Efficacy of Formalin for the Control of White Spot Syndrome Virus Infection in Black Tiger Shrimp (Penaeus monodon)

Abstract

White Spot Syndrome Virus (WSSV) is a virus found in invertebrates which is one of the leading causes of disease in commercially raised shrimp. The main method of controlling the disease is to prevent infections. This study found that formalin was effective in controlling WSSV in water. Concentrations of 100, 150 and 200 ppm of formalin could reduce the infection rate in shrimp that ate WSSV-infected shrimp. The survival rates for shrimp bathed in 100, 150 and 200 ppm formalin solutions were 33.33%, 30.00%, and 16.67%, respectively, compared to the control populations that were not exposed to formalin. Histopathological studies of shrimp tissue showed that shrimp infected with WSSV demonstrated histopathological changes within 24 hours even though on the outside they still looked normal. One method for controlling WSSV was to bathe post larvae in a 100 ppm formalin solution for 30 minutes before weeding out the weakest ones and putting the rest into the raising pond.