Lecture 1: ectoparasites of ruminants Flashcards
Why is production animal health important?
- Economical advantages
- Management of disease in an economic way is crucial
- animal health relates directly to welfare: Production, ethics and marketing/public perception
Definition of health
Health is a state of complete well-being and not merely the absence of disease, the animal has to be holistically healthy, not merely the absence of parasite and disease
define productivity
A healthy animal grows, reproduces and behaves in a manner which has come to be regarded as normal for its species and type
Classification of disease
- Clinical sign: Acute diarrhea
- Set of clinical signs (syndrome): Sudden death in cattle
- Anatomical abnormality: deformed cattle
- By “Cause”: Clostridial disease in cattle
Factors in an epidemiological triad
And explain their relationship
Host, agent and environment
These factors are all interlinked, its rare that one particular outcome will be caused by one factor, there will be multi-factorial things involved
All diseases are multi-factorial
How to detect disease
Clinical disease (Overt signs):
- Animals are dull, less responsive
- Rough coat, poor body condition
- Discharge, coughing, increased respiratory rate
- Diarrhea (Scours)
- Swelling
Subclinical disease (No overt signs) 1. Very mild form of disease 2. Decreased production 3. May be carriers of infectious agents Harder to pick up, look ok but not ok as there are no obvious signs
Why are subclinical disease important?
it can be the tip of the iceburg as nothing is full blown yet, if it is detected it can be treated early and prevent loses in production and death
preventing infection from spreading
If missed, it will turn from subclinical to clinical
Cost of disease
Production losses welfare impact public perception biosecurity occupational health and safety
Cost of controlling disease
Treatment costs
cost of culling
Prevention cost: How to protect farms around infected farms and how to manage (bio-security)
What do we choose to control:
Host - change genetics to make animals more parasite resistant
Agent
Environment: If too got sheep parasite can change to cows
Factors that affect animal production health and welfare
Genetics Nutrition: Feed quality and availability Seasonal variations (Climate, drought) Disease Cost of control measures (Labour and treatment)
Complex/indirect lifecycle vs direct lifecycle of parasite
A parasite that must infect more than one host species to complete its lifecycle is said to have a complex or indirect life cycle
A parasite that infects only one host is said to have a direct lifecycle
Facultative parasites
An organism that lives independent of a host (Free living) but may occasionally be parasitic under certain conditions
Obligate parasites
an organism that cannot complete its lifecycle without exploiting a suitable host
Host classification
Definitive host: A host that harbors a parasite while the parasite reproduces sexually
Intermediate host: A host that harbors a parasite during some of its developmental stages
Natural host: A host that is naturally infected with a certain species of a parasite
Accidental host: A host that is not normally infected with a particular parasite
Host interaction
Symbiosis
Mutualism
Commensalism: One benefit other unaffected
Parasitism: A relationship between 2 organisms where one benefits at the expense of the other
