Parasitology - Nematodes 5 Flashcards
What are the two superfamilies of Spirurida?
Filaroidea
Non-filaroidea
While spirurida is a diverse order and quite difficult to find general characteristics, what do all members have?
an arthropod as an intermediate host
What do spuririda parasitize?
variety of tissues in vertebrate host
Explain the morphology and location of filaroidea
not in GI tract - usually pulmonary arteries
long slender worms
What is the direct host and intermediate host of Spirurida?
arthropods - (mosquitoes are intermediate hosts)
dogs are definitive
What do Spirurida produce?
ovoviviparous - Microfilariae - pre-L1 stage
Explain the lifecycle of heartworm
Mosquito feeds and ingests microfilariae with blood
mosquito matures in infective L3 2 weeks post infection
larvae deposits during subsequent bites
L3 matures into L4 in SC tissue in 1-3 days
L4 larvae migrate through tissues and are sexually immature and migrate to heart and lungs
worms develop to maturity in pulmonary artery
What are the 3 main disease components of Dirofilaria immitis?
physical obstruction of vessels
inflammation in vessel wall
progressive fibrosis in vessel
What disease does Dirofilaria immitis cause?
heartworm
The pathogenesis of Dirofilaria immitis can progress and what happens to the heart?
reduced cardiac output and compensatory right heart enlargement and failure
How is Dirofilaria immitis diagnosed?
HWT annually
microfilaria blood sample check
Explain the role of Wolbachia in Dirofilaria immitis
filarid parasites have a symbiotic relationship with Wolbachia
What medication is being used for treatment of heartworm infection?
Doxycycline
Explain Dirofilaria immitis in cats
abnormal host
worms are less successful and cats show less clinical signs as the worms die soon after infection
and more likely to migrate to abnormal sites
What types of eggs do non-filaroidea superfamilies produce?
clear, elliptical shaped, smooth, thick shell wall containing a coiled larva
What are Habronema and Draschia spp?
live in nodules in equine stomach that causes summer sore a persistent cutaneous granuloma
What is the intermediate host of Habronema and Draschia spp?
stable and horse fly
Most Enoplida in domestic animals produce what types of eggs? What is unique about the larvae?
eggs with 2 polar plugs with infective larvae develop and remain inside egg
What is the worm of Trichuris vulpis
whipworm
Where are whipworms found?
large intestine of dogs
What is the infective stage of Trichuris vulpis?
embryonated egg
How are whipworms detected?
bipolar egg detection in feces
What is the pre-patent period of Trichuris vulpis?
3 months
What clinical disease is seen with whipworms?
diarrhea +/- blood –> anemia
What is Trichinella spp? Explain its life cycle and the important human disease associated with it
adult worms in small intestine of warm blood animals
larvae is produced, penetrates gut, and encysts in tissues
ingestion of pork leads to trichinosis in humans
Where are pinworms found?
small adults in large intestine
What species is pinworms found in?
horses, rodents, ruminants, reptiles, people
What is the life cycle of pinworms?
direct
What do the eggs of pinworms look like?
polar plug with flattened appearance on one side
How are pinworms detected?
detection of eggs in perianal swabs
What is the common equine pinworm?
Oxyuris equi
Explain the life cycle of oxyuris equi
infection from ingestion of eggs
fertilized females migrate from LI and rectum onto skin and glue eggs to perianal hairs
What does oxyuris equi cause clinically?
pruritis
T/F: human pinworm is related to animals
FALSE - transmitted person to person
Where are Rhabditida found?
free living in soil
Rhabditida is species specific. What is the species that infects Ruminants
Horses
Dogs
Ruminants - Strongyloides papillosus
Horse - westeri
dog - stercoralis
