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Medical virology , Laboratory session-1. Dr. Mohammed Arif. Associate professor. Consultant virologist. Head of the virology unit. Electron micrographs of medically important viruses. DNA - viruses : 1- Herpesviridae. 2- Adenoviridae. 3-Hepadnaviridae. 4- Poxviridae. - PowerPoint PPT Presentation
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DR. MOHAMMED ARIF.ASSOCIATE PROFESSOR.CONSULTANT VIROLOGIST.HEAD OF THE VIROLOGY UNIT.
Medical virology , Laboratory session-1
Electron micrographs of medically important viruses
DNA - viruses :
1- Herpesviridae. 2- Adenoviridae. 3-Hepadnaviridae. 4- Poxviridae .
1- Family - Herpesviridae .
Enveloped, lose envelope. Icosahedral nucleocapsid.The viral genome is ds-DNA.Eight human herpes viruses.Examples of diseases: HSV-1 : Gingivostomatitis, keratoconjunctivitis,
meningoencephalitis, herpetic whitlow. HSV-2 : Genital herpes, neonatal herpes. varicella –zoster virus ( VZV ) : varicella, zoster.
Family – Herpesviridae.
Cytomegalovirus (CMV) : Infectious mononucleosis like syndrome , congenital infection, severe diseases in the immunocompromized.
Epstein Barr virus (EBV ) : infectious mononucleosis, Nasopharyngeal carcinoma, Burkitts lymphoma.
EM of herpes virus .
EM of herpes virus
2- Family- Adenoviridae
Unenveloped.Icosahdral nucleocapsid ( spherical particle).The viral genome is ds-DNA.Examples of diseases : Pharyngoconjunctival
fever, keratoconjunctivitis, pneumonia, gastroenteritis, hemorrhagic cystitis.
EM of adenoviruses
EM of adenoviruses .
3- Family : Hepadnaviridae ( hepatitis B virus ).
Three forms of particles. The complete hepatitis B virus (HBV )
particle is enveloped with ds-DNA genome ( the large particles)
The free hepatitis B surface antigen particles (HBsAg), 22-nm in diameter.
The filament form of HBsAg particles .Diseases : hepatitis B .
EM of Hepatitis B virus (HBV ) .
4- Family : Poxviridae ( pox viruses ).
Brick shaped .The viral genome is ds-DNA .Complex structure .Diseases : smallpox ( variola).
EM of poxvirus .
RNA viruses .
1- Family : orthomyxoviridae ( Influenza viruses ).
2- Family : Rhabdoviridae ( Rabies virus ).3- Family : Reoviridae ( Rotaviruses).4- Family : Caliciviridae ( Caliciviruses).5- Family : Filoviridae ( Marburg virus &
Ebola virus). 6- Arenaviridae ( Lassa virus ) .
1- Family – Orthomyxoviridae ( influenza viruses ).
Pleomorphic.Enveloped.Covered with two glycoprotein spikes:Hemagglutinin and neuraminidase .The viral genome consists of 8- segments of
ss-RNA.Diseases : Influenza ( flue ), pneumonia .
EM of influenza viruses.
EM of influenza viruses .
2- Family : Rhabdoviridae ( Rabies Virus ).
Bullet shaped.Enveloped.The viral genome is ss-RNA , negative strand.Diseases : Rabies , acute encephalitis .
EM of Rabies virus .
3- Family : Reoviridae ( Rotaviruses).
Unenveloped.The virus particle has a wheel structure
(double capsid).Spherical particles .The viral genome consists of 11- segments of
ds-RNADiseases : The major cause of infantile
diarrhea.
EM of Rotaviruses.
4- Family : Caliciviridae ( caliciviruses ).
Unenvelpoed.Spherical particles with cup- shaped
depressions.The viral genome is SS-RNA with positive
polarity.Diseases : Diarrhea .
EM of caliciviruses .
EM of caliciviruses .
5- Family : Filoviridae. ( Marburg virus & Ebola virus).
The virus is filament in shape. Unenveloped. the viral genome is ss-RNA with negative
polarity.Diseases : Hemorrhagic fever .
EM of Marburg virus & Ebola virus .
Family : Arenaviridae
Sandy appearance .Enveloped .ss-RNA , 2-segments with negative polarity . Lassa virus .Diseases : Lassa hemorrhagic fever .
Family Arenaviridae ( Lassa virus ) .
family : Arenaviridae ( Lassa virus ) .
Egg inoculation routes .
1- Chorio allantoic membrane ( CAM ). 2- Allantoic membrane . 3- Yolk sac . 4- Amniotic cavity .
Chorioallantoic membrane ( CAM ) .
2-Allantoic cavity
3-Amniotic cavity
4-Yolk sac