Channel Catfish virus (Ictalurid herpesvirus 1) is a member of the Alloherpesviridae family that causes disease in catfish

Catfish

Catfishes 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 heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

. Infection with Channel catfish viral disease (CCVD) can cause significant economic loss in channel catfish farms.

Virology

The disease is endemic in the USA and there are reports of the virus in Honduras

Honduras

Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

 and Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. Transmission is both horizontal and vertical. Channel catfish

Channel catfish

Channel catfish, Ictalurus punctatus, is North America's most numerous catfish species. It is the official fish of Missouri, Iowa, Nebraska, Kansas, and Tennessee, and is informally referred to as a "channel cat". In the United States they are the most fished catfish species with approximately 8...

 and blue catfish

Blue catfish

The blue catfish, Ictalurus furcatus, is one of the largest species of North American catfish. Blue catfish are distributed primarily in the Mississippi River drainage including the Missouri, Ohio, Tennessee, and Arkansas rivers...

 are the only fish that are susceptible to CCVD. Reservoirs of disease are clinically affected fish and recovered covert carriers.

Disease occurs in fish less than a year old that weigh less than 10 grams. The critical environmental factor is water temperature with the disease occurring during warm weather. Outbreaks are normally seen only in farmed fish

Fish farming

Fish farming is the principal form of aquaculture, while other methods may fall under mariculture. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases young fish into the wild for recreational fishing or to supplement a species'...

.

Clinical signs

Affected fish have pot-bellied appearance, haemorrhages on the fins and musculature and exopthalmos. Affected fish seem off balance and tend to swim erratically or close to the surface, eventually sinking to the bottom.

Fish that survive the infection have lifelong protective immunity

Immunity (medical)

Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...

 but remain latent carriers of CCV. This is a significant source of disease for vulnerable fish.

Increased mortality in young catfish during warm weather, especially after stress is suggestive of CCVD.

Diagnosis

CCV can be detected in water containing infected fish and organs of diseased fish by virus neutralisation, fluorescent antibody testing

Direct fluorescent antibody

Direct fluorescent antibody is a laboratory test that uses antibodies tagged with fluorescent dye that can be used to detect the presence of microorganisms. This method offers straightforward detection of antigens using fluorescently labeled antigen-specific antibodies...

, ELISA

ELISA

Enzyme-linked immunosorbent assay , is a popular format of a "wet-lab" type analytic biochemistry assay that uses one sub-type of heterogeneous, solid-phase enzyme immunoassay to detect the presence of a substance in a liquid sample."Wet lab" analytic biochemistry assays involves detection of an...

 or PCR. FAT and ELISA should be used for diagnosis of clinically infected fish while virus neutralisation or PCR should be used to to detect carrier fish. Lesions are seen on the liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 and many other internal organs both histologically and grossly on postmortem examination

Autopsy

An autopsy—also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction—is a highly specialized surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...

.

Treatment and control

There is no available treatment. Stress and high stocking-densities should be avoided to reduce disease occurrence. Appropriate quarantine

Quarantine

Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....

 and hygiene measures should be employed to prevent spread of disease. The virus is sensitive to acidic pH

PH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

, heat and UV light and is inactivated by pond mud and sea water.