Childhood viral diseases II Flashcards
What are possible viral causes of macularpapular rashes? (in children)
Measles
Rubella
Echoviruses 4, 9, 16
Coxackievirus A9, 16, B5
Adenovirus
Parvovirus B19
What are viral causes of vesicular/papular rashes? (in children)
Varicella
Smallpox
Molluscum contagiosum
HSV
Coxsackievirus Group A members
What are viral causes of petechial or purpuric rashes? (in children)
Coxsackievirus group A
Echovirus
What are characteristics of paramyxoviruses?
Large, enveloped
(-) sense ssRNA
non-segmented RNA
Contain RNA-dependent RNA polymerase
What are characteristics of parainfluenza?
Paramyxovirus
5 serotypes cause local infections of respiratory tract
Clinical syndrome depends on strain of virus, age of patient and his/her history of previous infections
Reinfection is common
Infection stimulates local and system immunity; local Ab prevents reinfection, circulating Ab helps clear infection
Vaccines are not available; it’s difficult to vaccinate when immunological memory isn’t protective
What are the clinical and epidemiological features of parainfluenza and RSV strains?
Name the:
Virus
Major syndrome
Age occurs
Time of year
Parainfluenza Virus Type 1 and 2
Croup
6 months - 5 yrs
Autumn
PIV 3
Bronchiolitis Pneumonia
0-6months
endemic
PIV 4
URI
Children
Endemic
RSV
Bronchiolitis Pneumonia
0-6 months
Winter/epidemic
What are characteristis of RSV?
Pneumovirus (subset of paramyxoviridae) (no HA or NA activities)
HA = hemaglutinin
NA = neuraminidase
Has a F (fusion) glycoprotein
MOST important cause of lower respiratory tract infection in young children
infects virtually all children by age 2
Restricted to respiratory epithelium
Immunity is not long-lived
Prophylactic therapy: passive Ab therapies (palivizumab) for immunocompromised or CF patients
What are symptoms of mumps?
Systemic infection initially in respiratory tract
one serotype (infection confers lifelong immunity)
Viremia spreads to many different epithelial cells including:
parotid glands
testes
ovaries
pancreas
meninges
thyroid
bladder
kidney
Complications:
aseptic meningitis
meningoencephalitis
unilateral nerve deafess
orchitis (usually not causing sterility)
What are characteristics of the mumps vaccine?
live-attenuated vaccine (given in conjunction with measles and rubella - MMR)
What are symptoms of the measles virus?
Infects via respiratory tract, replicates locally, then spreads to lymphoid tissue by viremia and infects skin and lungs
* Symptoms due to immune response, rash depends on cell mediated immunity *
Symptoms:
Koplik’s spots
Conjunctivitis
Photophobia
Complications:
Post-infectious encephalomyelitis
Acute disseminated enecphalomyelitis
sequelae include: seizures and mental retardation
How do patients with reduced cell-mediated immunity respond to measles infection?
they do not get a rash, instead, they will develop Measles giant cell pneumonia
–> measles virus induced syncytia
What are characteristics of the measles vaccine?
One serotype worldwide allows for easy vaccination
Live attenuated virus vaccine
Boosters pose no problems, so several doses are now recommended
What are characteristics of Rubella virus?
Togavirus
small, enveloped
+ssRNA, nonsegmented
–> serves as template for protein synthesis
Attaches to host cell via glycoprotein spikes
Entry occurs through endocytosis (pH dependent)
What are symptoms of rubella?
most cases are subclinical
Symptoms:
Maculopapular rash
lympadenopathy
low-grade fever
conjunctivitis
sore-throat
arthralgia
—> Rash is most prominent feature
*Causes Congenital Rubella Syndrome
How does rubella spread through its host?
Respiratory entry
Srpeads to lymph nodes and RES = viremia
Secondary tissue spread = skin, fetus (teratogenic)
circulating Abs block viremia
