Parasitology 4: Nematodes 3- Strongyloidea, Ancylostomatoidea, Metastrongyloidea Flashcards
What species is strongyloidea important for?
Horses
What kind of feeder is strongyloidea?
Plug feeders
where does strongyloidea infect?
GIT
Three main general characteristics of strongyloidea?
- Parasites of GIT
- Generally have large buccal capsule
- Plug feeders
What taxonomy is strongyloidae
Family
What are cyanthostominae and strongylinae?
Subfamilies
cyanthostominae = small 2cm
strongylinae = large 5 cm
What are cyanthostominae and strongylinae diseases?
cyanthostominosis and strongylinosis
Cyathostomins characterisitcs?
- Small Strongyles
- about 50 similar species
- CANNOT tell eggs or immature stages apart
What is the lifecycle of Cyathostomins?
- Infection
- Larvae go into large intestine
- Enter intestinal crypts & penetrate mucosa for period of larval development
- Return to lumen to mature
What is the minimum patent period of Cyathostomins
2-3 months
Where do Cyathostomin larvae become hypobiotic?
In the intestinal wall
What is the relationship between Cyathostomins adults and larvae
Live in a dynamic relationship
- As adults are cleared out from the lumen
- New larvae move in from intestinal wall
- Maintaining population of adults
How do seasonal changes effect Cyathostomins?
Arrest?
Are Cyathostomins highly pathogenic? What are the numbers?
No
- Low to moderate numbers in healthy horses have no effect
What life-stage causes pathogenic effect and how?
- Larvae
- Pathogenic when emerge from intestinal wall and cause inflammation
Two syndromes of Cyathostomins?
- Chronic Cyathostominosis (type 1)
- Acute larval Cyathostominosis (type 2)
What is Chronic Cyathostominosis (type 1) look like?
- Gradual inflammation and thickening of gut wall
- Possible protein losing enteropathy
Clin signs of Chronic cyathostominosis?
- Intermittent diarrhea
- mild to moderate colic
- poor condition
- hypoproteinemia
What acute larval Cyathostominosis (type 2) onset and when does it occur?
- Rapid onset
- Occurs when a large number of arrested larvae synchronously emerge
What are the clin signs of acute larval Cyathostominosis (type 2)?
- Fever
- Diarrhea (dehydration)
- Edema (hypoproteinemia)
what season does acute larval Cyathostominosis (type 2) occur?
Late winter or early spring
What do treat acute larval Cyathostominosis (type 2)?
Deworming
How to diagnose chronic cyathostominosis vs acute larval Cyathostominosis (type 2)?
Chronic: large number of strongyle eggs in feces
Acute: May not be many eggs in manure
Population most susceptible to Cyathostomins?
<3-4 yr old horses
Most important large strongyle?
Strongylus vulgaris
What is the life cycle of large strongyles?
Infection through ingestion as L3
- Molt into L4 and migrate through arteries
- Reaches junction of cranial mesenteric artery and aorta
- Return to large intestine about 4 mo after infection
- Molt to L5 (adults)
- Occasionally larvae migrate to other location
What is the prepatent period of large stronglyes?
6 months
Strongylus vulgaris pathogenesis?
- Verminous arteritis
- Aneurysm
- Larvae damage arterial vessels leading to thrombus
—- thrombus reduces blood flow
—- thrombus may break off and block blood flow distally
—- Ischemia
—- In severe cases can lead to necrosis of bowel
—- Lesions regress after worms leave or treated
Clinical signs of Strongylus vulgaris?
- Colic: thromboembolic colic
- Abdominal pain
- In severe cases: death
- Diagnosis is difficult
What is Ancylostomatoidea?
Hook worms
Where do Ancylostomatoidea infect?
Small intestine of many animals and humans
What kind of feeders are Ancylostomatoidea?
Blood feeders via plug feeders
Types of canine hookworms?
Ancylostoma caninum
Ancylostoma braziliense
Uncinaria stencephala
Ancylostoma caninum importantance?
Most important/common in our region?
Ancylostoma braziliense inportance?
Significant in the southeast costal US and south america
- not pathogenic hookworm
- Vigorous skin penetrator (Public health importance)
Uncinaria stencephala importance?
Cold climate hookworm
Ancylostoma caninum infection?
Externally develop from egg to L3
- Ingestion of L3
- skin penetration by L3 (imporant)
What happens after skin penetration of Ancylostoma caninum?
- Larvae migrate to heart/lungs and then either coughed up, swallowed and develop in SI
- Travels in tissues and become dormant
What is the somatic reservior larvae of Ancylostoma caninum?
- Larvae of skin penetration laying dormant inside skin tissue
What is larval leak?
- After treatment of adult population
- Arrested larvae can move into the intestine and replace adults that were removed
Where can egg laying worms of Ancylostoma caninum come from?
- Skin penetration
- Transmammary infection
- Ingestion of L3
- Larval leak
- Paratenic host
What is paratenic host?
Not needed for the development of the parasite, but nevertheless serving to maintain the parasite’s life cycle
Ancylostoma caninum pathogenesis of low worm number?
Asymptomatic
Susceptible population of Ancylostoma caninum?
- very young animals
- heavily immunocompromised
How do hookworms behave?
- Blood-suckers
- Switch sites every few hours
Ancylostoma caninum clinical signs?
- Diarrhea
- Anemia, hypoproteinemia
- Skin lesions
Immunity of Ancylostoma caninum?
Develops following exposures
What is ancylostoma tubaeforme?
Feline hookworm
Characteristics of ancylostoma tubaeforme?
- Lower prevalence than canine hookworm
- Not as pathogenic as canine hookworm
- Little if ant perinatal transmission
Public health importance - hookworms
- larvae can penetrate human skin; especially A braziliense
- Coastal southern US, caribbean, Latine America
What human contact with hookworm- A braziliense causes?
- Produces serpiginous tracks known as cutaneous larva migrans (CLM)
- Frequent in people with lots of soil contact
What is cutaneous larva migrans (CLM)?
serpiginous tracks produced by A braziliense
What is Metastrongyloidea and where do they infect?
Long/slender worms that infect lungs and other tissue sites
- Minor importance in domestic animals
Diagnosis of Metastrongyloidea?
Larvae in feces
What kind of intermediate host does Metastrongyloidea use?
invertebrate
