Veterinary Parasitology Chapter 9 - Acanthocephalans

Study material for Chapter 9 of Diagnostic Parasitology for Veterinary Technicians. For class BIO225 at MWCC.

Acanthocephalans are also called what?

Thorny-headed worms

Acanthocephalans mostly affect which species?

Fish and aquatic birds

True or false: Acanthocephalans are endoparasites

True

What shape are Acanthocephalans?

Long and cylindrical, tapered on both ends

True or false: Acanthocephalans are dioecious

True

Acanthocephalans have a retractable proboscis on anterior end covered in what? And why?

Spines, for attachment

What do Acanthocephalans use to absorb their nutrients through?

Tegument (skin)

How many eggs can a female worm make per day?

250,000

Ancanthocephalans life cycle

1. Eggs released in host feces​

2. Spindle shaped egg with 3 layers​

3. Egg contains larva acanthor​

4. Intermediate host: arthropod​

5. Acanthor hatches into ancanthella then cystoacanth with inverted proboscis​

6. Definitive host ingests arthropod, adult pushes out proboscis and attaches to intestine wall

Macracanthorhynchus hirudinaceus

• Definitive host: Pig​

• Intermediate host: Dung beetle​

• Not zoonotic​

• Can perforate the intestine leading to peritonitis and even death.​

• Males average 10cm, Females 35cm but can grow as long as 70cm​

• Eggs are 3 layered, 2nd layer is brown and pitted, found on fecal float​

• Can look like Ascaris suum at necropsy, but is attached to wall, not free living

Oncicola canis

• Definitive host: Dog​

• Adult in small intestine​

• Intermediate host: Dung beetle​

• Cause of infection: Ingestion of dung beetle​

• Tiny, only 14mm long​

• Can also cause perforation​

• Egg found in fecal float