Echinococcus vogeli

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Echinococcus vogeli
Echinococcus vogeli.jpg
Echinococcus vogeli protoscolex
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Platyhelminthes
Class: Cestoda
Order: Cyclophyllidea
Family: Taeniidae
Genus: Echinococcus
Species:
E. vogeli
Binomial name
Echinococcus vogeli
Rausch & Bernstein, 1972

Echinococcus vogeli is a small cyclophyllid tapeworm found in Central and South America. [1] E. vogeli, as well as other members of the genus Echinococcus (especially Echinococcus multilocularis ), 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.

Contents

This parasite has a life cycle involving two mammalian hosts. Bush dogs and domestic dogs are the definitive hosts, harbouring the adult stage of E.vogeli. The ingestion of a rodent containing the hydatid cysts of the tapeworm by a bush or domestic dog often results in a heavy infestation of these tapeworms.

Signs and symptoms

Human polycystic echinococcosis is the rarest type of echinococcosis and is characterized by infiltrative, multi-compartment cysts. [2] Symptoms depend on the location of the cysts. For example, cysts located in a patient's lungs will result in shortness of breath, coughing, and/or chest pain. But, if the cysts reside in the patient's liver, symptoms will include jaundice, abnormal abdominal tenderness, abdominal pain, fever, and/or anaphylactic shock.

Life cycle

The life cycle of E. vogeli utilizes a definitive host and intermediate host, also known as primary and secondary host, respectively, each housing different stages of the parasite. Bush dogs and domestic dogs serve as the definitive host for the adult stage of E. vogeli. Researchers believe that domestic dogs have a role in infecting humans with this tapeworm. [2] The tapeworm attaches itself to the wall of the dogs small intestine via a rostellum armed with hooks. Once the tapeworm matures, eggs are released into the intestine and passed in feces. [3] Rodents, such as the paca, serve as the intermediate host. Eggs that are eaten by the rodent form hydatid cysts in the lungs, liver, and other internal organs. When a bush or domestic dog consumes an infected rodent, the life cycle is complete. Larvae from the cysts of the infected rodent mature inside the small intestine of the dog. [4] Humans are at risk of becoming infected when eating under cooked meat containing hydatid cysts or coming into contact with infected dog feces. But, humans are not the regular hosts of E. vogeli, meaning that humans are the dead-end host; which does not allow transmission to the definitive host.

Summary of life cycle

  1. Adult tapeworm is present in the small intestine of the dog
  2. Eggs are passed in the feces of the dog, which is ingested by human (dead-end host) or rodent (intermediate host)
  3. Oncosphere penetrates the gut wall, and migrates to other organs via blood vessels
  4. Hydatid cysts form in the organs of the rodent
  5. Infected rodent is eaten by a dog, transferring protoscolices into the definitive host
  6. Ingested protoscolices attach themselves to the wall of the small intestine and develop into mature strobila

Morphology

Echinococcus vogeli has the largest strobila within the Echinococcus genus, reaching a length of 12 mm. [4] This tapeworm resides in the small intestine of bush and domestic dogs. E. vogeli contains a scolox, where a hook-filled rostellum is located, and a long neck that attaches to up to six proglottids. The gravid proglottid, the sexually mature proglottid that releases eggs into the dogs feces, is cylindrical and takes up about half of the strobilar length. [4]

Diagnosis

The diagnosis of polycystic echinococcosis involves isolating the protoscoleces during surgery or after the patient's death in order to identify E. vogeli. Imaging, such as ultrasound and CT scans, can also be used to identify polystytic structures, but this method is not preferred as images are similar to other types of echinococcosis and liver cancer. New studies show that PCR may identify E. vogeli in the patient's tissues. [5]

Polycystic echinococcosis affecting the left side of the liver Polycystic echinococcosis affecting the left side of the liver.jpg
Polycystic echinococcosis affecting the left side of the liver

Disease staging

Polycystic echinococcosis (PE) is an extremely lethal helminthic disease in humans, which is caused by the larval form of E. vogeli. Type I PE consists of polycystic masses in the liver and abdominal cavity. Type II also has polcystic masses in the liver and abdominal cavity, but includes hepatic insufficiency. Type III has polcystic masses in the liver and chest cavity. In type IV polycystic masses occur only in the mesenteries. Type V has calcified cysts in the liver and lung. [4] Type II seems to have the highest mortality rate due to the complications involved with hepatic insufficiency. Due to the similarities between liver cancer and polycystic echinococcosis, PE is hard to diagnose and could deadly when metastasized to other organs.

Treatment

If patients do not undergo treatment, 94% of them will die within 20 years of diagnosis. [6] PE is treated the same as cystic echinococcosis, with mebendazole and albendazole showing definite progress in treating PE. [7] Surgery remains the top treatment against PE. There are less invasive surgical methods partnered with chemotherapy in development.

Epidemiology

The parasite E. vogeli resides neotropical areas, such as Central and South America. Polycystic echinococcosis has infected people in Panama, Columbia, Ecuador, Venezuela, Peru, Brazil, and Suriname. [4] E. vogeli infections seem to be on the rise, with 100 new cases over the past 10 years. [4]

Related Research Articles

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<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.

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Alveolar hydatid disease (AHD) is a form of echinococcosis, or a disease that originates from a parasitic flatworm. AHD is caused by an infection of the flatworm species Echinococcus multilocularis. Although alveolar echinococcosis is rarely diagnosed in humans and is not as widespread as cystic echinococcosis, it is also still a serious disease that has a significantly high fatality rate. It is considered one of the most life-threatening helminthic infections humans can have.

<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.

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

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<i>Echinococcus</i> Genus of worms

Echinococcus is a genus within Cestoda, a parasitic class of the platyhelminthes phylum. Human echinococcosis is an infectious disease caused by the following species: E. granulosus, E. multilocularis, E. vogeli or E. oligarthrus.

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

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<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>Dipylidium caninum</i> Species of flatworm

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<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.

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References

  1. "Echinococcus vogeli Rausch & Bernstein 1972 - Encyclopedia of Life". Eol.org.
  2. 1 2 Tappe, D; Stich, A; Frosch, M (2008). "Emergence of Polycystic Neotropical Echinococcosis". Emerging Infectious Diseases. 14 (2): 292–297. doi:10.3201/eid1402.070742. PMC   2600197 . PMID   18258123.
  3. "Alveolar Echinococcosis (AE): Practice Essentials, Background, Pathophysiology". 16 October 2021.
  4. 1 2 3 4 5 6 d'Alessandro, A; Rausch, R. L (2008). "New Aspects of Neotropical Polycystic (Echinococcus vogeli) and Unicystic (Echinococcus oligarthrus) Echinococcosis". Clinical Microbiology Reviews. 21 (2): 380–401. doi:10.1128/CMR.00050-07. PMC   2292577 . PMID   18400802.
  5. Knapp, J; Chirica, M; Simonnet, C; Grenouillet, F; Bart, J. M; Sako, Y; Itoh, S; Nakao, M; Ito, A; Millon, L (2009). "Echinococcus vogeli Infection in a Hunter, French Guiana". Emerging Infectious Diseases. 15 (12): 2029–2031. doi:10.3201/eid1512.090940. PMC   3044547 . PMID   19961693.
  6. Jura, Heike; Bader, Augustinus; Frosch, Matthias (1998). "In Vitro Activities of Benzimidazoles against Echinococcus multilocularis Metacestodes". Antimicrobial Agents and Chemotherapy. 42 (5): 1052–1056. doi:10.1128/AAC.42.5.1052. PMC   105743 . PMID   9593125.
  7. "WHO/OIE Manual on Echinococcosis in Humans and Animals: a Public Health Problem of Global Concern". Apps.who.int. Retrieved 1 April 2022.