''Edwardsiella ictaluri'' (also known as enteric septicaemia of catfish, hole in the head diseaseThis term is also used for

head and lateral line erosion Head and lateral line erosion, (HLLE) or hole-in-the-head (HITH) is a disease in fish. Chronic ulcerative dermatopathy or chronic erosive dermatopathy are symptoms of similar conditions with different etiology. Symptoms HLLE begins as small pits ...

, an unrelated disease affecting many aquarium fish species. and ESC) is a member of the family

Hafniaceae The ''Hafniaceae'' are a family (biology), family of Gram-negative bacteria. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Pseudomonadota. Genera in this family include the type genus ''Hafni ...

. The bacterium is a short,

gram negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists of ...

, pleomorphic rod with flagella. It causes the disease enteric septicaemia of

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

(ESC), which infects a variety of fish species (including many catfish species, knifefish and barbs). The bacteria can cause either acute

septicaemia Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...

or chronic

encephalitis Encephalitis is inflammation of the Human brain, brain. The severity can be variable with symptoms including reduction or alteration in consciousness, aphasia, headache, fever, confusion, a stiff neck, and vomiting. Complications may include se ...

in infected fish. Outbreaks normally occur in spring and autumn. ''Edwardsiella ictaluri'' can be found in

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, being of particular economic importance in the U.S. It is not a

zoonosis A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When ...

Clinical signs and diagnosis

Acute ESC infection causes an acute septicaemia that presents as multiple petechial haemorrhages that develop into depigmented

ulcers An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing ...

. Additional clinical signs include abnormal behavior,

exophthalmos Exophthalmos (also called exophthalmus, exophthalmia, proptosis, or exorbitism) is a bulging of the eye anteriorly out of the orbit. Exophthalmos can be either bilateral (as is often seen in Graves' disease) or unilateral (as is often seen in ...

hemorrhagic gastroenteritis Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

edema Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue (biology), tissue. Most commonly, the legs or arms are affected. S ...

and

ascites Ascites (; , meaning "bag" or "sac") is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdo ...

. Chronic ESC infection causes a chronic

. Clinical signs include abnormal behavior, abnormal swimming patterns, swelling and

ulceration An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected Organ (biology), organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caus ...

of the head and death. Any fish that survive the infection become latent carriers of the disease. A presumptive diagnosis can be made based on the clinical signs alone but PCR, indirect

immunofluorescence Immunofluorescence (IF) is a light microscopy-based technique that allows detection and localization of a wide variety of target biomolecules within a cell or tissue at a quantitative level. The technique utilizes the binding specificity of anti ...

bacterial culture A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diag ...

and

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay is a solid-phase type of enzyme immunoassay (EIA) to detect the presence of ...

can be used to definitively diagnose the disease.

Treatment and control

Several

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

can be used to treat the disease, but there are reports of resistance emerging.

Vaccination Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating ...

can be used to prevent disease. Management factors such as reducing stocking density and stress should be considered.

References

*''Edwardsiella ictaluri'', reviewed and published by Wikivet at http://en.wikivet.net/Edwardsiella_ictaluri, accessed 06/09/2011.

External links

Type strain of ''Edwardsiella ictaluri'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Enterobacterales Bacterial diseases of fish Bacteria described in 1962 {{Veterinary-med-stub

Clinical signs and diagnosis

Treatment and control

See also

References

External links