Candiru (fish)

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Candiru
Vandellia cirrhosa after a full meal of blood.jpg
A candiru after a full meal of blood
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Trichomycteridae
Genus: Vandellia
Species:
V. cirrhosa
Binomial name
Vandellia cirrhosa

Candiru (Vandellia cirrhosa), also known as cañero, toothpick fish, or vampire fish, is a species of parasitic freshwater catfish in the family Trichomycteridae native to the Amazon basin where it is found in the countries of Bolivia, Brazil, Colombia, Ecuador, and Peru.

The definition of candiru differs between authors. The word has been used to refer to only Vandellia cirrhosa, the entire genus Vandellia , the subfamily Vandelliinae, or even the two subfamilies Vandelliinae and Stegophilinae. [1] [2] [3] [4]

Although some candiru species have been known to grow to a size of 40 centimetres (16 in) in length, others are considerably smaller. These smaller species are known for an alleged tendency to invade and parasitise the human urethra and other bodily openings; however, despite ethnological reports dating back to the late 19th century, [5] the first documented case of the removal of a candiru from a human urethra did not occur until 1997, and even that incident has remained a matter of controversy.

Description

Candirus are small fish. Members of the genus Vandellia can reach up to 17 cm (7 in) in standard length, [6] but some others can grow to around 40 cm (16 in). Each has a rather small head and a belly that can appear distended, especially after a large blood meal. The body is translucent, making it quite difficult to spot in the turbid waters of its home. There are short sensory barbels around the head, together with short, backward pointing spines on the gill covers. [7]

Location and habitat

A candiru taking blood from the gills of a fish host. Vandellia cirrhosa taking blood from a host.jpg
A candiru taking blood from the gills of a fish host.

Candirus ( Vandellia ) inhabit the Amazon and Orinoco basins of lowland Amazonia, where they constitute part of the Neotropical fish fauna. Candirus are hematophagous and parasitize the gills of larger Amazonian fishes, especially catfish of the family Pimelodidae (Siluriformes).

Alleged attacks on humans

Although lurid anecdotes of attacks on humans abound, only one somewhat questionable case has evidence behind it, and some alleged traits of the fish have been discredited as myth or superstition. It is likely that, while the fish's spines can cause physical trauma, it merely poses as much danger of actually entering a human as any other fish of its size.

Historical accounts

The earliest published report of candiru attacking a human host comes from German biologist C. F. P. von Martius in 1829, who never actually observed it, but rather was told about it by an interpreter relaying the speech of the native people of the area, who reported that men would tie ligatures around their penises while going into the river to prevent this from happening. [8] Other sources also suggest that other tribes in the area used various forms of protective coverings for their genitals while bathing, though it was also suggested that these were to prevent bites from piranha. Martius also speculated that the fish were attracted by the “odor” of urine. [9] Later experimental evidence has shown this to be false, as the fish actually hunt by sight and have no attraction to urine at all. [10]

Another report, from French naturalist Francis de Castelnau in 1855, relates an allegation by local Araguay fisherman, saying that it is dangerous to urinate in the river as the fish “springs out of the water and penetrates into the urethra by ascending the length of the liquid column.” [11] While Castelnau himself dismissed this claim as “absolutely preposterous,” and the fluid mechanics of such a maneuver defy the laws of physics, it remains one of the more stubborn myths about the candiru. It has been suggested this claim evolved out of the real observation that certain species of fish in the Amazon will gather at the surface near the point where a urine stream enters, having been attracted by the noise and agitation of the water. [12]

In 1836, Eduard Poeppig documented a statement by a local physician in Pará, known only as Dr. Lacerda, who offered an eyewitness account of a case where a candiru had entered a human orifice. However, it was lodged in a native woman's vagina, rather than a male urethra. He relates that the fish was extracted after external and internal application of the juice from a Xagua plant (believed to be a name for Genipa americana ). Another account was documented by biologist George A. Boulenger from a Brazilian physician, named Dr. Bach, who had examined a man and several boys whose penises had been amputated. Bach believed this was a remedy performed because of parasitism by candiru, but he was merely speculating, as he did not speak his patients' language. [13] American biologist Eugene Willis Gudger noted that the area which the patients were from did not have candiru in its rivers, and suggested the amputations were much more likely the result of having been attacked by piranha. [12]

In 1891, naturalist Paul Le Cointe provides a rare first-hand account of a candiru entering a human body, and like Lacerda's account, it involved the fish being lodged in the vaginal canal, not the urethra. Le Cointe supposedly removed the fish himself, by pushing it forward to disengage the spines, turning it around and removing it head-first. [14]

However, the veracity of both Le Cointe's [15] and Poeppig's accounts are questionable, due to a trend of Europeans from various careers residing in Brazil including scientists, "explorers, medical men, and missionaries" regularly using exaggerated accounts of native people to advance their economic and social status through writing and building rapport with others with similar positions. [16]

Gudger, in 1930, noted there have been several other cases reported wherein the fish was said to have entered the vaginal canal, but not a single case of a candiru entering the anus was ever documented. According to Gudger, this lends credence to the unlikelihood of the fish entering the male urethra, based on the comparatively small opening that would accommodate only the most immature members of the species. [12]

Modern cases

To date, there is only one documented case of a candiru entering a human urethra, which took place in Itacoatiara, Brazil, in 1997. [17] [18] In this incident, the victim (a 23-year-old man named Silvio Barbossa, also known as "F.B.C.") claimed a candiru "jumped" from the water into his urethra as he urinated while thigh-deep in a river. [19] After traveling to Manaus on October 28, 1997, the victim underwent a two-hour urological surgery by Dr. Anoar Samad to remove the fish from his body. [18]

In 1999, American marine biologist Stephen Spotte traveled to Brazil to investigate this particular incident in detail. He recounts the events of his investigation in his book Candiru: Life and Legend of the Bloodsucking Catfishes. [20] Spotte met Dr. Samad in person and interviewed him at his practice and home. Samad gave him photos, the original VHS tape of the cystoscopy procedure, and the actual fish's body preserved in formalin as his donation to the National Institute of Amazonian Research. [21] Spotte and his colleague Paulo Petry took these materials and examined them at the institute, comparing them with Samad's formal paper. While Spotte did not overtly express any conclusions as to the veracity of the incident, he did remark on several observations that were suspicious about the claims of the patient and/or Samad himself.

When subsequently interviewed, Spotte stated that even if a person were to urinate while "submerged in a stream where candiru live", the odds of that person being attacked by candiru are "(a)bout the same as being struck by lightning while simultaneously being eaten by a shark." [26]

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The urethra is a tube that connects the mammalian urinary bladder to the urinary meatus. Male and female placental mammals release urine through the urethra during urination, but males also release semen through the urethra during ejaculation.

<span class="mw-page-title-main">Bladder</span> Organ in vertebrates that collects and stores urine from the kidneys before disposal

The bladder is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In placental mammals, urine enters the bladder via the ureters and exits via the urethra. In humans, the bladder is a distensible organ that sits on the pelvic floor. The typical adult human bladder will hold between 300 and 500 ml before the urge to empty occurs, but can hold considerably more.

<span class="mw-page-title-main">Catfish</span> Order of fish

Catfish are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia, and the piraíba of South America, to detritivores, and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa. Neither the armour-plated types nor the naked types have scales. Despite their name, not all catfish have prominent barbels or "whiskers". Members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly the genus Corydoras, are important in the aquarium hobby. Many catfish are nocturnal, but others are crepuscular or diurnal.

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<span class="mw-page-title-main">Amazon basin</span> Major drainage basin in South America drained via the Amazon River into the Atlantic Ocean

The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about 7,000,000 km2 (2,700,000 sq mi), or about 35.5 percent of the South American continent. It is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela, as well as the territory of French Guiana.

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<span class="mw-page-title-main">Trichomycteridae</span> Family of fishes

Trichomycteridae is a family of catfishes commonly known as pencil catfishes or parasitic catfishes. This family includes the candiru fish, feared by some people for its alleged habit of entering into the urethra of humans. They are one of the few parasitic chordates. Another species is the life monsefuano which was important to the Moche culture and still an important part of Peruvian cuisine.

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<span class="mw-page-title-main">Loricarioidea</span> Superfamily of fishes

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Paracanthopoma parva is a species of catfishes of the family Trichomycteridae. P. parva grows to about 2.7 centimetres (1.1 in) SL and is endemic to Brazil where it occurs in the Amazon and Essequibo River basins.

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<i>Cetopsis candiru</i> Species of fish

Cetopsis candiru, also known as candiru, candiru açú, candiru cobra or canero, is a carnivorous species of whale catfish found in the Amazon basin of Peru, Brazil and Bolivia. Similar to Cetopsis coecutiens, Cetopsis candiru is a large species of the genus Cetopsis and a widespread scavenger, known for its voracious feeding and the habit of burrowing into the carcasses of dead animals and humans. Despite its name, it is not closely related to the bloodsucking Candiru.

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List of reported attacks and species involved in Latin America.

References

Citations

  1. ↑ Froese, Rainer; Pauly, Daniel (eds.) (2007). "Vandellia cirrhosa" in FishBase . July 2007 version.
  2. ↑ Breault, J.L. (1991). "Candiru: Amazonian parasitic catfish". Journal of Wilderness Medicine. 2 (4): 304–312. doi:10.1580/0953-9859-2.4.304. Archived from the original on 2007-08-12.
  3. ↑ de Carvalho, Marcelo R. (2003). "Analyse D'Ouvrage" (PDF). Cybium. 27 (2): 82. Archived from the original (PDF) on 2009-02-07. Retrieved 2009-06-22.
  4. ↑ DoNascimiento, Carlos; Provenzano, Francisco (2006). "The Genus Henonemus (Siluriformes: Trichomycteridae) with a Description of a New Species from Venezuela". Copeia . 2006 (2): 198–205. doi:10.1643/0045-8511(2006)6[198:TGHSTW]2.0.CO;2. S2CID   84355922.
  5. ↑ Ricciuti, Edward R.; Bird, Jonathan (2003). Killers of the Seas: The Dangerous Creatures That Threaten Man in an Alien Environment. The Lyons Press. ISBN   978-1-58574-869-3.
  6. ↑ Froese, Rainer and Pauly, Daniel, eds. (2017). Species of Vandellia in FishBase . May 2017 version.
  7. ↑ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press, ISBN   978-0-313-33922-6.
  8. ↑ Gonzalez, Alyssa (2023-03-20). "The Candiru: A Six-Inch SciCom Failure". Talk Science to Me. Retrieved 2024-04-16.
  9. ↑ von Martius, C. F. P. 1829.Preface, p. viii, of van Spix, J. B., and Agassiz, L. Selecta Genera et Species Piscium ouos in Itinere ocr Brnsiliam annis 1817-20 Collcgit ... Dr. J. B. de Spix, etc. Monachii, 1829.
  10. 1 2 Spotte, Stephen; Petry, Paulo; Zuanon, Jansen A.S. (2001). "Experiments on the feeding behavior of the hematophagous candiru". Environmental Biology of Fishes. 60 (4): 459–464. doi:10.1023/A:1011081027565. S2CID   40239152.
  11. ↑ CASTELNAU, FRANCIS DE. 1855. Expedition dans les Partics Cent&es de I'AmPrique du Sud, 1843 a 1847. Animaux Nouveaux ou Rares-Zoology. Paris, 3: 50, p1. 24, fig. 4.
  12. 1 2 3 Gudger, E.W. (January 1930). "On the alleged penetration of the human urethra by an Amazonian catfish called candiru with a review of the allied habits of other members of the family pygidiidae". The American Journal of Surgery (Print). 8 (1). Elsevier Inc.: 170–188. doi:10.1016/S0002-9610(30)90912-9. ISSN   0002-9610.
  13. ↑ BWLENGER, G. A. 1898a. Exhibition of specimens, and remarks upon the habits of the siluroid fish, Vandellia cirrhosu. Proc. Zool. Sot. London [1897], p. 90 I.
  14. ↑ Le Cointe, Paul. 1922. L'Amazonie Bresilienne: Le Pays; Ses Inhabitants, scs Ressources. Notes et Statistiques jusqu'en 1920. Paris, II: 365.
  15. ↑ "What can the candiru (Vandellia cirrhosa) do? - Hektoen International". hekint.org. 2023-09-14. Retrieved 2024-04-16.
  16. 1 2 Bauer, Irmgard L. (2013-03-01). "Candiru—A Little Fish With Bad Habits: Need Travel Health Professionals Worry? A Review". Journal of Travel Medicine. 20 (2). International Society of Travel Medicine. doi:10.1111/jtm.12005. ISSN   1195-1982.
  17. ↑ Spotte 2002 , p. 211
  18. 1 2 3 "this was the only documented evidence of an accident involving humans." Anoar Samad, "Candiru inside the urethra". Google translation from Portuguese, with pictures.
  19. ↑ "Can the candiru fish swim upstream into your urethra (revisited)?". The Straight Dope. 7 September 2001.
  20. ↑ Spotte 2002
  21. 1 2 Spotte 2002 , p. 217
  22. ↑ Spotte 2002 , p. 216
  23. 1 2 Spotte 2002 , p. 218
  24. ↑ Spotte 2002 , p. 214
  25. ↑ Spotte 2002 , p. 215
  26. ↑ Dark Banquet: Blood and the Curious Lives of Blood-Feeding Creatures (via Google Books), by Bill Schutt, published by Random House, 2008

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