Global warming and viral diseases – Tilapia Lake Virus (TiLV) in tilapia, common carp, crucian carp, and rainbow trout - first results —

Recently, a global increase in temperature has been considered with a temperature rise. Therefore, new species and diseases are getting domestic in Europe. Particularly, tilapia is kept in "colder" areas like in European waters in indoor facilities. It was examined if the tilapia lake virus (TiLV) can infect native European fish. Common carp, crucian carp, and rainbow trout were chosen to be with infected tilapia. While tilapia were infected, the other species were always cohabitated. After keeping all species together, samples were collected. Tilapia and crucian carp at 20 °C as well as rainbow trout at 12°C, showed mortality. Besides necrosis, infiltrations and syncytia were observed. TiLV was detected by in-situ hybridization in all species. Sera were used for SNT to prove the replication. While tilapia developed neutralizing antibodies after 14 to 21 dpi, carp and rainbow trout started after 12 dpi. The highest neutralizing activities we found in sera from crucian carp. All fish (tilapia, crucian carp, and rainbow trout) that died during the experiment were inspected for the presence of TiLV by RT-qPCR, histology, and ISH. Due to the experience that clinically infected fish showing severe symptoms are not producing antibodies, serology was not carried out.