Define a parasite
An organism that is dependent metabolically on another, where that organism benefits at the expense of another - to survive and reproduce
What are the 4 types of infectious pathogen?
- Virus
- Bacteria
- Fungi
- Parasites
Define a virus and how they reproduce
- invade a host and attach themselves to a cell
- as they enter a cell they release genetic material which forces the cell to replicate, so the virus multiplies
- when the cell dies it releases the new viruses which go on to infect other cells
- A virus has a genetic code and protein coat
Define a fungi and how they reproduce
- Multi-cellular parasite that can decompose and then absorb organic matter using an enzyme
- Reproduce through spreading of spores
- Long and cylindrical with small filaments branching off the main body
Which infectious parasite is the smallest in size?
Viruses
Describe the host-parasite relationship
- parasites have evolved to survive in their host long enough to reproduce
- the hosts immune system has evolved to eliminate invaders but parasites persist
- they invade, suppress and manipulate a hosts immune system
What are the 3 main parasite groups?
- Helminths (worms)
- Arthropods
- Protozoa
Nematodes come under which parasite group?
Helminths
Define the term taxonomy
System of grouping organisms by characteristics and relationships
What is the class, order and family of Teladorsagia circumcincta?
Class = Nematoda Order = Strongylidae Family = Trichostrongylidae
Give 4 general features of nematodes
- roundworms
- cylindrical
- range of sizes
- free living and parasitic
What are the male nematode reproductive organs?
Testis
Vas deferens
Cloaca
What are the female nematode reproductive organs?
Ovary
Uterus
Vulva
What are the 3 layers of a nematode called?
Cuticle
Hypodermis
Muscle cells
What are the 6 parts of a nematodes digestive system?
Mouth Buccal cavity Excretory pore Oesophagus Intestine Anus
What are some external features nematodes have on the cuticle that can be used for identification?
- Cervical papillae (neck region)
- Dark brown chitinous spicules
- Vulval flap on female
- Eggs visible in uterus
- Bursa of a male
What costs come with parasitism?
- impact on welfare of diseases animals
- reproductive productivity
- cost of preventing disease: anthelmintic and prophylactic treatment
