20. a. Measles Flashcards
Which characteristic best describes an infection, such as measles, that can be eradicated globally?
The reservoir is confined to humans
How frequent is encephalitis following measles
1/1000
What is the best description of Koplik spots?
Red spots with whitish/bluey centres on the buccal mucosa
What should be administered to contacts of patients with acute measles, who themselves are susceptible, to reduce the likelihood of acquiring measles?
Human immunoglobulin
Is measles a DNA or RNA virus?
RNA
What is the genus of the measles virus?
Morbillivirus
What isolation precautions are taken for measles?
Airborne
What is the incubation period for measles?
10-12 days
When is measles infectious?
From 4 days before until 4 days after the rash appears
Why is measles so infectious?
Low infecting dose
Many virus particles are shed at once
What are the virulence factors of measles?
Haemaglutinin allows adhesion
Fusion protein allows fusion of the virus and the host cell membrane
How does measles get into the body?
Large or small droplets inhaled or deposited on eyes, nose, mouth
What cells does the measles virus bind to?
Dendritic cells in alveolar spaces and submucosa of the respiratory tract
Where does the measles virus migrate to after binding to DCs?
BALT and draining lymph node where it causes massive replication of B and T cells
What happens 2-3 days after replication in the respiratory tract and regional lymph nodes?
Primary viraemia
Infection of the reticuloendothelial system
What cells are involved in the reticuloendothelial system?
Monocytes Macrophages Lymphoid organs Bone Liver Lungs
What happens during the secondary viraemia?
5-7 days after the initial infection
Infection of the respiratory tract and other organs
What are the signs of acute measles?
Fever Cough, runny nose, conjunctivitis Koplik's spots and maculopapular rash Anorexia Generalised lymphadenopathy Diarrhoea
Describe the maculopapular rash associated with measles
Initially maculopapular but can join up
Begins at hairline towards feet and disappears in the same order
Initially blanch but don’t by day 3-4
What is the brown staining on the skin after the measles rash caused by?
Capillary leakage
How long does the measles rash last for?
5-6 days
Which groups of people are more likely to have complications of the measles?
Very young
Adults
Immunocompromised
What are the most common causes of death from measles?
Pneumonia
Diarrhoea
Encephalitis
What are other causes of morbidity?
Otitis media Respiratory infection Convulsions SSPE Reactivation of HSV
