It was first isolated in mortalities occurring in natural populations of white perch (Morone americana) and striped bass (M. saxatilis) in 1963 in Chesapeake Bay, USA (Snieszko et al., 1964)[incomplete short citation].

Since 1969, this disease has been one of the most important in Japan, affecting mainly yellowtail (Seriola quinqueradiata) (Kusuda & Yamaoka, 1972)[incomplete short citation].

Below this temperature, fish can harbour the pathogen as subclinical infection and become carriers for long time periods (Romalde, 2002)[incomplete short citation].

The disease is difficult to eradicate with antibiotic treatments, and there is evidence that carriers under stressful conditions could suffer from reinfection (Le Breton, 1999).

This spread can be rapid, and lethal effects may occur within a few days of challenge, affecting tissues containing large numbers of the pathogens (Evelyn, 1996).