SRG General Parasitology

Cestode Infections of Man

There are a number of Cestodes that have man as the main definitive host, in addition a number of Cestodes normally infecting animals may cause accidental infections in man. These infections may be either by the adult form of the parasite (i.e. a tapeworm), or more seriously by the larval parasite.

Cestodes with Man as the main host

Order Pseudophyllidea

Infection by Adult Tapeworm - Diphylobothrium latum - Fish Tapeworm (Broad Tapeworm)

Infection by Larvae (metacestodes) - None

Order Cyclophyllidea

Infection by Adult Tapeworm

Taenia saginata - Beef tapeworm

Taenia solium- Pork Tapeworm. Man may also be infected by larval forms of this parasite (Cysticercosis)

Hymenolepis nana - Dwarf tapeworm

Hymenolepis diminuta - Rat tapeworm

Dipylidium caninum - Dog tapeworm

Infection by Larvae (metacestodes)

Echinococcus granulosus - Hydatid disease

Echinococcus multilocularis - Alveolar Hydatid disease

Taenia solium - Cysticercosis in man, but the larvae are more normally found in the pig. Man may also be infected by adult forms of this parasite (the Pork Tapeworm)

In addition to these a number of tapeworms may cause accidental infections in man, reported cases including;

Order Pseudophyllidea

Infection by Larvae (metacestodes)

Spirometra mansonoides- Causes sparganosis in man.

Spirometra proliferum - Causes a branching sparganosis where the larvae may bud off to form new spargana in the tissues. Has been reported a few times from Japan and the USA. Nothing else is known about this parasite in terms of the lifecycle or adult worms.

Plerocercoids of other species of Spirometra have also been reported in man.

Order Cyclophyllidea

Infection by Adult Tapeworm

Mesocestoides variabilis - A very rare parasite of man, identified from a child in East Texas and another case in Denmark. Normally parasitic in foxes, skunks, dogs and racoons in the USA.

Bertiella studeri - a rare parasite of man, normally parasitic in apes and monkeys

Inermicapsifer arvicanthidis - A common parasite of rodents in Africa, this was first identified in humans in Cuba where it is an uncommon but not rare parasite of man. A few human cases have also been reported from Africa and Mauritius.

Raillietina siriraji - A rare parasite, identified from children in Bangkok.

Taenia taeniformis - The adult parasites are normally found in cats, but it has been reported from an Argentinean child.

Taenia bremneri(Syn. T. confusa) - reported from man in Africa, Japan and USA.

Infection by Larvae (metacestodes)

Echinococcus vogeli - This parasite is found in Central and Northern South America, with bush dogs as the definitive hosts, and pacas and other rodents as the normal definitive host. The cysts resemble E. granulosus, but often become septate , forming multichambered cysts (i.e. polycystic hydatids).
(NB. Not all authors recognise this species, it being very similar to E. granulosus)

Taenia africanus- reported a few times in East Africa

Taenia multiceps- The adult tapeworms of this species are found in dogs and related canids, whilst the larvae, a coenurus, is normally found in the brain or spinal cord of sheep and goats. The larval form may rarely infect man, where it causes coenurus cerebralis, on accidental ingestion of tapeworm eggs in the faeces of dogs.

Taenia serialis- A similar parasite to T. multiceps, the coenurus larvae usually being found in the subcutaneous and intramuscular tissues of lagomorphs. Has been reported very rarely in man.

Taenia glomerulatus- The larvae normally infect rodents, but it has also been reported in man in Africa.

Specific Cestodes