Introduction to Veterinary Parasitology

Parasitology

Parasitology

the study of parasitic relationships affecting domestic, wild, exotic, and lab animals as well as those, when applicable, which can cause zoonosis

Zoonosis

the transmission of any disease or infection from a vertebrate to a human

List 3 reasons why we care about parasitology?

• impact on domestic animals and human health (zoonosis)

• significant impact on agriculture and food medicine

• understanding environmental impact

List the 5 ways diseases can be transmitted.

• Airborne

• Vectors

• Direct Contact with animals

• food-borne

• close proximity to animals

Symbiosis

when at least 2 organisms of different species live together

What are the 5 types of symbiosis?

• Predator-Prey

• Phoresis

• Mutualism

• Commensalism

• Parasitism

Predator-Prey Symbiosis

short, one sided benefit

Phoresis Symbiosis

smaller member carried by larger member, not typically harmful

Mutualism Symbiosis

both species benefit

Commensalism Symbiosis

one benefits, the other is unharmed

Parasitism

two different organisms where one (parasite) lives on or in the other (host) and may cause harm

Parasitasis

parasite is present on or within the host but there are no clinical signs

Parasitosis

parasite present on or within the host and clinical signs are present

Ectoparsite

external parasite that causes infestations

Endoparasite

internal parasite that causes infections

Aberrant parasite

when a parasite moves to an organ it is not typically associated with

Incidental Parasite

parasite that occurs in a host it does not usually live on

Faculative Parasite

a parasite that lives in the enviornment in a non-parasitic form that can become parasitic in specific hosts

Obligatory Parasite

can not live without a host

Periodic Parasite

does not live for long periods in or on its host - makes frequent visits

Psuedoparasites

living creatures or objects that are mistaken for parasites

What are the majority of parasites in domesticated animals considered?

Obligatory parasites

Definitive Host

houses the adult, mature or sexually active stage of the parasite

Intermediate Host

houses the larval, juvenile, immature, or asexual stages of the parasite

• responsible for transferring this stage of parasite to the host

Parentic Host

a second or third intermediate host where the parasite remains in an encysted form within the tissues of the host

• typically eaten by the definitive host which is when the parasites “activate”

• aka transport host

Reservoir Host

vertebrate host occurring in nature that is a source of infection for humans or domestic species

Vector

arthropod, mollusk, or other agent that transmits parasites from one vertebrate to another vertebrate

Biological Vector

parasite develop within the vector

Mechanical Vector

parasite does not develop inside the vector

Fomite

inanimate objects like shoes, clothing, stethoscopes, buckets that are capable of carrying infection from one area to another

Prepatent Period

the length of time from initial infection within a parasite until the ability of the parasite to be diagnosed within the host either by blood test or fecal analysis

Homoxenous (monoxenous)

infects only one type of host

Stenoxenous

have a narrow host range and typically infect a specific location of that host

Euryxenous

very broad host range

Indirect Lifestyles

require an intermediate host to cause infection within the definitive host

Direct Lifestyle

do not require and intermediate host

• once the larval stage in the enviornment, it can directly infect the definitive host

What are two ways a direct lifecycle parasite infects a host?

• ingestion of an egg within the enviornment (fecal-oral)

• molted infective stage 3 larvae infiltrates definitive host

Anthelmintics

kill worms

• roundworms, tapeworms, flukes, thorny-headed worms

Acarcides

kill mites and ticks

Insecticides

kill insects

Antiprotozoa

kill protozoa

Protozoology

the specific study of protozoa