Rubella | Adenovirus Flashcards
What family does the Rubella virus belong to, and what are its key structural properties?
The Rubella virus belongs to the family Matonaviridae (previously classified as Togaviridae). It is an enveloped ssRNA virus with positive polarity, and its spikes have hemagglutinin activity.
How is Rubella virus transmitted, and what is its natural host?
Rubella virus is transmitted by respiratory droplets and transplacental transmission. The natural host is humans, and the disease is worldwide.
What are the clinical features of Congenital Rubella Syndrome (CRS)?
The clinical features of Congenital Rubella Syndrome are grouped into three categories:
1- Transient: growth retardation, rash, jaundice, hepatosplenomegaly.
2- Permanent: appear at birth or during the first year.
3- Developmental abnormalities: appear in childhood & adolescence.
What are the diagnostic methods for Rubella virus infection?
The diagnostic methods for Rubella virus infection include:
1- Isolation of virus in cell culture.
2- RT-PCR, throat swabs are appropriate samples for molecular method.
3- Serology for detection of IgM or IgG antibodies.
4- In a pregnant woman, the presence of IgM antibody indicates recent infection, and a 1:8 or greater titer of IgG antibody indicates immunity and protection of the fetus.
What are the prevention strategies for Rubella virus?
Prevention strategies for Rubella virus include:
1- Live attenuated rubella vaccines given in two doses to girls at 15 months of age and at school entry age, with an additional dose for girls aged 10-14 years.
2- Vaccine can be given to unimmunized young adult women if not pregnant and will use contraception for the next 3 months.
3- Immune globulin intravenous (IGIV) can be given to pregnant women exposed to rubella to decrease disease severity.
4- Termination of pregnancy if it is accepted (optional).
What diseases are caused by Adenoviruses?
Adenoviruses cause diseases such as:
1- Respiratory tract infections (upper/lower): common cold, pharyngitis, pneumonia.
2- Gastrointestinal tract (GIT) infections: gastroenteritis.
3- Eye infections: conjunctivitis, keratoconjunctivitis.
4- Urinary tract infections: hemorrhagic cystitis.
What are the key structural properties of Adenoviruses?
Adenoviruses are non-enveloped, dsDNA viruses. They have a special structure protruding from each of the 12 vertices of the capsid called fibers, which are important for attachment, hemagglutinin activity, and are toxic to human cells.
How are Adenoviruses transmitted?
Adenoviruses are transmitted through:
1- Respiratory aerosol droplets.
2- Fecal-oral route (common among children).
3- Direct inoculation of conjunctiva by fingers.
4- Direct contact and contaminated fomites.
What are the prevention methods for Adenovirus infections?
Prevention methods for Adenovirus infections include:
1- Three live, nonattenuated vaccines of serotypes 4, 7, 21 are available, used only by the military.
2- Epidemic keratoconjunctivitis can be prevented by strict asepsis and hand washing of healthcare personnel.
3- Swimming pool conjunctivitis can be minimized by chlorination of pools.
4- Environmental surfaces can be disinfected with sodium hypochlorite.
What are the clinical features of Adenovirus eye infections?
Adenovirus eye infections include:
1- Swimming pool conjunctivitis mainly in children, lasting 1–2 weeks with complete recovery.
2- Epidemic keratoconjunctivitis mainly in adults, which is highly contagious, usually resolves in 2 weeks but may leave subepithelial opacities in the cornea for up to 2 years.
