Appearance of red mark syndrome / cold water strawberry disease in Switzerland and Austria

Abstract

Red mark syndrome (RMS) or cold water strawberry disease (CWSD) is a non-lethal skin disease of rainbow trout Oncorhynchus mykiss that is of high economic importance in the UK. The disease is temperature-dependent, with up to 60% morbidity at water temperatures below 15°C. Although CWSD is horizontally transmissible, the aetiology is still unknown. Here we describe the first cases of RMS on the European mainland in the alpine regions of Switzerland and Austria. In Switzerland, morbidity remained around 1% after the first outbreak, whereas in Austria no further cases were diagnosed.KEY WORDS: Red mark syndrome · Coldwater strawberry disease · Oncorhynchus mykiss · Austria · Switzerland · Water temperature Resale or republication not permitted without written consent of the publisherDis Aquat Org 88: 65-68, 2009 al. 2008). It is notable that Lloyd et al. (2008) also reported no statistical association between SD lesions and F. psychrophilum based on PCR assays, but they did find a strong association between SD lesions and a Rickettsia-like organism. Verner-Jeffreys et al. (2008) proposed that RMS is caused by 1 or more infectious agents with a long latency (> 500 day-degrees).RMS was first reported in 2003 in Scotland. RMS seemed to spread in the UK, as it was subsequently diagnosed in England and Wales (Verner-Jeffreys et al. 2008). Outbreaks outside the UK have not been reported yet. Here we describe the first likely cases of RMS on the European mainland, in 2 Swiss and 1 Austrian trout farm. CASE STUDIES AND DISCUSSIONThe 2 affected Swiss farms exclusively raise rainbow trout. Despite belonging to the same owner, they are completely separated. Farm A consists of a hatchery and a grow-out facility, which are located at 2 different sites with separate water supplies. The farm produces 250 t of trout yr spring water with a temperature of 5 to 14°C. Eggs are supplied by brood stock kept in the grow-out facility. Additionally, each year 2 batches of eggs are imported from different farms in the European Union, but not from the UK. In the hatchery, fingerlings up to 50 g are reared in separate troughs and concrete raceway systems with gravel bottoms. Older animals are moved into the grow-out facility that is supplied by spring water at 250 l s -1 with water temperature of 4 to 14°C. Trout are reared in separate tanks and concrete raceway systems.Farm B produces 100 t of rainbow trout yr -1 hatched on site in recirculation units supplied with tap water. Afterwards, fish are reared in separated flow-through troughs and tanks and then moved to independent recirculation systems. The farm is supplied by 80 to 110 l s -1 spring water flowing in an open channel for about 1 km that is inhabited by wild fish. The water is not disinfected before entering the fish farm. Water temperature ranges from 5 to 15°C. In 2007, rainbow trout from Farm A were once transported to Farm B.Water parameters of both farms were checked regularly and showed no unusual variation. Rainbow trout from both farms regularly tested negative...

Molecular evidence for a bacterium of the family Midichloriaceae (order Rickettsiales) in skin and organs of the rainbow trout Oncorhynchus mykiss (Walbaum) affected by red mark syndrome

“…; Schmidt‐Posthaus et al . ). This disease is generally associated with water temperatures below 16 °C and can still be present at 2 °C (Verner‐Jeffreys et al .…”

“…; Schmidt‐Posthaus et al . ). In some RMS‐affected individuals, acute necrotizing myocarditis, inflammation of intestinal muscle, splenic congestion, peritonitis and perivascular lymphocyte infiltrate can be observed (Oidtmann et al .…”

Acute dermatitis in farmed trout: an emerging disease

“…RMS has now been reported in rainbow trout in a number of other European countries, including Switzerland and Austria (Schmidt‐Posthaus et al . ).…”

Ultrastructural and biomolecular detection of Rickettsiales‐like organisms in tissues of rainbow trout with Red Mark Syndrome

“…), Austria and Switzerland (Schmidt‐Posthaus et al . ), Italy (Galeotti et al . ) and more recently in Turkey (Kubilay et al .…”