Development of a nanoparticle Tilapia Lake Virus (TiLV) vaccine for tilapia aquaculture in India
Aquaculture is the fastest growing food-production sector globally, with over 1 billion people relying on fish as their major protein source. Tilapia (Oreochromis sp.) is a major trade commodity for many low to middle-income countries (LMIC), with its production estimated to be around 6.4 million tons per annum (FAO, 2017). The hardiness of tilapia, its adaptability to various production systems and its rapid growth, makes it an excellent fish species for aquaculture. Intensification of tilapia farming has promoted severe disease outbreaks, however, resulting in high mortalities and economic hardship for tilapia farmers. Tilapia Lake Virus (TiLV), a highly virulent and contagious novel orthomyxo-like virus has recently been associated with disease outbreaks in tilapia aquaculture, resulting in massive mortalities in both wild and cultured tilapines. First reported in Israel in late 2009, TiLV-related disease outbreaks have now been reported across Asia, Africa, and North and South America. In Indian tilapia aquaculture, the virus is associated with mortality levels around 80-90%. Vaccination has proven a successful tool for controlling viral diseases in aquaculture, with most vaccines delivered by intraperitoneal (IP) injection. Many tilapia farmers will not vaccinate by injection once the fish have been moved onto the farm and would prefer fish to be vaccinated in the hatchery. It is difficult to inject small fish, however. Also TiLV tends to affect small fingerlings, some of which are too small to inject. Alternative vaccine delivery methods, such as oral or immersion delivery, are therefore needed. We will investigate a novel and innovative nanoparticle for delivery of the TiLV vaccine, comparing its efficacy when delivered by immersion, orally or by IP injection. Ultimately we aim to develop a cost-effective, easily administered vaccine for use in a large scale tilapia-production both for use in India and globally.