Coenurosis in humans

Last updated
Coenurosis in humans
Bulldog from 1915.JPG
The usual reservoir for coenurosis in man is the dog
Specialty Infectious diseases

Coenurosis is a parasitic infection that results when humans ingest the eggs of dog tapeworm species Taenia multiceps , T. serialis, T. brauni, or T. glomerata.

Contents

It is important to distinguish that there is a very significant difference between intestinal human tapeworm infection and human coenurosis. Humans are the definitive hosts for some tapeworm species, the most common being T. saginata and T. solium (beef and pork tapeworms). This means that these species can develop into full grown, reproductively capable adult worms within the human body. People infected with these species have a tapeworm infection. In contrast, the four species that cause human coenurosis can only grow into mature, reproductively capable worms inside their definitive hosts, canids such as dogs, wolves, foxes and coyotes. Humans who ingest eggs from any of these four species of Taenia become intermediate hosts, or places where the eggs can mature into larvae but not into adult worms. When humans ingest these eggs, the eggs develop into tapeworm larvae that group within cysts known as coenuri, which can be seen in the central nervous system, muscles, and subcutaneous tissues of infected humans. People with coenurosis do not develop a tapeworm infection because the larvae of coenurosis-causing parasites cannot develop into worms inside of humans. [1] [2]

Symptoms and signs

In humans, this parasitic infection causes a variety of symptoms, depending on where the cyst occurs. The tapeworm larvae group together to form fluid filled cysts in various body tissues. These cysts start out small, but as the larvae grow, the cyst can reach the size of an egg. The cysts of T. multiceps are usually between 2 and 6 cm in diameter and are most commonly found in the CNS and can contain anywhere from a few to over a hundred worm larvae within them. T. serialis and T. glomerata cysts present in the CNS, muscles, or subcutaneous tissue, and T. brauni cysts occupy these same areas but occur in the eye more frequently than the other three species. [1] [3]

When the cyst occurs in the brain, as it often does, the infected individual may experience neurological symptoms of headaches, seizures, vomiting, ataxia, paralysis affecting one side of the body (hemiplegia), paralysis involving one limb (monoplegia), and loss of ability to coordinate muscles and muscle movements. [4] Many of these symptoms are due to the buildup of inter-cranial pressure from the growing cyst or from the cyst pressing on other parts of brain. [5]

When the cyst occurs in the spinal cord, it can cause severe pain and inflammation, and loss of feeling in some nerves (arachnoiditis). [4]

When the cyst occurs in the eyes, it causes decreased vision and headaches. [4]

In the muscular and subcutaneous tissues, the cyst causes disfiguring nodules that can protrude out of the body. These nodules can be painful, uncomfortable, and can cause loss of muscle function. [1] [3]

Transmission

The definitive hosts for these Taenia species are canids. The adult tapeworms live in the intestines of animals like dogs, foxes, and coyotes. Intermediate hosts such as rabbits, goats, sheep, horses, cattle and sometimes humans get the disease by inadvertently ingesting tapeworm eggs (gravid proglottids) that have been passed in the feces of an infected canid. This can happen from ingesting food, water or soil that has been contaminated by dog feces. The disease cannot be transmitted from one intermediate host to another, but it is still not a good idea to eat meat that presents with cystic nodules from coenurosis. [1]

Reservoir

Wild carnivores/ canids like dogs, coyotes, foxes and wolves. [1] [3]

Incubation period

Cysts can present in humans anywhere from a few months to a few years after ingestion. Once the cyst develops, symptoms associated with the cyst develop rapidly. [1]

Morphology

The following are pictures of coenurosis cysts, some which have been surgically removed from humans and others that have been removed from animals after death.

Life cycle

Eggs and gravid proglottids are shed in feces into the environment by infected definitive hosts (canids). Many animals may serve as intermediate hosts, including rodents, rabbits, cattle, sheep, goats and humans. These intermediate hosts ingest the eggs. Once ingested, the eggs hatch in the intestine, releasing oncospheres. These oncospheres circulate in the blood until they lodge in suitable organs (skeletal muscle, eyes, brain, muscles or subcutaneous tissue). After about three months or so, the oncospheres develop into cystic like larvae balls called coenuri. The cycle perpetuates when a canid (definitive host) ingests the tissue of an infected intermediate host. When this happens, the maturing larvae reside in the small intestine of the definitive host until they mature into adult worms and begin producing eggs (which will eventually be passed through feces into the environment once again). [1] [3]

Diagnosis

Since coenurosis is very rare in humans, there are not many ways to diagnose the disease. [6] The most common method for diagnosis involves using CT or MRI scans to visualize the cysts in the body. [7] Some other clinical findings that can be used for diagnosis include papilledemas, hypoglycorrhacia, and high intracranial pressure caused by obstruction of the ventricles. [7] Some serological and microscopic tests can confirm the presence of Taenia larvae once surgery has taken place and a portion of the cyst can be removed to undergo examination and biopsy. Because of the lack of specificity in diagnostic technique, coenurosis can be misdiagnosed as neurocysticercosis or echinococcosis, other parasitic diseases affecting nervous system tissue. [2] [8]

An important consideration in diagnosing coenurosis properly is learning about the infected person’s exposure history. If the person presenting symptoms lives in an area with poor sanitation, high wild dog population, or known endemic tapeworm, his chance of having coenurosis is much higher. Also, this disease is seen more often in children than adults because children spend time outside in the mud and generally are more likely than adults to come into contact with canid feces. [1]

Prevention

This disease has no vaccination. [9] Preventative measures can be taken at community and individual levels. Communities and governments can make sure their water supply remains sanitary and free of dog feces and avoid fertilizing fields with dog manure. [9] Communities can control wild dog populations, thus preventing infection of the definitive host. Individuals should wash all fruits and vegetables thoroughly before eating and make sure their dogs are not infected with tapeworm. [1] [5]

Management

The most common and widely recognized treatment for this disease is surgical removal of the cysts. The disease is more complicated and severe when the oncosphere cysts form in the central nervous system tissue since this makes operating more difficult than when the disease presents in the muscles or subcutaneous tissues.

Alternative methods for treating coenurosis include administering anthelmintics and glucocorticoids. [10]  Praziquantel, Niclosamide, and Albendazole are the anthelminthics that are commonly used to treat coenurosis. Praziquantel works by causing contraction of the parasite by altering the permeability of the cell membrane. [11] This causes paralysis of the parasite from loss of its intracellular calcium. The drug also causes vacuolization and disintegration of the parasite. [11] Niclosamide works by uncoupling oxidative phosphorylation and inhibiting glucose uptake in the parasite. [12] Albendazole works by binding to β- tubulin sites and inhibiting their polymerization into microtubules. [13] This decreases the absorption ability of the parasite, leading to decreased glucose uptake and glycogen stores. [13] The lack of glucose prevents the parasite from making enough ATP leading to the parasite’s death. Dexamethasone is the glucocorticoid that is normally administered for coenurosis. [10] It inhibits pro-inflammatory signals and promotes anti-inflammatory signals in the body. [14] Dexamethasone also causes decreased vasodilation in capillaries and inhibits apoptosis in neutrophils. [14] Glucocorticoids can be used to help subdue the inflammatory symptoms of the disease. [3] [5]

Prevalence

This disease is very rare in humans and only about 100 cases have ever been recorded. It is a more common problem in sheep [15] and cattle and can be problematic for farmers in endemic regions of the world. Most human cases occur in developing countries such as India and Sub Saharan Africa where the dog population is not controlled or treated for tapeworm, and in areas lacking proper sanitation. T. multiceps has been reported in regions all over the world (both human and animal infections) and is the most common coenurosis causing species. T. serialis has been seen in North America, Europe and Africa, and T. brauni and T. glomerata have only been seen in Africa. This disease still occurs, even in developed countries. Some of the most recent reported cases occurred in France, Italy, Israel, Canada and the United States. Some experts suspect under reporting of this disease, especially in impoverished and developing countries where reporting technologies are more difficult to obtain. The global prevalence might be much higher than present data suggest. [8] [16] [5] [17]

History

Because this disease so rarely occurs in humans, it took a long time for it to become recognized within the population, and species differentiation among the four different types is still somewhat difficult. Many cases of coenurosis probably existed years before it was recognized or discovered, but the first cases to be diagnosed for each of the four Taenia spp. were as follows: [8]

Cases

Recently (within the last 25 years), human cases have been recorded in Uganda, Kenya, Ghana, South Africa, Rwanda, Nigeria, Italy, Israel, Mexico, Canada and the United States, and animal cases have been found in many other countries as well. (9)

In 1983, a 4-year-old girl in the USA was admitted to the hospital with progressive, generalized muscle weakness, inability to walk, rash, abdominal pain and deteriorating neurological ability. When the doctors did a CT scan, they saw fluid filled lumps in her brain and decided to operate. While operating, coenuri were found and the patient was immediately given chemotherapy with praziquantel. Unfortunately, the coenurosis had already done too much damage in the CNS and the little girl did not survive. [2]

The most recent North American case took place in 1994 in Los Angeles, CA, when a 39-year-old man presented an enlarging mass on his back. When doctors tried to operate a large intramuscular capsule was found. The surgery was terminated, and a fine needle aspiration test revealed muscular coenurosis. The man was treated with praziquantel. The drug successfully killed the larvae and his infection never returned. [2]

The most recent case on record to date took place in Israel in 2006. A 4-year-old girl had T. multiceps in her subcutaneous tissue. She received proper treatment and made a full recovery. In all of these recent cases, the infected individuals had been exposed to wild dogs in regions where canid tapeworm is considered endemic, and probably ingested the parasite accidentally through contact with contaminated food or water. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Cysticercosis</span> Tissue infection caused by the young form of the pork tapeworm

Cysticercosis is a tissue infection caused by the young form of the pork tapeworm. People may have few or no symptoms for years. In some cases, particularly in Asia, solid lumps of between one and two centimetres may develop under the skin. After months or years these lumps can become painful and swollen and then resolve. A specific form called neurocysticercosis, which affects the brain, can cause neurological symptoms. In developing countries this is one of the most common causes of seizures.

Hymenolepiasis is infestation by one of two species of tapeworm: Hymenolepis nana or H. diminuta. Alternative names are dwarf tapeworm infection and rat tapeworm infection. The disease is a type of helminthiasis which is classified as a neglected tropical disease.

<i>Taenia solium</i> Species of Cestoda

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 as its definitive host and pigs as the intermediate or secondary hosts. It is transmitted to pigs through human feces that contain the parasite eggs and contaminate their fodder. Pigs ingest the eggs, which develop into larvae, then into oncospheres, and ultimately into infective tapeworm cysts, called cysticercus. Humans acquire the cysts through consumption of uncooked or under-cooked pork and the cysts grow into an adult worms in the small intestine.

Spirometra is a genus of pseudophyllid cestodes that reproduce in canines and felines, but can also cause pathology in humans if infected. As an adult, this tapeworm lives in the small intestine of its definitive host and produces eggs that pass with the animal's feces. When the eggs reach water, the eggs hatch into coracidia which are eaten by copepods. The copepods are eaten by a second intermediate host to continue the life cycle. Humans can become infected if they accidentally eat frog legs or fish with the plerocercoid stage encysted in the muscle. In humans, an infection of Spirometra is termed sparganosis.

<i>Taenia</i> (tapeworm) Genus of flatworms

Taenia is the type genus of the Taeniidae family of tapeworms. It includes some important parasites of livestock. Members of the genus are responsible for taeniasis and cysticercosis in humans, which are types of helminthiasis belonging to the group of neglected tropical diseases. More than 100 species are recorded. They are morphologically characterized by a ribbon-like body composed of a series of segments called proglottids; hence the name Taenia. The anterior end of the body is the scolex. Some members of the genus Taenia have an armed scolex ; of the two major human parasites, Taenia saginata has an unarmed scolex, while Taenia solium has an armed scolex.

<i>Echinococcus granulosus</i> Species of flatworm

Echinococcus granulosus, also called the hydatid worm, hyper tape-worm or dog tapeworm, is a cyclophyllid cestode that dwells in the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and humans, where it causes cystic echinococcosis, also known as hydatid disease. The adult tapeworm ranges in length from 3 mm to 6 mm and has three proglottids ("segments") when intact—an immature proglottid, mature proglottid and a gravid proglottid. The average number of eggs per gravid proglottid is 823. Like all cyclophyllideans, E. granulosus has four suckers on its scolex ("head"), and E. granulosus also has a rostellum with hooks. Several strains of E. granulosus have been identified, and all but two are noted to be infective in humans.

<i>Echinococcus multilocularis</i> Species of flatworm

Echinococcus multilocularis, the fox tapeworm, is a small cyclophyllid tapeworm found extensively in the northern hemisphere. E. multilocularis, along with other members of the Echinococcus genus, produce diseases known as echinococcosis. Unlike E. granulosus,E. multilocularis produces many small cysts that spread throughout the internal organs of the infected animal. The resultant disease is called Alveolar echinococcosis, and is caused by ingesting the eggs of E. multilocularis.

<i>Hymenolepis nana</i> Species of flatworm

Dwarf tapeworm is a cosmopolitan species though most common in temperate zones, and is one of the most common cestodes infecting humans, especially children.

<i>Hymenolepis diminuta</i> Species of flatworm

Hymenolepis diminuta, also known as rat tapeworm, is a species of Hymenolepis tapeworm that causes hymenolepiasis. It has slightly bigger eggs and proglottids than H. nana and infects mammals using insects as intermediate hosts. The adult structure is 20 to 60 cm long and the mature proglottid is similar to that of H. nana, except it is larger.

<i>Taenia crassiceps</i> Species of Cestoda

Taenia crassiceps is a tapeworm in the family Taeniidae. It is a parasitic organism whose adult form infects the intestine of carnivores, like canids. It is related to Taenia solium, the pork tapeworm, and to Taenia saginata, the beef tapeworm. It is commonly found in the Northern Hemisphere, especially throughout Canada and the northern United States.

<i>Taenia pisiformis</i> Species of flatworm

Taenia pisiformis, commonly called the rabbit tapeworm, is an endoparasitic tapeworm which causes infection in lagomorphs, rodents, and carnivores. Adult T. pisiformis typically occur within the small intestines of the definitive hosts, the carnivores. Lagomorphs, the intermediate hosts, are infected by fecal contamination of grasses and other food sources by the definitive hosts. The larval stage is often referred to as Cysticercus pisiformis and is found on the livers and peritoneal cavities of the intermediate hosts. T. pisiformis can be found worldwide.

<span class="mw-page-title-main">Eucestoda</span> Subclass of flatworms

Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda. Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodaria. All tapeworms are endoparasites of vertebrates, living in the digestive tract or related ducts. Examples are the pork tapeworm with a human definitive host, and pigs as the secondary host, and Moniezia expansa, the definitive hosts of which are ruminants.

Spirometra erinaceieuropaei is a parasitic tapeworm that infects domestic animals and humans. The medical term for this infection in humans and other animals is sparganosis. Morphologically, these worms are similar to other worms in the genus Spirometra. They have a long body consisting of three sections: the scolex, the neck, and the strobilia. They have a complex life cycle that consists of three hosts, and can live in varying environments and bodily tissues. Humans can contract this parasite in three main ways. Historically, humans are considered a paratenic host; however, the first case of an adult S. erinaceieuropaei infection in humans was reported in 2017. Spirometra tapeworms exist worldwide and infection is common in animals, but S. erinaceieuropaei infections are rare in humans. Treatment for infection typically includes surgical removal and anti-worm medication.

Sparganosis is a parasitic infection caused by the plerocercoid larvae of the genus Spirometra including S. mansoni, S. ranarum, S. mansonoides and S. erinacei. It was first described by Patrick Manson in 1882, and the first human case was reported by Charles Wardell Stiles from Florida in 1908. The infection is transmitted by ingestion of contaminated water, ingestion of a second intermediate host such as a frog or snake, or contact between a second intermediate host and an open wound or mucous membrane. Humans are the accidental hosts in the life cycle, while dogs, cats, and other mammals are definitive hosts. Copepods are the first intermediate hosts, and various amphibians and reptiles are second intermediate hosts.

<i>Nanophyetus</i> Genus of flukes

Nanophyetus salmincola is a food-borne intestinal trematode parasite prevalent on the Pacific Northwest coast. The species may be the most common trematode endemic to the United States.

<span class="mw-page-title-main">Coenurosis</span> Parasitic disease

Coenurosis, also known as caenurosis, coenuriasis, gid or sturdy, is a parasitic infection that develops in the intermediate hosts of some tapeworm species. It is caused by the coenurus, the larval stage of these tapeworms. The disease occurs mainly in sheep and other ungulates, but it can also occur in humans by accidental ingestion of tapeworm eggs.

Taenia serialis, also known as a canid tapeworm, is found within canines such as foxes and dogs. Adult T. serialis are parasites of carnivores, particularly dogs, with herbivorous lagomorph mammals such as rabbits and hares, serving as intermediate hosts. In definitive hosts, T. serialis is acquired by eating tissues from a variety of intermediate hosts. Accidental infection of humans though, can occur when eggs are ingested from food or water contaminated with dog feces and the human then becomes the T. serialis intermediate host.

<i>Taenia hydatigena</i> Species of flatworm

Taenia hydatigena is one of the adult forms of the canine and feline tapeworm. This infection has a worldwide geographic distribution. Humans with taeniasis can infect other humans or animal intermediate hosts by eggs and gravid proglottids passed in the feces.

<i>Echinococcus vogeli</i> Species of flatworm

Echinococcus vogeli is a small cyclophyllid tapeworm found in Central and South America. E. vogeli, as well as other members of the genus Echinococcus, produce a disease called echinococcosis. Echinococcosis, also known has hydatidosis, is a result of ingesting the eggs of the genus Echinococcus. E. vogeli is similar to E. multilocularis in that both species produces many small cysts that spread throughout the internal organs of the infected animal. The ingestion of E. vogeli eggs, and the spreading of the cysts through infected host, will results in Polycystic Echinococcosis.

<span class="mw-page-title-main">Cat worm infections</span> Worm infections in cats

Cat worm infections, the infection of cats (Felidae) with parasitic worms, occur frequently. Most worm species occur worldwide in both domestic and other cats, but there are regional, species and lifestyle differences in the frequency of infestation. According to the classification of the corresponding parasites in the zoological system, infections can be divided into those caused by nematode and flatworms - in the case of the latter, mainly cestoda and trematoda - while other strains are of no veterinary significance. While threadworms usually do not require an intermediate host for their reproduction, the development cycle of flatworms always proceeds via alternate hosts.

References

  1. 1 2 3 4 5 6 7 8 9 10 "DPDx - Coenurosis". Division of Parasitic Diseases, Centers for Disease Control & Prevention. Archived from the original on 2010-03-20. Retrieved 2010-03-15.
  2. 1 2 3 4 Ing, Michael B.; Schantz, Peter M.; Turner, Jerrold A. (September 1998). "Human coenurosis in North America: case reports and review". Clinical Infectious Diseases. 27 (3): 519–23. doi: 10.1086/514716 . PMID   9770151.
  3. 1 2 3 4 5 "Taenia Infections" (PDF). The Institute for International Cooperation in Animal Biologics and the Center for Food Security and Public Health, College of Veterinary Medicine, Iowa State University. May 2005. Retrieved 17 March 2010.
  4. 1 2 3 Principles and Practice of Pediatric Infectious Diseases. 2018. doi:10.1016/c2013-0-19020-4. ISBN   9780323401814.
  5. 1 2 3 4 "Coenurosis". ParaSites2005. stanford.edu. May 19, 2008. Retrieved 17 March 2010.[ permanent dead link ]
  6. ↑ Principles and Practice of Pediatric Infectious Diseases. 2018. doi:10.1016/c2013-0-19020-4. ISBN   9780323401814.
  7. 1 2 Hermos, John A.; Healy, George R.; Schultz, Myron G.; Barlow, John; Church, William G. (1970-08-31). "Fatal Human Cerebral Coenurosis". JAMA. 213 (9): 1461–1464. doi:10.1001/jama.1970.03170350029006. ISSN   0098-7484. PMID   5468450.
  8. 1 2 3 4 Benifla M, Barrelly R, Shelef I, El-On J, Cohen A, Cagnano E (December 2007). "Huge hemispheric intraparenchymal cyst caused by Taenia multiceps in a child. Case report". Journal of Neurosurgery. 107 (6 Suppl): 511–4. doi:10.3171/PED-07/12/511. PMID   18154024 . Retrieved 2010-03-07.
  9. 1 2 "Coenurosis". web.stanford.edu. Retrieved 2020-04-30.
  10. 1 2 "Coenurosis". web.stanford.edu. Retrieved 2020-04-30.
  11. 1 2 Chai, Jong-Yil (2013). "Praziquantel Treatment in Trematode and Cestode Infections: An Update". Infection & Chemotherapy. 45 (1): 32–43. doi: 10.3947/ic.2013.45.1.32 . ISSN   2093-2340. PMC   3780935 . PMID   24265948.
  12. ↑ Chen, Wei; Mook, Robert A.; Premont, Richard T.; Wang, Jiangbo (January 2018). "Niclosamide: Beyond an antihelminthic drug". Cellular Signalling. 41: 89–96. doi:10.1016/j.cellsig.2017.04.001. ISSN   0898-6568. PMC   5628105 . PMID   28389414.
  13. 1 2 Firth, Mary (1984). Albendazole in helminthiasis. Royal Society of Medicine. ISBN   978-0-19-922001-4. OCLC   10207175.
  14. 1 2 Tsurufuji, Susumu (1981). "Molecular mechanisms and mode of action of anti-inflammatory steroids". Mechanisms of Steroid Action. Biological Council The Co-ordinating Committee for Symposia on Drug Action. Macmillan Education UK. pp. 85–95. doi:10.1007/978-1-349-81345-2_7. ISBN   978-1-349-81347-6.
  15. ↑ Scala A, Varcasia A (June 2006). "Updates on morphobiology, epidemiology and molecular characterization of coenurosis in sheep". Parassitologia. 48 (1–2): 61–3. PMID   16881398.
  16. 1 2 web.gideononline.com https://web.gideononline.com/web/epidemiology/country_info.php?source=&country_id=G100&disease_id=10450&country_name=%3C%20Worldwide%20%3E%20@ . Retrieved 2022-02-18.{{cite web}}: Missing or empty |title= (help)
  17. ↑ Ibechukwu BI, Onwukeme KE (July 1991). "Intraocular coenurosis: a case report". The British Journal of Ophthalmology. 75 (7): 430–1. doi:10.1136/bjo.75.7.430. PMC   1042412 . PMID   1854698.
  18. ↑ "Coenurosis". web.stanford.edu. Retrieved 2020-04-30.
  19. ↑ Hermos, John A.; Healy, George R.; Schultz, Myron G.; Barlow, John; Church, William G. (1970-08-31). "Fatal Human Cerebral Coenurosis". JAMA. 213 (9): 1461–1464. doi:10.1001/jama.1970.03170350029006. ISSN   0098-7484. PMID   5468450.
  20. ↑ "Coenurosis". web.stanford.edu. Retrieved 2020-04-30.
  21. ↑ Hermos, John A.; Healy, George R.; Schultz, Myron G.; Barlow, John; Church, William G. (1970-08-31). "Fatal Human Cerebral Coenurosis". JAMA. 213 (9): 1461–1464. doi:10.1001/jama.1970.03170350029006. ISSN   0098-7484. PMID   5468450.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.