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;
Haemaglutinin-
Neuraminidase (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, espec i ally 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:
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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:
Via aerosols & fomites saliva
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

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Causes measles (robeola)
One of the most contagious respiratory infections
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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
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
2-3 days
2-Koplick spots
Persist 1-3 days
Disappear after the rash onset
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
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Otitis media & bacterial pneumonia: common
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Giant cell pneumonia in patients with impaired CMI ( rare but fatal)
II- Neurological
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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
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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
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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.

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Transient symptoms : growth retardation, anemia & thrombocytopenia
Permanent defects : congenital heart diseases, total or partial blindness, deafness & mental retardation
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Progressive rubella panencephalitis:
Extremely rare slow virus disease, develops in teens with death within
8 yrs

During Pregnancy After Birth
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Detection of maternal
IgM or rising IgG in serum
Then, detection of rubella Ag in the amniotic fluid by DIF
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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?