Measles, Mumps and Rubella Flashcards
[6-minute video]: Measles - Professor Dave Explains
[6-minute video]: Mumps - Osmosis from Elsevier
[7-minute video]: Rubella - Animated Biology with Arpan
🛸
Briefly discuss the structure and genome of Paramyxoviruses.
🛸 enveloped, spherical or pleomorphic
🛸 non-segmented negative-sense RNA
[Diagram]
Paramyxovirus, which causes measles, is classified under the genus ____________.
Morbillivirus
Discuss the pathogenesis of measles.
🛸 The measles virus enters the body through the respiratory tract. It attaches to host cells using the hemagglutinin (H) protein, which binds to receptors like CD150 (Signalling Lymphocytic Activation Molecule: SLAM) on immune cells.
🛸 The fusion (F) protein facilitates the fusion of the viral envelope with the host cell membrane, allowing the viral RNA to enter the host cell.
🛸 Inside the host cell, the viral RNA-dependent RNA polymerase transcribes the negative-sense RNA genome into positive-sense mRNA, which is then translated into viral proteins.
🛸 The virus initially replicates in the alveolar macrophages and dendritic cells and then spreads to local lymphoid tissues.
🛸 The virus then disseminates through the bloodstream to various organs, including the skin, liver and spleen.
[Diagram] [Diagram 2] [Diagram 3]
Outline signs and symptoms of measles.
fever, dry cough, runny nose, sore throat, conjunctivitis, Koplik’s spots, maculopapular rash
[Diagram 1] [Diagram 2] [Image 1] [Image 2]
Koplik spots: [Image 3] [Image 4]
Further notes:
🛸 A maculopapular rash is characterized by both flat and raised skin lesions. Features:
(a) Macules: flat, discolored spots on the skin
(b) Papules: small, raised bumps
🛸 [Short video]: Measles vs Chickenpox
What complications may be associated with Measles infection?
(1) Bronchopneumonia: It is the most common cause of death from measles in young children. [It affects about 1 in 20 children with measles.]
(2) Otitis media: An ear infection that can lead to hearing loss if not treated properly. [It occurs in about 1 in 10 children with measles.]
(3) Laryngotracheobronchitis: Inflammation of the larynx, trachea, and bronchi, causing barking cough and difficulty breathing.
(4) Diarrhea
(5) Blindness: Can result from severe measles infection, particularly in malnourished children or those with vitamin A deficiency.
(6) Encephalitis: This includes:
✔ Acute Meningoencephalitis (AME): Inflammation of the brain and its surrounding membranes, leading to severe neurological symptoms.
✔ Subacute Sclerosing Panencephalitis (SSPE): A rare, fatal brain disorder that occurs years after the initial measles infection.
Further notes:
Subacute Sclerosing Panencephalitis (SSPE) is a devastating and rare neurological disorder that typically develops 7 to 10 years after a person has recovered from measles.
Pathogenesis:
Cause: SSPE is caused by a persistent infection with a mutated form of the measles virus that remains in the brain.
Mechanism: The virus slowly damages the central nervous system, leading to progressive neurological deterioration.
Symptoms:
Early Symptoms: Behavioral changes, memory loss, and intellectual decline.
Progression: As the disease advances, symptoms include muscle spasms, seizures, and loss of motor skills.
Late Stages: Severe neurological impairment, leading to coma and eventually death.
Prognosis:
Outcome: SSPE is almost always fatal, with most patients dying within 1 to 3 years of diagnosis.
Treatment: There is no cure, but antiviral medications and supportive care can help manage symptoms and potentially slow progression.
Briefly discuss diagnostic tests for Measles.
(1) Serology
🦠 IgM antibodies: Detection of measles-specific IgM antibodies in the blood is a primary method for diagnosing acute measles infection. These antibodies typically appear within a few days of rash onset and can be detected for up to a month.
🦠 Paired IgG: Measuring IgG antibodies in paired serum samples taken during the acute and convalescent phases can show a four-fold increase, confirming recent infection.
(2) PCR testing of throat, nasopharynx, blood or urine samples
(3) Lymph Node Biopsy: Examination of a lymph node biopsy can reveal multinucleated giant cells, known as Warthin-Finkeldey cells, with paracortical hyperplasia. These findings are characteristic of measles infection and can support the diagnosis, especially in complicated cases. [Slide 1] [Slide 2] [Slide 3] [Slide 4]
(4) Culture: This method is less commonly used due to the availability of PCR.
Briefly discuss treatment of Measles.
✔ treatment is supportive
✔ no specific antiviral medications have been licensed for the treatment of measles
Briefly discuss prevention of Measles.
💉 Administration of MMR (Measles/Mumps/Rubella) vaccine which contains live attenuated viruses.
Name three types of Measles-containing vaccines.
(a) Measles & Rubella vaccine (MR) [given in Kenya at 9 and 18 months]
(b) Measle Mumps & Rubella vaccine (MMR)
(c) Measles, Mumps, rubella and varicella Vaccine (MMRV)
Further notes:
Measles-only is currently not available.
Which vitamin has been used in the treatment of measles?
Vitamin A
Mumps virus
(a) Family
(b) Basic structure
(c) Genome type
Mumps transmission
🩺 Respiratory droplets
🩺 Direct contact with saliva of infected persons e.g through sharing utensils
🩺 Touching surfaces or objects contaminated with the virus and then touching the mouth or nose
Further notes:
It most commonly affects children between the ages of 5 and 9.
