A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells. Virosis is a disease or infection caused by a virus.
Examples include the common cold, gastroenteritis, COVID-19, the flu, and rabies.see below in this article
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. Double-stranded DNA families: three are non-enveloped (Adenoviridae, Papillomaviridae and Polyomaviridae) and two are enveloped (Herpesviridae and Poxviridae). All of the non-enveloped families have icosahedral capsids. Partly double-stranded DNA viruses: Hepadnaviridae. These viruses are enveloped. One family of single-stranded DNA viruses infects humans: Parvoviridae. These viruses are non-enveloped. Positive single-stranded RNA families: three non-enveloped (Astroviridae, Caliciviridae and Picornaviridae) and four enveloped (Coronaviridae, Flaviviridae, Retroviridae and Togaviridae). All the non-enveloped families have icosahedral nucleocapsids. Negative single-stranded RNA families: Arenaviridae, Bunyaviridae, Filoviridae, Orthomyxoviridae, Paramyxoviridae and Rhabdoviridae. All are enveloped with helical nucleocapsids. Double-stranded RNA genome: Reoviridae. The Hepatitis D virus has not yet been assigned to a family, but is clearly distinct from the other families infecting humans. 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.
Pragmatic rules Human-infecting virus families offer rules that may assist physicians and medical microbiologists/virologists.
As a general rule, DNA viruses replicate within the cell nucleus while RNA viruses replicate within the cytoplasm. Exceptions are known to this rule: poxviruses replicate within the cytoplasm and orthomyxoviruses and hepatitis D virus (RNA viruses) replicate within the nucleus. Segmented genomes: Bunyaviridae, Orthomyxoviridae, Arenaviridae, and Reoviridae (acronym BOAR). All are RNA viruses. Viruses transmitted almost exclusively by arthropods: Bunyavirus, Flavivirus, and Togavirus. Some Reoviruses are transmitted from arthropod vectors. All are RNA viruses. One family of enveloped viruses causes gastroenteritis (Coronaviridae). All other viruses associated with gastroenteritis are non-enveloped.
Baltimore group This group of analysts defined multiple categories of virus. Groups: I - dsDNA II - ssDNA III - dsRNA IV - positive-sense ssRNA V - negative-sense ssRNA VI - ssRNA-RT VII - dsDNA-RT
+Clinically important virus families and species with characteristics FamilyBaltimore group Important speciesEnvelopmentAdenoviridaeIAdenovirus NTable 1 in: HerpesviridaeIHerpes simplex, type 1, Herpes simplex, type 2, Varicella-zoster virus, Epstein–Barr virus, Human cytomegalovirus, Human herpesvirus, type 8 YPapillomaviridaeIHuman papillomavirus NPolyomaviridaeIBK virus, JC virus NPoxviridaeIsmallpox virus,monkeypox virus YParvoviridaeIIParvovirus B19 NReoviridaeIIIRotavirus, Orbivirus, Coltivirus, Banna virus NAstroviridaeIVHuman astrovirus NCaliciviridaeIVPage 273 in: Norwalk virus NCoronaviridaeIVHuman coronavirus 229E, Human coronavirus NL63, Human coronavirus OC43, Human coronavirus HKU1, Middle East respiratory syndrome-related coronavirus, Severe acute respiratory syndrome coronavirus, Severe acute respiratory syndrome coronavirus 2 YFlaviviridaeIV yellow fever virus, dengue virus, West Nile virus,, Japanese encephalitis virus,Saint Louis encephalitis virus,TBE virus, Zika virus YHepaciviridaeIVHepatitis C virus YHepeviridaeIVHepatitis E virus NMatonaviridaeIVRubella virus YPicornaviridaeIVcoxsackievirus,echovirus,hepatitis A virus,poliovirus,rhinovirus NArenaviridaeVLassa virus YBunyaviridaeVCrimean-Congo hemorrhagic fever virus, Hantaan virus,Rift Valley fever virus YFiloviridaeVEbola virus, Marburg virus YOrthomyxoviridaeVInfluenza virus YParamyxoviridaeVHendra virus,Measles virus,Mumps virus,Nipah virus,Parainfluenza virus YPneumoviridaeV Respiratory syncytial virus,human metapneumovirusYRhabdoviridaeVRabies virus YKolmioviridaeVHepatitis D virus YRetroviridaeVIHIV,HTLV-1,HTLV-2 YHepadnaviridaeVIIHepatitis B virus Y
Clinical characteristics
The clinical characteristics of viruses may differ substantially among species within the same family:
Type Family Transmission Diseases Treatment Prevention Adenovirus Adenoviridae droplet contact fecal-oral venereal direct eye contact gastroenteritis keratoconjunctivitis pharyngitis pharyngoconjunctival fever None Adenovirus vaccine hand washing covering mouth when coughing or sneezing avoiding close contact with the sick Coxsackievirus Picornaviridae fecal-oral respiratory droplet contact Hand, foot and mouth disease pleurodynia aseptic meningitis pericarditis myocarditis None hand washing covering mouth when coughing/sneezing avoiding contaminated food/water improved sanitation Cytomegalovirus Herpesviridae vertical transmission bodily fluids infectious mononucleosis Cytomegalic inclusion disease Premature birth liver, lung and spleen diseases in the newborn Small size at birth Small head size congenital seizures in the newborn ganciclovir cidofovir foscarnet hand washing avoid sharing food and drinks with others safe sex Epstein–Barr virus Herpesviridae saliva infectious mononucleosis Burkitt's lymphoma Hodgkin's lymphoma nasopharyngeal carcinoma None avoiding close contact with the sick Hepatitis A virus Picornaviridae fecal-oral acute hepatitis Immunoglobulin (post-exposure prophylaxis) Hepatitis A vaccine avoiding contaminated food/water improved sanitation Hepatitis B virus Hepadnaviridae bodily fluids Vertical and sexual acute hepatitis chronic hepatitis hepatic cirrhosis hepatocellular carcinoma Lamivudine immunoglobulin Adefovir Entecavir Pegylated interferon alfa-2 Hepatitis B vaccine immunoglobulin (perinatal and post-exposure prophylaxis) avoiding shared needles/syringes safe sex Hepatitis C virus Hepaciviridae blood sexual contact acute hepatitis chronic hepatitis hepatic cirrhosis hepatocellular carcinoma Ribavirin Pegylated interferon alfa-2 avoiding shared needles/syringes safe sex Herpes simplex virus, type 1 Herpesviridae direct contact saliva herpes labialis, cold sores – can recur by latency gingivostomatitis in children tonsillitis & pharyngitis in adults keratoconjunctivitis acyclovir famciclovir foscarnet penciclovir avoiding close contact with lesions safe sex Herpes simplex virus, type 2 Herpesviridae sexual contact vertical transmission Skin vesicles, mucosal ulcers, Oral and/or genital Can be latent Aseptic meningitis acyclovir famciclovir foscarnet penciclovir cidofovir avoiding close contact with lesions safe sex HIV Retroviridae sexual contact blood breast milk vertical transmission AIDS HAART, such as protease inhibitors and reverse-transcriptase inhibitors zidovudine (perinatally) blood product screening safe sex avoiding shared needles/syringes Human coronavirus 229E (HCoV-229E) Coronaviridae droplet contact fomites common cold pneumonia bronchiolitis Human coronavirus NL63 (HCoV-NL63) Coronaviridae droplet contact common cold rhinitis bronchitis bronchiolitis pneumonia croup Human coronavirus OC43 (HCoV-OC43) Coronaviridae common cold pneumonia Human coronavirus HKU1 (HCoV-HKU1) Coronaviridae common cold pneumonia bronchiolitis Human herpesvirus, type 8 Herpesviridae Saliva Sexual Kaposi sarcoma multicentric Castleman disease primary effusion lymphoma many in evaluation-stage avoid close contact with lesions safe sex Human papillomavirus Papillomaviridae direct contact sexual contact vertical transmission (common, flat, plantar and anogenital warts, laryngeal papillomas, epidermodysplasia verruciformis) Malignancies for some species (cervical carcinoma, squamous cell carcinomas) liquid nitrogen laser vaporization cytotoxic chemicals interferon cidofovir HPV vaccine avoiding close contact with lesions safe sex Influenza virus Orthomyxoviridae droplet contact influenza (Reye syndrome) amantadine rimantadine zanamivir oseltamivir influenza vaccine amantadine rimantadine hand washing covering mouth when coughing/sneezing avoiding close contact with the sick Measles virus Paramyxoviridae droplet contact measles postinfectious encephalomyelitis None MMR vaccine quarantining the sick avoiding contact with the sick Middle East respiratory syndrome-related coronavirus (MERS-CoV) Coronaviridae close human contact Middle East respiratory syndrome (MERS) Mumps virus Paramyxoviridae droplet contact mumps None MMR vaccine avoiding close contact with the sick Parainfluenza virus Paramyxoviridae droplet contact croup pneumonia bronchiolitis common cold None hand washing covering mouth when coughing/sneezing Poliovirus Picornaviridae fecal-oral poliomyelitis None Polio vaccine avoiding contaminated food and water improved sanitation Rabies virus Rhabdoviridae animal bite droplet contact rabies (fatal encephalitis) Post-exposure prophylaxis rabies vaccine avoiding rabid animals Respiratory syncytial virus Pneumoviridae droplet contact hand to mouth bronchiolitis pneumonia influenza-like syndrome severe bronchiolitis with pneumonia (ribavirin) hand washing avoiding close contact with the sick palivizumab in high risk individuals covering mouth when coughing/sneezing Rubella virus Togaviridae Respiratory droplet contact congenital rubella German measles None MMR vaccine avoiding close contact with the sick Severe acute respiratory syndrome coronavirus (SARS-CoV) Coronaviridae droplet contact severe acute respiratory syndrome (SARS) Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Coronaviridae droplet contact coronavirus disease 2019 (COVID-19) Molnupiravir, Nirmatrelvir/ritonavir hand washing covering mouth when coughing or sneezing social distancing Varicella-zoster virus Herpesviridae droplet contact direct contact chickenpox herpes zoster Congenital varicella syndromeVaricella: acyclovir famciclovir valacyclovir Zoster: acyclovir famciclovirVaricella: varicella vaccine varicella-zoster immunoglobulin avoiding close contact with the sick Zoster: vaccine varicella-zoster immunoglobulin
See also List of latent human viral infections Pathogenic bacteria
References
External links