MEDICALLY IMPORTANT VIRUS - PowerPoint Presentation

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MEDICALLY IMPORTANT VIRUS

(The DNA Virus)

Prepared by:Miss Norzawani JaffarBsc (Hons) Biomedical Sciences, UKM

Lecture 17Slide2

Learning Outcomes

At the end of this learning session, student must be able to;Classify the virusesUnderstand and explain the medically important virus to humanDifferentiate the viruses that infects human.Slide3

Viruses

Obligate parasitesInfect animals, plants, & other microbesAll DNA viruses are doublestranded except for parvoviruses, which have ssDNA.All RNA viruses are single-stranded except for dsRNA

reoviruses.Viruses are limited to a particular host or cell type.Slide4

Most DNA viruses are budded off the nucleus.

Most RNA viruses multiply in & are released from the cytoplasm.Viral infections range from very mild to life threatening.Many viruses are strictly human in origin, others are zoonoses transmitted by vectors.Most DNA & a few RNA viruses can become permanent resident of the host cell.Several viruses can cross the placenta & cause developmental disturbances.Slide5
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Pox Virus

Produce eruptive skin pustules called pocks or pox, that leave scarsLargest & most complex animal virusesHave the largest genome of all virusesdsDNAMultiply in cytoplasm in factory areasVariola – cause of smallpoxVaccinia

– closely related virus used in vaccinesMonkey poxCowpoxSlide7
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Small Pox

First disease to be eliminated by vaccinationExposure through inhalation or skin contactInfection associated with fever, malaise, prostration and a rash.Variola major – highly virulent, caused toxemia, shock and intravascular coagulation.Variola minor – less virulentRoutine vaccination ended in US in 1972

Vaccine reintroduced in 2001Slide9

Herpesviridae

Large enveloped icosahedra dsDNAReplication within nucleusLarge family; 8 infect humansHSV1HSV2VZVCMVEBV

HHV6HHV7HHV8Slide10

Herpes VirusSlide11
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H

erpesviridaeLatency & recurrent infectionsComplications of latency & recurrentInfections become more severe with age, cancer chemotherapy, etcMost common & serious opportunists among AIDS patientsSlide13

Herpes Simplex Virus (HSV)

HSV-1 lesions on the oropharynx, cold sores, fever blistersoccurs in early childhoodHSV-2 lesions on the genitaliaoccurs in ages 1429can be spread without visible lesions

Humans only reservoirTreatment: acyclovir, famciclovir, valacyclovirSlide14
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Varicella

-Zoster Virus (VZV)Causes chickenpox & shinglesTransmitted by respiratory droplets & contactPrimary infection – chickenpox – vesiclesVirus enters neurons & remains

latentLater, reactivation of the virus results in shingles withVesicles localized to distinctive areas, dermatomesTreatment : acyclovir, famciclovir, interferonLive attenuated vaccineSlide20
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Cytomegalovirus (CMV)

Produce giant cells with nuclear & cytoplasmic inclusionsTransmitted in saliva, respiratory mucus, milk, urine, semen, cervical secretions & fecesCommonly latent in various tissuesMost infections are asymptomatic3 groups develop a more virulent form of disease: fetuses, newborns, immunodeficient

adultsSlide23
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CMV

Newborns may exhibit enlarged liver & spleen, jaundice, capillary bleeding microcephaly, & ocular inflammation, may be fatalBabies who survive develop neurological sequelae; hearing, visual disturbances & mental retardationperinatal

CMV infection – mostly asymptomatic, or pneumonitis, & a mononucleosislike syndromeAIDS patients – CMV mononucleosis, disseminated CMV, retinitis.Transplant patients pneumonitis, hepatitis, myocarditis, meningoencephalitis

Treatment:

ganciclovir

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valvcyclovir

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foscarnet