viral shedding

Examples of viral shedding in the following topics:

• Viral Exit

  • Viral populations do not grow through cell division because they are acellular.
  • The viral genome is then known as a "provirus" or, in the case of bacteriophages a "prophage. " Whenever the host divides, the viral genome is also replicated.
  • The viral genome is mostly silent within the host.
  • Viral shedding refers to the successful reproduction, expulsion, and host-cell infection caused by virus progeny.
  • Viral budding uses the host's cell membrane eventually causing cell death.

• Viral Skin Diseases

  • Three common skin conditions that result from viral infections are cold sores, shingles, and warts.
  • Herpes simplex is a viral disease from the herpesviridae family caused by both Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2).
  • Transmission may also occur through skin-to-skin contact during periods of asymptomatic shedding.
  • Treatments with antivirals can reduce viral shedding and alleviate the severity of symptomatic episodes.
  • They are caused by a viral infection, specifically by one of the many types of human papillomavirus (HPV).

• Plant Virus Life Cycles

  • Attachment, or adsorption, occurs between the viral particle and the host cell membrane.
  • A hole forms in the cell membrane, then the virus particle or its genetic contents are released into the host cell, where viral reproduction may commence.
  • The process by which virus progeny are released to find new hosts, is called shedding.
  • This is the final stage in the viral life cycle.

• Attachment and Entry of Herpes Simplex

  • Herpes simplex virus attaches to a host's cells with viral envelope glycoproteins, which then allows entry of the viral capsid into the host cell.
  • They can be spread when an infected person is producing and shedding the virus.
  • Finally, a stable entry pore is formed through which the viral envelope contents are introduced to the host cell .
  • Afterward, gB interaction with the gH/gL complex creates an entry pore for the viral capsid.
  • Following attachment, the viral envelope fuses with the host cell membrane and the viral capsid gains entry into the cell.

• Arboviral Encephalitis

  • Arthropod vectors transmit the virus upon biting, allowing the virus to enter the circulatory system and replicate and shed additional infection into the bloodstream (viremia).
  • Because the arboviral encephalitides are viral diseases, antibiotics are not effective for treatment and no effective antiviral drugs have been discovered yet.

• Replication of Herpes Simplex Virus

  • On entering the cell, an α-TIF protein joins the viral particle and aids in immediate-early transcription.
  • The virion host shutoff protein (VHS or UL41) is very important to viral replication.
  • This enzyme shuts off protein synthesis in the host, degrades host mRNA, helps in viral replication, and regulates gene expression of viral proteins.
  • The viral genome immediately travels to the nucleus but the VHS protein remains in the cytoplasm.
  • An enzyme shuts off protein synthesis in the host, degrades host mRNA, helps in viral replication, and regulates gene expression of viral proteins.

• Viral Replication and Gene Expression

  • Replication of viruses primarily involves the multiplication of the viral genome.
  • Replication also involves synthesis of viral messenger RNA (mRNA) from "early" genes (with exceptions for positive sense RNA viruses), viral protein synthesis, possible assembly of viral proteins, then viral genome replication mediated by early or regulatory protein expression.
  • Viral replication usually takes place in the cytoplasm .
  • Uncoating of the viral RNA is mediated by receptor-dependent destabilization of the virus capsid (2).
  • Cleavage of the viral protein VPg is performed by a cellular phosphodiesterase, and translation of the viral RNA occurs by a cap-independent (IRES-mediated) mechanism (3).

• General Features of Virus Replication

  • Viruses must first penetrate and enter the cell before viral replication can occur.
  • This is often called viral entry.
  • Uncoating is a process in which the viral capsid is removed: This may be by degradation by viral or host enzymes or by simple dissociation.
  • This is accomplished through synthesis of viral messenger RNA (mRNA) from "early" genes (with exceptions for positive sense RNA viruses), viral protein synthesis, possible assembly of viral proteins, then viral genome replication mediated by early or regulatory protein expression.
  • Whenever the host divides, the viral genome is also replicated.

• Virus Attachment and Genome Entry

  • Attachment is a specific binding between viral capsid proteins and specific receptors on the host cellular surface.
  • Viral populations do not grow through cell division, because they are acellular.
  • Attachment is a specific binding between viral capsid proteins and specific receptors on the host cellular surface.
  • Attachment to the receptor can induce the viral envelope protein to undergo changes that results in the fusion of viral and cellular membranes, or changes of non-enveloped virus surface proteins that allow the virus to enter.
  • This is often called "viral entry. " The infection of plant and fungal cells is different from that of animal cells.

• Viral Genomes

  • The viral genome is the complete genetic complement contained in a DNA or RNA molecule in a virus.
  • Viral diseases have an enormous impact on human health worldwide.
  • An enormous variety of genomic structures can be seen among viral species; as a group, they contain more structural genomic diversity than plants, animals, archaea, or bacteria.
  • Viral genomes are circular, as in the polyomaviruses, or linear, as in the adenoviruses .
  • A viral genome, irrespective of nucleic acid type, is almost always either single-stranded or double-stranded.