Since 2009 Tilapia lake virus (TiLV) has been responsible for large numbers of of farmed tilapia (a significant global food source) deaths in Israel,Ecuador,and more recently Thailand. Outbreaks are associated with seasonality – they have occurred in May-October when the water has a relatively high temperature. This implicates an infectious agent as warmer waters encourage the emergence of parasitic, bacterial, and viral diseases such as TiLV. TiLV is anorthomyxo-like virus and has a 10-segment,anti-sense RNA genome. Segment 1 is the biggest segment and has an ORF with some sequence homology to influenza C virus PB1 subunit and is likely to encode the polymerase of TiLV. In situ hybridisation assays used to investigate TiLV in diseased fish showed that in the brain, segment 1 genomic RNA and mRNA was confined to the leptomeninges, predominantly adjacent to blood vessels. In the liver, signals from segment 3 were detected in hepatocytes. Typical symptoms of infected fish include lethargy, endophthalmitis, skin erosions, renal congestion and encephalitis. Infected fish can transfer the virus to naïve fish via waterborne method, a typical mortality of 80-100% occurs within a few days post infection. Tilapia is the second most important group of farmed fish in the world, the economic impact of TiLV on worldwide trade in tilapia has been estimated as 7.5 billion USD annually. Asthis virus has such a great potential impact on the economy and food source for millions of people, fast accurate identification by real time PCR could be extremely beneficial.