Zoonotic Diseases
Overview
Some diseases do not stay inside the species they start in. A sick goat can pass its illness to the farmer who milks it; a dog with rabies can pass its infection to the child it bites; a cow with tuberculosis can pass the bacteria to the family that drinks its unboiled milk. Diseases that cross this way, from animal to human, are called zoonotic diseases, and they turn animal health from a farm concern into a public health one.
In this lesson you will learn what makes a disease zoonotic, meet the zoonoses that matter most on Nigerian farms, trace the specific routes by which each one reaches a human host, and learn the everyday precautions that close those routes. You will also see why this topic reaches far beyond the farm gate, to abattoir workers, veterinarians and the general public who never touch a live animal at all.
Objectives
- Define zoonotic diseases
- Give examples of zoonotic diseases common in Nigeria
- Explain how zoonotic diseases are transmitted from animals to man
- State the precautions taken to prevent zoonotic disease transmission
- Explain the public health importance of zoonotic diseases
Mind map
This topic is mapped out so you can see how the ideas connect.
Flashcards
Quick recall practice on the facts this topic is tested on.
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Zoonotic Diseases. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- A zoonotic disease is best defined as a disease that is: A. Found only in wild animals B. Naturally transmissible from animals to humans C. Passed from one human to another D. Caused only by poor nutrition Answer: B
- Which of the following is caused by a virus? A. Anthrax B. Brucellosis C. Rabies D. Ringworm Answer: C
- Bovine tuberculosis is most commonly transmitted to humans through: A. Tick bites B. Unpasteurised milk and infected meat C. Airborne dust in poultry houses D. Contact with dog saliva Answer: B
- Which precaution chiefly protects a person handling a carcass from direct-contact zoonoses such as anthrax? A. Boiling drinking water B. Wearing protective clothing and gloves C. Vaccinating poultry D. Improving housing ventilation Answer: B
- Which of these is generally regarded as a milder, common zoonosis spread by skin contact with an infected animal? A. Rabies B. Anthrax C. Avian influenza D. Ringworm Answer: D
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Recommended Books
Revision Questions
Wondering what past questions for this topic looks like? Here are a number of questions about Zoonotic Diseases from previous years
Question 1 Report
(a) Discuss anthrax disease under the following headings:
- causative organisms
- two modes of transmission;
(b) Draw and label the reproductive tract of a hen. [6 marks]
Answer Details
(a) Anthrax disease
Causative organism:
Anthrax is caused by the bacterium Bacillus anthracis, a large, rod-shaped, spore-forming bacterium. Its spores are extremely resistant and can survive in the soil for many years.
Two modes of transmission:
- Ingestion of contaminated feed and water - animals swallow anthrax spores while grazing on pasture, or feeding and drinking from feeders, drinkers or water sources contaminated with the spores.
- Through open wounds or body contact - spores enter the body through cuts, wounds or abrasions on the skin; the disease can also be spread mechanically by biting flies and other vectors, or by inhalation of spores.
(b) The reproductive tract of a hen
The domestic hen has a single functional reproductive system on the left side of the body (the right ovary and oviduct remain undeveloped). The tract consists of an ovary bearing a cluster of developing ova (yolks) and a long, coiled oviduct made up of the infundibulum, magnum, isthmus, uterus (shell gland) and vagina, which opens into the cloaca (vent).
As the yolk (ovum) is released from the ovary it is caught by the infundibulum, then passes through the magnum (where thick albumen/egg white is added), the isthmus (where the shell membranes are formed), the uterus or shell gland (where the hard calcareous shell and shell pigment are deposited), and finally through the vagina and out through the cloaca (vent) as a fully formed egg.