IHNV stands for Infectious Hematopoietic Necrosis Virus. It is a negatively-sense, single-stranded RNA virus that primarily affects salmonid fish species, including salmon and trout. IHNV belongs to the Rhabdoviridae family, specifically the genus Novirhabdovirus, and it is responsible for causing infectious hematopoietic necrosis, a severe and often fatal disease in salmonids.
The virus is highly contagious and can spread rapidly through infected fish populations, causing significant economic losses in the aquaculture industry worldwide. IHNV is transmitted through direct contact between infected and susceptible fish, as well as through waterborne transmission. The virus primarily targets the fish's hematopoietic tissues, including the kidney, spleen, and liver, leading to severe anemia, internal bleeding, organ damage, and ultimately death.
Clinical signs of IHNV infection include darkened coloration, lethargy, loss of appetite, erratic swimming behavior, and hemorrhagic lesions on the skin and eyes. Infected fish may also exhibit curled or disoriented swimming patterns, weakness, and reduced growth rates. Diagnostic tests, such as viral isolation, serology, and molecular techniques like polymerase chain reaction (PCR), are used to confirm IHNV infection.
Prevention and control of IHNV mainly involve biosecurity practices, such as quarantine, disinfection, and strict movement controls to limit the spread of the virus. Vaccination may be used in certain cases to protect fish populations against the disease. As IHNV is considered a notifiable disease in many countries, reporting outbreaks to appropriate authorities is crucial to implement control measures and prevent further spread.
