Midterm 2 - Notes 1 (Part 2) Flashcards
What are 3 examples of vectors?
- Fleas
- Ticks
- Mosquitos
What are 2 general methods of transmitting diseases?
- Mechanical transmission
2. Biological transmission
Mechanical transmission
Anthropod carries pathogen on its feet
Biological transmission
Pathogen reduces in the vector
- transmitted through bites or feces
HAI
Healthcare Associated Infections
Where do you get a HAI?
Acquired while receiving treatment in a health care facility
- nosoinfection
- noso = disease
What does HAI result from? (3)
- microorganisms in the hospital environment
- Weakened status of the host
- weakened immune system - Chain of transmission in a hospital
- eg) needles
Compromised host
An individual whose resistance to infection is impaired by disease, therapy of burns
What are 3 examples of microorganisms involved in HAI?
- Staphylococcus aureus
- Clastridium difficile
- Enterococcus spp.
What are 4 ways of reducing pathogens?
- Hand washing
- Disinfecting tubs used to bathe patients
- Cleaning instruments scrupulously
- Using disposable bandages and intubation
What is the downside to controlling HAI?
It generates a lot of waste
Emerging infectious diseases
Diseases that are new, increase in incidence or showing a potential to increase in the near future
What are most types of emerging infectious diseases? (2)
Most are zoonotic and vector borne
Re-emerging disease
Are infectious diseases that once were major health problems globally and then decreased dramatically, but are again becoming health problems for a significant portion of the population
What are 2 examples of a re-emerging disease?
- TB
2. Malaria
How are re-emerging diseases likely passed on?
Through a vector
- eg) a bite from a tick or insect
What are 8 contributing factors to re-emerging diseases?
- Genetic recombination
- E.coli O157 and avian flu (H5N1) - Evolution of new strains
- vibrio cholerae O139 - Widespread use of antibiotics and pesticides
- antibiotic resistant strains like TB - Changes in weather patterns
- hantavirus - Modern transportation
- chikungunya and west nile virus; both were introduced to be who came by planes - Ecological disasters, war and expanding human settlement
- coccidioidomycosis (fungal infection) - Animal control measure
- lyme disease (ticks to humans) - Public health failure
- diphtheria which is a re-emerging disease
Epidemiology
The study of where and when disease occur and how they are transmitted in a population
What do epidemiologists do? (4)
- Determine etiology of a disease
- Identify other important factors concerning the spread of diseases
- Develop methods for controlling a disease
- Assemble data and graphs to outline incidence of diseases
John Snow
Mapped the occurrence of cholera in London
- 1848 - 1849
Ignaz Semmelweis
Showed that hand washing decreased the incidence of peurperal sepsis, which helped control the outbreaks
- 1846 - 1848
Florence Nightingale
Showed that improved sanitation decreased the incidence of epidemic typhus
What does an increase in lyme disease suggest?
Transmission through a vector
Descriptive epidemiology
Collection and analysis of data
- Snow
Analytical epidemiology
Analyzes a particular disease to determine its probable cause
- Nightingale
Experimental epidemiology
Involves a hypothesis and a controlled environment
- Semmelweis
- eg) hand washing experiment
What does the centres for disease control and prevention do?
Collects and analyzes epidemiological info in the US
Morbitity
Incidence of a specific notifiable disease
Mortality
Deaths from notifiable diseases
Notifiable infectious disease
Diseases in which physicians are required to report occurrences
Morbidity rate
The number of deaths from a disease in relation to the population in a given time period
Mortality rate
The number of deaths from a disease in relation to the population in a given disease
What are 4 basic techniques in molecular biology?
- PCR
- Hybridization
- Cloning
- DNA sequencing
PCR
Is a technique used to amplify a segment of DNA
What are the 3 phases of PCR?
- Denaturation of the double stranded DNA into single stranded molecules
- Annealing of the primers to the specific area of interest
- Extension phase (amplification)
Hybridization
Is a technique that measures the degree of genetic similarity between pools of DNA sequences
- is typically used to determine the genetic differences between 2 organisms
What are the 5 phases of hybridization?
- Cells from the specimen affixed to filter
- Lyse cells and generate single stranded target DNA
- Add reporter labeled probe; allowing for re-annealing to target
- Measure hybridization directly if reporter is radioactive or fluorescent
- add enzyme to substrate if reporter is an enzyme
- whatever is bound to the membrane is what will be read - Detection
- radioactivity detector
- fluorimeter
- colorimeter/ visual inspection
Cloning
Is a technique that the lab processes used to produce offspring that are genetically identical to the donor parent
- uses a vector insertion
What are the 3 different types of cloning?
- Gene cloning
- Reproductive cloning
- Therapeutic cloning
Why do we clone?
To be able to understand more about the function of particular genes
- good for tracking
What does cloning require?
A vector
Vector
A plasmid DNA used as a tool to make more copies of or produce a protein from a certain gene
DNA sequencing
Is a process of determining the precise order of nucleotides within a DNA molecule
- you have multiple sequences to allow for less error
What do you need in DNA sequencing?
A radioactive primer
- typically uses radioactive P32
Primer
Is a short strand of RNA or DNA that serves as a starting point for DNA synthesis
What happens to the reaction products in DNA sequencing?
They are separated by electrophoresis on polyacrylamide gel and identified by autoradiography
- it generates fragments of different size
