Parasite and Hosts Effects

Which type of disease is especially harmful to production animals?

– Internal parasites

-Theleria

-cattle tick

-Buffalo fly

Tick fever

helminthosis

parasite factors

-distribution according to climate

Lifecycles

Larval ecology

helminthosis

host factors

Immunity

breed/genetic differences

Physiological state

Nutrition

helminthosis

parasite factors - distribution

Three regions: summer, intermediate/non-seasonal, winter

-Summer rainfall: tropical/some tropical

– Temperate: winter rainfall

– Climate factors are very critical for LC stages on pastures

– Very temperature and moisture requirements

– Species vary with region

Most significant nematode?

-strongylids

-Trichostrongylids

helminthosis

parasite factors - summer

•Haemonchus (sheep, goats,

•Trichostrongylus spp. (sheep & goats)

•Cooperia spp. (cattle)

•Oesophagostomum (cattle)

helminthosis

parasite factors - winter

•Ostertagia Teladorsagia (sheep, goats,

•Trichostrongylus spp. (sheep, goats, cattle)

•Cooperia spp. (cattle)

•Oesophagostomum (cattle)

When is the PPP longer?

– For Ig bowel parasites

Factors for free living on pasture?

– Environment: temperature, moisture

Factors for parasitic phase?

– Influenced by Arrested Development

helminthosis

parasite factors - LC - initiating factors

-comment: Arrested Development at early L4 stage

-immune responses inhibiting normal development

– Seasonal influences on pasture is a marker for to be able to survive a period of harsh conditions

helminthosis

parasite factors - LC - sig

– Allows worms to survive adverse conditions

– Control complications

– Eight in effective against hypobiotic larva

– Development resumption of large numbers

helminthosis

parasite factors - larval ecology

– Egg and pre-living larval determine levels of pasture contamination

helminthosis

parasite factors - resistance

Host ability to prevent, reduce or clear infection

helminthosis

parasite factors - resilience

Capacity of an animal to compensate for negative negative effects of parasitism by the maintenance of productive parameters ((health))

helminthosis

parasite factors - immunity

– Neonate immunologically naïve to parasites

• Acquired immunity develops

• Weaning is critical

– Immunity development affected by interactions between:

• Gender (males are susceptible)

• age

• Social adjustments at weaning a.k.a. stress

• Nutritional adjustments at weaning

helminthosis

parasite factors - – Host species, and GIN immunity

sheep

– max immunity at two years old

helminthosis

parasite factors - – Host species, and GIN immunity

Cattle

– Cuddled about better immunity to worms than other large animals

Strong acquired immunity by 18 months

Disease most common in calves

helminthosis

parasite factors - – Host species, and GIN immunity

Goats

Never develop a strong immunity

helminthosis

parasite factors - – goat immunity

– Browsers

– weaker degree of acquired immunity

– Intensive production on lush pastures

– AH pharmocokinetics different

-drugs demonstrate considerably lower bio availability goats so require higher doses

helminthosis

host factors - breed/genetic differences in immunity

cattle: No distinct brain differences in resistance, but

– P.Indicus have higher capacity to withstand pathogenic effects

Sheep: some braids are more resistant

helminthosis

host factors - breed/genetic differences in immunity

periparturient rise

inc in FEC during peripartirient period peaks at week 6 of lactation

-major source of pasture contamination-

– Timing new crops susceptible are beginning to grace

– Mostly in sheep, goats, pigs

helminthosis

host factors - physio state and immunity

PPR relaxation of immunity -w hy?

-reproduction and pregnancy imposes considerable MP demands reducing immunity

helminthosis

host factors - physio state and immunity

PPR demands

– Highest: maintenance function

– High: reproductive effort

– Relative low: immune functions

– Lowest: attainment of desired fatness

helminthosis

host factors - physio state and immunity

PPR relaxation of immunity - impairment

– Failure to resist establishment of incoming larva

– Failure to suppress the quantity of adults

– Failure to expel adult worms

– Maturation of a portion of arrested larva

helminthosis

host factors - nutrition

– Complex interaction between nutrition and immunity

– Better nutrition equals more resistant and resilient to infection

helminthosis

host factors - nutrition

best way to maintain

protein and E

helminthosis

host factors - nutrition

young

– Nutrition, even more critical

– Protein effects rate of immunity development

Young sheep, nutrition → increases worm burdens and FEC