Egyptian fish farms have faced unexplained mortality of tilapia during the summer months in recent years. Epidemiological surveys indicated that 37% of fish farms were affected in 2015 with an average mortality rate of 9.2% and a potential economic impact of around US$ 100 million. Despite a number of researchers and organizations investigating potential causes results so far have been inconclusive. The aim of this study was to identify the effect of various production factors on the incidence of disease outbreaks in Egyptian pond based aquaculture. Also, as Egypt shares a border with Israel and is on an important bird migration route passing through Israel it seemed likely that TiLV could also be present in Egypt and might be linked to 'summer mortalities'.