Parasitology Flashcards
Parasite
smaller organism that lives on or in and at the expense of a larger organism
Role of veterinarian
Cause disease Clinically relevant Zoonoses Diagnostic measures Minimize impact (production) Treatment and management
Three classes of Parasites
Helminths
Ectoparasites
Protozoa
Diagnostic methods
Host Species
Site of Infection
Size of parasite
Understand the parasites
Select the samples to collect
Select the appropriate diagnostic methods
Treatment and management
Parasiticides
Sustainable management of the host
Management of the environment
Life cycle is used to determine treatment and prevention
Must understand:
Taxonomic classification; scientific and common name Clinical signs Pathogenesis and lesions Site of infestation/infection Life cycle Identification Host(s);zoonotic
Parasites of importance
Nematodes Cestodes Trematodes Insects Arachnids Protozoa
Nemotodes
Roundworms Free-living or parasitic Elongate/cylindrical Alimentary canal present Sexes usually separate Life cycle direct or indirect
Cestodes
Tapeworms Flat body and no alimentary canal Scolex (holdfast organ) Strobila (body) with proglottids Each proglottid (section) is hermaphroditic Indirect life cycle Types of characteristic larval stages
Trematodes
Flukes Dorso-ventrally flattened Leaf-like Oran and ventral suckers Indirect life cycle- molluscan IH Usually genetically independent
Insects
Adults: 3 pairs of legs
Head, thorax, abdomen
Antenna
Flies, fleas, live, bedbugs
Arthropods/Arachnids
Ticks, mites Nymphs and adults: 4 pairs of legs Larvae: 3 pairs of legs Body: cephalo-thorax and abdomen No antennae, but palps
Protozoa
Uniccellular, eukaryotic animals
Classified based on their mode of locomotion
Locomotion accomplished by: pseudopodia, flagella, gliding movements, cilia
Endoparasites
Live in the host
Cause infections
Ectoparasites
Live ON the host
Cause infestations
Definitive Host
Final
Harbors the adult or sexual stage of the parasite
Intermediate Host
Host in which a larval or immature stage of the helminth parasite develops before becoming infective to the final host
Paratenic host
Transport host
host in which larval stages of helminth do not develop further
Host specific parasites
Parasites have specificity for particular definitive and intermediate hosts
Often parasite life cycles can only be completed in a particular host
Routes of entry
Ingestion Skin or mucosal penetration Arthropod bite Transplacental Transmammary Sexual contact
Pathogenesis
The development of morbid conditions or disease (the cellular events, reactions and other mechanisms occurring in the development of disease)
Virulence
The degree of pathogenicity; capability of a microorganism to cause disease
Effect from parasites
Highly variable and dependent on a number of factors:
Parasites and types oh hosts
severity- infection dose and number of organisms acquired over time
Route of exposure
Effect from parasites: severity
Depends- age of host nutritional status previous exposure extent of parasite burden
