An immunofluorescent staining technique for the rapid detection of the ciliate protozoan Uronema sp. was developed during 1995 and 1996. The initial test was developed using seven cultures of Uronema sp. from various sources which were identified as Uronema nigricans  by microscopical and histochemical techniques. These seven strains were maintained in a medium containing bacteria as their food source. Antisera against two of the strains were raised in rabbits and against one in sheep. These were then adsorbed with the bacteria and unrelated ciliates to eliminate cross-reactivity.

More recently, an axenic (bacteria-free) culture of Uronema sp. has been accomplished and high-titre antisera raised in rabbits for use in the immunofluorescent staining technique.

Arrangements have been made to have a monoclonal antibody to the axenic Uronema prepared at the Atlantic Veterinary College, University of Prince Edward Island in Canada. This will then provide a reliable supply of highly specific antibody for future research in this area.

The substantial southern bluefin tuna mortality event in 1996 impacted on the delivery of the project objectives, particularly those associated with the application of the immuno-staining technique developed to:

• screen potential sources of infection associated with farming tuna; and based on this
• provide advice to farmers on how to improve farm management techniques so as to minimise infections.

Keywords: Uronema, aquaculture, southern bluefin tuna.