Transcript Paramyxoviruses

Dr. Nehal Draz
Myxo = affinity to mucin
Myxoviruses
Orthomyxo
viruses
-Smaller
-Segmented RNA genome
-Liable to Agic variation
Influenza viruses
Paramyxo
viruses
-Larger
-Single piece of RNA
- Not liable to Agic variation
- Parainfluenza
- Mumps vairus
- Measles virus
- Respiratory
syncytial virus
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Large Spherical
envelopped
Unsegmented –ve sense
RNA
The lipid envelope is
associated with 2-virus
specific glycoptns;
HaemaglutininNeuraminidase (HN)
ptn& fusion (F) ptn
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Commonest cause of bronchitis &
pneumonia among infants< 1yr.
Causes repeated infections
throughout life, usually associated
with moderate- to severe cold –like
symptoms
Severe lower respiratory tract
disease may occur at any age,
especially elderly & those with
compromised cardiac, pulmonary or
immune systems
Specimens: nasal secretionsnasopharyngeal aspirate
1- Direct virus demonstration:
- DIF: for detection of viral Ag
- RT-PCR for detection of viral RNA
2- Viral isolation:
- nasal secretions inoculated onto (HeLa)
- Growth is recognized by development of
CPE in the form of giant cells & syncytia
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Symptomatic treatment for mild
disease
Oxygen therapy & may be
mechanical ventilation in children
with severe disease
Ribavirin aerosol
No vaccine is yet available
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HPIVs are second to RSV as a
common cause of lower respiratory
tract disease in young children
Similar to RSV, HPIVs can cause
repeated infections throughout life,
usually upper respiratory tract illness
Can also cause severe lower
respiratory tract infections ammong
immunocompromised patients
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Each of the four HPIVs has different
clinical & epidemiologic features
The most distinctive clinical feature
of HPIV-1& HPIV-2 is croup
HPIV-3 is more associated with
bronchiolitis & pneumonia
HPIV-4 is infrequently detected,
because it is less likely to cause
severe disease
Croup (laryngotracheobronchitis
difficulty in breathing, hoarseness and
a seal bark-like coughing
Specimens: nasal secretionnasopharyngeal aspiratebronchoalveolar lavage
1- Direct virus demonstration:
- DIF: for detection of viral Ag
- RT-PCR for detection of viral RNA
2- Viral isolation:
- Specimens are inoculated onto (MKTC)
- Growth is recognized by hemadsorption
using guinea pig RBCs or by direct IF
3- Serological tests:
 Based on Nt, HI, or ELISA for
detection of IgM or IgG
 Paired acute & convalescent sera are
necessary for IgG detection
 A four fold or more rise in the titre
indicates infection
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Causes epidemic parotitis ( non
suppurative inflammation of parotid)
Mode of transmission:
saliva
Via aerosols & fomites
The virus is secreted in urine so
urine is a possible source of
infection
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Infects children 5-15years
Replicates in the nasopharynx
&regional LNs
Incubation period: 2-25 d
Lasts 3-5 d
viremia
-Salivary
-Pancreas
-Testes
-ovaries
glands
meninges
Long life immunity due to IgG neutralizing Abs
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Severe aseptic meningitis in adults
Orchitis in adult males which might
cause sterility
Pancreatitis
Oophritis & thyroiditis
Specimens: - saliva
- CSF
- urine
1- Direct virus demonstration:
- RT-PCR for detection of viral RNA
2- Viral isolation:
- Specimens are inoculated onto (MKTC)
or chick embryo
- Growth is recognized by hemadsorption
or by direct IF & by characteristic CPE
giant cell formation
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3- serology:
ELISA is used for detection of IgM or
IgG
For IgG, paired acute & convalescent
sera are necessary
Four fold or more rise in IgG titer
indicates infection
Mumps vaccine
Active immunization
-Live attenuated
-Given by subcutaneous injection
-Long term immunity
-Monovalent form or MMR vaccine
Causes measles (robeola)
 One of the most contagious respiratory
infections
 It can nearly affect every person (in a given
population) by adolescence, in the absence of
immunization programs
Mode of transmission:
- Large repiratory droplet
-airborne
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Most infectious in the early stage
Before the rash appears
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Replication initially in the upper &
lower respiratory tract
Followed by LNs replication
Viremia & growth in a variety of
epithelial tissue
Incubation period: 1-2 wks
In 2-3 days, no rash but fever,
running nose, cough & conjunctivitis
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Koplick spots: slightly raised white
dots, 2-3 mm in diameter are seen on
the inside of the cheek shortly before
rash onset persist for 1-3 days
A characteristic maculopapular rash
extending from face to extremities
involving palms & soles : this seems to
be associated with T-cells attacking
virally infected endothelial cells in small
blood vessels
The rash lasts from 3-7 d & may be
followed by skin exfoliation
1-Respiratory
symptoms
2-Koplick
spots
Persist 1-3 days
Disappear after the rash onset
2-3 days
3-Maculopapular
rash
Lasts for 3-7 days
4-Skin
exfoliation
Long life immunity due to IgG neutralizing Abs
The virus invades the body via blood vessels
reaches surface epithelium
first in the respiratory tract where
there are only 1-2 layers of epithelial cells
Then in mucosae (Koplik's spots)
and finally in the skin (rash).
I- Respiratory
 Otitis media & bacterial pneumonia:
common
 Giant cell pneumonia in patients with
impaired CMI ( rare but fatal)
II- Neurological
 Postinfectious encephalitis. Few
days after the rash (1:1000)
 Subacute sclerosing panencephalitis
(SSPE) (1:100.000)
Specimens: nasal secretionsnasopharyngeal aspirate or swab- urine
1- Direct virus demonstration:
- DIF: for detection of viral Ag
- RT-PCR for detection of viral RNA
2- Viral isolation:
- nasal secretions inoculated onto (MKTC)
- Growth is recognized by development of
CPE in the form of multinucleated giant
cells containing both intranuclear &
intracytoplasmic IBs
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3- serology:
ELISA is used for detection of IgM or
IgG
For IgM single serum specimen 1-2
wks after the rash onset
For IgG, paired acute & convalescent
sera are necessary
Four fold or more rise in IgG titer
indicates infection
Passive
immunization
Measles IGs
- For
immunocompromised patients
-Intramuscular within 6 days of exposure
-Prevent measles symptoms in 80% of cases
Active
immunization
Mumps vaccine
-Live attenuated
-Given by subcutaneous injection
-Long term immunity
-Monovalent form or MMR vaccine
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Causes German measles which is
the mildest of common viral
exanthems
It is a member of rubiviruses but not
an arbovirus
Envelopped +ve sense ss RNA
Posseses hemaglutinating ability
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1- German measles: acute febrile
illness with rash & lymphadenopathy
affecting children & young adults
2- Congenital Rubella Syndrome:
Serious abnormalities of the fetus as
a consequence of maternal infection
during early pregnancy
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Mode of transmission: droplet
Initial viral replication occurs in the
respiratory mucosa followed by
multiplication in the cervical lymph
nodes
Viremia develops with spread to other
tissues. As a result the disease
symptoms develop in 50% of cases
after an incubation period of 12-23 days
Possibly 50% of infections are
apparently subclinical
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Fever & malaise (prodromal symptoms)
for 1-2 days
Maculopapular rash appears on the
face,then the trunk, then the
extremities and disappears within 3
days
Suboccipital and postauricular
lymphadenopathy
Extremely rare complications, self
limiting encephalopathy
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Extremely rare (1/6000)
Rubella encephalopathy
6 days after the rash appears
Complete recovery with no sequalae
Specimens: nasal secretionsnasopharyngeal aspirate or swab
1- Direct virus demonstration:
- DIF: for detection of viral Ag
- RT-PCR for detection of viral RNA
2- Viral isolation:
- nasal secretions inoculated onto
(MKTC)
- Growth is recognized by interference
with coxsakie virus
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3- serology:
ELISA is used for detection of IgM or
IgG
For IgM single serum specimen
For IgG, paired acute & convalescent
sera are necessary
Four fold or more rise in IgG titer
indicates infection
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Congenital rubella is a group of
physical problems that occur in an
infant when the mother is infected
with the virus that causes German
measles.
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Congenital rubella is caused by the
destructive action of the rubella virus
on the fetus at a critical time in
development. The most critical time is
the first trimester (the first 3 months of
a pregnancy). After the fourth month,
the mother's rubella infection is less
likely to harm the developing fetus.
The rate of congenital rubella has
decreased dramatically since the
introduction of the rubella vaccine.
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Risk factors for congenital rubella
include:
Not getting the recommended
rubella immunization
Contact with a person who has
rubella (also called the 3-day
measles or German measles)
Pregnant women who are not
vaccinated and who have not had
rubella risk infection to themselves
and damage to their unborn baby.
Transient symptoms:
 growth retardation, anemia &
thrombocytopenia
 Permanent defects: congenital heart
diseases, total or partial blindness,
deafness & mental retardation
 Progressive rubella panencephalitis:
Extremely rare slow virus disease,
develops in teens with death within
8 yrs
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During Pregnancy
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Detection of maternal
IgM or rising IgG in
serum
Then, detection of
rubella Ag in the
amniotic fluid by DIF
After Birth
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Live newborn:
detection of IgM
antirubella Abs in the
serum of the baby by
ELISA
Stillbirth: virus
isolation on MKTC
vaccinate
-Women in the childbearing age
-School age children
Pregnancy should be avoided 3 months after vaccination
Maternal rubella infection confirmed during the first trimester????
Therapeutic
abortion
MMR
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Contains 3 live attenuated viruses:
mumps, measles and rubella
Given in 2 doses
The first dose: to children 12-15
months of age by subcutaneous
injection
Why not before that?
When is the second dose?
Contraindications?
Thank you