parasites

Question 1

What are the possible symbiotic association categories? Explain them

Answer 1

Phoresis, Commensalism, mutualism and parasitism.

Phoresis: In this reltionship, there is no physiological or biochemical dependece on the part of the host or symboint. Means to carry

Commensalism: “eating at same table” neither metabolically depended on one another but one may benefit

Mutualism: occurs when each member of relationship benefits from the other. They are metabolically dependent on one another. eg clown fish and coral

Parasitism: when one specie lives at the expense of another.

Question 2

In the wild, why do parasites rarely cause mass death?

Answer 2

The animals in the wild are naturally dispersed preventing pathogen spread. In captivity animals are usually kept in confined areas increasing the density of parasites in the soil.

Question 3

What type of hosts are considered vectors?

Answer 3

Definitive and intermediate hosts

Question 4

How are clinical signs caused?

Answer 4

Removal of something (metabolities/blood)
Loss of body fluids (proteins-->oedema)
Interference with absorption
Blockage of something
Irritation
Aberrant migration (in CNS)

Question 5

How can we break the cycle of a parasite?

Answer 5

Rotate cattle or livestock and use the sun to naturally get rid of the parasites as chemical dont always work
Get rid of intermediate hosts such as snails. Complication could be due to chemicals been to strong and killing other animals. Also fencing is expensive if we want to seperate the livetock from infested areas.

Question 6

Write about the pathogenesis of cryptosporidium

Answer 6

Its prevalence is high in young (first months). It has a direct life cycle and cattle are the hosts. It sheds infectious oocyts in feces which are then ingests and remain extremely resistant and viable for yeras in cool and moist environment. It is a major water bourne disease. It causes diarrhoe in young ruminants (5days to 6 months) and the best way to prevent and cotnrol it is to pay attention to hygiene and management. Overcrowding should be avoided and animals should be kept with similar age groups.
Main way to detect it is through immunoflurences and flotation techniques

Question 7

write about coccidia

Answer 7

affects young cattle also.
It has a direct life style and its host is cattle. It infects the intestinal tract, inside the enterocytes. oocytes shed in feces but need to SPORULATE to become infectious. Animals are infected when they ingest sporulated oocyts.
OOcysrs are detected in feces with flotation procedures

Question 8

Write about trichostrongyloid

Answer 8

Affects ruminats and has a direct life cycle. Adult worms in the GIT and produce eggs that develop in manure in the environment. Infective larvae released onto pasture, they can infect grazing animals. Eggs in feces detected using flotation techniques.

Question 9

write about fasciola hepatica

Answer 9

Fasciolosis affects the bile ducts of ruminants (adults). It has an indirect lifestyle where the fasciola hepatica embryo emerges from eggs and invades snails (intermediate host). While in the intermediate host, they undergo asexual multiplication and cercaria are produced which attach to vegetation. These are then ingested by grazing animals and the larvae leave their GIT and migrate through the liver to reach the bile ducts.Youn animals are most susceptible to clinical disease: diarrhoea, anemia, recued growth and death in severe cases.
detected via sedimentation teset- detects the large brownish eggs