General Properties General Properties and Genetics of and Genetics of

VirusVirusJohan LucianusJohan Lucianus

Department of MicrobiologyDepartment of MicrobiologyFaculty of MedicineFaculty of Medicine

Maranatha Christian UniversityMaranatha Christian University

Life:Life:a complex set of processes a complex set of processes resulting from the actions of resulting from the actions of

proteins specified by proteins specified by nucleic acidnucleic acid

Phylogeny of the living worldPhylogeny of the living world

Viral StructureViral Structure• A virionA virion consists of consists of genomegenome (nucleic acid) and (nucleic acid) and capsidcapsid (structural protein). (structural protein).

• In some viruses, the capsid is covered by an In some viruses, the capsid is covered by an envelopeenvelope (lipid) that may and may not be covered (lipid) that may and may not be covered by by spikesspikes..

• Viral genome may be either dsDNA, ssDNA, Viral genome may be either dsDNA, ssDNA, dsRNA, +sense ssRNA, or -sense ssRNA.dsRNA, +sense ssRNA, or -sense ssRNA.

• Capsid architecture may be either polyhedral, Capsid architecture may be either polyhedral, helical, or complex.helical, or complex.

A polyhedral virusA polyhedral virus

An An enveloped enveloped

helical helical virusvirus

Viral MultiplicationViral MultiplicationAttachmentAttachment

PenetrationPenetration

UncoatingUncoating

BiosynthesisBiosynthesis

MaturationMaturation

ReleaseRelease

demo

demo

demo

Multiplication of a DNA-containing virusMultiplication of a DNA-containing virus

demo

demo

demo

Growing VirusGrowing Virus• In living animals.In living animals.

• In embryonic eggs.In embryonic eggs.

• In cell cultures.In cell cultures.

Oncogenic VirusesOncogenic Viruses• Some DNA viruses and retroviruses.Some DNA viruses and retroviruses.

• Viral genetic material integrates into Viral genetic material integrates into the host cell’s DNA and replicates the host cell’s DNA and replicates along with the host cell’s along with the host cell’s chromosome.chromosome.

• The host cell will undergo The host cell will undergo transformation.transformation.

Infeksi virus latenInfeksi virus laten

Infeksi virus lambat/persistenInfeksi virus lambat/persisten

PrionPrion

ViroidViroid

Characteristic Live Vaccine K illed VaccineDuration of immunity Longer ShorterEffectiveness of protection Greater LowerImmunoglobulins produced IgA1 and IgG IgGCell-mediated immunity produced Y es Weakly or noneInterruption of transmission of virulent virus More effective Less effectiveReversion to virulence Possible NoStability at room temperature Low HighExcretion of vaccine virus and transmissionto nonimmune contacts

Possible No

1 If the vaccine is given by natural route.

Usage Vaccine Live or K illed VirusCommon Measles

MumpsRubellaVaricella (chickenpox)PolioInfluenzaHepatitis AHepatitis BRabies

LiveLiveLiveLiveBoth1

K illedK illedK illed2

K illedSpecial situations Y ellow fever3

J apanese encephalitis3

Adenovirus4

Smallpox4

LiveK illedLiveLive

1 In the USA, primarily live polio vaccine is used.2 Vaccine contains surface antigen.3 Used when traveling in endemic areas.4 Used for military personnel.

The EndThe End