Lecture 1 Flashcards
polymicrobial
mixed organisms infecting an area
How do bats explain disease transmission?
tree roosting bats see different bats every night, urban bats sleep in same hole every night, seeing same bats.
Disease transmission is higher in Urban bats populations
infectious dose
number of infectious organisms or particles needed to cause an infection
what alters infectious dose?
it changes between individuals and diseases d/t differences in immune response and virulence
How is ebola transmitted?
blood to blood contact.
- can not be through mosquitos as they eat the blood but do not put it back inside
- needles hold blood inside them and then reinfect it into blood. so this could cause infection
- could be a nosocomial infection because requires contact
Necrotizing fasciitis
- staph aureus causing “flesh eating disease”
- usually polymicrobial (bacteria doesn’t cause tissue damage, immune response does)
How do microbes affect the earth
equal over 50% of carbon on earth
- 90% of nitrogen and phosphate is produced by bacteria
- contribute O2, recycle nutrients like N2
enrichment culture
the use of selective growth media that support certain classes of microbial metabolism while excluding others
Why are microbes beneficial?
- make vitamins (B12)
- enzyme functions d/t bacteria
- breath sulphur, fix nitrogen
- diverse and abundant
- live in many extreme environments
where are microbes located in body
everywhere, diverse populations grow in different areas of the body d/t different levels of sweat, salt, sun, nutrients
- “normal flora” - live in body and aide human with everyday processes (if too little or too many cn cause issues), may only be helpful in certain environments
- contais 10 times as many microbes as cells
how are microbes bad?
small portion of microbes are bad (causative agent of disease)
-principle cause of mortality
how are antibiotics bad, was is the post antibiotic era
- becoming less useful d/t antibiotic resistant pathogens
- an end to modern medicine – pathogens may become leading cause of death once gain
MRSA
Methicillin Resistance Staphylococcus aureus
- bacteria is normal habitant of skin, nose, resp and GI tracts.
- can causes skin/soft tissue/ bone infections, pneumonia, sepsis
- MR means first line treatments oil, second are less effective and have more side effects; need IV not pill forms
- in SASK 8% of SA is MR
how many antibiotic resistant infections were there in 2013?
how many in canada, how many deaths?
23000
-18000 in canada and 2000 deaths
how many people die annually from C. Diff? what is this?
15000
-infection of the bowel linked to long term antibiotic abuse
golden age of microbiology
19th century; principles of disease pathology and microbial ecology were established
autoclaving
physical method of controlling microbial growth by applying pressure to water to create steam (sterilizing materials like surgical instruments)
Robert Hooke
1665
First microscopist to publish a systematic study of the world as seen under a microscope
Built the first compound microscope and observed biological materials
Published his findings in Micrographia (looked at nematodes, mites and mold filaments)
First to observe distinct units of living material (termed “cells” to describe cork)
Antonie van Leeuwenhoek
1680
First individual to observe single-celled microbes (such as bacteria)
Single-lens magnifier (stronger than Hooke’s)
Observed insects (lice and fleas), large single cells (protists and algae), and bacteria (from mouth)
-Detailed observations about the shape and size of the species
-Observed microbes in his mouth before and after drinking hot coffee (suggested that heat kills microbes)
Louis Pasteur
- believed in biogenesis; not spontaneous generation
- discovered pasteurization –> heat liquid to 55 degrees destroying bad bacteria and preserving food
- Germ theory of disease
spontaneous generation
theory that living microbes can arise spontaneously without parental organisms
biogenesis
complex living things come only from other living things, by reproduction
germ theory of disease
microorganisms cause disease by invading and replicating within it’s host
Robert Koch
- isolated pathogenic and showed how that bacteria caused disease:
- microb is found in disease but not healthy subjects
- microb isolated from diseased subject and are in pure culture
- the pure culture is injected into healthy subject which dies of disease
- same microbe collected from new disease subject
-confirmed germ theory of disease
1) Bacillus anthracis (anthrax)
- Mycobacterium tuberculosis (TB)
- Vibrio cholera (cholera)
Joseph Lister
Surgeon that developed aseptic technique in 20th century
-sterilized instruments/ wounds c/ phenol
(noticed pole diving from infectious wounds and less infection c/ clean instruments
bacteriology
study of prokaryotes
mycology
study of fungi
phycology
study of algea
protistology
study of protozoa
virology
study of viruses
immunology
study the immune system
prokaryotes
lack membrane bound nucleus, small, single cells, no organelles, cell wall
- bacteria
- archaea –>extremophiles (extreme environments) and methanogens (produce methane for digestion and gas production); do not cause disease
eukaryotes
have membrane bound nucleus
what are the three types of eukaryotic microbes
Protozoa and algae (protists)
- protozoa –> motile heterotophes (eat organic food). Ex) ameba
- Algae –> chloroplasts for photosynthesis. Base of the food web.
Fungi
heterotrophic, nonmotile, grow by nutrient source. Include single cell (yeast), filament (mold), complex (mushrooms). Can cause infection in immunocompromised pts
Virus
nonliving, infectious particles
Genetic material takes over cell metabolism to generate viral particles (duplicates)
E.coli
- 5 um in length
- bacterial prokaryote
- live in intestine, normally harmless and aid in digestion
- some can cause gastroenteritisand lead to kidney failure
Saccharomyces cerevisiae
size: 7 um
- eukaryotic yeast used to make beer and wine
explain Log scales
10^8 = 100 000 000 10^5 = 100 000
endemic
a native disease that prevails continuously in a geographic region (Ebola in the Congo)
Epidemic
a sudden and simultaneous outbreak or increase in the number of cases of disease in a community
Pandemic
a disease afflicting people over a wide geographic area (sometimes worldwide).
Ebola Virus
characterized by hemorrhagic fever
- virion (particle) contains 1 RNA strand –> new particles are formed by buds of host cells
- bats are the reservoir
- only transmittable after symptoms appear.
zoonotic disease
transmitted through animals
symptoms of ebola
- fever, headache, diarrhea, vomiting, stomach pain, unexplained bleeding or bruising, muscle pain
- can only spread when individual has symptoms
-how is ebola transmitted
direct contact with:
- body fluids of individuals infected with ebola (blood, vomit, urine, faces, sweat, semen, spit, eat)
- contaminated objects (needles)
- infected animals (contact c/ infected blood, meat)
-portal of entry: broken skin or unprotected mucous membranes (eyes, nose, mouth)
epidemiology
statistical analysis to determine cause of disease
public health
assessing the role of infectious disease in the health of large populations
Ebola Virus: Outbreak
- 2014 was the largest
- usually outbreaks are localized in remote locations
- 2016 outbreak 30 thousand suspected cases, 15000 confirmed. 11000 deaths
-death rate only 35% compared to the previous 50-90%
ebola: therapeutic interventions
- vaccines and meds (antivirals) being tested to fight ebola: ZMapp (provides passive immunity), rVSV-ZEBOV (winnepeg one - has single ebola gene causing body to create antibodies - cured 100% of test subjects)
- test symptoms as appear
- significant interventions to increase chance of survival: provide IV fluids and electrolytes, maintain O2 and BP, treat infections
how did ebola have a re-outbreak in guinea?
- survivor of ebola had virus in seminal fluid for more than 500 days after cured - wife died d/t transmission.
- humans can be a resivoir for a little bit of time
PCR?
DNA sequencing, texting for virus
- smaller the number the more viral particles in system
