3.7.10Inquiry Process
Zoonoses — IB Biology HL Revision Notes & Topical Questions
5 min read 5 parts Lesson 151 of 160
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 5What Zoonoses Are
Definition
- Definition A zoonosis is an infectious disease that can be transmitted from other animals to humans.
Examples
- Examples Rabies from dogs and bats, bovine tuberculosis from cattle, avian influenza from birds and Ebola from wild animals.
Reservoir host
- Reservoir host The animal species in which the pathogen normally lives, often without showing serious disease.
Spillover
- Spillover The jump of a pathogen from its animal host into humans, which may be followed by human-to-human spread.
Importance
- Importance Many emerging infectious diseases of humans are zoonotic, so understanding them is central to protecting public health worldwide.
Part 2 of 5Causes of Emergence
Causes of Emergence
Habitat loss
- Habitat loss Clearing forest brings people and livestock into closer contact with wild animals and their pathogens.
Intensive farming
- Intensive farming Large numbers of closely packed animals allow pathogens to spread rapidly and to mutate.
Wildlife trade
- Wildlife trade Live animals of different species kept close together in markets provide chances for pathogens to cross species.
Travel and climate
- Travel and climate Global travel spreads infections fast, and warmer climates extend the range of insect vectors.
Mutation
- Mutation Pathogens that spread through new hosts can mutate, and some changes allow efficient human-to-human transmission.
| Route | Example | Prevention |
|---|---|---|
| Direct contact with animals | Rabies | Vaccinate dogs |
| Contaminated food | Salmonella | Cook food well |
| Vector bite | West Nile virus | Control mosquitoes |
Part 3 of 5Control Measures
1
Monitor animal and human populations so that a new outbreak is detected early.
2
Vaccinate domestic animals, as in mass vaccination of dogs against rabies, to reduce the pathogen reservoir.
3
Improve hygiene, cooking practices and the handling of meat and animals.
4
Regulate trade in wild animals and protect habitats to reduce contact between species.
5
Isolate and treat infected people to prevent human-to-human spread.
Part 4 of 5Worked Example
Question
- A town has 2 000 dogs, and a vaccination programme aims to immunise 70% of them against rabies.
- How many dogs must be vaccinated, and how many remain unprotected if the target is met?
- Dogs to vaccinate = 2 000 × 0.70 = 1 400.
- Unprotected = 2 000 − 1 400 = 600.
- Vaccinating most dogs lowers transmission to humans.
Answer 1 400 dogs vaccinated and 600 unprotected, enough to greatly reduce the chance of human rabies.
Part 5 of 5Exam Checklist & Tips
3.7.10 – Key Points for the Exam
- Zoonosis A disease passed from animals to humans.
- Reservoir host Species in which a pathogen normally lives and persists.
- Spillover Transmission of a pathogen from an animal species to humans.
- Surveillance Continuous monitoring of disease to detect outbreaks early.
Common Mistakes
- Saying a zoonosis can only pass from human to human; the origin is an animal.
- Assuming reservoir animals always look sick; they often do not.
- Forgetting that human activities, such as habitat clearing, increase the risk.
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