Lecture 29: Cylocphyllidian Tapeworms of Domestic Livestock & Others

What larg family of tapeworms has eggs enclosed in 3 delicate membranes?

Hymenolepididae

What is the lifecycle of hymenolepididae?

indirect with fleas and beetles as most common IH, most live in small intestine

True or false: Hymenolepididae are generally nonpathogenic.

true

What Hymenolepididae species are potentially zoonotic?

H. nana and H. diminuta

Hymenolepis nana

Hymenolepis dimunuta

Hymenolepidae-type

What are the 2 tapeworm genera of veterinary importance in domestic livestock and what species do they affect?

• Anoplocephala sp.: horses

• Monezie sp.: cattle, sheep, goats, camelids

What are the characteristics of anoplocephalidea?

• Scolex without a rostellum or hooks

• Proglottids wider than long

• distinctive eggs with pyriform onchosphere

• all species use “oribatid” mites as obligate intermediate host

Anoplocephalidea

What anoplocephalidea species is pathogenic in horses?

anoplocephala perfoliata

What are the clinical signs and pathology of an anoplocephala perfoliata infection in horses?

• ulceration and reactive inflammation at ileal-cecal junction

• predisposition to colic

• extreme infections → intussusception and rupture of bowel wall

How is Anoplocephala perfoliata treated?

pyrantel, praziquantel combined with macrocyclic lactone, pasture renovation to break up breeding habitat for mites

What tapeworm is characterized by ribbon tike worms in small intestines of cattle, sheep, goats, and ruminants?

Monezia sp.

Monezia sp. are generally non-pathogenic, but can cause disease in what at risk population?

young lambs 1st season on pasture

How are Monezia sp. infestations treated?

fenbendazole, praziquantal, pasture renovation

Human Taeniasis generally has no person-to-person transmission, what is the exception?

T. solium

How does a T. solium infection occur?

accidental ingestion of pork tapeworm eggs via fecal/oral route

What are the pathological signs of T. solium neurocysticercosis?

metacestode stage (cysticercus) encysts in brain and CNS causing epilepsy and other neurologic disease

How can humans be the intermediate host and definitive host of T. solium?

• When humans ingest eggs they become intermediate host (with neuro disease)

• When humans eat tissues with the infective cysticercius stage they become definitive host with adult tapeworms