Lecture 33 (Acanthocephalan Parasites of Veterinary Importance)

Made by Harley Chase and Kylee Wood

Thorny-headed worms

What are Acanthocephala known as?

In the digestive tract of vertebrate hosts
- Mammals
- Fish
- Birds
- Reptiles

Where are adult Acanthocephala found?

67-110 um x 40-65 um

How big are Acanthocephala eggs?

Yes

Are Acanthocephala eggs distinctive?

Across the tegument - No digestive system

How is nutrients absorbed in Acanthocephala?

Acanthocephala

What is seen in the following image?

Acanthocephala

What is seen in the following image?

Acanthocephala eggs

What is seen in the following image?

Adult Tapeworms

What do Acanthocephala have a superficial resemblance to for the lay person?

Acanthocephala

What is seen in the following image?

Acanthocephala

What is seen in the following image?

Acanthocephala

What is seen in the following image?

Thought to manage hydraulic controls of proboscis

Why do Acanthocephala have a unique musculature in the anterior end?

Nutrient and waste transport in the absence of a digestive/excretory system

What might the musculature of the middle body of Acanthocephala assist with?

Yes

Does Acanthocephala musculature have low membrane potential?

Slow Conduction

Acanthocephala are electrically inexcitable with what?

Acetylcholine Stimulation

What type of stimulation is seen in Acanthocephala?

Nervous control of contraction

What is not well demonstrated in Acanthocephala?

Drug activity and overall efficacy

What do Acanthocephala have implications for?

Obligate Indirect

What type of life cycle do Acanthocephala have?

Arthropod

What type of intermediate host do Acanthocephala have?

Wildlife species

Who are Acanthocephala common in?

Companion animals

Who are Acanthocephala occasionally seen in?

Swine production

What does Acanthocephala have prior association with?

Yes

Was Acanthocephalans incidentally found to be zoonotic?

SW United States

Where do Acanthocephalans have prehistoric association?

Grasshoppers

What is the aboriginal diet of Acanthocephalans based on?

Macroacanthorhynchus hirudinaceus

What was once an important parasite in swine production but was eliminated with confinement production?

A comeback of Macroacanthorhynchus hirudinaceus

What should be expected with the recent trend to "range produced pork"?

Taenia solium

What is Macroacanthorhynchus hirudinaceus often mistaken for by 4th year students and 1st year residents when observed on necropsy?

No

Do adult tapeworms occur in the small intestine of swine?

No - infrequent occurence

Do Taenia solium occur frequently in swine production?

Small Intestine

Where is Oncicola canis parasitic?

Dogs and Cats

Who is Oncicola canis occasionally seen in?

Wildlife Species - Coyotes, Fox, Bobcat, Lynx

Who is it more common to see Oncicola canis in?

- Lizards
- Birds
- Small Mammals

Who facilitates transmission of Onicola canis?

Cystacanth stage

What do paratenic hosts of Oncicola canis have in tissues?

Yes

Is it possible that Oncicola canis is more prevalent than we know?

No

Do Oncicola canis eggs float well?

Rarely

Is Oncicola canis associated with clinical disease?

South and Central American Primate Populations

Who is Prosthenorchis elegans enzootic in?

Zoological and Laboratory Primate Colonies

Who is Prosthenorchis elegans important in?

Cockroaches

Who is the suitable intermediate host population for Prosthenorchis elegans?

By coming in close proximity with a suitable intermediate host

How do animals become infected with Prosthenorchis elegans?

Accumulation of clinically significant worm burdens

What is seen with infections of Prosthenorchis elegans?

Penetration of proboscis

What is trauma in the definitive host in association with Prosthenorchis elegans caused by?

Significant pain and trauma to the intestinal mucosa

What is the attachment, release and re-attachment of Prosthenorchis elegans associated with?

Gut perforation and peritonitis

What does trauma associated with Prosthenorchis elegans lead to?

Morbidity and Mortality

What is significant about Prosthenorchis elegans infestations in laboratory primate colonies?

- Diarrhea
- Dysorexia
- Death

What clinical signs are seen with Prosthenorchis elegans infestations in laboratory primate colonies?

- Association with clinical signs
- Residence with infected individuals
- Availability and access to intermediate hosts
- Fecal exam to demonstrate eggs

How is Prosthenorchis elegans diagnosed?

No

Do Prosthenorchis elegans eggs float well?

Gravitational sedimentation

What will be seen on a fecal exam with Prosthenorchis elegans eggs?

- Oval shaped
- Layered with hooked "acanthor"

What is the appearance of Prosthenorchis elegans eggs?

70 um x 45 um

How big are Prosthenorchis elegans eggs?

Prosthenorchis elegans

What is seen in the following image?

Albendazole

What can be given - PO, at 100 mg/kg BID x 3 and repeated bi weekly for 4 treatments when treating Prosthenorchis elegans?

Fenbendazole

What is effective against treatment of Prosthenorchis elegans in marmosets when given PO, at 50 mg/kg SID x 7?

- By treatment of infective egg shedders
- Removal of Intermediate hosts

How can Prosthenorchis elegans be controlled?

Terrestrial Lifecycle

What lifecycle are Cyclophyllidian tapeworms a part of?

Aquatic Lifestyle

What lifecycle are Pseudophyllidian tapeworms a part of?

Yes

Do some trematodes have 2 intermediate hosts?

Single Eggs vs. Egg Packets

What are the diagnostic differences between Taenia and Dipylidium?