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Viral disease

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Viral disease
Classification and external resources
MeSH D014777

These are tables of the clinically most important[1] viruses. A vast number of viruses cause infectious diseases, but these are the major ones[citation needed].

Structural characteristics

Basic structural characteristics, such as genome type, virion shape and replication site, generally share the same features among virus species within the same family. There are currently 21 families of viruses known to cause disease in humans.

There are five double stranded DNA families: three are non enveloped (Adenoviruses, Papillomavirus and Polyomavirus) and two are enveloped (Herpesvirus and Poxvirus). All the non enveloped families have icosahedral nucleocapsids.

There is one family of partly double stranded DNA viruses: the Hepadnaviridae. These viruses are enveloped.

There is one family of single stranded DNA viruses that infect humans: the Parvoviridae. These viruses are non enveloped.

There are seven positive single stranded RNA families: three non enveloped (Astrovirus, Calicivirus and Picornavirus) and four enveloped (Coronovirus, Flavivirus, Retrovirus and Togavirus). All the non enveloped families have icosahedral nucleocapsids.

There are six negative single stranded RNA families: Arenavirus, Bunyavirus, Filovirus, Orthomyxovirus, Paramyxovirus and Rhabdovirus. All are enveloped with helical nucleocapsids.

There is one family with a double stranded RNA genome: the Reoviridae.

There are two additional viruses (Hepatitis D and Hepatitis E) which have not yet been assigned to a family but are clearly distinct from the other families infecting humans.

There is one family and one genus of viruses known to infect humans that have not been associated with disease: the family Anelloviridae and the genus Dependovirus. Both of these taxa are non enveloped single stranded DNA viruses.

Useful rules of thumb

Among the human infecting families there are a number of rules that may assist physicians and medical microbiologists/virologists.

As a rule DNA viruses replicate within the nucleus while RNA viruses replicate within the cytoplasm. Exceptions are known to this rule: poxviruses (DNA viruses) replicate within the cytoplasm and orthomyxoviruses and hepatitis D virus (RNA viruses) replicate within the nucleus.

Four families have segmented genomes: Bunyavirus, Orthomyxovirus, Arenavirus and Reovirus (acronym BOAR). All are RNA viruses.

Three families are transmitted almost exclusively by arthropods: Bunyavirus, Flavivirus and Togavirus. Some Reoviruses are transmitted from arthropod vectors as well. All are RNA viruses.[2]

Only one family of enveloped viruses causes gastroenteritis (Coronaviridae). All other viruses associated with gastroenteritis are non enveloped.

 

Important species

Adenovirus

Herpes simplex, type 1, Herpes simplex, type 2, Varicella-zoster virus, Epstein-barr virus, Human cytomegalovirus, Human herpesvirus, type 8

Human papillomavirus

BK virus, JC virus

Smallpox

Hepatitis B virus

Human bocavirus, Parvovirus B19

Human astrovirus

Norwalk virus

coxsackievirus, hepatitis A virus, poliovirus, rhinovirus

Severe acute respiratory syndrome virus

Hepatitis C virus, yellow fever virus, dengue virus, West Nile virus

Rubella virus

Hepatitis E virus

Human immunodeficiency virus (HIV)

Influenza virus

Guanarito virus, Junin virus, Lassa virus, Machupo virus, Sabiá virus

Crimean-Congo hemorrhagic fever virus

Ebola virus, Marburg virus

Measles virus, Mumps virus, Parainfluenza virus, Respiratory syncytial virus, Human metapneumovirus, Hendra virus, Nipah virus

Rabies virus

Hepatitis D

Rotavirus, Orbivirus, Coltivirus, Banna virus

 

Clinical characteristics

The clinical characteristics of viruses may differ substantially among species within the same family:

Clinical characteristics

The clinical characteristics of viruses may differ substantially among species within the same family:

Type

Transmission

Diseases

Treatment

Prevention

laboratory diagnosis

Adenovirus

  • droplet contact
  • fecal-oral
  • venereal
  • direct contact (ocular infections)

None

  • vaccine
  • hand washing
  • covering mouth when coughing/sneezing
  • avoiding close contact with the sick

Coxsackievirus

  • fecal-oral
  • droplet contact

None

  • hand washing
  • covering mouth when coughing/sneezing
  • avoiding contaminated food/water
  • improved sanitation

Cell culture, antibody detection

Epstein-Barr virus

  • saliva

None

  • avoiding close contact with the sick

Hepatitis A virus

  • fecal-oral

Immunoglobulin (post-exposure prophylaxis)

  • vaccine
  • avoiding contaminated food/water
  • improved sanitation

antibody detection

Hepatitis B virus

  • vaccine
  • immunoglobulin (perinatal and post-exposure prophylaxis)
  • avoiding shared needles/syringes
  • safe sex
  • viral antigen detection
  • antibody detection
  • nucleic acid detection

Hepatitis C virus

  • blood
  • sexual contact
  • avoiding shared needles/syringes
  • safe sex
  • antibody detection
  • nucleic acid detection

Herpes simplex virus, type 1

  • direct contact
  • saliva
  • avoiding close contact with lesions
  • safe sex

Herpes simplex virus, type 2

  • sexual contact
  • vertical transmission
  • avoiding close contact with lesions
  • safe sex

Cytomegalovirus

  • hand washing
  • avoid sharing food and drinks with others
  • safe sex

antibody and nucleic acid detection

Human herpesvirus, type 8

  • bodily fluids

many in evaluation-stage

  • avoid close contact with lesions
  • safe sex

Nucleic acid and antibody detection

HIV

HAART

  • zidovudine (perinatally)
  • blood product screening
  • avoiding shared needles/syringes
  • safe sex
  • nucleic acid,
  • p24
  • antibody detection

Influenza virus

  • droplet contact
  • vaccine
  • hand washing
  • covering mouth when coughing/sneezing
  • avoiding close contact with the sick

Measles virus

  • droplet contact

None

  • vaccine
  • quarantining the sick
  • avoiding contact with the sick

antibody detection

Mumps virus

  • droplet contact

None

  • vaccine
  • avoiding close contact with the sick

antibody detection

Human papillomavirus

  • vaccine
  • avoiding close contact with lesions
  • safe sex
  • Visual inspection
  • Antigen detection
  • Nucleic acid detection

Parainfluenza virus

  • droplet contact

None

  • hand washing
  • covering mouth when coughing/sneezing

Antibody detection

Poliovirus

  • fecal-oral

None

  • vaccine
  • avoiding contaminated food and water
  • improved sanitation

Antibody detection

Rabies virus

  • saliva
  • droplet contact

Post-exposure prophylaxis

  • vaccine
  • avoiding rabid animals

Histology (postmortem)

Respiratory syncytial virus

  • droplet contact
  • direct contact

(ribavirin)

  • hand washing
  • avoiding close contact with the sick
  • palivizumab in high risk individuals
  • covering mouth when coughing/sneezing

antibody and antigen detection

Rubella virus

  • droplet contact

None

  • vaccine
  • avoiding close contact with the sick

Antibody detection

Varicella-zoster virus

  • direct contact
  • droplet contact

Varicella:

Zoster:

Varicella:

Zoster:

  • vaccine
  • varicella-zoster immunoglobulin
  • Cell culture
  • antigen and nucleic acid de
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