Lecture 1: Parasitology Foundations

Comprehensive vocabulary flashcards covering symbiosis, host types, parasite classifications, life cycles, and laboratory diagnostic procedures for veterinary parasitology.

Symbiosis

Any association, temporary or permanent, between at least two living organisms of different species.

Symbiont

Each individual member of a symbiotic association.

Predator-Prey Relationship

An extremely short-term relationship where the predator benefits at the expense of the prey, which serves as a food source.

Phoresis

A symbiotic relationship where a smaller member is carried about by a larger member, such as Moraxella bovis carried on the foot pads of Musca atumnalis.

Mutualism

A symbiotic association in which both organisms benefit from the relationship.

Commensalism

A symbiotic association in which one organism benefits and the other member is unharmed.

Parasitism

An association where one organism benefits and the other is harmed.

Parasitiasis

A condition where the parasite is present on or in the host and is pathogenic, but the host shows no signs of disease.

Parasitosis

A condition where the parasite is present on or in the host and the host is showing clinical signs of disease.

Ectoparasite

A parasite that lives on the body of the host; the condition is referred to as an infestation.

Endoparasite

A parasite that lives within the body of the host; the condition is referred to as an infection.

Antihelminthics

Parasiticidal compounds that kill roundworms, tapeworms, and flukes.

Helminth

A term meaning 'worm'.

Acaricides

Parasiticidal compounds designed to kill mites and ticks.

Antiprotozoals

Parasiticidal compounds that kill single-celled protozoal organisms.

Aberrant/Erratic Parasite

A parasite that wanders from its usual site of infection into an organ or location where it does not normally live.

Incidental Parasite

A parasite that occurs in a host species in which it does not normally live.

Facultative Parasite

Normally free-living, nonparasitic organisms that can become parasitic in certain hosts, such as P. strongyloides found in soil.

Obligatory Parasite

An organism that must always lead a parasitic existence to complete its life cycle.

Periodic Parasite

A parasite that makes frequent, short visits to its host to obtain nourishment, such as a mosquito.

Pseudoparasite

Nonparasitic creatures or objects, such as pollen grains, that may be mistaken for parasites during microscopic examination.

Prepatent Period

The time required for a parasite to mature from an egg to a reproductive adult within the definitive host.

Definitive Host

The host that harbors the adult, sexual, or mature stages of a parasite.

Intermediate Host

A host that harbors the larval, juvenile, or asexual stages of a parasite.

Paratenic Host

A transport host used by the parasite where no developmental changes occur.

Reservoir Host

A host that harbors a parasite without being affected by it, serving as a source of infection for humans or domestic animals.

Direct Life Cycle

A life cycle that requires no intermediate hosts; the parasite transfers from one host to another of the same species.

Indirect Life Cycle

A life cycle requiring at least one intermediate host to complete development.

Linnaean Classification Order

Kingdom, Phylum, Class, Order, Family, Genus, Species.

Nematodes

Members of Phylum Nematoda, characterized as roundworms with separate sexes.

Platyhelminthes

Flatworms that are all hermaphrodites; includes Cestodes (tapeworms) and Trematodes (flukes), and free living planarias.

Arthropods

Animals with jointed appendages, segmented bodies, and an exoskeleton made of chitin; includes insects and arachnids.

Simple Fecal Flotation

The most common diagnostic procedure based on specific gravity; used to identify and isolate intestinal parasites such as eggs, larvae, and cysts from fecal samples.

Centrifugal Flotation

The method of choice for recovering eggs, larvae, and cysts; requires a centrifuge that which helps separates parasites from fecal debris based on density

Fecal Sedimentation

A procedure best used for suspected fluke infections, as it concentrates both feces and heavy eggs.

Direct Smear

The simplest and shortest procedure used primarily to detect motile protozoans. However, it should be noted that it is considered the least accurate diagnostic method because of the small sample size used.

Trophozoites

The motile, active stage of protozoans that are difficult to find on standard floats and often require Lugol's iodine for staining. It’s what you’re looking for in fecal smears.

Buffy Coat Method

A blood parasite detection technique that examines the layer of WBCs between RBCs and plasma in a microhematocrit tube. The procedure is quick, easy, and detects mircofilariae, but also considered largely inaccurate.

Modified Knott's Technique

A rapid method using blood and $2 \%$ formalin to differentiate between microfilariae species.

ELISA Test

A snap test used to detect antigens produced by female heartworms, specifically useful for amicrofilaremic infections.

Skin Scraping

A common dermatologic diagnostic tool using a scalpel blade and mineral oil to find mites like Cheyletiella or lice.

Dioecious

The biological word that refers to species in which male and female reproductive organs or distinct unisexual flowers are located on completely separate individual organisms.