''Edwardsiella ictaluri'' (also known as enteric septicaemia of catfish, hole in the head diseaseThis term is also used for head and lateral line erosion, an unrelated disease affecting many aquarium fish species. and ESC) is a member of the family Hafniaceae. The bacterium is a short,

gram negative The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to th ...

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

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) 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 ...

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

septicaemia Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...

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

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, 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 bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. ...

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 o ...

. 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, edema and

ascites Ascites 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 abdominal size, increased weight, a ...

. Chronic ESC infection causes a chronic encephalitis. 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. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...

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,

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 diagn ...

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 uses a solid-phase type of enzyme immunoassay (EIA) to detect the presen ...

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 bacterial infections, and antibiotic medications are widely used in the treatment and prevention o ...

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