Taenia crassiceps
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''Taenia crassiceps'' is a tapeworm in the family
Taeniidae The Taeniidae are a family of tapeworms. It is the largest family representing the order Cyclophyllidea. It includes many species of medical and veterinary importance, as ''Taenia solium'' (pork tapeworm), '' Taenia saginata'' (beef tapeworm), ...
. It is a parasitic organism whose adult form infects the intestine of carnivores, like canids. It is related to ''
Taenia solium ''Taenia solium'', the pork tapeworm, belongs to the cyclophyllid cestode family Taeniidae. It is found throughout the world and is most common in countries where pork is eaten. It is a tapeworm that uses humans (''Homo sapiens'') as its definit ...
'', the pork tapeworm, and to ''
Taenia saginata ''Taenia saginata'' (synonym ''Taeniarhynchus saginatus''), commonly known as the beef tapeworm, is a zoonotic tapeworm belonging to the order Cyclophyllidea and genus ''Taenia''. It is an intestinal parasite in humans causing taeniasis (a type ...
'', the beef tapeworm. It is commonly found in the Northern Hemisphere, especially throughout Canada and the northern United States. Natural intermediate hosts of this organism are usually small rodents and moles. The larval stages of ''T. crassiceps'' develop subcutaneously or in their body cavities as cysticerci which are cyst-like structures. ''Taenia crassiceps'' begins its life in the intestines of wild canines, such as the wolf. Inside the wolf, the tapeworm reproduces. Its eggs are passed in the wolf's feces and are eaten by a rat. When the rat is eaten by another wolf, the parasite's life cycle repeats. ''Taenia crassiceps'' rarely infect humans, but if they do, they often cause ocular larva migrans that can progress to blindness. An adult human's immune system typically removes the parasite before permanent damage is done, however, juveniles are typically less defended.


Human pathologies

''Taenia crassiceps'' is described as an opportunistic infection in severe
immunodeficiency Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that aff ...
, as in
AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...
. But human infection are rare, with only eight cases reported and individuals who were infected tended to be immunosuppressed patients where parasites accumulated on skeletal muscles and subcutaneous tissue, and some with intraocular infections. Rodents are natural intermediate hosts, and they harbor the cyst-like larvae (metacestodes, cysticerci) in the peritoneal cavity, where they multiply by asexual budding. Humans serve as intermediate hosts when food or water contaminated with feces from infected
canids Canidae (; from Latin, ''canis'', "dog") is a biological family of caniform carnivorans, constituting a clade. A member of this family is also called a canid (). The family includes three subfamilies: the Caninae, and the extinct Borophaginae ...
or
felids Felidae ( ) is the family of mammals in the order Carnivora colloquially referred to as cats. A member of this family is also called a felid ( ). The 41 extant Felidae species exhibit the greatest diversity in fur patterns of all terrestria ...
is consumed. A case of intracranial ''T. crassiceps'' tapeworm cysticercosis with severe involvement of the cerebellum is described. A 51-year-old German woman was hospitalized because of progressive
headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...
,
nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat. Over 30 d ...
, and vomiting. The signs and symptoms had started two weeks before, and intensity had been increasing ever since. At the time of admission, the patient showed
cerebellar ataxia Cerebellar ataxia is a form of ataxia originating in the cerebellum. Non-progressive congenital ataxia (NPCA) is a classical presentation of cerebral ataxias. Cerebellar ataxia can occur as a result of many diseases and may present with symptoms ...
but no further neurologic deficits. She did not have fever or other symptoms. She had no known chronic preconditions or recent hospital stays and had never taken immunosuppressant drugs. She had no family history of neurologic symptoms or malignant diseases. Combined surgical removal of the larvae and treatment with
albendazole Albendazole is a broad-spectrum antihelmintic and antiprotozoal agent of the benzimidazole type. It is used for the treatment of a variety of intestinal parasite infections, including ascariasis, pinworm infection, hookworm infection, trichuri ...
and
praziquantel Praziquantel, sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat schist ...
led to a complete cure in this nonimmunocompromised patient. The organism was unequivocally identified by molecular methods, thus avoiding a misdiagnosis of ''
Taenia solium ''Taenia solium'', the pork tapeworm, belongs to the cyclophyllid cestode family Taeniidae. It is found throughout the world and is most common in countries where pork is eaten. It is a tapeworm that uses humans (''Homo sapiens'') as its definit ...
'' tapeworm cysticercosis.


Symptoms

There may be no symptoms. Symptoms may include headaches, nausea, and vomiting.


Laboratory studies

Positive test results from a serum enzyme-linked immunosorbent assay
ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay is a solid-phase type of enzyme immunoassay (EIA) to detect the presence of ...
for anticysticercal antibodies help confirm the diagnosis; however, negative test results do not exclude cysticercosis. A CBC count may reveal eosinophilia.


Treatments

Surgical removal is mandatory for individuals with intraocular cysts.
Corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...
s administered perioperatively may help reduce inflammation associated with
uveitis Uveitis () is inflammation of the uvea, the pigmented layer of the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea. The uvea consists of the middle layer of pigmented vascular structures of the eye and ...
. Extraocular cysticercosis can be effectively treated with antihelminthics such as
albendazole Albendazole is a broad-spectrum antihelmintic and antiprotozoal agent of the benzimidazole type. It is used for the treatment of a variety of intestinal parasite infections, including ascariasis, pinworm infection, hookworm infection, trichuri ...
or
praziquantel Praziquantel, sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat schist ...
and oral corticosteroids.


Immunoregulation

The immune response elicited by ''T. crassiceps'' and its antigens in human and mice cells was studied, suggesting that it had a strong capacity to induce chronic Th2-type responses that are primarily characterized by high levels of Th2 cytokines, low proliferative response in lymphocytic cells, immature and LPS-tolerogenic profile in dendritic cells, the recruitment of myeloid-derived suppressor cells, and activated macrophages.


References

''Includes public domain text from the CDC as cited''


External links

{{Taxonbar, from=Q287611 Cestoda Zoonotic parasitic diseases Animal diseases Parasitic animals of mammals Animals described in 1800