Twenty nine participants representing competent authorities, academe and service providers completed the TILV 7-day intensive course from 18-24 June 2018.

A collaborative capacity building initiative between China's National Fisheries Extension Center (NFTEC) and Sun Yat-Sen University (SYSU) and FAO, was successfully concluded on 24 June 2018. Dr Jianguo He (SYSU) and Dr Feng Zang and Ms Qing Li (NFTEC) were special guests during the opening and closing, respectively.

Some 29 participants representing competent authorities, academe and service providers from Brasil, China, Indonesia, Malaysia, Mozambique, Myanmar, Peru, the Philippines, Sri Lanka and Viet Nam completed the above course. Under the technical oversight of FAO, the course was delivered by Chinese (Dr Yang Hong, Prof Anxing Li, Dr Hong Liu and Prof JunHong Xia) and FAO experts (Dr Kathy F.J. Tang/ USA, Dr Win Surachetpong/ Thailand, Dr Ha Thanh Dong/ Viet Nam, Dr Mona D. Jansen/Norway).

Seven sessions including 22 expert presentations, a field visit, laboratory activities and several interactive working group exercises gave the participants the currently available information on the biology, pathology, diagnostics, surveillance and economics, farm level management of TiLV and emergency preparedness. These learnings reinforced their capacity in preparing a preliminary action plan on TiLV.

Tilapias, the second-most important farmed finfish worldwide, with Nile Tilapia (Oreochromis niloticus), ranked 6th among the most important cultured species, affordable, with widespread source of low cost but high quality protein and micronutrients. TiLV represents a serious threat to food security especially in developing world where tilapia is farmed.

TiLV, an enveloped, negative-sense, single stranded RNA virus, appears to have a narrow host specificity [e.g. farmed tilapia such as hybrid tilapia (Oreochromis niloticus x O. aureus hybrid), Nile tilapia, and red tilapia (Oreochromis sp.)] and reported as well from several wild tilapines.

Histopathology, RT-PCR and RT-qPCR, and in-situ hybridization are currently the methods that can be used to identify TiLV. The most common histopathological lesion found in TiLV outbreaks is syncytial hepatitis.

Although the precise mechanism for transmission is unknown, nor is there information available on virus stability free in the water or in contaminated fomites, horizontal disease transmission is likely to be the main mode of disease spread. Vertical transmission needs to be investigated.

At least 14 tilapia producing countries had TiLV reports (e.g. through local and international scientific literature, OIE notifications). As live tilapia is a widely traded commodity, TiLV may have spread significantly over the years since its first reported occurrence in 2009. Information is still lacking on the role played by the trade in uncooked tilapia products.

Tilapia producing countries need to assess risks, undertake surveillance to determine national TiLV health status, investigate unexplained tilapia mortalities and introduce risk management measures where deemed necessary. The status of TiLV in a country can be politically sensitive due to the range of potential implications. It is thus essential that competent authorities are immediately informed of any observation (field or research) before such findings are made publicly available.

Further information about the course and other related activities on TiLV of FAO can be obtained by writing to Melba.Reantaso@fao.org