Microbiology 7-9 Flashcards
What does quasi species mean?
A group of related viruses due to similar mutations, competing in a highly mutagenic environment.
What two characteristics of bacteria promote ABR?
- Short replication time
- High mutation rate (lack of proof-reading)
What is antigenic drift?
Mechanism for variation that involves the accumulation of mutations for antibody-binding sites.
How do new viruses emerge? (5)
1) Zoonosis
2) Genetic variation
3) Spread of vectors
4) New discoveries
5) Increased exposure (world-wide travelling)
What are the global factors influencing emergence of viruses? (8)
- Migration and travel
- Demographics
- Farming practices (and living close to animals)
- World population
- Immunosuppressed patients
- Medical progress
- Decrease in mosquito control
- Climate change
How many cases of Dengue fever and haemorrhagic dengue fever?
100 million and 300,000
How many forms fo DFV are there?
4
What characteristic do the DFV strains display?
Cross reactivity. Previous antibodies can enhance secondary infection (DHF) and in fact make it worse.
What is hyper-endemic transmission?
Two or more serotypes of a disease circulating simultaneously at high levels.
What does SARS stand for?
Severe Actor Respiratory Syndrome (coronavirus)
What happens with SARS?
Destruction of the lung tissue due to an over-reactive immune response. Most infectious when symptomatic.
What is herd immunity?
When enough of the community is vaccinated against a certain disease so that transmission stops and vaccination is not necessary.
What is the formula for vaccine effectiveness?
(1 - (incidence in vaccinated)/(incidence in unvaccinated) )x 100%
What are the three components of a vaccine?
- Antigen (stimulates the immune response)
- Adjuvant (enhance and modulate immune response)
- Excipients (maintain pH, osmolarity and stability and contains preservative)
What is the name of the diphtheria, tetanus and whooping cough vaccine?
DtaP-Hib-IPV vaccine
