Emerging infectious diseases. Sep 10.
- Over 60 perc. Of deaths due to infectious diseases
- Very few vaccines available at the time
- In general, during the time of (1887) there was more health problems than any.
- Because effective control methods were unknown, more people were prone to infectious diseases.
Especially within mothers who gave birth.
- Life expectancy went up 20 percent during the 20th century thanks to vaccines (main reason) and
antibiotics. It started to give the protection needed that otherwise would’ve killed people
- the influenza of 1918 lowered the trend of life expectancy.
- There is a huge gap of life expectancy from rich countries like Canada to poor countries. AIDS
was a reason why life expectancy lowered.
- Biggest cause of death in third world countries is HIV, tuberculosis and malaria.
- There is not an acceptable coverage of therapy in low- and middle-income countries. During the
- Many people contributed for aid such as bill and Melinda gates and David cameron who pledged
60 million for polio vaccine.
Microbes- continued on second lecture
- Microbes have caused the most devastating epidemics in recent human history
- Beneficial role: microbes are responsible mostly for our health, we need them in order to
survive, develop immune systems, digest foods, keep dangerous pathogens away.
Sept 12, lecture 2
Beneficial role of Microbes
- Very important for the environment, they turn inorganic molecules, (nitrogen, CO2) into organic
compounds. Into organic compounds (e.g. nucleic, amino acids)
- Microbes are also responsible for oxygen
- Responsible for life because of their ability to break down waste, ability to recycle, such as trees
- Agricultural society: because of microbes.
- The natural microbial flora provides protection against more virulent microbes.
- Used to prepare drugs such as penicillin, insulin
- Make vitamins, e.g.: vitamin k
How it’s used:
- Wine, take the grapes already covered in microbes (white stuff), put under a certain condition
makes alcohol from the sugar
- Bread is made from yeast/bacteria
- Food production e.g., milk products
Microbes- host equilibrium.
- Microbes need the host alive and well.
- Microbial diseases can be severe e.g: Small pox killed millions of peoples, Ebola, rabies if they’re
not treated appropriately.
- Most microbes don’t cause many diseases that kill their host. b/c Microbes normally have the
general ability to kill all of us e.g.:
• Tuberculosis versus the Ebola virus (both can kill)
• 1.7 people worldwide are infected with tuberculosis, doesn’t kill the infected person
quickly the disease normally lasts 30 years. Infection takes place in early stages of life
• Successful pathogen (stays around for a while within the host)
• Ebola has been around for the last 50 years or so, only a few are infected. Acute disease,
death of up to 90 % of infected people shortly after the infection.
• Very aggressive pathogen but doesn’t stay within the host for a while, it kills easily.
- Microbial natural section, evolution, favours less or non-virolunt microbes.
- In general, we can say, many infection diseases can be viewed as a failure of the microbe to adapt
to its host.
- Although microbes are good for our health, they cause diseases
Microbes and disease
- Microbes can cause infectious diseases; they have caused the most devastating epidemics in
recent human history:
• Small pox,
• bubonic plague,
• Spanish flu most well-known pandemic (global epidemic) 1918-1919, 50-100 million
Proportions of deaths due to infectious diseases
- High income countries today are 6 %
- High income countries in 1918 over 50 %
- Population increased because of better sanitation, simple as hand washing
- Population increased because of vaccines
Away from infectious disease?
- During the mid 1900’s, most scientists and policy makers were shifting their attention away from
infectious disease as better sanitation, vaccines and antibiotics made these diseases rare, at least in
the developed world. Up until the end of the 60’s.
- Improved sanitation
• Water supply, hospitals
• Smallpox had been eradicated by the mid 1970’s. everyone got immunized.
- Infectious diseases appeared to be on the way out
- 1969 US surgeon general to congress “it’s time to close the book on infectious diseases” … but
not yet and probably never.
Emerging infectious diseases
- Infectious diseases as a group will not disappear
- Drug resistant strains.
- New disease-causing agent
• HIV/AIDS generally a new disease, wasn’t around in people before.
• SARS, MERS came around November 2002. Originated in China
• Ebola, 50 years can live in certain animals such as bats.
- Outbreaks of existing diseases \
• West Nile virus (WNV) made the jump to North America, through mosquitos
• Influenza- most severe pathogen.
• Monkey pox, common to small pox.
Video – tutorial sept 17.
- Superbugs, might be created that are resistant to antibiotics or drugs.
- Finding new antibiotics, antibiotics are one of the miracles of modern medicine
- In some place’s antibiotics aren’t working
Antimicrobial drug resistance
- Tuberculosis, before antibiotics, tuberculosis was the leading cause of death. People infected each
other. (Mycobacterium tuberculosis)
- Acinetobacter spp
- Pseudomonas aeruginosa
- Klebsiella pneuomiae
- Staphylococcus aureus
- Surgery needs to done to remove the infected part, before antibiotics
- Microbes spread by dividing in 2
Development of drug resistant microbes
- The development of resistant organisms in population
o Drug sensitive mutant will remain when exposed to drugs 9low concentration, short
duration) , instead of drug sensitive mutants. The drug sensitive are killed by exposure to
How to slow down the development of drug resistant organisms in populations?
- When you’re using high enough concentration of drug for the appropriate time frame ( long
treatment), you are going to kill both drug resistant & drug sensitive mutants.
- More likely to kill the drug resistant pathogens.
Who should be blamed for antibiotic resistance?
- Misuse/abuse of antibiotics
o Farmers, the farming industry, antibiotics are acting as growth factors, trying to get
poultry bigger to sell. They’re money makers for the farmers. Because they want to grow
faster. We then eat this
o Health workers, not giving the appropriate dosage or giving antibiotics when its not
o Patients Can lead to more exposure to sickness and need antibiotics when being in
o Hospitals; a lot of infected people, can lead to catching diseases. And exposure to a lot of
o Antibiotics policy in 3rd world countries, there is no strict policy and antibiotics can be
o Mother nature
▪ Selective pressure (induced evolution)
▪ Microbial “genetic internet”
• Non- pathogenic bacteria can be transferred to its pathogenic neighbours.
Monkeypox in the USA
- Related to smallpox
- Symptoms include rash, fever chills and sores
- Not usually fatal
- No vaccine and symptoms are not usally fatal
Very few vaccines available at the time. In general, during the time of (1887) there was more health problems than any. Because effective control methods were unknown, more people were prone to infectious diseases. Life expectancy went up 20 percent during the 20th century thanks to vaccines (main reason) and antibiotics. It started to give the protection needed that otherwise would"ve killed people the influenza of 1918 lowered the trend of life expectancy. There is a huge gap of life expectancy from rich countries like canada to poor countries. Aids was a reason why life expectancy lowered. Biggest cause of death in third world countries is hiv, tuberculosis and malaria. There is not an acceptable coverage of therapy in low- and middle-income countries. Many people contributed for aid such as bill and melinda gates and david cameron who pledged. Microbes have caused the most devastating epidemics in recent human history.