EESA10 Final Exam Notes (Lecture #07 – Biological Hazards August 15th
2026 exam prep material University of Toronto
EESA10 Final Exam Notes
EESA10 Lecture #07 – Biological Hazards
Infectious Disease
- Is a host-centered concept
- Human body is a habitat and host to many organisms
- Associations that harm or bother us are infectious diseases; agents are pathogens
- Zoonosis
o Infectious disease transmissible to humans from other animals
Types of Pathogens
- Worms, multicellular and parasitic
- Protozoa, unicellular and parasitic
- Bacteria, unicellular and most not parasitic
o Aerobic versus anaerobic, or tolerate either
o Some form spores
- Viruses, strand of DNA or RNA, parasitic
Body’s Defense Against Pathogens
- Immune system
o Distinguishes ‘self’ from ‘foreign’
o Active immunity on first exposure to antigen, body produces antibodies
- Vaccination
o Antigen preparation, active immunity
o Antibody preparation, passive immunity
- Herd Immunity, practical protection
o If enough members of a group are immune, hard to maintain chain of infection
Evolution of Strategies for Managing Transmission of Disease
- Segregation of sick or exposed persons
- Isolation
o The separation of persons who have an infectious illness
- Quarantine
o The separation of persons who have been exposed to an infectious agent
- Sanitation is beneficial
- Vaccination to prevent illness
- Antibiotics to prevent illness
o Populations of pathogens become resistant over time
o High reproductive rate allows them to become genetically resistant quickly
o Overuse of antibiotics
▪ Methicillin-resistant Staphylococcus aureus (MRSA)
▪ Antibiotics in food additive to boost livestock
, - Pesticides to control vectors
Transmission of Infectious Disease
- Transmission through closeness / contact
o Droplet transmission: coughing and sneezing
▪ Diphtheria, tuberculosis, pertussis, influenza, measles, mumps, rubella,
Covid
o Direct oral contact
▪ Strep, herpes simplex-1, infectious mononucleosis
o Transmission by fomite (object or substance capable of carrying infectious
organisms)
▪ Skin cells, hair, clothing, bedding
- Airborne transmission in aerosols (distinct from droplet transmission)
- Fecal-oral transmission of diarrheal disease
o Fecal-oral pathway, one person’s infectious diarrheal disease becomes next
persons disease of fecal origin
o If sewage not well controlled, waterborne transmission dominates
o Fecal-oral transmission also vial soil and by hand-to-mouth transmission
o Cholera, typhoid fever, dysentery, giardiasis, cryptosporidium (zoonoses);
hepatitis A, Norwalk virus and polio
- Non-Fecal organisms also transmitted in water or soil
o Guinea worm diseases
o Tetanus
- Via Food (foodborne transmission)
o Housefly as mechanical vector
Global Facts
- 12.3 Million deaths in 2008
o Respiratory infections (29%), diarrheal disease (20%), and HIV/AIDS (14%) are
leading infectious causes of death
- Worldwide, 22% of all deaths in 2008
o Highest in Africa (53%), Southeast Asia (27%), and Eastern Mediterranean (25%)
Infectious Disease as a Cause of Cancer
- Infection can increase cancer risk
o Chronic irritation, cell proliferation
- Known infectious causes of cancer account for 18% of cancers worldwide
o Liver (hepatitis B and C viruses, liver fluke)
o Cervix (human papilloma virus)
o Stomach (Helicobacter pylori bacterium)
- Higher percentage in lower-income countries
,Important Types of Pathogens
- Bacteria
o Tuberculosis
o Anthrax
o Plague
- Viruses
o Yellow Fever
o HIV
o Bird Flu
o West Nile Virus
- Protozoa
o Malaria
BACTERIAL DISEASES
Tuberculosis (TB)
- One of the world’s deadliest diseases:
o 1/3 of world infected with TB
o 9 million people annually sick with TB
o 1.4 million TB related deaths worldwide
o Leading killer of HIV infected people
- Attacks the lungs
- Symptoms include chest pain, coughing blood, coughing for more than 3 weeks, fever,
chills, night sweats, appetite loss, weight loss, paleness, and getting tired easily
- Transmission from cough, sneeze, speak, kiss, or spit from ill person
Anthrax
- Bacillus anthracis (large, spore forming bacteria)
- Produce toxin
- May lead to septicemia and death
- Bioterrorism related: No smell or taste, and too small to be seen by naked eye
- Can’t be transmitted from person to person
- Three major clinical forms
o Cutaneous on the skin
o Inhalation
o Gastrointestinal
- Cutaneous Anthrax
o Most common naturally occurring type (more than 95%)
o After skin contact with contaminated meat, wool, or leather from infected
animals
o The incubation period ranges from 1-12 days
, o Begins as a small raising bump, progresses into vesicle and then a painless ulcer
o Fever, headache, and lymph glands swell
o 20% oof untreated cases results in death
- Inhalation Anthrax
o Most lethal form
o Inhalation of spores of anthrax
o Incubation period 1-60 days
o Starts as viral respiratory illness, sore throat, mild fever, and muscle aches
o May progress to respiratory failure and shock with developing meningitis
o 75% of cases results in death even with all possible supportive care
- Gastrointestinal Anthrax
o Consumption of raw or undercooked contaminated meat
o Incubation period 1-7 days
o Nausea, loss of appetite, vomiting, and fever, followed by adnominal pain,
vomiting blood and bloody diarrhea
o 25% - 60% cases result in death
o Effect of early treatment is not defined
- Bioterrorism Related Anthrax
o Mixed with powder to transport the bacteria
o Suspicious mails
o What should people do when they get a suspicious letter/parcel?
▪ Environmental testing
▪ Diagnosis
▪ Cure (antibiotics and vaccine)
Plague
- Caused by bacteria Yersinia pestis
- Bubonic Plague
o Most common
o When a person is bitten by a flea that has been infected by biting an infected
rodent
o Also, through a break in a person’s skin
o Swollen, tender lymph glands (buboes), fever, headache, chills, and weakness
o Does not spread from person to person
- Pneumonic Plague
o Infection on lungs
o From person (or animal) to person through air
o Complication of bubonic plague
- Septic emic Plague
o When plague bacteria multiply in the blood
o Complications of Pneumonic or Bubonic Plague or it can occur by itself
o Some symptoms as Bubonic plague but not buboes
o Does not spread from person to person
2026 exam prep material University of Toronto
EESA10 Final Exam Notes
EESA10 Lecture #07 – Biological Hazards
Infectious Disease
- Is a host-centered concept
- Human body is a habitat and host to many organisms
- Associations that harm or bother us are infectious diseases; agents are pathogens
- Zoonosis
o Infectious disease transmissible to humans from other animals
Types of Pathogens
- Worms, multicellular and parasitic
- Protozoa, unicellular and parasitic
- Bacteria, unicellular and most not parasitic
o Aerobic versus anaerobic, or tolerate either
o Some form spores
- Viruses, strand of DNA or RNA, parasitic
Body’s Defense Against Pathogens
- Immune system
o Distinguishes ‘self’ from ‘foreign’
o Active immunity on first exposure to antigen, body produces antibodies
- Vaccination
o Antigen preparation, active immunity
o Antibody preparation, passive immunity
- Herd Immunity, practical protection
o If enough members of a group are immune, hard to maintain chain of infection
Evolution of Strategies for Managing Transmission of Disease
- Segregation of sick or exposed persons
- Isolation
o The separation of persons who have an infectious illness
- Quarantine
o The separation of persons who have been exposed to an infectious agent
- Sanitation is beneficial
- Vaccination to prevent illness
- Antibiotics to prevent illness
o Populations of pathogens become resistant over time
o High reproductive rate allows them to become genetically resistant quickly
o Overuse of antibiotics
▪ Methicillin-resistant Staphylococcus aureus (MRSA)
▪ Antibiotics in food additive to boost livestock
, - Pesticides to control vectors
Transmission of Infectious Disease
- Transmission through closeness / contact
o Droplet transmission: coughing and sneezing
▪ Diphtheria, tuberculosis, pertussis, influenza, measles, mumps, rubella,
Covid
o Direct oral contact
▪ Strep, herpes simplex-1, infectious mononucleosis
o Transmission by fomite (object or substance capable of carrying infectious
organisms)
▪ Skin cells, hair, clothing, bedding
- Airborne transmission in aerosols (distinct from droplet transmission)
- Fecal-oral transmission of diarrheal disease
o Fecal-oral pathway, one person’s infectious diarrheal disease becomes next
persons disease of fecal origin
o If sewage not well controlled, waterborne transmission dominates
o Fecal-oral transmission also vial soil and by hand-to-mouth transmission
o Cholera, typhoid fever, dysentery, giardiasis, cryptosporidium (zoonoses);
hepatitis A, Norwalk virus and polio
- Non-Fecal organisms also transmitted in water or soil
o Guinea worm diseases
o Tetanus
- Via Food (foodborne transmission)
o Housefly as mechanical vector
Global Facts
- 12.3 Million deaths in 2008
o Respiratory infections (29%), diarrheal disease (20%), and HIV/AIDS (14%) are
leading infectious causes of death
- Worldwide, 22% of all deaths in 2008
o Highest in Africa (53%), Southeast Asia (27%), and Eastern Mediterranean (25%)
Infectious Disease as a Cause of Cancer
- Infection can increase cancer risk
o Chronic irritation, cell proliferation
- Known infectious causes of cancer account for 18% of cancers worldwide
o Liver (hepatitis B and C viruses, liver fluke)
o Cervix (human papilloma virus)
o Stomach (Helicobacter pylori bacterium)
- Higher percentage in lower-income countries
,Important Types of Pathogens
- Bacteria
o Tuberculosis
o Anthrax
o Plague
- Viruses
o Yellow Fever
o HIV
o Bird Flu
o West Nile Virus
- Protozoa
o Malaria
BACTERIAL DISEASES
Tuberculosis (TB)
- One of the world’s deadliest diseases:
o 1/3 of world infected with TB
o 9 million people annually sick with TB
o 1.4 million TB related deaths worldwide
o Leading killer of HIV infected people
- Attacks the lungs
- Symptoms include chest pain, coughing blood, coughing for more than 3 weeks, fever,
chills, night sweats, appetite loss, weight loss, paleness, and getting tired easily
- Transmission from cough, sneeze, speak, kiss, or spit from ill person
Anthrax
- Bacillus anthracis (large, spore forming bacteria)
- Produce toxin
- May lead to septicemia and death
- Bioterrorism related: No smell or taste, and too small to be seen by naked eye
- Can’t be transmitted from person to person
- Three major clinical forms
o Cutaneous on the skin
o Inhalation
o Gastrointestinal
- Cutaneous Anthrax
o Most common naturally occurring type (more than 95%)
o After skin contact with contaminated meat, wool, or leather from infected
animals
o The incubation period ranges from 1-12 days
, o Begins as a small raising bump, progresses into vesicle and then a painless ulcer
o Fever, headache, and lymph glands swell
o 20% oof untreated cases results in death
- Inhalation Anthrax
o Most lethal form
o Inhalation of spores of anthrax
o Incubation period 1-60 days
o Starts as viral respiratory illness, sore throat, mild fever, and muscle aches
o May progress to respiratory failure and shock with developing meningitis
o 75% of cases results in death even with all possible supportive care
- Gastrointestinal Anthrax
o Consumption of raw or undercooked contaminated meat
o Incubation period 1-7 days
o Nausea, loss of appetite, vomiting, and fever, followed by adnominal pain,
vomiting blood and bloody diarrhea
o 25% - 60% cases result in death
o Effect of early treatment is not defined
- Bioterrorism Related Anthrax
o Mixed with powder to transport the bacteria
o Suspicious mails
o What should people do when they get a suspicious letter/parcel?
▪ Environmental testing
▪ Diagnosis
▪ Cure (antibiotics and vaccine)
Plague
- Caused by bacteria Yersinia pestis
- Bubonic Plague
o Most common
o When a person is bitten by a flea that has been infected by biting an infected
rodent
o Also, through a break in a person’s skin
o Swollen, tender lymph glands (buboes), fever, headache, chills, and weakness
o Does not spread from person to person
- Pneumonic Plague
o Infection on lungs
o From person (or animal) to person through air
o Complication of bubonic plague
- Septic emic Plague
o When plague bacteria multiply in the blood
o Complications of Pneumonic or Bubonic Plague or it can occur by itself
o Some symptoms as Bubonic plague but not buboes
o Does not spread from person to person
