Infectious Disease and Microbiology – Multiceps multiceps

Overview

Multiceps multiceps is a cestode (tapeworm) helminth primarily associated with dogs. Humans are accidental intermediate hosts and acquire infection by ingesting eggs shed in dog feces.

Human infection is extremely rare but can produce coenurosis, characterized by development of larval cysts within tissues. Involvement of the central nervous system (CNS) is the most clinically important manifestation.

Classification

Genus: Multiceps

Species: M. multiceps

Type: Cestode helminth (tapeworm)

Definitive host: Dogs and other canids

Human role: Accidental intermediate host

Taxonomic Note

Multiceps multiceps has historically been used for this parasite, although it is also commonly classified within the genus Taenia as:

Taenia multiceps

The larval infection produced in intermediate hosts is called:

Coenurosis

Microbiologic Characteristics

M. multiceps is a cestode whose adult form normally inhabits the intestine of its definitive canid host.

The important infectious stage for humans is the:

Egg

After eggs are accidentally ingested, larvae can migrate through tissues and develop into characteristic cystic structures called:

Coenuri

Incubation Period

The incubation period is:

Unknown

Clinical manifestations may not become apparent until a larval cyst has enlarged sufficiently to produce local tissue effects.

Epidemiology

M. multiceps has a:

Worldwide distribution

However, human infection is:

Very rare

The parasite primarily circulates between dogs or other canids and their normal intermediate hosts.

Transmission

Humans acquire infection through:

Ingestion of eggs from dog feces

This can occur through fecal contamination of:

• Hands

• Food

• Water

• Soil

Humans therefore act as accidental hosts rather than being necessary for continuation of the parasite’s normal life cycle.

Life Cycle

Adult tapeworm in dog/canid intestine

↓

Eggs released in feces

↓

Accidental human ingestion of eggs

↓

Larvae penetrate intestinal wall

↓

Hematogenous dissemination

↓

Development of coenurus cyst in tissue

↓

Possible CNS, ocular, subcutaneous, or other tissue disease

Coenurosis

Human infection with the larval stage is called:

Coenurosis

The characteristic lesion is a:

Coenurus cyst

A coenurus differs from some other cestode larval cysts because it can contain:

Multiple protoscolices

within a single cyst.

Central Nervous System Coenurosis

The source particularly emphasizes:

CNS cyst formation

Scattered cases of cerebral coenurosis have been reported in humans.

Clinical Manifestations

Neurologic manifestations depend on the:

• Location of the cyst

• Size of the cyst

• Degree of surrounding inflammation

• Intracranial pressure

Possible manifestations include:

• Headache

• Seizures

• Focal neurologic deficits

• Visual abnormalities

• Symptoms of increased intracranial pressure

High-Yield CNS Pattern

Dog exposure

• ●

Possible fecal contamination

• ●

Cestode larval cyst in CNS

→ Consider Multiceps multiceps coenurosis

Other Forms of Coenurosis

Although CNS disease is particularly important, larval cysts may occasionally involve other tissues, producing:

• Ocular coenurosis

• Subcutaneous coenurosis

• Muscular or other tissue involvement

Clinical manifestations depend on the affected anatomical site.

Diagnosis

The source emphasizes:

Histopathologic examination of surgically removed affected tissue

Identification of characteristic parasitic structures within the cyst can establish the diagnosis.

Histopathology

Examination of an excised cyst may demonstrate:

Coenurus larval structures

with multiple developing protoscolices.

Because infection is rare, definitive diagnosis may require careful parasitologic and histopathologic evaluation.

Imaging

When CNS involvement is suspected, imaging such as:

CT or MRI

can identify cystic lesions and define their:

• Location

• Size

• Number

• Relationship to surrounding structures

Imaging alone may not reliably distinguish coenurosis from other parasitic or nonparasitic cystic lesions.

Differential Diagnosis

CNS coenurosis may need to be distinguished from:

• Neurocysticercosis due to Taenia solium

• Echinococcosis

• Brain abscess

• Primary or metastatic tumors

• Other intracranial cystic lesions

Coenurosis vs. Cysticercosis

Coenurosis – Taenia (Multiceps) multiceps

→ Dogs/canids are definitive hosts

→ Humans ingest eggs from canid fecal contamination

→ Coenurus cyst contains multiple protoscolices

→ CNS, ocular, or subcutaneous disease

Cysticercosis – Taenia solium

→ Humans ingest T. solium eggs

→ Individual cysticercus generally contains one scolex

→ Neurocysticercosis is much more common than human coenurosis

High-Yield Morphologic Distinction

Coenurus

→ Multiple protoscolices in one cyst

Cysticercus

→ Typically single invaginated scolex

This is an important parasitologic distinction.

Treatment

The primary treatment described in the source is:

Surgical removal of the cyst

whenever anatomically possible.

Surgery can provide both:

Definitive diagnosis

and

Treatment

Praziquantel

The source states that:

High-dose praziquantel (>50 mg/kg)

may also be helpful.

Because human coenurosis is exceptionally rare, evidence for antiparasitic treatment is limited and management depends heavily on cyst location and surgical feasibility.

Treatment Principle

Localized accessible coenurus cyst

↓

Surgical excision when feasible

• ●

Histopathologic confirmation

↓

Consider antiparasitic therapy in selected cases

Prevention

Prevention focuses on interrupting fecal–oral transmission from dogs and other canids.

Important measures include:

• Handwashing after handling dogs

• Avoiding food or water contaminated with dog feces

• Appropriate disposal of dog feces

• Veterinary parasite control and deworming

• Preventing dogs from consuming infected animal tissues

High-Yield Clinical Pattern

Rare cestode infection

• ●

Dog is the definitive host

• ●

Human ingests eggs from dog feces

• ●

CNS cyst containing multiple protoscolices

→ Think Multiceps multiceps (Taenia multiceps)

→ Coenurosis

Exam Essentials

Organism: Multiceps multiceps

Alternative classification: Taenia multiceps

Type: Cestode (tapeworm)

Definitive host: Dogs and other canids

Human role: Accidental intermediate host

Transmission to humans: Ingestion of eggs from dog fecal contamination

Distribution: Worldwide

Human infection: Very rare

Disease: Coenurosis

Larval lesion: Coenurus cyst

Characteristic morphology: Multiple protoscolices within a cyst

Important site: Central nervous system

Other sites: Eye, subcutaneous tissue, and other tissues

Diagnosis: Histopathology of excised tissue; imaging assists localization

Main treatment: Surgical removal when possible

Source additional treatment: High-dose praziquantel may help

Prevention: Hygiene, avoidance of dog-fecal contamination, and veterinary parasite control

Key clinical pearl: Multiceps multiceps (Taenia multiceps) is a rare dog-associated cestode that causes human coenurosis after accidental ingestion of eggs from dog feces. CNS disease is particularly important, and the characteristic coenurus cyst contains multiple protoscolices—distinguishing it from the usually single-scolex cysticercus of Taenia solium.