Flashcards in Lecture 16 Deck (82)
types of non enveloped RNA viruses
polio virus, coxsaki virus, Hepatitis A, Rhino virus, Rota virus
Types of enveloped RNA viruses
influenza, measels, mumps, rubella, rabies, retro virus (HIV, HTLV)
What does Influenze virus cause?
3 serological types of influenza
A, B, C
Define envelop of influenza virus
has two types of spikes- hemaglutinin & Neuraminidase- the envelop protein determines type specificity
Other name for influenza virus
orthomyxovirus which interacts with mucin and has an 8 segmented genome
What is the present strain causing swine flu?
Who is the influenza A virus present in?
humans- also in birds, chicken, sqine and horses-- sources for antigenic shift and pandemics
Who is the influenza B virus present in?
Transmission of influenza
air born- respiratory droplets- group A- antigenic shift every 10/11 years- group B is antigenic shift yearly
When does the infection of influenza occur?
in winter months; restricted respiratory tract- systemic symptoms ar not due to viremia
What are systemic systems of influenza due to?
due to circuating cytokines
What gives immunity to influenza?
clinical features of influenza
24-48 hours-- will have fever, myalgia, sore throat, cough- sudden onset. Resolves spontaneously in 4-7 days
Treatment for influenza?
Zanamvir & Tamiflu- inhibits release of virus from cell- effective against A and B
Amantadin effective against A
What is the natural host of Measles
single serotype- humans are the natural host
Transmission of Measles
transmission by respiratory droplets- world wide distribution-
What stage is Measles highly contagious in?
prodromal stage- non infectious after development of rashes- cough and sneezing spread disease
How often does the Measles epidemic occur?
once in 2-3 years
Clinical features of Measles?
fever, photophobia, runny nose and cough- red spot with white center on buccal mucosa of oral cavity
Define development of rash in Measles
rashes develop on face and then spreads downwards- become brownish several days later
What affect can measles have on pregnant women?
still births in pregnant women- affords life long immunity
Complications of measles
encephalitis- very rare
Sub acute schlerosing Pan- can develop years later but rare
Lab diagnosis for Measles
NONE- diagnosed on clinical grounds
Is there an antiviral drug for Measles?
Prevention of Measles
live attenuated vaccine- given at 15 months or later because before then vaccine will have no effect because maternal Abs still present
single sero type- infects URT and blood spreads to parotid gland, testes, ovaries, pancreas and sometimes meningitis
Can you get mumps more than once?
How is mumps transmitted?
through respiratory droplets- world wide distribution- peak incidence in winter