3.6.10Additional lessons
Zoonoses — IB Biology SL Revision Notes & Topical Questions
5 min read 5 parts Lesson 79 of 142
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Part 1 of 5Species Barriers
A zoonosis is a disease that passes from a non-human animal to humans.
Species-specific disease
- Species-specific disease Many pathogens infect only one species, because they need specific receptors on host cells.
Receptors
- Receptors If an animal pathogen can bind receptors found on human cells, it may infect humans.
Body temperature
- Body temperature A pathogen adapted to one body temperature may not develop in a host with a different temperature.
Crossing the barrier
- Crossing the barrier Mutation and close contact between species can allow a pathogen to cross the barrier.
Part 2 of 5Examples and Routes
Rabies
- Rabies The virus is carried by mammals such as dogs and passes to humans through bites.
Influenza
- Influenza Some influenza viruses circulate in birds or pigs and can occasionally infect people.
COVID-19
- COVID-19 Evidence suggests that the virus that caused the pandemic originated in an animal host.
HIV
- HIV The virus emerged from related viruses in non-human primates, and then developed into a human-only strain.
Transmission
- Transmission Routes include direct contact, bites, eating infected animal products and vectors such as ticks.
| Route | Example |
|---|---|
| Bite | Rabies |
| Contact with infected animals | Some influenza viruses |
| Food | Infection from undercooked meat |
| Vector | Ticks carrying bacteria |
Part 3 of 5Why Zoonoses Are a Growing Concern
Why Zoonoses Are a Growing Concern
Close contact
- Close contact Farming, markets, travel and habitat loss bring people and animals into closer contact.
Hard to eradicate
- Hard to eradicate The pathogen can persist in an animal population, so removing it from humans may not remove it entirely.
Pandemic potential
- Pandemic potential A new pathogen has no existing immunity in humans, so it can spread widely.
Animal products
- Animal products Zoonoses can also harm livestock and the food supply.
Part 4 of 5Control
1
Monitor animal and human populations to detect new infections early.
2
Vaccinate pets and livestock where vaccines exist, as with rabies in dogs.
3
Improve hygiene, cook meat thoroughly and reduce unprotected contact with wild animals.
4
Work with veterinary and medical services together to protect both animal and human health.
Part 5 of 5Exam Checklist & Tips
3.6.10 – Key Points for the Exam
- Zoonosis A disease that spreads from animals to humans.
- Species barrier A limit that prevents a pathogen of one species infecting another.
- Reservoir host An animal population that carries a pathogen.
- Pandemic An outbreak spreading across many countries.
Common Mistakes
- Saying all diseases can infect all species.
- Writing that zoonoses spread only by bites.
- Thinking that vaccinating humans alone removes the source of a zoonosis.
- Confusing epidemic and pandemic; a pandemic is much wider in scale.
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