Rubella Virus Infections Flashcards

Rubella Virus Overview

• Known as German measles or 3-day measles, first distinct clinical entity described in German literature.
• Classified as a single member of the genus Rubivirus within the family Togaviridae.
• Unlike other togaviruses, rubella functions as a respiratory virus.

Structural Characteristics

• Contains three structural polypeptides: two membrane glycoproteins, E1 and E2, and a single non-glycosylated RNA-associated capsid protein, C.

RNA Properties

• The rubella virus RNA is single-stranded and spherical in shape.

Clinical Features

• Characterized by rash and lymphadenopathy, primarily affecting children and young adults.
• Associated with congenital rubella syndrome, which can have severe implications for infants.

Pathogenesis

• Follows a pathway: entry, spread via blood, lymphadenopathy, rash development, leading to potential fetal abnormalities like cataracts, heart defects, and hearing loss.

Onset of Symptoms

• Postnatal rubella symptoms become apparent on the day of birth, with the virus detected in blood and throat.

Clinical Findings and Complications

• Initial symptoms include malaise, low-grade fever, and facial rash that spreads to the body.
• Complications may include arthralgia or arthritis in 70% of adult females, rarely seen in children, alongside thrombocytopenia.

Diagnosis, Treatment, and Prevention

• Diagnosis involves culture, serology, and nucleic acid detection.
• No specific treatment exists; prevention achieved through attenuated live rubella vaccination.

Vaccine Information

• The rubella vaccine is composed of the live RA 27/3 strain.
• Efficacy of 95% observed with one dose, providing lifelong immunity.
• At least one dose is required for effective immunity.

Epidemiology and Transmission

• Transmitted through respiratory routes, less contagious than measles.
• Epidemic peaks occur in spring, with cycles every 6-10 years and pandemics every 20-25 years.
• By 2005, rubella cases in the USA were significantly low.

Congenital Rubella Syndrome

• Can lead to severe outcomes for infants, affecting all organs, causing death, premature delivery, deafness, cataracts, and heart defects.
• An estimated 85% of affected infants were exposed during the first trimester.

Important True/False Fact

• Rubella infection in pregnant women can indeed lead to fetal death or congenital defects, known as congenital rubella syndrome.

Test your knowledge on rubella virus infections with these flashcards. Learn about the virus's classification, structural components, and its historical background. Perfect for students studying virology or infectious diseases.