Ticks on bull. Image credit morningagclips.com
ZIMSEC O Level Combined Science Notes: Animal Parasites and diseases
- Farmers in Zimbabwe typically raise goats, cattle, chickens and sheep.
- Disease spread much more quickly where large numbers of the same type of livestock are kept close together when compared to the wild.
- Livestock diseases are caused by pathogens.
- These organisms live on or in the host animal.
- Pathogens include parasites and microorganisms e.g. bacteria and viruses.
- Pathogens destroy tissues of the host animal and use it for food.
- This results in reduced productivity, reduced amount and quality of milk and meat.
- Infected female animals may become infertile.
- Some pathogens also produce toxins which cause diseases and results in the host animal becoming sick.
- Some diseases are spread by .
- Vector-a carrier of diseases and infection. For example a mosquito is a vector that carries and transfers the infectious agent.
- Parasite-an organism which lives in or on another organism (its host) and benefits by deriving nutrients (food) at the host’s expense.
- Parasites do not always cause diseases but still result in reduced productivity in the host animal.
- Parasites such as fleas, ticks and lice live outside the host.
- Parasites like worms and liver flukes may live inside the host.
- Tapeworms live inside the intestine and uses up the host’s food leaving the host thin and weak.
- Flukes are small flatworms that infect the host’s liver.
- They can be controlled by dosing the whole herd even those that appear unaffected.
- The risk of fluke infection can also be reduced by rotational grazing.
- Infected animals should be quarantined (kept separate) to prevent diseases from spreading.
- The movement of animals should be controlled to prevent them from being infected especially in rural areas where herds may come into contact with infected herds.
Ticks
Cattle Dip tank. Image credit daily-mail.zm
- Ticks cause a number of diseases in cattle e.g. heart water and redwater.
- Ticks are common vectors in cattle although they have been known to affect other animals such as goats.
- Ticks also suck blood weakening the host and resulting in reduced productivity.
- They can be controlled by dipping the livestock.
- The dips have a chemical that will kill the ticks.
- They can also be controlled by tick birds.
| Disease | Cause | Symptoms | Control |
|---|---|---|---|
| Foot and mouth (Cattle and Goats) | virus | Fever, excessive saliva production, loss of weight, reduced milk production, mouth blisters, possible death, loss of appetite and dullness. | There is no specific cure for the disease as surviving animals usually recover after 7-10 days. Take preventative action such as vaccinating, kill diseases animals or keep them in quarantine. Notify the responsible authorities. |
| Anthrax (In cattle and goats) | bacterium | Fever, loss of appetite, watery faeces with traces of blood, blood in noses and mouth of the dead animals, blown up stomachs, death usually occurs in 24 hours. | Can be treated with antibiotics. Burn or Bury dead animals. Notify the responsible authorities. |
To access more topics go to the Combined Science Notes page.
