Pork tapeworm
Encyclopedia
Taenia solium, also called the pork tapeworm, is a cyclophyllid cestode in the family Taeniidae
. It infects pig
s and humans in Asia
, Africa
, South America
, parts of Southern Europe
and pockets of North America
. In the larval stage, it causes cysticercosis
which is a major cause of seizures in humans. Like all cyclophyllid cestodes, T. solium has four suckers on its scolex ("head"). T. solium also has two rows of hooks.
T. solium has a very similar life cycle
to Taenia saginata
. Cysticerci
have three morphologically distinct types. The common one is the ordinary "cellulose
" cysticercus
which has a fluid filled bladder
that is 0.5 cm to 1.5 cm in length and an invaginated scolex. The intermediate form has a scolex while the "racemose" has no evident scolex but are believed to be larger and much more dangerous. They are 20 cm in length and have 60 ml of fluid and 13% of patients might have all three types in the brain. Humans are usually infected through eating infected pork, fostering adult tapeworms in the intestine, and passing eggs through feces
, but autoinfection
is also possible. In that case, a cysticercus (a larva
sometimes called a "bladder worm") develops in the human and the human acts like an intermediate host
. This happens if eggs get to the stomach
, usually as a result of contaminated hands, but also due to retroperistalsis
. Cysticerci
often occur in the central nervous system
, which can cause major neurological problems like hydrocephalus
, paraplegy, meningitis
, convulsion
s and even death. The condition of having cysticerci
in one's body is called cysticercosis
.
Eggs can be diagnosed only to the family
level, but if a proglottid's uterus
is stained with India ink
, the number of visible uterine branches can help identify the species: unlike the Taenia saginata
uteri, T. solium uteri have only five to ten uterine branches on each side.
Infection with T. solium adults is treated with niclosamide
, which is one of the most popular drugs for adult tapeworm infections, as well as for fluke infections. As cysticercosis
is a major risk, it is important to wash one's hands before eating and to suppress vomiting if a patient may be infected with T. solium. If neurocysticercosis occurs the drug of choice is either albendazole
or praziquantel
. These drugs damage the parasites skin internally causing it to disintegrate and is then removed by the host's immune system
.
Infection may be prevented with proper disposal of human feces around pigs, cooking meat thoroughly and/or freezing the meat at -10oC for 5 days. Most cases occur because infected food handlers contaminate the food.
This infection is caused by ingestion of eggs shed in the feces of a human tapeworm carrier. Pigs and humans become infected by ingesting eggs or gravid proglottids. Humans are infected either by ingestion of food contaminated with feces containing eggs, or by autoinfection. In the latter case, a human infected with adult T. solium can ingest eggs produced by that tapeworm, either through fecal contamination or, possibly, from proglottids carried into the stomach by reverse peristalsis
. Once eggs are ingested, oncospheres hatch in the intestine, invade the intestinal wall, and migrate to striated muscles, as well as the brain, liver, and other tissues, where they develop into cysticerci
. In humans, cysts can cause serious sequelae if they localize in the brain
, resulting in neurocysticercosis. The parasite life cycle is completed, resulting in human tapeworm infection, when humans ingest undercooked pork containing cysticerci
. Cysts evaginate and attach to the small intestine by their scolex. Adult tapeworms develop, (up to 2 to 7 m in length and produce less than 1000 proglottids, each with approximately 50,000 eggs) and reside in the small intestine
for years.
e to migrate into host tissue and cause cysticercosis
. This is the most frequent and severe disease caused by T. solium. In symptomatic cases, a wide spectrum of symptoms may be expressed including headaches, dizziness and occasional seizures. In more severe cases, dementia or hypertension
due to perturbation of the normal circulation of cerebrospinal fluid can occur. The severity of cysticercosis
depends on location, size and number of parasite larvae in tissues, as well as the host immune response. Other symptoms include sensory deficits, involuntary movements and brain system dysfunction. In children ocular
location of cysts is more common than cystation in other locations of the body. If a person is heavily infected with T. solium, it can lead to neurocysticercosis which can lead to epilepsy
, seizures, lesions in the brain, blindness
and tumor
like growths. This kind of patient will also show the low level of eosinophils when they run the blood test.
and not cysticercosis
. Cysticercosis is diagnosed primarily on confirming the presence of hooks on the scolex of T. solium. Radiological test such as X-ray, CT scans and MRIs can also be used to detect diseases. X-rays are used to identify calcified larvae in the subcutaneous and muscle tissues and CT scans and MRIs are used to find lesions in the brain.
) is the drug of choice for the treatment of T. solium infection. Some consider Niclosamide
to be the drug of choice for all types of Tapeworms. For cysticercosis
, one can be treated with albendazole
combining with steroid
to reduce the inflammation
. Surgical intervention may be necessary to treat CNS lesions. Albendazole
appears to be more effective and a safe drug for Neurocysticercosis, infection of the brain with T. solium larva
e.
are intermediate host
s of the parasite, completion of the life cycle
occurs in regions where humans live in close contact with pigs and eat undercooked pork. Cysticercosis is often seen in areas where poor hygiene allows for contamination of food, soil or water supplies. Prevalence rates in the United States have shown that immigrants from Mexico
, Central and South America
and South-east Asia account for most of the domestic cases of cysticercosis. Taeniasis and cysticercosis are very rare in predominantly Muslim
countries, as Islam forbids the consumption of pork. It is important to note that human cysticercosis is acquired by ingesting T. solium eggs shed in the feces
of a human tapeworm carrier via gravid proglottids, and thus can occur in populations that neither eat pork nor share environments with pigs, although, as stated, the completion of the life cycle
can occur only where humans live in close contact with pigs and eat pork.
In 1990 and 1991, four unrelated members of an Orthodox Jewish community in New York City
developed recurrent seizures and brain lesions which were found to have been caused by cysticercosis from T. solium. In keeping with their religion, none of the patients ate pork; additionally, none had any history of recent foreign travel. Several immediate family members of these four patients with seizures were found to have cysticercus antibodies. The families of the four patients had all employed housekeepers from Latin American countries, and one of the housekeepers tested positive for cysticercus antibodies, leading to the conclusion that the housekeepers were the most likely source of the infections.
Taeniidae
Taeniidae is a family of flatworms. It includes many tapeworms of medical and veterinary importance, as Taenia solium and Taenia saginata ....
. It infects pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
s and humans in Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, parts of Southern Europe
Southern Europe
The term Southern Europe, at its most general definition, is used to mean "all countries in the south of Europe". However, the concept, at different times, has had different meanings, providing additional political, linguistic and cultural context to the definition in addition to the typical...
and pockets of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. In the larval stage, it causes cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
which is a major cause of seizures in humans. Like all cyclophyllid cestodes, T. solium has four suckers on its scolex ("head"). T. solium also has two rows of hooks.
Description
T. solium is normally 2 m to 3 m in length, but can become very large, over 50 m long in some situations.T. solium has a very similar life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
to Taenia saginata
Taenia saginata
Taenia saginata, also known as Taeniarhynchus saginata or the beef tapeworm, is a parasite of both cattle and humans, causing taeniasis in humans. Taenia saginata occurs where cattle are raised by infected humans maintaining poor hygiene, human feces are improperly disposed of, meat inspection...
. Cysticerci
Cysticercoid
A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infestations, cysticercoids can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal...
have three morphologically distinct types. The common one is the ordinary "cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
" cysticercus
Cysticercoid
A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infestations, cysticercoids can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal...
which has a fluid filled bladder
Bladder
Bladder usually refers to an anatomical hollow organBladder may also refer to:-Biology:* Urinary bladder in humans** Urinary bladder ** Bladder control; see Urinary incontinence** Artificial urinary bladder, in humans...
that is 0.5 cm to 1.5 cm in length and an invaginated scolex. The intermediate form has a scolex while the "racemose" has no evident scolex but are believed to be larger and much more dangerous. They are 20 cm in length and have 60 ml of fluid and 13% of patients might have all three types in the brain. Humans are usually infected through eating infected pork, fostering adult tapeworms in the intestine, and passing eggs through feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
, but autoinfection
Autoinfection
Autoinfection is the infection of a primary host with a parasite, particularly a helminth, in such a way that the complete life cycle of the parasite happens in a single organism, without the involvement of another host. Therefore, the primary host is at the same time the secondary host of the...
is also possible. In that case, a cysticercus (a larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
sometimes called a "bladder worm") develops in the human and the human acts like an intermediate host
Intermediate host
A secondary host or intermediate host is a host that harbors the parasite only for a short transition period, during which some developmental stage is completed. For trypanosomes, the cause of sleeping sickness, humans are the primary host, while the tsetse fly is the secondary host...
. This happens if eggs get to the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
, usually as a result of contaminated hands, but also due to retroperistalsis
Retroperistalsis
Retroperistalsis is the reverse of the involuntary smooth muscle contractions of peristalsis. It usually occurs as a precursor to vomiting. Local irritation of the stomach, such as bacteria or food poisoning, activates the emetic center of the brain which in turn signals an imminent vomiting reflex...
. Cysticerci
Cysticercoid
A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infestations, cysticercoids can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal...
often occur in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, which can cause major neurological problems like hydrocephalus
Hydrocephalus
Hydrocephalus , also known as "water in the brain," is a medical condition in which there is an abnormal accumulation of cerebrospinal fluid in the ventricles, or cavities, of the brain. This may cause increased intracranial pressure inside the skull and progressive enlargement of the head,...
, paraplegy, meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
, convulsion
Convulsion
A convulsion is a medical condition where body muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body. Because a convulsion is often a symptom of an epileptic seizure, the term convulsion is sometimes used as a synonym for seizure...
s and even death. The condition of having cysticerci
Cysticercoid
A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infestations, cysticercoids can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal...
in one's body is called cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
.
Eggs can be diagnosed only to the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
level, but if a proglottid's uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
is stained with India ink
India ink
India ink is a simple black ink once widely used for writing and printing and now more commonly used for drawing, especially when inking comic books and comic strips.-Composition:...
, the number of visible uterine branches can help identify the species: unlike the Taenia saginata
Taenia saginata
Taenia saginata, also known as Taeniarhynchus saginata or the beef tapeworm, is a parasite of both cattle and humans, causing taeniasis in humans. Taenia saginata occurs where cattle are raised by infected humans maintaining poor hygiene, human feces are improperly disposed of, meat inspection...
uteri, T. solium uteri have only five to ten uterine branches on each side.
Infection with T. solium adults is treated with niclosamide
Niclosamide
Niclosamide is a teniacide in the anthelmintic family especially effective against cestodes that infect humans...
, which is one of the most popular drugs for adult tapeworm infections, as well as for fluke infections. As cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
is a major risk, it is important to wash one's hands before eating and to suppress vomiting if a patient may be infected with T. solium. If neurocysticercosis occurs the drug of choice is either albendazole
Albendazole
Albendazole, marketed as Albenza, Eskazole, Zentel and Andazol, is a member of the benzimidazole compounds used as a drug indicated for the treatment of a variety of worm infestations. Although this use is widespread in the United States, the U.S. Food and Drug Administration has not approved...
or praziquantel
Praziquantel
Praziquantel is an anthelmintic effective against flatworms. Praziquantel is not licensed for use in humans in the UK; it is, however, available as a veterinary anthelmintic, and is available for use in humans on a named-patient basis....
. These drugs damage the parasites skin internally causing it to disintegrate and is then removed by the host's immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
.
Infection may be prevented with proper disposal of human feces around pigs, cooking meat thoroughly and/or freezing the meat at -10oC for 5 days. Most cases occur because infected food handlers contaminate the food.
Life cycle
Peristalsis
Peristalsis is a radially symmetrical contraction and relaxation of muscles which propagates in a wave down the muscular tube, in an anterograde fashion. In humans, peristalsis is found in the contraction of smooth muscles to propel contents through the digestive tract. Earthworms use a similar...
. Once eggs are ingested, oncospheres hatch in the intestine, invade the intestinal wall, and migrate to striated muscles, as well as the brain, liver, and other tissues, where they develop into cysticerci
Cysticercoid
A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infestations, cysticercoids can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal...
. In humans, cysts can cause serious sequelae if they localize in the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
, resulting in neurocysticercosis. The parasite life cycle is completed, resulting in human tapeworm infection, when humans ingest undercooked pork containing cysticerci
Cysticercoid
A cysticercoid is the larval stage of certain tapeworms, similar in appearance to a cysticercus, but having the scolex filling completely the enclosing cyst. In tapeworm infestations, cysticercoids can be seen in free form as well as enclosed by cysts in biological tissues such as the intestinal...
. Cysts evaginate and attach to the small intestine by their scolex. Adult tapeworms develop, (up to 2 to 7 m in length and produce less than 1000 proglottids, each with approximately 50,000 eggs) and reside in the small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
for years.
Pathogenesis
Ingestion of T. solium eggs or proglottid rupture within the host intestine can cause larvaLarva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e to migrate into host tissue and cause cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
. This is the most frequent and severe disease caused by T. solium. In symptomatic cases, a wide spectrum of symptoms may be expressed including headaches, dizziness and occasional seizures. In more severe cases, dementia or hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
due to perturbation of the normal circulation of cerebrospinal fluid can occur. The severity of cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
depends on location, size and number of parasite larvae in tissues, as well as the host immune response. Other symptoms include sensory deficits, involuntary movements and brain system dysfunction. In children ocular
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
location of cysts is more common than cystation in other locations of the body. If a person is heavily infected with T. solium, it can lead to neurocysticercosis which can lead to epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
, seizures, lesions in the brain, blindness
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
and tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
like growths. This kind of patient will also show the low level of eosinophils when they run the blood test.
Diagnosis
Diagnosis requires biopsy of the infected tissue and examination of feces. T. solium eggs and proglottids found in feces diagnoses taeniasisTaeniasis
Taeniasis is a form of tapeworm infection which is caused by tapeworms of the genius Taenia.The two most important human pathogens in the genus are Taenia solium and Taenia saginata . Infection is acquired by eating undercooked contaminated meat. The adult worms live in the lumen of the intestine...
and not cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
. Cysticercosis is diagnosed primarily on confirming the presence of hooks on the scolex of T. solium. Radiological test such as X-ray, CT scans and MRIs can also be used to detect diseases. X-rays are used to identify calcified larvae in the subcutaneous and muscle tissues and CT scans and MRIs are used to find lesions in the brain.
Treatment
PZQ (praziquantelPraziquantel
Praziquantel is an anthelmintic effective against flatworms. Praziquantel is not licensed for use in humans in the UK; it is, however, available as a veterinary anthelmintic, and is available for use in humans on a named-patient basis....
) is the drug of choice for the treatment of T. solium infection. Some consider Niclosamide
Niclosamide
Niclosamide is a teniacide in the anthelmintic family especially effective against cestodes that infect humans...
to be the drug of choice for all types of Tapeworms. For cysticercosis
Cysticercosis
Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm. The disease is spread via the fecal-oral route through contaminated food and water, and is primarily a food borne disease. After ingestion the eggs pass through the lumen of the intestine into the...
, one can be treated with albendazole
Albendazole
Albendazole, marketed as Albenza, Eskazole, Zentel and Andazol, is a member of the benzimidazole compounds used as a drug indicated for the treatment of a variety of worm infestations. Although this use is widespread in the United States, the U.S. Food and Drug Administration has not approved...
combining with steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
to reduce the inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
. Surgical intervention may be necessary to treat CNS lesions. Albendazole
Albendazole
Albendazole, marketed as Albenza, Eskazole, Zentel and Andazol, is a member of the benzimidazole compounds used as a drug indicated for the treatment of a variety of worm infestations. Although this use is widespread in the United States, the U.S. Food and Drug Administration has not approved...
appears to be more effective and a safe drug for Neurocysticercosis, infection of the brain with T. solium larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e.
Prevention and control
The best way to control of getting tapeworms is by not eating under-cooked pork. Moreover, high level of personal hygiene and prevention of fecal contamination of pig foods also play major roles in prevention of getting the parasites.Epidemiology
T. solium is found worldwide, however, it has shown to be more common in cosmopolitan areas. Because pigsPIGS
PIGS is a four letter acronym that can stand for:* PIGS , Phosphatidylinositol glycan anchor biosynthesis, class S, a human gene* PIGS , the economies of Portugal, Italy , Greece and Spain...
are intermediate host
Intermediate host
A secondary host or intermediate host is a host that harbors the parasite only for a short transition period, during which some developmental stage is completed. For trypanosomes, the cause of sleeping sickness, humans are the primary host, while the tsetse fly is the secondary host...
s of the parasite, completion of the life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
occurs in regions where humans live in close contact with pigs and eat undercooked pork. Cysticercosis is often seen in areas where poor hygiene allows for contamination of food, soil or water supplies. Prevalence rates in the United States have shown that immigrants from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, Central and South America
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
and South-east Asia account for most of the domestic cases of cysticercosis. Taeniasis and cysticercosis are very rare in predominantly Muslim
Muslim
A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...
countries, as Islam forbids the consumption of pork. It is important to note that human cysticercosis is acquired by ingesting T. solium eggs shed in the feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
of a human tapeworm carrier via gravid proglottids, and thus can occur in populations that neither eat pork nor share environments with pigs, although, as stated, the completion of the life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
can occur only where humans live in close contact with pigs and eat pork.
In 1990 and 1991, four unrelated members of an Orthodox Jewish community in New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
developed recurrent seizures and brain lesions which were found to have been caused by cysticercosis from T. solium. In keeping with their religion, none of the patients ate pork; additionally, none had any history of recent foreign travel. Several immediate family members of these four patients with seizures were found to have cysticercus antibodies. The families of the four patients had all employed housekeepers from Latin American countries, and one of the housekeepers tested positive for cysticercus antibodies, leading to the conclusion that the housekeepers were the most likely source of the infections.