How can the virus in whiteleg shrimp (Litopenaeus vannamei) fry be stopped? Industry and academia join hands to give the answer

Live, bouncing fresh shrimp with plump, delicious meat are the favorite of gourmets. Taiwan was once the shrimp-farming kingdom; in Pingtung, Hsinchu and Yilan, fish and shrimp ponds stretched as far as the eye could see. Taiwan's shrimp farming peaked in 1987, with annual output reaching one million tons, more than half of it exported, ranking first in the world in both output and exports.

The lightning-fast killer of shrimp

In the early days, shrimp-fry farming technology was introduced from Japan and adopted high-density farming methods. Although the farming risk was not low, the relative profit was considerable, earning Taiwan over 100 million yuan in foreign exchange every year. Unfortunately, environmental pollution, plus the fact that some shrimp farmers introduced shrimp fry from different regions, meant that under intensive farming, once the fry were attacked by a virus, it spread like wildfire and could not be stopped.

White spot disease in shrimp is currently one of the most serious diseases harming the global shrimp-farming industry; infected shrimp have a mortality rate as high as 100% within three to ten days. Even with a mild infection, if the shrimp do not die immediately, the virus may still lie dormant in the shrimp's body. Once the farming environment changes, it can still trigger the white spot virus latent in the shrimp to multiply massively and rapidly infect the whole pond, causing mass deaths. The currently available preventive method is to regularly test whether shrimp ponds are infected with the virus during the grow-out process.

Ruiji International, originally engaged in testing human genetic diseases, had nothing to do with aquaculture at all. Its entry into the market for shrimp viral disease testing products came about entirely by chance. Liu Zhengzhong, general manager of Ruiji International, and Su Cheng, its chief executive, had a good friend who was a shrimp farmer. When something went wrong with the shrimp being farmed, he asked whether they could help. Since virus testing was Ruiji International's specialty, in 1995 the company expanded from testing human disease viruses to developing testing products for viral diseases in aquatic animals.

Testing viruses to save shrimp farmers

Taiwan has two advantages in developing shrimp virus testing. First, Taiwan was once the shrimp-farming kingdom; in pursuit of profit, shrimp farmers introduced broodstock and fry from different regions. Although this caused shrimp disasters, it also meant that samples of diseased shrimp were easy to obtain. Second, Taiwan is a major center for shrimp virus research; Professor Guo Guangxiong and Professor Luo Zhufang of the Department of Zoology at National Taiwan University, as well as Professor Huang Chongxiong of the Department of Entomology, can be called world-class authorities.

Through technology transfer, Ruiji International obtained several research results on shrimp white spot virus from Professor Luo Zhufang and others, and combined them with biotechnology to develop the IQ2000 test kit, which can classify samples according to the degree of infection into four levels: extremely mild, mild, moderate and severe infection. These test results are of great help in virus prevention and control; sensitivity is high, yet the price and equipment are much cheaper.

Under traditional farming methods, if shrimp farmers buy fry of unknown origin that have not undergone quarantine, then during the stocking period from the Spring Festival to Qingming Festival, as long as the weather is unstable, a large-scale shrimp disease outbreak may occur. Therefore, many shrimp farmers have the mindset of "relying on heaven for a living; if they die, at worst I'll just restock." Ruiji International persuaded shrimp farmers to use the IQ2000 test kit to establish testing at every stage of the farming process, from broodstock and fry to processing plants, so as to detect hidden crises in advance, immediately take response measures, and reduce wasted resources in handling the problem.
Shrimp white spot virus is the lightning-fast killer that brought down Taiwan's shrimp-farming kingdom, and it is also giving shrimp farmers around the world splitting headaches. With the help of the "shrimp white spot virus pondside testing system," which shrimp farmers can use themselves DIY-style, the fate of farmers depending on the sky for their livelihood has been reversed, and a victory song of the shrimp sea is being sung.
(The author is a consultant at the China Productivity Center)