Parasitic Diseases in Animals

Study Notes

Parasitic Disease in Animals

Parasitic diseases cause pathophysiological changes that manifest in clinical disease, affecting animal health and economy.
Internal parasites cause:
- Diarrhea, anemia, and tissue insult from larval migration
- Predisposition to pneumonia, enteritis, intestinal rupture, cirrhosis, and liver abscess
- Aneurysm and embolism
- Increased susceptibility to viral and bacterial invasion
- Decreased productivity (weight gain, feed efficiency, carcass value, and milk production)
External parasites cause:
- Skin irritation, loss of hair, sunburn, and infection
- Upset of the animal's nervous system
- Loss of blood and fluids, and anemia
- Decreased productivity (weight gain, feed efficiency, hide and carcass value, and milk and wool production)

Parasitic Control Measures

Good management and husbandry, sanitation, and natural immunity
Acquired immunity and anti-parasitic drugs
Judgments for anti-parasitic drug use:
- Efficacy: spectrum, efficacy, and timing
- Safety: adverse effects, drug interactions, and economic soundness
- Precautions: toxicity, dose, route of administration, and precautions

Anti-Parasitic Drugs

All are potentially toxic, with direct toxic action on the animal and secondary pathology
Follow label directions, use with care in young, old, and debilitated animals, and avoid use in pregnant animals unless labeled
Know absorption, excretion, and inactivation of drugs
Contraindications due to idiosyncratic adverse reactions in specific species or breeds

General Toxic Anti-Parasitic Drug Reactions

Local irritations: pharynx, larynx, stomach, intestine, or skin
Difficult breathing, emesis, diarrhea, perforation of intestinal wall
Systemic: organ toxic reactions (liver, kidney, CVS, Respiratory S., CNS, and ANS)
Drug interactions, actions not intended, and secondary pathology

Anthelmintics

Definition: drugs that kill or remove parasitic worms, mainly in the digestive tract and associated organs
Helminthiasis in animals has significant economic importance worldwide
Properties of ideal anthelmintics:
- Non-toxic to the host, highly effective on worms, wide therapeutic index, low cost, and easy administration
Anthelmintic resistance:
- Resistance and cross-resistance occur among anthelmintics
- Resistance transmitted through genes via eggs of helminthes
- Changes in anthelmintics may lead to confusion and difficulty in diagnosis

Description

This quiz covers the effects of parasitic diseases on animal health, including pathophysiological changes and clinical manifestations. Topics include diarrhea, anemia, and tissue damage caused by internal parasites.