Water temperature influences viral load and detection of White Spot Syndrome Virus (WSSV) in Litopenaeus vannamei and wild crustaceans

Abstract

The Pacific white shrimp Litopenaeus vannamei is particularly affected by White Spot Syndrome Virus (WSSV) as this virus can cause high mortality in infected populations. Presently, there are no known treatments for shrimp affected by WSSV and management tools for preventing this disease are limited to the exclusion of the virus from cultured shrimp populations. Previous studies have shown that warm-water culture conditions inhibit the replication rate of WSSV, as well as two other important shrimp viruses in L. vannamei. The purpose of this study was to evaluate the effect of thermal stress on the replication rate of WSSV in shrimp held in warm water (29 ± 0.5 °C), compared to the replication rate of WSSV in shrimp held in cool water (18 ± 0.5 °C), looking for improve virus detection in epidemiological programs. Furthermore, post larvae and captured wild crustaceans were screened for the WSSV after being held in warm water for 2 days (48 h). The results indicate that water temperature had a profound effect on the replication rate of WSSV in L. vannamei and a protocol for WSSV screening after thermal stress is proposed. Our results support the findings of previous studies and further point out to the potential application of environmental temperature as a management strategy to selecting WSSV-free spawning shrimp within the shrimp farming industry in Mexico and possibly in other producing countries.