Childhood viral diseases Flashcards
Biology of Measles including family, genome, virion
measles family: paramyxovirus genome: - ssRNA virion: enveloped A helical enveloped virus that replicates in cytoplasm and buds outside of cell
Measles Virus replication
replicates in cell in the cytoplasm fusion protein causes syncytia formation
describe measles the disease
infected by inhalation of aerosolized droplets with a inoculation period of 10-14 days
recovery of about 20 days
most deadly of childhood viruses
symptoms onset coincides with second round of virus replication. occurs in LN, tonsils, lungs, GI tract, spleen
one in spleen secondary viremia
what is viremia
viremia is virus in the blood
characteristics of measles
virus and immune response damage to epithelial and endothelial cells, kopik spots
Complications of measles
immune suppression: interference with CD46 and signaling lymphocyte activation molecule (slam molecules)
Opportunistic infections- streps, staph, influenza
blindness from vitamin A deficeincy
ADEM - rare demyelinating disease
SSPE: very rare, 7-10 years after infection progressive neurological deterioration
diagnosis of measles
symptoms: 2-3 days fever and cough, coryza and conjunctivitis
rash: koplik spots (small bright red spots with bluish centers on buccal mucosa.
Lab: virus isolation in culture, Serology, ELISA RT-PCR
Measles Prevention
one infection causes 15- 20 very very contagious
infectious 2-3 prior to rash
humans only host
Vaccine: life long immunity, live vaccine, (Autism and colitis correlation retracted)
providing vitamin A can reduce severity
NO ANTIVIRALS
primary replication of measles?
local lymph nodes to lungs to aerosol spread
aerosol spread = transmission
Measles can lead to what?
ADEM and SSPE
Treatment of Measles is what?
prevention with vaccine
Measles in USA
measles declared eliminated in 2000 from USA. introduced to USA from international visitors outbreaks common in 2013 and 2011
Respiratory Syncytial Virus (RSV) Biology including family, genome and virion
Family: paramyxovirus
genome: -ssRNA
virion: enveloped
has several proteins including polymerase which is needed for replication
Replication of RSV
replicated in cytoplasm needs polymerase
like measles replication
RSV biology in cell and body
RSV infects ciliated cells in the respiratory tract epithelium
fusion protein creates syncytia and virus buds from cellular surface
Describe the infection of RSV
RSV limited to respiratory tract and recovery is 7 to 12 days after onset. Very serious in children where infection occurs by inhalation of aerosol famine.
inoculation period: 4-5 days. upper respiratory symptoms then lower
IgA response to measles is ______ so ______
IgA response to RSV _____ so _____
IgA response to measles is high so life long immunity occurs
IgA response to RSV is low so no immunity
RSV viral characteristics
RSV has no life long immunity and no animal reservoirs
low cytotoxicity thought to result in slower immune response
infection risk factors? day care, school
risk for more severe disease? premature birth, male, second hand smoke, lack of breast feeding
RSV prevention and treatment
No antiviral No Vaccine.
Passive immunoprophylaxis- targets F protein given IM once a month
Varicella Virus biology including family, genome, virion
Family: alphaherpersvirus
genome: dsDNA and large
virion: enveloped
lots and lots of proteins
Varicella bio facts
replicates in nucleus of cell, needs active cell for replication, infects neighboring cells first
Varicella transmission, infection
transmission: inhalation of aerosolized droplets
incubation: 10-21 days
varicella symptoms
fever, malaise, headache
rash 1 to 2 days after symptom onset rash progress for 3 -6 days, rash on scalp, face, trunk
recovery about 2 weeks
recovery from varicella induces what
cell mediated immunity
what happens when varicella becomes latent
can later develop into shingles
prevention and treatment of varicella
vaccination: primary option, life long immunity, life virus
antivirals: acyclovir: interferes with genome replication, cannot eliminate latent virus, does not prevent infection of cells, drug resistance being observed
Polovirus bio family, genome, and virion
family: picornavirus
genome: +ssRNA replicates in cytoplasm
virion: non enveloped
proteins: capsid non structural proteases and polymerases
polovirus bio facts
replicates in cytoplasm, virus particle creates pore in cell membrane, genome serves as mRNA
replication happens primarily in Peyers patches of small intestine and secondary in major viremia
Polio disease facts
prevalent in endemic areas in native children, infection occurs by ingestion of material with polio virus, low infectious dose, leaps from intestines to blood to nervous system where it causes greatest problems
fecal shedding of virus for 6 weeks
Polio disease and CNS
CNS involvement in 1 out of 200 infections.
Virus replicates in gray matter of brain and spinal cord causing limb paralysis from anterior horn damage and respiratory paralysis from damage to medulla
Polio prevention and treatment
Vaccine: salk (killed), sabin (live)
no animal reservoir
targeted for eradication
Rotavirus family, genome, vision, proteins
family: reoviridae
genome: dsRNA 11 segments (genome never exposed)
virion: non enveloped
proteins: VP4: attachment and fusion
VP1: polymerase
VP2: RNA binding
VP3: transferase
Rotavirus biology facts
replication in cell, disrupts membrane and genome is never exposed diagnosed by antigens in stool
how is rotavirus diagnosed
antigens in stool
Rotavirus the disease infections, symptoms
infection by ingestion of materials w virus
incubation: 2 days of vomitting and fever
diarrhea: 2 to 3 days after puking lasts 3 to 8 days
virus shedding for weeks
severest in children 6 to 24 months olds
treatment of rotavirus and prevention
prevention: vaccines for infants
NO antivirals
oral rehydration, hand washing
