Control of horizontal transmission of white spot syndrome virus by ultraviolet light

Abstract

Bacterial and viral diseases are common problems in aquaculture. The use of flow-through systems frequently represents a risk of contamination by introducing pathogenic microorganisms, resulting in diseases that economically damage the industry. White spot syndrome virus (WSSV) causes a shrimp disease responsible for substantial economic losses in many countries. The present study was conducted to determine if the specific pathogen-free (SPF) indicator shrimp might take WSSV from infected water flow after treatment with UV light: specific pathogen-free L. vannamei shrimp, 2.5-g avg Wt, were acclimated to 25 UPS artificial seawater. Once acclimated, they were distributed in four pairs of tanks (20/tank). Each pair of tanks had one tank infected by per os and one exposed to water from the infected tank. Water flow from the per os infected tank was pumped to the non-infected tank and returned to the per os infected tank by gravity. Two pairs of tanks had UV light (G15T8) to irradiate the flow of water before passing it to the non-infected tank. The other two pairs of tanks (control group) had no UV light irradiation to the recirculating water. Moribund and dead shrimp were collected and frozen to determine if they were infected with WSSV by using PCR. After 12 days of shrimp in, the tanks exposed to water contaminated with WSSV and treated with UV did not have any mortality. The water contaminated with WSSV and not treated with UV resulted in significant numbers of WSSV-infected and dead shrimp. This study demonstrated that it is possible to eliminate the transmission of WSSV by treating the water with UV.