Animal Husbandry WAEC

Zoonotic Diseases

Aperçu

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.

Objectifs

  1. Define zoonotic diseases
  2. Give examples of zoonotic diseases common in Nigeria
  3. Explain how zoonotic diseases are transmitted from animals to man
  4. State the precautions taken to prevent zoonotic disease transmission
  5. Explain the public health importance of zoonotic diseases

Carte mentale

Ce theme est schematise pour montrer comment les idees se relient.

Cartes memoire

Entrainement rapide sur les faits evalues dans ce theme.

Note de cours

A butcher in Kano skins a cow that died overnight, undiagnosed, with a small cut on his hand. Three days later he is gravely ill: the cow had died of anthrax, and the bacteria entered through the cut. Understanding zoonotic diseases protects every farmer, trader and household that keeps livestock.

Évaluation de la leçon

Félicitations, vous avez terminé la leçon sur Zoonotic Diseases. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.

Vous rencontrerez un mélange de types de questions, y compris des questions à choix multiple, des questions à réponse courte et des questions de rédaction. Chaque question est soigneusement conçue pour évaluer différents aspects de vos connaissances et de vos compétences en pensée critique.

Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.

  1. 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
  2. Which of the following is caused by a virus? A. Anthrax B. Brucellosis C. Rabies D. Ringworm Answer: C
  3. 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
  4. 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
  5. 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

Questions de révision

Vous vous demandez à quoi ressemblent les questions passées sur ce sujet ? Voici plusieurs questions sur Zoonotic Diseases des années précédentes.

Question 1 Rapport

(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]

Détails de la réponse

(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:

  1. 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.
  2. 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).

figure
The reproductive tract of a hen, showing the ovary and the parts of the oviduct.

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.