parasitology

parasite

smaller organism that lives on or in and at the expense of a larger organism called the host

endoparasites

parasites within the bodies of hosts

ectoparasites

live on the external surface of host or in the skin

obligate parasites

parasites that always require a host

facultative parasites

organisms that are parasites only if given the opportunity

definitive host

host in whic the adult or sexually reproductive processes of the parasite occur

intermediate host

host in which there is required development of intermediate or larval stages

paratenic host / transport host

host infected by a parasite that does not undergo any required development, though in may grow in size, the parasite should be transferable from paratenic host until it makes it’s way into the final host.

reservoir host

parasites may cycle other than the host we consider to be interest

vector

organism that transmits parasites directly from host to host

mechanical vector

transmits parasites without the need for the parasite to develop in the vector, syringes for ex.

biological vector

a vector that is required in the life cycle of the parasite

direct life cycle

infective stage is reached in the environment, no intermediate host

indirect life cycle

infective stage is reached in an intermediate host

prepatent period

period (days/months) form infection production of parasite offspring

zoonosis

a disease of animals transmitted to people

helminths

worms

3 groups of helminths

roundworms = nematodes

flukes = trematodes

tapeworms = cestodes

nematodes

elongated and tubular

have cuticle secreted by living cellular tegument

digestive tract like a tube

excretory/secretory products-released from specialized excretory or secretory organs through the cuticle or via oral and anal openings = host/parasite interactions

nervous and muscular tissues to allow for serpentine movement

males and females have specialized organs and structures to produce offspring, facilitating mating = genetic recombination

direct/indirect lifec cycles

example of direct nematodes

no intermediate host, egg to adult in one host

trichostrongyloid

example if indirect nematode

intermediate host, molluscan or annelid as intermediate host

metastrongyloid

superfamilies of nematodes are grouped based on what characteristics

morphology

life cycle

predilection site in host

nematodes / 4 superfamilies of the order stronglylida

strongyloidea

trichostrongyloidwa

ancylostomatoidea

metastrongyloidea

family strongyloidea

part of nematodes

large bowels strongylees of horses. nodular worms of ruminants, swine and primates

family trichostronglyloidea

abomasal and small intestinal hairworms of ruminants

family ancylostomatoidea

intestinal hookworms of diverse mammal

family metastrongyloidea

lungworms

families of nematodes that have direct life cycles

strongyloidea

trichostrongyloidea

ancylostomatoidea

families of nematodes that have indirect life cycles

metastrongyloidea

strongyloids

well developed, often have teeth

buccal cavity with plug of mucosa, blood suckling

trichostrongyloids

have a tooth or lancet

may be blood suckling and damage mucosa

hook worms

have teeth or cutting plates on ventral

blood suckling mat cause anemia

metastrongyloid

no teeth

occupy space in respiratory tract

which family of strogylids are seen as larvae and not eggs on feces?

metastrongyloid

characteristics of strongyloid eggs

ellipsoidal

smooth surface

thin-shelled

contain an embryo in morula stage

cannot determine species or even genus, based on appearance of eggs

what type of strongylids eggs we see in horses?

strongyle type eggs

what type of strongylids eggs we see in ruminants?

trichostrongyle type eggs

what type of strongylids eggs we see in dogs?

hookworms

strongyloides spp. /Order Rhabditoidea of nematodes contains the superfamily

rhabditoidea

order rhabditoidea/ superfamily rhabditoidea are found where in the host

small and delicate nematodes of the small intestine

free living and parasitic lifestyles

only females are parasitic

strongyloidess females reproduce via

asexual repro. via parthenogenesis

life cycle is direct

strongyloidess. spp (order rhabditoidea) infect hosts via

percutaneous

oral

tansmammary

transplacental

larval stages may migrate through lungs

characteristics of strongyloides spp.

ellipsoidal

smooth surface

thin shelled

contain fully formed larva when pased in feces

order ascaridida of nematodes contain the superfamily

ascaridoidea (roundworms)

t/f ascarids are some of the largest nematodes parasites

true

ascarids are mainly found in the

small intestine

ascarids have wht type of cycle

direct

hepatotracheal migration

by ascarids

migrate through the liver and are carried through the bloodstream to the lungs

characteristics of ascarids eggs

round to slightly oval

surface may be pitted

thick walled

contain single cell\

whistanding of extreme temperatures, chemical and physical insults and remain inefective for years

t/f ascarids eggs can remain inefective for years

true

females like to lay a lot of eggs and are a problem to erradicate

ascarids

order enoplida contains the superfamily

trichinelloidea

2 groups of Trichuris spp (order enoplida)

whipworms

capillarids

whipworms (trichuris spp) characteristics

resemble a fine hair like anterior region with a stout posterior region

whipworms are usually found in ____ and will cause____

wall of large intestine or cecum, blood flecked feces

capillarids characteristics

not whip like, but hardly ever seen

capillarids are usually found in

airways, intestinal tract, bladder

characteristics of whipworm eggs

football shaped

thick walled

symmetrical bipolar plugs

remain inefective for years

characteristics of capillarid eggs

similar to trichuris but bipolar plugs are assymetrical

can determine genus based on appearance of surface of shell wall

Order Oxyurida contains the superfamily

Oxyuroidea (pinworms)

pinworm that infects horses_____ and where do they infect

oxyuris equi

large intestine

pinworms have what type of cycle?

direct life cycle

characteristics of pinworm eggs

flattened on one side, convex on the other

operculum on one end

may be embryonated

The order spirurida (spirurids) contains the superfamilies

physalopteroidea

spiruidea

habronematoidea

filaroi

ex. of nematode of the family physalopteroidea from spirurids

physaloptera

ex. of nematode from the family spiruroidea

spirocerca lupi

ex. of nematode from the family habronematoidea

stomach nematodes of horses

the canine heartworm is part of the spirurids, which family?

filaroidea (dirofilaria immitis)

filarial nematodes such as canine heartworm release

microfilariae

characteristics of spirurid egss

ellipsoidal

thick walled

embryonated

characteristics of cestodes (tapeworms)

flattened

no body cavity

strobila-chain of independent, progessively maturing reproductive units

scolex- immature segments

proglottids-more mature segments

tapeworms live in the

digestive tract

strobila

independent, progessively maturing reproductive units

tapeworms absorb nutrient via the

integument

t/f cestodes are hemaphroditic

true

cestodes have what type of life cycles?

indirect

2 groups of cestodes

cyclophyllidea

diphyllobothriidea

characteristics of cyclophyllidea

one intermediate host

non-motile egg, ingested by intermediate host

metacestode stages

the intermediate phase, called metacestode, of the group cyclophyllidea occurs in which animals

vertebrates

cysticercus

coenurus

strobilocercus

hydatid cyst

multilocular cyst

invertebrates, cysticercoid

characteristics of spirometra

2 intermediate hosts

eggs hatches in aquatics conditions

ciliated coracidium

the egg of the diphyllobothriidea is called cor

1 intermidiate host = copepod in crustraceans

2 intermediate host = mammal, amphibian, reptile, fish