PID BLOCK 3- parasit Flashcards
Phoresis
Association where 2 organisms merely traveling together
Mutualism
both organisms are benefited
Commensalism
one partner is benefited and the other is unaffected
Parasitism
One partner is benefited, the other is harmed
Host
the partner who is harmed in parasitism
Parasite
the partner who is benefited in parasitism
Definitive host
harbors adult (sexual) stage of a parasite
Intermediate host
harbors larval (asexual) stage of a parasite
Paratenic host
harbors a parasite that does not undergo required development
a transfer host
Reservoir
an animal host that serves to maintain the parasites life cycle in nature
Incidental host
unusual host, unnecessary for the maintenance of the parasite in nature
Obligate parasite
totally dependent upon its host
Temporary parasite
parasitic for limited periods, for feeding or repro
Facultative parasite
not normally parasitic but can survive for a limited period when they accidently find themselves within another organism
Ectoparasite
- lives on host
- causes infestations
Ex: lice
Endoparasite
- lives in host
- causes infections
Protozoa
multiply in definitive host
- single celled, nucleated
Locomotion by pseudopodia, flagella, cilia
6 types of parasites
- Nematodes
- Cestodes
- Trematodes
- Insects
- Arachnids
- Protozoa
Nematodes
Roundworms
-round, cylindrical
- complete alimentary canal
- celom, body cavity
- sexes usually separate
Cestodes
Tapeworms
- flat, no colem (body cavity)
- no alimentary canal
- hermaphroditic
- Scolex (head) with 4 suckers or bothria
- Strobila (body) w head, neck, and proglottids (segments)
- parasitic with indirect life cycle
Vector
object or organism that transmits parasite from host to host
Biological or Mechanical
Mechanical Vector
transmits parasite unchanged from host to host
Biological vector
parasite multiplies or develops
Helminths
adult worms dont multiply in definitive host
Worms die over time unless host is re-exposed, metazoans
Severity proportional to worm load
Ex: Nematode, cestode, trematode
Conditions required for endemic parasitism
- Reservoir of infection
- Means of transmission to susceptibile host
- Ability to invade and establish in new host
- Ability to reproduce
Trematodes
Flukes
- dorso ventrally flattened, leaf like
- incomplete alimentary canal
- no celom
- Hermaphroditic
- Oral and ventral suckers for attachment
Types of arachnids
- Ticks
- Mites
Types of insects?
- Flies
- Fleas
- Lice
- Hemiptera
Identification of insects
Adults: 3 pairs of legs
Has a head, thorax and abdomen
Antenna
Ex: flies, fleas, lice, Hemiptera
Identification of arachnids
Nymphs and adults: 4 pairs of legs
Larvae: 3 pairs of legs
Body: cephalo-thorax + abdomen
No antenna
Palps
Identification of mites
microscopic, <1 mm
scaley body, spines, setae (hairs)
legs have claws or suckers to attach to host
What are the 3 groups of eukaryotic organisms that affect health and wellbeing of animals?
- Protozoa
- Helminths
- Arthropods
Routes of parasite entry
- Ingestion
- Skin/ mucosal penetration
- Transplacental
- Transmammary (milk)
- Arthropod bite (vector)
- Sexual intercourse
Attachment to host via…
- Oral cavity (capsule)
- Attachment organs
- Suction disk
- Biting mouthparts
- Direct penetration
Cell and tissue damage
- Mechanical damage
- Toxic products
- Immunopathologic rxns
Mechanical tissue damage
- Blockage of internal organs
- Pressure atrophy
- Migration through tissues
Toxic parasitic products
- Destructive enzymes: hookworms
- Endotoxins: malaria
- Toxic secretions: tick paralysis
What parasite causes nutrient loss?
Hookworm
