– Small
– Icosahedral capsids
– Outer
envelope is derived from the host's plasma membrane.
–
Arboviruses (arthropod borne viruses) and
rubella virus.
Rubivirus genus comprises the rubella virus.
- Rubella, aka, German measles is transmitted via respiratory droplets.
– Upon inhalation, the virus infects the
upper respiratory tractand travels to the
lymph nodes.
–
Viremia disseminates the virus systemically.
- Infection may be asymptomatic.
- When present, symptoms are attributed to the formation of immune complexes.
– In
children, symptoms are typically mild, and include rash.
– In older children and
adults, symptoms can be more severe, and include rash and arthralgia.
- Infection triggers antibody and T-cell responses that clear the virus from the host.
- Immunity is life-long.
Congenital rubella syndrome aka Gregg Syndrome
– "Blueberry muffin lesions"
– Cataracts
– Serious long-term congenital defects include
deafness, blindness, cardiac dysfunction, and developmental impairment.
Vaccine
- MMR (Measles, Mumps, and Rubella) vaccine prevents rubella infection and congenital defects.
– Recommended for all children.
Alphaviruses
Broadly separated into those that cause encephalitis, and those that cause arthritis.
- Equine encephalitic viruses include the Eastern, Western, and Venezuelan strains.
- Infections are often asymptomatic.
- Mild cases produce flu-like symptoms including fever, chills, and myalgia.
- More severe cases progress to encephalitis.
- Arthritic viruses include Sindbis virus (SINV) and Chikungunya viruses.
Although Sindbis virus can cause arthritic symptoms, it is also classified as a member of the Western Equine Encephalitis complex.
- "Chikungunya" means "to become contorted"
– Its name derives from the bent posture of individuals experiencing arthritic symptoms.
– The arthritis may be short lived, but some individuals experience recurrent episodes.
– Many individuals experience rash.
Image References
“Chikungunya.” Wikipedia, July 31, 2018. https://en.wikipedia.org/w/index.php?title=Chikungunya&oldid=852854180.
“Eastern Equine Encephalitis.” Wikipedia, July 19, 2018. https://en.wikipedia.org/w/index.php?title=Eastern_equine_encephalitis&oldid=851047709.
“Rubella.” Wikipedia, June 27, 2018. https://en.wikipedia.org/w/index.php?title=Rubella&oldid=847770501.