Bertielliasis

Last updated
Bertielliasis
Specialty Infectious disease

Bertielliasis is the infection of Bertiella , a cestode tapeworm parasite that primarily infects nonhuman primates, rodents and Australian marsupials. Occasionally, human infections have been documented by one of two species: Bertiella studeri , or Bertiella mucronata . Of 29 different Bertiella species, only these two can infect humans.

Contents

These infections present with symptoms similar to most tapeworm cases, and are frequently misdiagnosed. Bertiella transmission is through oribatid mites that are often present in the soil of problem areas, and can be easily prevented by avoiding contact with nonhuman primates, rodents and soil in these areas.

Signs and symptoms

Bertielliasis can be asymptomatic, or present with symptoms similar to many other tapeworms. These can include epigastric pain after meals accompanied by nausea, diarrhea, anorexia, loss of weight and, generally, a tender abdomen. Fever is not typically a symptom, but there are also reported cases of constipation. [1] The symptoms may be intermittent or continuous [2] and seem to be more common in children. [1] There are rare cases where the abdominal pain and vomiting have become severe. The incubation period is unknown.

Cause

Transmission

While it is a parasite infecting mostly primates, rodents and other mammals, Bertiella is transmitted to humans by the accidental consumption of oribatid mites, which are the intermediate hosts. These mites are important components of soil fauna, and are widely distributed. In the rare cases that dogs and humans have contracted an infection, it is attributed to proximity and frequency of soil contact in certain regions. More than 50 cases of Bertiella have been cited, with a high frequency of those being children. The disease is reportedly endemic to 29 countries. [2] In documented cases in Mauritius, the infection was traced back to the consumption of guavas which had been picked up from the ground.

Reservoir

Non-human primates, rodents, Australian marsupials.

Morphology

Like all Cyclophyllidea, Bertiella has a scolex, suckers, and many segments called proglottids. These are released into the body from the adult tapeworm, contain both male and female anatomical structures, and are in stages of mature, postmature and gravid. In general, human Bertiella morphology is not well understood due to the rarity of infection, and therefore limited possibility for study and observation. Particularly lacking are descriptions of adult stages of the species. Most common are studies of proglottids passed in stool samples of infected hosts. Studies have shown that specimens collected from humans are essentially morphologically the same as specimens collected from monkey hosts, except for some anatomical differences in reproductive organs. However, these discrepancies in morphological findings have led researchers to postulate that there may be more than two human Bertiella species, as previously believed. These gravid proglottids in stool are white and can measure around 11 mm for maximum length and 8 mm for maximum width. Full tapeworm observations in the past have included a worm that was 130 mm long, 15 mm in width, and 2.5 mm in thickness. It had a scolex, neck, and 418 proglottids.

Differences in human species: B. mucronata has smaller eggs than B. studeri. There are filaments arising from the pyriform apparatus clearly identifiable on B. studeri but not B. mucronata.

Life cycle

There is relatively little known about the life cycle of Bertiella, but inferences and assumptions can be made about it through observations of specific parts of the worm, and knowledge of other cases in the same family (Anoplocephalidae). Anoplocephalids are heteroxenous parasites and require both an intermediate and definitive host to complete their cycle. For Bertiella, nonhuman primates are generally the definitive host, and oribatid mites are the intermediate host.

Human infection occurs when a person inadvertently consumes an oribatid mite infected with Bertiella larvae. Within the human (the definitive host) the larvae migrate through the gastrointestinal tract, using their morphology to stick onto parts of the intestines. From there, the adult tapeworms can live for at least two years, [3] feeding off the host and producing/shedding eggs and proglottids. The eggs and proglottids are passed in stool, and the eggs are taken up by oribatid mites (the intermediate host) in the soil. In the mites, Bertiella develops into the infective cysticercoid and begin producing larvae. The mites are then consumed by humans again, or by the nonhuman primate or rodent reservoir.

Diagnosis

A Bertiella infection is typically diagnosed by observing eggs or proglottids in stool. They can be white, around 8 mm wide and 11 mm long, and moving. It can also be identified by presenting with common signs and symptoms in an area where disease is present, and there is close contact with soil and/or nonhuman primates. In many of these areas, other parasitic diseases can be a problem to the population, and finding the proglottids in stool samples can be the only way to distinguish Bertiella from other parasites. The appearance of the eggs has been described as "slightly oval and thin-shelled" while the "embryo is encased in a capsule or pyriform apparatus with two blunt horns." [1]

Prevention

Due to the low occurrence of this infection in humans, and non-lethal symptoms, it is not considered a public health crisis where large steps have to be taken toward prevention or the development of a vaccine. The most common way to prevent this infection in humans is to avoid contact with nonhuman primates and the soil in their proximity. In Mauritius and other similar regions, children (specifically) and adults are strongly discouraged from eating guavas that have fallen on the ground.

Management

There is not an officially established treatment due to rarity of disease. Most are misdiagnosed anyway and treated with general medicines against cestodes. One record of treatment in a Bertiella case in Equatorial Guinea, documented a patient treated with praziquantel in a 40 mg/kg body weight, in a single dose, followed by a second, similar dose 20 days later. From then, the proglottid excretion and oesophageal pain desisted. In another instance of B. studeri infection, niclosamide was recommended as an appropriate anti-helminthic therapy.

Epidemiology

The two forms of human Bertiella are distributed geographically: B. studeri is a parasite of monkeys in the Old World (Asia and Africa), and B. mucronata is found in the New World (South America and Cuba). As of 1999, 56 cases had been reported in the literature, 45 cases due to B. studeri, 7 due to B. mucronata, 4 due to unspecified Bertiella species. [4] Additional case reports of B. studeri were published from Vietnam in 2003 and China in 2006.

History

The suborder of Anoplocephala was named in 1891 by Blanchard, and the family Anoplocephalidae created in 1928 by Mola. Bertia, already named by Blanchard in 1891, was placed in this group. With some shuffling throughout the years, this family remained mostly the same, categorized by its similar transmission by oribatid mites. As of 1994, within the Cyclophyllidea order, Anoplocephalidae is considered one of the four subfamilies established by classifying uterine development, the others being Linstowiinae, Inermicapsiferinae and Thysanosomatinae. Bertia was first described in a chimpanzee as Bertia satyri, and in an orangutan as B. studeri by Blanchard (1891). The genus Berti was later changed to Bertiella on the proposal from Stiles and Hassall (1902), and the human forms were identified as Bertiella studeri and Bertiella mucronata. The first case of human bertielliasis was reported by Blanchard in 1913 of a child in Mauritius.

Related Research Articles

<i>Diphyllobothrium</i> Genus of flatworms

Diphyllobothrium is a genus of tapeworms which can cause diphyllobothriasis in humans through consumption of raw or undercooked fish. The principal species causing diphyllobothriasis is D. latum, known as the broad or fish tapeworm, or broad fish tapeworm. D. latum is a pseudophyllid cestode that infects fish and mammals. D. latum is native to Scandinavia, western Russia, and the Baltics, though it is now also present in North America, especially the Pacific Northwest. In Far East Russia, D. klebanovskii, having Pacific salmon as its second intermediate host, was identified.

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</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>Dipylidium caninum</i> Species of flatworm

Dipylidium caninum, also called the flea tapeworm, double-pored tapeworm, or cucumber tapeworm, is a cyclophyllid cestode that infects organisms afflicted with fleas and canine chewing lice, including dogs, cats, and sometimes human pet-owners, especially children.

<span class="mw-page-title-main">Hymenolepididae</span> Family of flatworms

The Hymenolepididae are family of cyclophyllid tapeworms. Their characteristic feature is the small number of testes. The unilateral genital pores and large external seminal vesicle allow for easy recognition. Most species are small, transparent, and easy to study. The family contains over 90 genera with over 900 species, having as their definitive host birds or mammals. Most reside in the intestines of their definitive hosts. The majority of species with known lifecycles have arthropods as intermediate hosts.

<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.

<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.

Diphyllobothriasis is the infection caused by tapeworms of the genus Diphyllobothrium.

<i>Hymenolepis</i> (tapeworm) Genus of worms

Hymenolepis is a genus of cyclophyllid tapeworms responsible for hymenolepiasis. They are parasites of humans and other mammals. The focus in this article is in Hymenolepis commonly parasitizing humans.

<span class="mw-page-title-main">Cestoda</span> Class of flatworms

Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites.

<i>Raillietina</i> Genus of flatworms

Raillietina is a genus of tapeworms that includes helminth parasites of vertebrates, mostly of birds. The genus was named in 1920 in honour of a French veterinarian and helminthologist, Louis-Joseph Alcide Railliet. Of the 37 species recorded under the genus, Raillietina demerariensis, R. asiatica, and R. formsana are the only species reported from humans, while the rest are found in birds. R. echinobothrida, R. tetragona, and R. cesticillus are the most important species in terms of prevalence and pathogenicity among wild and domestic birds.

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

Bertiella is a genus of cestode tapeworm parasites that primarily infects nonhuman primates, rodents and Australian marsupials. Infections by Bertiella are known as bertielliasis. Occasional human infections have been documented by one of two species: Bertiella studeri, or Bertiella mucronata. Bertiella transmission is through oribatid mites that are present in the soil of problem areas, and can be easily prevented by avoiding contact with nonhuman primates, rodents and soil in these areas.

Moniezia expansa is commonly known as sheep tapeworm or double-pored ruminant tapeworm. It is a large tapeworm inhabiting the small intestines of ruminants such as sheep, goats and cattle. It has been reported from Peru that pigs are also infected. There is an unusual report of human infection in an Egyptian. It is characterized by unarmed scolex, presence of two sets of reproductive systems in each proglottid, and each proglottid being very short but very broad.

<i>Anoplocephala perfoliata</i> Species of flatworm

Anoplocephala perfoliata is the most common intestinal tapeworm of horses, and an agent responsible for some cases of equine colic.

Bertiella studeri is a species of Bertiellia, a type of cestodes (tapeworms). It is a parasite of primates which was first described in the rhesus macaque in 1940. The intermediate host are oribatid mites, which ingest the eggs, and are themselves ingested by the vertebrate host. Oribatid mites infected with Bertiella transfer the developmental cysticercoid stage to a human host through tissue feeding.

Bertiella mucronata is a species of Bertiella, a type of cestode tapeworms known to cause Bertielliasis. It belongs to the genus Bertiella, family Anoplocephalidae. This is one of two species of Bertiella that can cause the condition in humans.

Anoplocephala manubriata is a host-specific tapeworm, or cestode, that parasitizes African and Asian elephants. These parasites require intermediate and definitive hosts to complete its life cycle. A. manubriata causes gastrointestinal inflammation in elephants. When ingested in the elephant, the cestode is attached to the intestinal mucosae. The life cycle of A. manubriata have not been completely elucidated, however studies have shown through examining oribatid mites from a dung pile near an elephant site that an immature stage exists. The study concluded at least five species were contained at least one immature life stage of the cestode.

References

  1. 1 2 3 Acha, Pedro; Szyfres, Boris (2003). Zoonoses and Communicable Diseases Common to Man and Animals: Parasitoses . Washington, D.C.: Pan American Health Organization. pp.  161. ISBN   978-9275119914.
  2. 1 2 Berger, Stephen (2010). Infectious Diseases of Egypt 2010 edition. Los Angeles: GIDEON Informatics, Inc. ISBN   9781617550638.
  3. ↑ Berger, Stephen (2010). Infectious Diseases of the World 2010 edition. Los Angeles: GIDEON Informatics, Inc. ISBN   9781617550003.
  4. ↑ Szyfres, B; Acha, PN (2003). "Bertielliasis". Zoonoses and communicable diseases common to man and animals (3rd ed.). Washington, D.C.: Pan American Health Organization. pp.  160–161. ISBN   9789275119938.
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.