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
What is a conjugate vaccine?
A vaccine made up on an immunogenic protein chemically linked to a carbohydrate.
What are the advantages and disadvantages of using conjugate vaccines?
Advantages:
- Safe and simple
- Very effective when humoral immunity is required
- Long-lived
- Boostable
Disadvantages:
- Expensive due to complicated technology required
How many serotypes are associated with pneumococcal disease?
Over 90
What kind of vaccine is used for pneumococcal disease?
Conjugate vaccine
How do fungi obtain nutrients?
Externally digest their food using hydrolytic enzymes. The broken down biopolymers are then absorbed for nutrition.
How do fungi spread?
Can produce large numbers of spores which can be dispersed over long distances.
What allergy-related diseases can fungi cause?
- Rhinitis
- Dermatitis
- Asthma
- Broncho-pulmonary aspergillus
What is mycotoxicosis?
A reaction caused by the ingestion or inhalation of a mycotoxin.
What are the symptoms of a mycotoxicosis reaction?
- Vomitting
- Dehydration
- Breathlessness
- Hepatic/renal failure
What is a superficial infection?
When the hair or the hair shaft is affected but no living tissue is.
Where do the candida species colonise?
- GI tract
- Resp tract
- Urethra
- Vagina
- Skin
- Fingernails
How can a fungal infection be diagnosed? (tests)
- Skin
- Sputum
- Bronchoalveolar lavage
- Spinal fluid
- Vaginal fluid/smear test
- Tissue biopsy
- Blood (culturing or microscopy)
What mechanisms do anti fungal treatments target?
- Membrane ergosterol biosynthesis
- Membrane function
- Nucleic acid synthesis
- Cell wall synthesis
Which class specifically of anti-fungals has a problem with ABR?
Azoles
