

42
Q

Describe the genome of Rubivirus (Rubella).

A
  • Single stranded positive sense (the particular viral RNA sequence can be directly translated into viral proteins) non-segmented RNA virus.
43
Q

What is meant by positive sense RNA?

A

The particular viral RNA sequence can be directly translated into viral proteins.

44
Q

Where does Rubivirus replicate?

A

In the cytoplasm of cells in the respiratory mucosa.

45
Q

What is the treatment for Rubivirus?

A

No therapy or treatment, only supportive care.

Prevented with the MMR vaccine.

46
Q

How is Rubivirus (Rubella) transmitted ?

A
  • Transmitted via direct or droplet contact with respiratory secretions
47
Q

Where (in general) does Rubivirus (Rubella) infect?

A

The lymphatic system.

48
Q

Outline some symptoms of Rubella Virus.

A
-	Red rash on the face
o	Number of small spots, which may be itchy
o	Usually starts behind the ears and spreads to the head and neck
o	Spreads to trunk and limbs
o	Usually fades after 3 days
-	Low grade fever
-	Swollen parotid glands
-	Headache
-	Conjunctivitis
49
Q

What is congenital Rubella syndrome? What does it cause?

A
  • Infection of the foetus in utero
  • Mother acquires Rubella during first trimester of pregnancy
  • 20% children suffer severe congenital abnormalities
  • 10-20% death rate
    o Deafness
    o Blindness
    o Congenital heart disease
    o Mental retardation
    o Growth retardation
    o Hepatosplenomegaly – enlarged liver and spleen
50
Q

Outline some of the complications of Rubella.

A
  • Thrombocytopenic purpura
    o Lack of platelets leading to a red rash
    o Post infections encephalopathy
     (Infection of the brain).