Measles-Small Pox Flashcards
(60 cards)
Historical Perspective
In ancient times, measles often confused with other skin diseases, especially smallpox
First identification of measles as distinct disease separate from smallpox was made in 10th Century A.D.
Distinction between measles and smallpox was then lost for several centuries
Distinction again made in 17th Century
Measles resembles….
The Plague
How does measles resemble the plague
due to a rash common to both diseases
Measles is caused by what type of virus?
enveloped RNA-containing virus
What virus causes measles?
paramyxovirus
What is the meaning of paramyxovirus?
para(alternate)
myxa(mucus)
virions bind to mucoproteins
Virion components of Measles?
Envelope derived from plasma membrane
Coiled helical nucleocapsid
Diameter 150 - 300 nm (filaments
Genome components of Measles?
Linear single stranded RNA (negative sense)
single segment
(3) genus of the subfamily paramyxovirinae?
paramyxovirus
Rubulavirus
morbillivirus
(1) genus of the subfamily pneumovirinae?
pneumovirus
The clinical disease caused by measles virus is known as…
rubeola
How is measles transmitted?
Respiratory Route via respiratory droplets
Where does initial site of infection occur for measles? Incubation?
epithelial cells of the respiratory tract
9 to 11 days
What are the clinical symptoms of measles?
sudden onset of sneezing, congestion, cough, rapidly increasing fever, redness of the eyes, and photophobia
Where does the virus spread during measles?
local lymph nodes and into the blood where a viremia is established in macrophages
Koplik spots
tiny bluish white spots on a red base that appear within the mouth within 2 to 4 days after infection
What part of the skin does the virus infect?
endothelial cells of small blood vessels
(3)What does the skin rash indicate?
Onset of rash coincides with appearance of cellular immunity
Rash is due to action of CD4+ DTH cells that recognize virus-infected endothelial cells
Destruction of virus-infected endothelial cells results in tiny hemorrhages that appear under the skin resulting in rash characteristic of measles
What is the pathogenesis for the rash during measles?
appears first on forehead and behind ears
within 24-48 hours; spreads to face, neck, trunk, and limbs
persists for next 10 days
recovery accompanied by life- long immunity to re-infection
What does SSPE stand for?
Subacute Sclerosing Panencephalitis
What is unique about multiple sclerosis?
it has a unique north-south geographical gradient
Upon migration studies what can you infer about multiple sclerosis?
migration prior to 15 years of age- same risk as native born
migration after 15 years of age- same risk as birthplace
What type of vaccines were licensed in the US in 1963?
both killed & live attenuated measles
Why was the formalin-fixed killed vaccine withdrawn from the market?
recognition of “atypical” measles in recipients associated with encephalitis