On 18th of May 2021, the Danish Food and Veterinary administration declared the first outbreak of Infectious Haematopoietic Necrosis (IHN) in a rainbow trout fish farm located in Stouby northeast of Vejle, Denmark. Currently (January 2022) the infection with IHNV has been confirmed in eight fish farms and three put and take lakes.
Danmark has withdrawn the status as IHN free country and further measures for disease control are under discussion.
According to the legislation sampling for surveillance of infection with IHNV shall be conducted at water temperatures below 14°C. It was therefore debated if IHNV could still be detected at higher temperatures during summer. A study was initiated to assess the capability of IHNV detection at higher water temperatures and assess how confident we could be in testing fish staying at temperatures above 14°C.
The results are reported in Laboratory investigation of two IHNV infected farms in Denmark by Niccoló Vendramin, Argelia Cuenca, Tine Iburg, Lone Madsen and Niels Jørgen Olesen.