Cestodes: The Tapeworms Overview

The first stage larva of tapeworms, infective to intermediate host (IH).

An organism that harbors the larval stage of a parasite.

Tapeworm larvae stage that is infective to the definitive host (DH).

The second stage larvae in IH, usually in a fluid-filled sac bearing the scolex.

The final host that harbors the adult tapeworm.

A tapeworm whose IH is a flea or louse.

A genus of tapeworms infecting mammals

Time interval between infection and detectable symptoms/parasite eggs.

Adult worms live in a dog's small intestine. The proglottids release oncospheres, which are ingested by intermediate hosts (sheep, cattle, etc). Larvae form hydatid cysts in various tissues, completing the cycle when the intermediate host is consumed by a dog.

A type of Echinococcus species with a life cycle similar to E. granulosis, except intermediate hosts are usually rodents (mice) and sometimes humans.

A fluid-filled cyst formed by Echinococcus larvae in intermediate hosts. It is analogous to a bladder worm.

Cysts produced by Echinococcus multilocularis larvae characterized by continuous growth and tissue infiltration that resembles a malignant neoplasm. It typically causes fatal disease.

An animal that harbors the larval stage of a parasite.

The animal that harbors the adult stage of a parasite.

Requires identification of adult worms because ova cannot be differentiated from Taenia spp. Adult worms can sometimes be collected through purgatives.

Involves a complex cycle with multiple hosts, including moose, wolves, sled dogs, and people. People can be infected by handling dog feces or consuming undercooked infected meat.

This tapeworm species requires two intermediate hosts: a copepod (small crustacean) and a fish.

This tapeworm requires two intermediate hosts: a copepod and a second host that can be an amphibian, reptile, bird, or mammal, including humans.

Examining proglottids helps identify tapeworm species. Requires rehydration and careful examination.

Can differentiate Dipylidium ova from Taenia/Echinococcus ova. However, Taenia and Echinococcus ova look similar.

Specific medications like Praziquantel and Epsiprantel are effective treatments for most tapeworm infections.

Signs in pets can be subtle and include scooting, licking the anal area, unthriftiness, and mild diarrhea.

This equine cestode resides at the junction of the ileum and cecum, as well as the large intestine.

This equine tapeworm prefers to hang out in the small intestine.

This equine cestode primarily resides in the small intestine, but sometimes you can find it in the stomach.

The lifecycle starts with adult worms in the horse, then gravid proglottids are released in the manure. These proglottids dry out, releasing eggs that are ingested by oribatid mites. Inside the mites, they develop into larvae. Finally, the horse ingests the infected mites while grazing, completing the cycle.

The intermediate host for Equine Cestodes is a free-living oribatid mite, which lives in humus.

Heavy infestations can cause poor growth, diarrhea, colic, abscesses, and intestinal problems.

It's tricky to diagnose. While you might see proglottids around the anus or in manure, eggs are difficult to find using traditional methods.

Treatment options are available and can be effective. Consult your veterinarian for specific recommendations.

The cyst-like second stage larva of tapeworms found in the tissues of intermediate hosts (IH). It's infective to the definitive host (DH) and is commonly known as a 'bladderworm'.

A disease caused by the presence of hydatid cysts in the body, usually in the liver or lungs.

The attachment end of a tapeworm, also known as the 'holdfast'. It's located at the anterior (front) end of the tapeworm.

The chain of proglottids that makes up the majority of the tapeworm's body.

One of the segments that make up the strobila, or chain, of a tapeworm. Each proglottid typically contains reproductive organs.

A term used for a pregnant proglottid, meaning it's filled with developing eggs.

A trematode parasite commonly known as the liver fluke, impacting livestock worldwide. It's crucial for animal health, especially in regions with wet environments.

Primarily found in the Gulf Coast, Pacific Northwest, and Rocky Mountain regions, where mild climates and wetlands support its life cycle.

Involves an indirect cycle with snails as the intermediate host and ruminants as the definitive host. Transmission happens through ingestion of infected vegetation with metacercariae.

It can cause chronic and acute fascioliosis, leading to reduced productivity, anemia, and even death. It also contributes to Black Disease, a fatal condition in sheep.

Chronic fascioliosis is a slow, debilitating condition, while acute fascioliosis is rapid and often fatal. Black Disease is a severe liver infection caused by a bacteria.

A slow disease, characterized by fibrotic hepatitis, anemia, edema, and reduced productivity in livestock.

A rapid and serious disease marked by abdominal pain, anemia, and a high risk of death, primarily affecting sheep.

A fatal liver infection in sheep caused by Clostridium novyi bacteria, often introduced through damaged liver tissue following fluke migration.

By detecting fluke eggs in fecal samples, indicating the presence of adult flukes in the animal.

Yes, but rarely. Humans can become infected by ingesting metacercariae found in raw watercress.