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Virology Review 4
Emerging Viruses
| Question | Answer |
|---|---|
| Definition of EMERGING | New or recently identified viruses to humans |
| Defintion of REEMERGING | viruses once thought to be under control but are reappearing |
| Examples of Emerging Viral Disease | HIV?AIDS, Hantavirus pulmonary syndrome (HPS), West Nile encephalitis (WNV), Severe Acute respiratory syndrome (SARS), and Monkeypox |
| Arboviruses | arthropod-borne viruses, all RNA viruses |
| Future HCV (Flaviviridae) | Account for 40-50% of chronic liver diseases, unknown transmission route |
| Point-Mutation Rate of RNA viruses | 1 per 10,000 nucleotides |
| Point-Mutation Rate of DNA viruses | 1 per 100,000,000 nucleotides |
| Antigenic Drift | mutations caused by replication error |
| Reassortment | occurs when very similar segmented viral genomes coinfect the same cell. Example: Influenza A |
| Recombination - 2 viruses | occurs when 2 viruses infect same cell & a new chimeric or hybrid genome is formed via intramoleculr exchange of viral genomes. occurs when viral RdRp complex switches, mid-replication, from one RNA molecule to another. Example: SARS-CoV & coronaviruses |
| Recombination - stealing host genes | virus steal genes from host through recombination with the cellular chromosome. Example: Retroviruses |
| Antigenic Shift | occurs by gene swapping, either between 2 viruses, or between virus & host cell |
| Norovirus | Can not be cultured in lab, no animal modeals, hard to determine genetic changes in the virus that trigger outbreaks |
| Crossing species border: exotic pet trading | Example: Monkeypox |
| Crossing species border: free-range farming | |
| Crossing species border: live markets | Example: SARS |
| Extension of farmland into unused land exposes farmers to zoonotic diseases | (especially rodents carrying viruses)Example: 1958-1974, Argentine hemorrhagic fever (caused by Junin viruses carried by rodents) |
| Deforestation is the removal of trees in forests (e.g. Amazon) | 2005 Brazil, vampire-bat related rabies1998-1999 Malaysia, Nipah virus infecting pigs, humans, dogs and cats |
| Importing Animals for Biomedical Research and Vaccine Production | Example: 1967, Infected African green monkeys imported to Marburg, Germany and Belgrade, Yugoslavia for research and preparation of poliovirus vaccine; Monkeys infected with Marburg virus—cause of hemorrhagic fever in humans (high mortality rate) |
| Environmental Changes | 1993: 4 Corners Area, U.S. Sin Nombre hantavirus outbreak (deer mouse was the carrier)Correlated with rainfall increase, more piñon nuts (food for deer mice) |
| VIRAL INFECTIONS THAT MAY BE/HAVE BEEN CONTROLLED | Must have human or readily controllable reservoir; Must be able to induce an effective and lasting immune response; Effective vaccine (Ex. Smallpox, Next polio and measles?) |
| OTHER VIRUSES WILL NOT BE ELIMINATED | Viruses that cause persistent infections; Viruses that counter the immune system (Ex. HIV); Viruses that have a nonhuman reservoir (arboviruses) |
| Human Bocavirus (HBoV) An Emerging Viral Pathogen? | a new virus found in respiratory secretions of Swedish children with lower respiratory tract infections; HBoV cannot be cultivated in the laboratory. |
Created by:
lbr9349
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