Parasitology

trichostrongyloidea

Superfamily of Order Strongylida which are the most important RUMINANT helminths

strongyloidea

Superfamily of Order Strongylida which are the most important horse helminths

ancylostomatoidea (hookworms)

Superfamily of Order Strongylida which are plug feeders in the small intestines of many animals and humans, particularly dogs

pasture (don’t do well in housing or on dirt)

Where does the life cycle of parasites in Superfamily Trichostrongyloidea occur most readily?

all grazing ruminants

What ruminants will have trichostrongyle parasites?

hypobiosis

____________ is common in parasites in the Superfamily Trichostrongyloidea which affects the epidemiology and control of disease related to these parasites based on when pathologic signs occur and when anthelmintics will be effective

abomasum

Where are the Haemonchus (Haemonchus contortus/Haemonchus placei) Trichostronglyes located within the host animal?

abomasum

Where are Ostertagia/Teladorsagia Trichostronglyes located within the host animal?

abomasum

Where is Trichostrongylus axei (Trichostronglye) located within the host animal?

small intestine

Where are Trichostrongylus spp (except Trichostrongylus axei) Trichostronglyes located within the host animal?

small intestine

Where are Cooperia spp. Trichostronglyes located within the host animal?

small intestine

Where are Nematodirus spp. Trichostronglyes located within the host animal?

parasitic gastroenteritis (PGE)

All together helminths in superfamily Trichostrongyloidea can cause a condition called ___________________ which causes diarrhea and weight loss

Haemonchus

What is the only Trichostrongyle that does NOT contribute to parasitic gastroenteritis (PGE) because it does not cause diarrhea?

Ostertagia ostertagi (brown stomach worm)

What is the most important helminth in cattle?

Haemonchus contortus (Barber’s pole worm)

What is the most important helminth in small ruminants?

L4 (emerging from the gastric glands into the lumen destroys abomasal mucosa)

What is the pathogenic life stage of Ostertagia ostertagi (Brown stomach worm) in cattle?

gastric glands

After ingestion, Ostertagia ostertagi larvae enter the _________________ in the abomasum of cattle, where they stay for several days to months (depending upon whether they enter hypobiosis) until they emerge into the lumen and become adults

Ostertagia spp (in superfamily Trichostrongyloidea)

What type of helminth causes the formation of nodules in the stomach of infected hosts?

Ostertagia ostertagi

________________ in cattle:

1. Impacts the gastric glands by inducing cell differentiation, hyperplasia, and formation of nodules

2. Changes stomach function

decreasing (destroys HCl production capacity), pepsinogen

Ostertagia ostertagi larvae impact gastric glands of host animals by:

1. _____________ (increasing, decreasing) the acidity of the abomasal fluid which is responsible for activating pepsinogen to pepsin and has a bacteriostatic effect

2. Increasing the permeability of abomasal epithelium which leads to the leakage of ____________ into circulation and loss of plasma proteins

adult, immunocompetent

_______________ cattle generally have little to no effects from light to moderate infection of Ostertagia ostertagi as infections are usually subclinical

young, immunocompromised

Heavy infections of Ostertagia ostertagi in ______________________ cattle cause clinical disease with signs of diarrhea, weight loss, bottle jaw (hypoproteinemia), and death within weeks

hypoproteinemia

Bottle jaw is a clinical sign related to __________________ which is a common clinical sign of severe parasitic infection, particularly pertaining to Ostertagia ostertagi in cattle and Haemonchus contortus in small ruminants

adults (because of the blood feeding)

What is the pathogenic life stage of Haemonchus contortus?

blood feeding

Haemonchus contortus are more pathogenic than most other trichostrongyles because of _______________, making them the MOST important helminth in small ruminants in the world

Haemonchus contortus

Abomasal parasite in small ruminants which causes anemia, anorexia, bottle jaw (hypoproteinemia), weight loss, and death in heavier infections, but which does NOT cause diarrhea

reduced weight gain

What is the primary sign of subclinical infection with Haemonchus contortus?

anemia

In low amounts, host animals infected with Haemonchus contortus can compensate the blood loss with no measurable illness, but when infections are heavier, the host is unable to compensate, resulting in disease characterized by _____________

I

Type ____ disease caused by Haemonchus and Ostertagia is caused by larvae that continuously develop without interruption such that there is a gradual accumulation of adult worms during the grazing season

II

Type _____ disease caused by Haemonchus and Ostertagia is caused by the synchronous emergence of arrested larvae (those in hypobiosis) as they resume their life cycle which can quickly produce SEVERE fatal disease

strongyloidea

What Strongylid superfamily is made up of plug feeders of the GI tract which generally have a large buccal capsule

strongylidosis

Infection of parasites from order Strongylida

strongylosis

Infection of parasites from superfamily Strongyloidea which are the most important helminths of horses

cyanthostominae

Small equine strongyles of family Strongylidae

strongylinae

Large equine strongyles of family Strongylidae

strongylinosis

Infection of parasites from subfamily Strongylinae

cyathostominosis (aka cyathostomosis)

Infection of parasites from subfamily Cyathostominae

large intestine

Cyathostomins (small strongyles) infect the host as L3 larvae and travel to the _______________ where they enter mucosa of crypts of Lieberkuhn for larval development before returning to the lumen to mature

dynamic

Cyathostomins (small strongyles) have a ___________ relationship in that as adults are lost from the lumen, new larvae will move in to maintain the population of adults

hypobiosis

Cyathostomin larvae in L3 can enter ___________ in the wall of the large intestine based on seasonal effects

L4

What is the pathogenic life stage of Cyathostomins?

chronic

Type I clinical disease is _______ cyathostominosis in which gradual inflammation and thickening of the gut wall occurs with possible protein losing enteropathy which can lead to intermittent diarrhea, mild to moderate colic, poor condition, and hypoproteinemia

acute

Type II clinical disease is _______ cyathostominosis in which large numbers of arrested larvae (those in hypobiosis) synchronously emerge, producing rapid onset of clinical signs such as fever, diarrhea (leading to dehydration), edema, and hypoproteinemia

acute larval cyathostominosis

When treating horses that have a high worm burden with anthelmintics, it is important to be prepared for _______________________ because you are killing off the adult population which can lead to the emergence of larvae from hypobiosis to repopulate the lumen

false (supportive of chronic but not necessarily acute since may not be adults present)

True or False: A large number of strongyle eggs in the feces of horses is supportive of both chronic and acute cyathosominosis

Strongylus vulgaris

Large strongyle which causes THROMBOEMBOLIC colic, abdominal pain, and in severe cases death

cranial mesenteric artery, aorta

Strongylus vulgaris is a large strongyle with complex larval migration:

1. Following infection as L3, the larvae molt and the L4 migrates through the arteries to the junction of the _____________________ and __________, where they molt to L5

2. They return to the large intestine ~4 months after initial infection

thrombus (platelet clot)

Strongylus vulgaris:

1. Causes verminous arteritis/aneurysm

2. Larvae damage arterial vessels leading to ____________ formation which can reduce blood flow and may break of as an embolus, blocking blood flow distally and causing ischemia

ancylostomatidae

Hookworm family that are of great importance in canines

anemia

All three species of canine hookworms (ancylostomatidae) induce __________ in diseased host animals

Ancylostoma caninum

The most important canine hookworm in this region which causes diarrhea, melena, anemia, hypoproteinemia, and skin lesions in dogs with heavy exposure

skin penetration (can also infect via ingestion)

What is the more important form of infection by Ancylostoma caninum (type of canine hookworm) which is unique to this species?

small intestine

Where do infections of Ancylostoma caninum live in the host?

heart/lungs, somatic

Following skin penetration, Ancylostoma caninum larvae can migrate to:

1. _____________ (what organs) where they are coughed up, swallowed, then develop into the small intestine

2. Tissues where they become dormant, called _________ reservoir larvae

whelping (travel to mammary gland)

What triggers the reactivation of Ancylostoma caninum larvae that are in hypobiosis in large skeletal muscles?

left

If Ancylostoma caninum larvae infect the _________ heart, they enter hypobiosis in large skeletal muscles until whelping triggers them to reactivate and migrate to the mammary gland

right

If Ancylostoma caninum larvae infect the _________ heart or lungs, they are coughed up, swallowed, and mature in the small intestine, same as if they were ingested

larval leak

The movement of arrested larvae (those in hypobiosis) into the intestine to replace adults that were removed following treatment against the adult population

skin, L3, paratenic

Egg-laying worms of Ancylostoma caninum can come from 5 routes of infection:

1. _____ penetration

2. Transmammary infection

3. Ingestion of ______ larvae

4. Larval leak (emergence of hypobiotic larvae following treatment of adults)

5. ___________ hosts

fecal exam

How are Ancylostoma caninum infections diagnosed in dogs?

uncinaria stenocephala

Cold climate canine hookworms

Ancylostoma tubaeforme

Feline hookworm which is both lower prevalence and lower pathogenicity than Ancylostoma caninum in canines

Ancylostoma braziliense

Canine hookworm in dogs and cats in costal southern US, Carribean, and Latin America which has minimal pathogenicity in the definitive hosts but is a vigorous skin penetrator such that it is important in Public Health

cutaneous larva migrans

Serpiginous tracks in the skin caused by the larval migration of hookworms, especially Ancylostoma braziliense

ascarids (Order Ascardida)

Roundworms which are generally larger than most other nematodes and are highly successful parasites in all vertebrate classes

direct

Do parasites in order Ascaridida have a direct or indirect life cycle?

small intestine

Adult Ascarids live in the lumen of the _________________ where they feed on lumen contents and host fluids

ascarid egg (unembryonated)

The egg from what parasite is shown which passes through feces and has a thick shell allowing it to be highly resistant to environmental conditions and disinfectants?

larvated (embryonated with L3) eggs

What is the infective stage of parasites in order Ascaridida?

fully embryonated

An ascarid egg must be _________________ before it can be infective

swallowed

Ascarid larva will NOT hatch until the embryonated egg is ______________ by the host

patent

_________ infections of Ascarids are usually not hard to detect through eggs in fecal floats

do not

After INGESTION, hookworms _________ (do, do not) migrate in the host

do

After INGESTION, ascarids _________ (do, do not) migrate in the host

Parascaris spp

Equine ascarids that live in the small intestine, primarily causing clinical disease in young horses

hepatotracheal migration

Movement of parascaris spp. (equine ascarids) from the intestines into the liver via the blood, where they enter the hepatic portal system and reach the lungs to be coughed up and re-swallowed to return to the small intestine

patent

Adult horses don’t play a role in parasite transmission because they rarely have ________ infections

pot belly

What is the characteristic clinical sign of ascarids?

adult

_________ parascaris (equine ascarids) compete with the host for nutrition in the small intestine, leading to poor condition, a rough hair coat, pot belly, and in very heavy infections can lead to perforation or impaction

larval

_________ parascaris (equine ascarids) in the lung cause mechanical and inflammatory damage leading to nasal discharge

pasture (grazing)

Transmission of strongylids occurs in the _____________ (pasture, barn)

barn

Transmission of ascarids occurs in the _____________ (pasture, barn)

toxocara

Ascarids in small animals (cats and dogs)

toxocara canis

Ascarids in dogs that cause diarrhea/constipation, colic/pot belly, vomiting, poor hair coat, intestinal obstruction, and pneumonia when burden is moderate to heavy, most commonly in puppies

toxocara cati

Ascarids in cats

heptatotracheal (hepatic portal system to lungs to trachea to small intestine)

In young dogs that ingest toxocara canis, larvae will hatch and move through ________________ migration

somatic (skel muscle for hypobiosis)

In older dogs (more than a few months old) that ingest toxocara canis, larvae will hatch and move through ________________ migration

transplacental, transmammary

In female dogs, emergence of toxocara canis larvae in hypobiosis in skeletal muscle (somatic migration) is triggered by pregnancy which can lead to _______________ or ______________ infection of the pups

hookworms, roundworms (toxocara canis), whipworms

What are the three big canine nematodes?

transplacental

Unlike in toxocara canis in canines, toxocara cati in felines cannot be transmitted to kittens via ________________ infection and transmammary transmission is less important as a mechanism of infection

toxocara cati

Does toxocara canis or cati have a longer pre-patent period?

toxocara

Zoonotic roundworm that most commonly infects young children causing visceral and ocular larva migrans