Ancylostoma Braziliense
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''Ancylostoma braziliense'' is a species of
hookworm Hookworms are intestinal, blood-feeding, parasitic roundworms that cause types of infection known as helminthiases. Hookworm infection is found in many parts of the world, and is common in areas with poor access to adequate water, sanitation ...
belonging to the genus ''
Ancylostoma ''Ancylostoma'' is a genus of nematodes that includes some species of hookworms. Species include: : '' Ancylostoma braziliense'', commonly infects cats, popularly known in Brazil as ''bicho-geográfico'' : '' Ancylostoma caninum'', commonly in ...
''. It is an intestinal parasite of domestic
cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
s and
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relativ ...
s. Severe infection is often fatal to these pets, especially in puppies and kittens. The infection is particularly endemic in the southern United States. It is most often confused with the
zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. ...
hookworm species ''
Ancylostoma ceylanicum ''Ancylostoma ceylanicum'' is a parasitic roundworm belonging to the genus ''Ancylostoma''. It is a hookworm both of humans and of other mammals such as dogs, cats, and golden hamsters. It is the only zoonotic hookworm species that is able to pro ...
'' because of their uncanny resemblance. ''Ancyclostoma braziliense'' larvae can cause accidental infection in humans called cutaneous larval migration or creeping eruption, which produces severe itching in the skin. It is the most common skin infection in tropical region, particularly along the beaches of the Caribbean.


Discovery and history

When ''A. braziliense'' was described by Gomes de Faria in 1910, and ''A. ceylanicum'' by
Arthur Looss Arthur Looss (16 March 1861 – 4 May 1923) was a German zoology, zoologist and Parasitology, parasitologist. Looss was born in 1861 in Chemnitz, and was educated both there and in Łódź, Poland. Thereafter, he studied at the University of Leipz ...
in 1911, the two species were regarded as
synonymous A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
because of their apparent similarities in almost all respect. Especially in 1913, comparison of specimens from human,
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relativ ...
,
cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
and
lion The lion (''Panthera leo'') is a large Felidae, cat of the genus ''Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end of its tail. It is sexually dimorphi ...
infections in India led to the conclusion that they were definitely of the same species. In 1915 Gomes de Faria realised that the two were distinct species based on their
anatomical Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...
structures. Till 1921 the two hookworms were accepted as a two valid species. However, in 1922 Gordon made an exhaustive comparison from specimens collected in Brazil, South Africa and India, and his conclusion was that there were no significant distinction. Other
parasitologist Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question but by their way of life. This means it f ...
s were also convinced of this so that the two names were again considered synonymous. In 1951 Biocca made an elaborate study on different hookworms in the collection of
London School of Hygiene and Tropical Medicine The London School of Hygiene and Tropical Medicine (LSHTM) is a public research university in Bloomsbury, central London, and a member institution of the University of London that specialises in public health and tropical medicine. The inst ...
, the
Liverpool School of Tropical Medicine The Liverpool School of Tropical Medicine (LSTM) is a higher education institution with degree awarding powers and registered charity located in Liverpool, United Kingdom. Established in 1898, it was the first institution in the world dedicated ...
and personal collections. He finally identified the defining characters between the two for classifying them as distinct species, which eventually gained general acceptance.


Distribution

''A. braziliense'' is endemic in the southern United States. It is also found in a number of subtropical regions around the world, including
Central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known a ...
and
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...
, South Africa, and southern Asia. In southern Asia, infection is confined to Indonesia,
Borneo Borneo (; id, Kalimantan) is the List of islands by area, third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java Isl ...
, and Malaysia.


Physical description

Like many other worms, the female worm is larger than the male. Also, the females are more difficult to distinguish because the teeth sizes appear very similar among the various species of ''Ancylostoma.'' Male worms, however, have two broad lateral lobes and a smaller dorsal lobe with rays on the copulatory bursa. These bursal rays' aids in distinguishing the different species of ''Ancylostoma.''


Life cycle

''Ancylostoma braziliense'' eggs are passed into the environment through the
faeces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...
of cats and dogs. The eggs incubate on warm, moist soil, where they hatch into larvae. The infective juvenile penetrate the skin of the host. At this stage, the larvae are present in the
epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the ...
,
hair follicles The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction betwe ...
, and glands of the skin, sometimes extending to
sebaceous gland A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest numb ...
s where they form coils. Then they migrate to the
heart The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon diox ...
and lung by moving along the blood circulation. In the lungs, the juveniles enter the
alveoli Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * M ...
and are propelled by cilia up the respiratory tract. From this, the host swallow them and deposit them in the small intestine. They get attached to the intestinal
mucosa A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...
via the buccal capsule. Here they undergo two successive molts to become sexually mature individuals.


Etymology

Etymology: ''Ancylo'' = curved + ''stoma'' = mouth; ''braziliense'' for the geographical location where the worms were first found.


Pathology

It can cause "
creeping eruption Creep, Creeps or CREEP may refer to: People * Creep, a creepy person Politics * Committee for the Re-Election of the President (CRP), mockingly abbreviated as CREEP, an fundraising organization for Richard Nixon's 1972 re-election campaign Ar ...
" or "ground itch". It occurs when the larvae from the faeces of cats and dogs accidentally penetrate the human skin, causing severe itching and skin eruption. It is the most common ailment of tropically acquired
dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...
, particularly along the beaches of the Caribbean. However, humans are not the natural
definitive host In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include a ...
s, and are therefore a dead-end for the parasites. In humans, the larvae die after few months without further development.


Symptoms

Ancylostoma braziliense is a parasite that infects cats and dogs and occasionally humans. And, they survive by eating blood from the intestine of cats and dogs, causing anemia. Pale gums and weakness are common signs of anemia. The infected animals also experience significant weight loss, bloody diarrhea, and are not able to grow up to their right size. Other symptoms like, skin irritation and itching is also caused by the larvae burrowing into the skin.


Diagnosis and treatment

''A. braziliense'' is difficult to differentiate from other hookworms. Microscopic examination of
scatological In medicine and biology, scatology or coprology is the study of feces. Scatological studies allow one to determine a wide range of biological information about a creature, including its diet (and thus where it has been), health and diseases su ...
samples can identify the eggs as they are generally smaller than those of other species. Most
benzimidazole Benzimidazole is a heterocyclic aromatic organic compound. This bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and imidazole. It is a colorless solid. Preparation Benzimidazole is produced by condensation of ...
s are effective.
Mebendazole Mebendazole (MBZ), sold under the brand name Vermox among others, is a medication used to treat a number of parasitic worm infestations. This includes ascariasis, pinworm infection, hookworm infections, guinea worm infections, hydatid disea ...
,
triclabendazole Triclabendazole, sold under the brand name Egaten among others, is a medication used to treat fascioliasis and paragonimiasis. It is very effective for both conditions. Treatment in hospital may be required. It is taken by mouth with typically ...
and
fenbendazole Fenbendazole is a broad spectrum benzimidazole anthelmintic used against gastrointestinal parasites including: giardia, roundworms, hookworms, whipworms, the tapeworm genus '' Taenia'' (but not effective against '' Dipylidium caninum'', a co ...
are commonly used.
Ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat ...
and
pyrantel pamoate Pyrantel is a medication used to treat a number of parasitic worm infections. This includes ascariasis, hookworm infections, enterobiasis (pinworm infection), trichostrongyliasis, and trichinellosis. It is taken by mouth. Side effects inclu ...
are also effective. The combination of ivermectin 6 μg/kg and pyrantel pamoate at 5.0 mg/kg is 100% efficacious against adult worms in dogs. Human infection in case of
cutaneous larva migrans Cutaneous larva migrans (abbreviated CLM) is a skin disease in humans, caused by the larvae of various nematode parasites of the hookworm family (Ancylostomatidae). These parasites live in the intestines of dogs, cats, and wild animals and should ...
is treated with oral
thiabendazole Tiabendazole (INN, BAN), also known as thiabendazole ( AAN, USAN) or TBZ and the trade names Mintezol, Tresaderm, and Arbotect, is a preservative, an antifungal agent, and an antiparasitic agent. Uses Preservative Tiabendazole is used prima ...
at 500 mg in 4 daily dose.


References


External links


''Ancylostoma braziliense'' Homepage
{{Taxonbar, from=Q4118359 Parasitic diseases Ancylostomatidae Nematodes described in 1910