Parasitic Diseases

4-H Veterinary ScienceExtension Veterinary Medicine

Texas AgriLife Extension ServiceCollege of Veterinary Medicine and Biomedical Sciences

Texas A&M Systemhttp://aevm.tamu.edu

Objectives

Describe diseases caused by arthropods Describe diseases caused by nematodes Describe diseases caused by tapeworms Describe diseases caused by flukes Describe diseases caused by protozoa

Overview

Remember Five infectious diseases

Bacterial Viral Fungal Parasitic Rickettsial

Infectious disease An illness due to a specific infectious agent or its

toxic products that arises through transmission of that agent or its products from an infected person, animal or reservoir to a susceptible host, either directly or indirectly

Parasite An organism that grows, feeds, and is sheltered

on or in a different organism while contributing nothing to the survival of its host

Types Arthropods Worms Protozoa

Arthropods Affect

Skin Digestive system

Examples Flies Ticks Fleas Lice Mites

Worms Affect

Skin Digestive system Circulatory system

Types Nematodes Tapeworms Flukes

Protozoa Single-celled organisms Affects

Digestive system Reproductive system

Types Amoebas Ciliates

Infestation To inhabit or overrun in numbers or quantities

large enough to be harmful, threatening, or obnoxious

Infection Invasion by and multiplication of pathogenic

microorganisms in a bodily part or tissue, which may produce subsequent tissue injury and progress to overt disease through a variety of cellular or toxic mechanisms

Parasites may be vectors Mechanical

Carries the pathogen, but the pathogen is not altered while on the vector

Example Arthropods Animals (wild or domestic) People

Biological An organism that is needed for the life cycle of a

pathogen Disease agent multiplies or develops within parasite Example

Arthropods

Skin

Arthropods Ectoparasites

External parasites Cause infestations Not worms, bacteria, viruses or fungi

Affect health Tissue damage Blood loss Annoyance Vectors

Flies Blood-suckers

Annoyance Anemia Disease transmission

Anaplasmosis Bluetongue Heartworms

Examples Horseflies Deerflies Stableflies Hornflies Mosquitoes Gnats

Non-blood suckers Annoyance Example

Houseflies

Housefly

Mosquito

Heartworms

Flies

Heelflies Larval stages

Cattle grubs Cause

Migratory damage Internal tissue Hide

Heelfly

Cattle grub

Development Process of a Heelfly

Ticks Two groups

Hard ticks Soft ticks

Adults are free-living

Hard ticks Feed for several days Vectors

Anaplasmosis Lyme disease

Soft Ticks Intermittent feeders Spinose ticks