Childhood Viral Diseases

Question 0

Describe measles the disease

infection, incubation, recovery, special features

Answer 0

Infection: inhalation of droplets
Primary viremia: respiratory epithelial tissues
Secondary viremia: LN, tonsils, lungs, GI tract & spleen
Incubation: 10-14 days
Recovery: 20 days
Most deadly of childhood rash/fever illnesss
rash caused by virus and immune response damage to epithelial and endothelial cells (koplik spots)

Question 1

Describe the measles virus

Answer 1

Genome: (-)ssRNA
Virion: enveloped
fusion protein causes syncytia formation

Question 2

Measles– Possible Complications

Answer 2

Immune suppression (interference with CD46 & SLAM)
Opportunistic infections
Blindness in vitamin A deficient children

ADEM and SSPE development (rare and very rare)

Question 3

Measles: Symptoms and Diagnosis

Answer 3

2-3 days fever & cough, coryza and conjunctivitis
rash: Koplik spots (small bright red spots with bluish centers on buccal mucosa)

virus culture difficult, serology, ELISA, RT-PCR

Question 4

Measles Prevention

Answer 4

humans are only host
very contagious, people infections 2-3 days prior to rash
vaccination
providing vitamin A can reduce severity

Question 5

Describe the Respiratory Syncytial Virus

Answer 5

Genome: (-)ssRNA
Virion: enveloped
Paramyxovirus
fusion protein creates syncytia

Question 6

Describe the Respiratory Syncytial Virus Disease

infection, incubation, special charateristics

Answer 6

infects ciliated cells of respiratory tract epithelium,
replication limited to respiratory tract
infection by inhalation of aerosol, fomites
“ the most important viral agent of serious pediatric respiratory tract infections”
incubation: 4-5 days
recovery 7-12 days after symptom onset, upper respiratory symptoms first

Question 7

Respiratory Syncytial Virus: Prevention and Risk Factors

Answer 7

No antivirals
No vaccines
Passive immunoprophylaxis
human only reservoir
infection doesn’t yield life long immunity
risk factors: day care, school age sibilings, infants at greatest risk

Question 8

Describe Varicella Zoster Virus Biology

Answer 8

Alphaherpes virus
genome: dsDNA, large
enveloped
hundreds of proteins
replication: active and resting cells
infects neighboring cells first

Question 9

Describe Chickenpox (VZV) the disease
infection, incubation, symptoms, recovery, unique characteristics

Answer 9

infection: inhalation of droplets
incubation: 10-21 days
symptoms: fever, malaise, headache, rash
rash: 1-2 days after symptom onset, progresses for 3-6 days, on scalp, face and trunk primarily
recovery: 2 weeks (typically)
usually establishes latent infections (shingles)

Question 10

Chickenpox prevention

Answer 10

vaccination: life long immunity
antivirals: acyclovoir, interferes with genome replication, can’t eliminate latent virus, doesn’t prevent infection of cells

Question 11

Describe Poliovirus biology

Answer 11

picornavirus
genome: (+)ssRNA
non-enveloped
virus creates pore in host cell membrane

Question 12

Describe Poliovirus the disease

infection, replication, unique features

Answer 12

more common in endemic areas
infection: by material containing virus (small infectious dose)
primary replication: Peyer’s patches of small intestine (minor viremia)
secondary replication: major viremia
CNS involvment in 1:200 infections, virus replicates in grey matter of brain and spinal cord
mild disease
feccal shedding of virus for 6 months

Question 13

Poliovirus Prevention

Answer 13

vaccination (Salk-killed, Sabin-live attenuated)

targeted for eradication

Question 14

Describe Rotavirus Biology

Answer 14

Reoviridae
genome: dsRNA, 11 segments
virion: non-enveloped
membrane distruption (for entry)
genome never exposed

Question 15

Describe Rotavirus the disease

infection, incubation, symptoms, unique features

Answer 15

infection by ingestion of material containing the virus
incubation: 2-3 days
symptoms: vomiting & fever then diarrhea
virus shedding weeks before and days after recovery
severe disease most common in 6-24 month old children

Question 16

Rotavirus diagnosis and prevention

Answer 16

diagnose by antigens in stool
infant vaccines available
no antivirals
good hygiene
treatment: oral rehydration