Animal Health Parasites Their Life Cycles and Classification

Infectious Agents Causing Disease can be divided into Three General Groups: Bacteria Viruses Parasites

Bacteria Simple plant life Microscopic Can be Pathogenic and beneficial Live outside of host Sensitive to antibiotics

Viruses Are Ultra-microscopic Live in tissue of host cells Are resistant to antibiotics highly contagious

Parasites Live in, on, or at the expense of the host. Infections develop slowly Difficult to eradicate completely Animals do not develop resistance Animals may not show symptoms Host-specific Include fungi, protozoa, arthropods, and helminths Bot fly common horse parasite

The Parasites in this Group Cause tissue damage Absorb nutrients Suck blood and lymph Obstruct passages Causes growths General irritation Secondary infections Cause serious economic damage

Non-infectious Agents That Cause Disease Chemical and poisons Poor Nutrition Injuries Physical stress from breeding, conception, lactation, and birth Any other stress or trauma that weakens the animal or its immune system to secondary infections

Causes Of Disease Nutritional Defects –Result from unbalanced diets Physiological Defects –Improper functioning of body parts Morphological Defects –Physical disabilities Pathogenic Organisms –Tiny living things capable of causing disease

Life Cycle of Tapeworm in a Sheep

Ascarids

Strongyles

Beef and Pork Tapeworms

The Life Cycle of Flies Occurs in Four Stages

Lice

Ticks Tick infested horse