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Dr. Nehal Draz. Myxoviruses Orthomyxo viruses Paramyxo viruses -Smaller -Segmented RNA genome -Liable to Agic variation -Larger -Single piece of RNA -

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Presentation on theme: "Dr. Nehal Draz. Myxoviruses Orthomyxo viruses Paramyxo viruses -Smaller -Segmented RNA genome -Liable to Agic variation -Larger -Single piece of RNA -"— Presentation transcript:

1 Dr. Nehal Draz

2 Myxoviruses Orthomyxo viruses Paramyxo viruses -Smaller -Segmented RNA genome -Liable to Agic variation -Larger -Single piece of RNA - Not liable to Agic variation Influenza viruses - Parainfluenza - Mumps vairus - Measles virus - Respiratory syncytial virus Myxo = affinity to mucin

3  Large Spherical envelopped  Unsegmented –ve sense RNA  The lipid envelope is associated with 2-virus specific glycoptns; Haemaglutinin- Neuraminidase (HN) ptn& fusion (F) ptn

4  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

5 Specimens: nasal secretions- nasopharyngeal 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

6  Symptomatic treatment for mild disease  Oxygen therapy & may be mechanical ventilation in children with severe disease  Ribavirin aerosol No vaccine is yet available

7  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

8  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

9 Specimens: nasal secretion- nasopharyngeal aspirate- bronchoalveolar 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

10 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

11  Causes epidemic parotitis ( non suppurative inflammation of parotid)  Mode of transmission:  Via aerosols & fomites  The virus is secreted in urine so urine is a possible source of infection saliva

12  Infects children 5-15years  Replicates in the nasopharynx ®ional LNs  Incubation period: 2-25 d viremia Lasts 3-5 d meninges glands -Salivary -Pancreas -Testes -ovaries Long life immunity due to IgG neutralizing Abs

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14  Severe aseptic meningitis in adults  Orchitis in adult males which might cause sterility  Pancreatitis  Oophritis & thyroiditis

15 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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17  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

18 Mumps vaccine Active immunization -Live attenuated -Given by subcutaneous injection -Long term immunity -Monovalent form or MMR vaccine

19  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 Most infectious in the early stage Before the rash appears

20  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

21  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

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23 2-Koplick spots 3-Maculopapular rash 4-Skin exfoliation Persist 1-3 days Disappear after the rash onset Lasts for 3-7 days 1-Respiratory symptoms 2-3 days Long life immunity due to IgG neutralizing Abs

24 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).

25 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: )

26 Specimens: nasal secretions- nasopharyngeal 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

27  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

28 Active immunization Mumps vaccine -Live attenuated -Given by subcutaneous injection -Long term immunity -Monovalent form or MMR vaccine Passive immunization Measles IGs - For immunocompromised patients -Intramuscular within 6 days of exposure -Prevent measles symptoms in 80% of cases

29  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

30  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

31  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 days  Possibly 50% of infections are apparently subclinical

32  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

33  Extremely rare (1/6000)  Rubella encephalopathy  6 days after the rash appears  Complete recovery with no sequalae

34 Specimens: nasal secretions- nasopharyngeal 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

35  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

36  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.

37  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.

38  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.

39  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

40  Detection of maternal IgM or rising IgG in serum  Then, detection of rubella Ag in the amniotic fluid by DIF  Live newborn: detection of IgM antirubella Abs in the serum of the baby by ELISA  Stillbirth: virus isolation on MKTC

41 -Women in the childbearing age -School age children Pregnancy should be avoided 3 months after vaccination vaccinate Maternal rubella infection confirmed during the first trimester???? Therapeutic abortion

42  Contains 3 live attenuated viruses: mumps, measles and rubella  Given in 2 doses  The first dose: to children months of age by subcutaneous injection Why not before that? Contraindications? When is the second dose?

43 Thank you


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