Introduction

Infectious pancreatic necrosis (IPN) is a severe viral disease of salmonid fish. It is caused by Infectious Pancreatic Necrosis Virus, which is a member of the birnaviridae

Birnaviridae

The birnaviridae are a family of viruses, including the following genera:*Genus Aquabirnavirus; type species: Infectious pancreatic necrosis virus*Genus Avibirnavirus; type species: Infectious bursal disease virus...

family. This disease mainly affects young salmonids, such as trout

Trout

Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

 or salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

, of less than 6 months, although adult fish may carry the virus without showing symptoms. Resistance to infection develops more rapidly in warmer water. It is highly contagious and found worldwide, however some regions have managed to eradicate or greatly reduced the incidence of disease. The disease is normally spread horizontally

Horizontal transmission

Horizontal transmission is the transmission of a bacterial, fungal, or viral infection between members of the same species that are not in a parent-child relationship....

 via infected water but spread also occurs vertically

Vertical transmission

Vertical transmission, also known as mother-to-child transmission, is the transmission of an infection or other disease from mother to child immediately before and after birth during the perinatal period. A pathogen's transmissibility refers to its capacity for vertical transmission...

. It is not a zoonosis

Zoonosis

A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...

.

Clinical Signs & Diagnosis

A sharp rise in mortality is often seen (depending on the virulence

Virulence

Virulence is by MeSH definition the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its...

 of the disease). Other clinical signs include abdominal swelling

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

, anorexia

Anorexia (symptom)

Anorexia is the decreased sensation of appetite...

, abnormal swimming, darkening of the skin and trailing of the feces from the vent

Cloaca

In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...

. On postmortem

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...

 there is often internal damage (viral necrosis

Necrosis

Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

) to the pancreas

Pancreas

The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...

and thick mucus in the intestine

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

.

Suriviving fish should recover within 1-2 weeks.

Diagnostic methods for the detection of the disease include: characteristic histological

Histology

Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...

 pancreatic

Pancreas

The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...

 lesion

Lesion

A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...

, PCR, indirect fluorescent antibody testing, 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...

 and virus culture

Cell culture

Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from singlecellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes,...

. High virus titers

Titer

A titer is a way of expressing concentration. Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inherently only evaluates as positive or negative. The titer corresponds to the highest dilution factor that still yields a positive...

can be isolated from carrier animals.

Treatment & Control

There is currently no treatment.

Good husbandry measures such as high water quality, low stocking density and no mixing of batches help to reduce disease incidence. To eradicate the disease very strict protocol with regards to movement, water sources and stock replacement must be in place - and still it is difficult to achieve and comes at a high economic cost.

External links

• Infectious pancreatic necrosis - The Scottish Government: Marine and Fisheries
• Infectious Pancreatic Necrosis, reviewed and published by Wikivet at http://en.wikivet.net/Infectious_Pancreatic_Necrosis, accessed 09/09/2011.