Paramyxovirus and Rubella Flashcards
What type of virus is paramyxovirus?
- negative sense single-stranded RNA virus
- helical nucleocapsid
- enveloped
How is paramyxovirus spread?
- respiratory secretions
- person to person
- fomites
- hands
so, considered contagious virus
What are syncytia in paramyxovirus?
- infected cell can fuse membranes of neighboring cells to form a large multinucleated cell
- because of this, they can easily escape neutralizing antibodies
- common feature of paramyxovirus
What is the spread and seasonality of respiratory syncopal virus (RSV)?
- spread: person to person via respiratory droplets
- seasonality: winter/spring (Nov to Apr)
Is RSV local or generalized reaction?
local
- no viremic stage (no virus in blood)
- short incubation time: 2 to 4 days and starts with an upper respiratory tract infection
- becomes more severe reaction (bronchiolitis or pneumonia) if spread to middle and lower respiratory tract
Where is RSV restricted to?
- epithelial cells
- spreads through respiratory tract mostly by cell to cell spread or aspiration of upper respiratory tract secretions
What is the #1 cause of lower respiratory tract infections in kids over 1 and 5 and primary cause of bronchiolitis in children over 1?
RSV
Who has a higher risk of severe complications with RSV?
- premature infants due to under developed lungs and not as many maternal antibodies
- people older than 65 due to waning immunity and underlying comorbidities
- able to infect all ages
Is immunity to RSV long lasting?
No, it is not
- possible to get reinfected with the same strain
Why do older children/adults usually just have mild upper respiratory tract infections?
- partial immunity
- still get sick; just not as bad or asymptomatic
Who receives the vaccine for RSV?
- people older than 60 and pregnant people (so maternal ab can spread to infant)
What are treatment options for RSV?
- ribavirin (not very effective)
- preventive treatment: Palivizumab which is a monoclonal antibody to surface protein of RSV (downside: expensive. only given to preterm infants)
What is Human Metapneumovirus?
- another paramyxovirus which is similar to RSV but tends to infect slightly older kids
What is Parainfluenza virus?
- another paramyxovirus: spread via respiratory droplets, local, short incubation time, similar to RSV
What is distinctive about Parainfluenza?
- primary cause of croup (laryngotracheitis- inflammation of larynx and trachea)
- seal like barking cough
What type of infection is mumps: generalized or local?
- generalized/systemic
- means longer incubation times, viremic stage, can affect several different parts of body
How is mumps spread?
respiratory route via saliva
What are major defining characteristics of mumps?
- parotitis (swelling of parotid)
- orchitis (testicular swelling) which can lead to lower fertility
- unilateral hearing loss
How soon is a person infectious before symptoms with Mumps?
2 days before symptoms and 5 days after
Before the mumps vaccine, what was it a major cause of?
encephalitis and meningits
What is the vaccine for Mumps?
- part of MMR
- attenuated live virus
- outbreaks have been happening in adults and college age student even with a vaccine due to waning vaccine immunity/crowded living conditions but fewer complications with the vaccine
What type of infection is Measles: generalized or local?
- generalized
- so, longer incubation and viremic stage
How are measles spread?
- respiratory route and can be aerosolized
- very few are asymptomatic
How soon is a person infectious with measles?
4 days before and 4 days after
How many people who are in contact with someone who has measles will become infected?
90%
What are the 3 C’s of measles?
symptoms: cough, coryza, and conjunctivitis with high fever
What are Koplik spots in measles?
- appear 1 to 2 days before rash and stay 1-2 days into the rash
- know you have measles with these
- located on buccal membrane and opposite of 2nd molars or can cover entire mucous membrane
- “grains of sand/salt surrounded by red halo”
What is the cause of Measles Rash?
- cytotoxic T cells killing measle infected cells
- rash may not be present in immunocompromised people
What are some complications that can arise from measles?
- pneumonia
- encephalitis
- rare: subacute sclerosis panencephalitis (years after measles infection) which can lead to come and death
What type of vaccine is measles?
- live attnuated
- part of MMR
- given at 1 year of age because if given earlier can interfere with maternal antibodies
Is there post-exposure prophylaxis for measles?
Yes
- vaccine if given up to 72 hours may prevent disease
- immune globulin may prevent or modify disease if given up to 6 days after exposure (blood from regular blood donors bc assumed most people have antibodies to measles)
What type of virus is rubella?
- family: togavirus
- +ssRNA
- icosahedral
- enveloped
- inactivated the same way as paramyxoviruses
- systemic infection
What does Rubella cause?
- German measles (3day measles)
- congenital rubella syndrome
- milder but same as measles symptoms but also with post-auricular lymphadenopathy
- sometimes forchheimer spots on soft palate
What is rubella spread by?
respiratory droplets
When does Congenital Rubella Syndrome occur?
- if infected during the 1st trimester of pregnancy up to 20 weeks
- large outbreak in 60’s causing many neonatal deaths and congenital problems
What type of vaccine is their for Rubella?
- live attenuated
- part of MMR
