Tamanho da fonte:
DEVELOPMENT OF A LOOP MEDIATED ISOTHERMAL AMPLIFICATION (LAMP) ASSAY FOR THE DETECTION OF WHITE SPOT SYNDROME VIRUS (WSSV) IN SHRIMP IN MOZAMBIQUE
Última alteração: 2025-07-16
Resumo
Abstract
White spot syndrome virus (WSSV) is a significant risk to shrimp farming worldwide, including in Mozambique. In 2011, a WSSV disease outbreak in Mozambique almost crippled the shrimp industry by inflicting heavy economic losses through mortalities. Since then, virus testing using a PCR kit produced by a Taiwanese company became a standard means of disease monitoring. This kit was the only one in use at the start of this study and was very expensive. The present study explored the potential of the loop-mediated isothermal amplification (LAMP) technique as a diagnostic tool for rapid and sensitive detection of (WSSV). Different primer sets were designed based on wsv343 (3) and wsv360 (4) genes. The best primer set was found to be based on the wsv343 gene with optimal conditions of 61°C for 60 minutes, and minimum virus detection of 10-9 ng/µl. The LAMP assay demonstrated high specificity, as confirmed by the absence of cross-reactivity with Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and Decapod Iridescent Virus 1 (DIV1). These results highlight its reliability in distinguishing WSSV from other viral pathogens, offering an advantage over conventional PCR methods. Using the assay, the occurrence of WSSV in shrimps was assessed in five districts of Zambezia province of Mozambique. Ten shrimps per district were tested and the results showed 43% occurrence in P. monodon in Chuabo Dembe district, relatively close to where the outbreak was recorded in 2011. Twenty-five percent occurrence of WSSV in P. indicus, both in Chinde and Maganja da Costa was found. The virus was not detected in any of the samples from Zalala and Pebane. Put together, these findings demonstrate that the LAMP assay is a feasible alternative diagnostic tool for the detection of WSSV in Mozambique. The high incidence of WSSV in Chuabo Dembe suggests that either the virus persists long in the environment or has continued to spread from the epicenter over the years.
Key-words: WSSV, white spot syndrome virus, loop-mediated isothermal amplification, LAMP and Shrimp;
White spot syndrome virus (WSSV) is a significant risk to shrimp farming worldwide, including in Mozambique. In 2011, a WSSV disease outbreak in Mozambique almost crippled the shrimp industry by inflicting heavy economic losses through mortalities. Since then, virus testing using a PCR kit produced by a Taiwanese company became a standard means of disease monitoring. This kit was the only one in use at the start of this study and was very expensive. The present study explored the potential of the loop-mediated isothermal amplification (LAMP) technique as a diagnostic tool for rapid and sensitive detection of (WSSV). Different primer sets were designed based on wsv343 (3) and wsv360 (4) genes. The best primer set was found to be based on the wsv343 gene with optimal conditions of 61°C for 60 minutes, and minimum virus detection of 10-9 ng/µl. The LAMP assay demonstrated high specificity, as confirmed by the absence of cross-reactivity with Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and Decapod Iridescent Virus 1 (DIV1). These results highlight its reliability in distinguishing WSSV from other viral pathogens, offering an advantage over conventional PCR methods. Using the assay, the occurrence of WSSV in shrimps was assessed in five districts of Zambezia province of Mozambique. Ten shrimps per district were tested and the results showed 43% occurrence in P. monodon in Chuabo Dembe district, relatively close to where the outbreak was recorded in 2011. Twenty-five percent occurrence of WSSV in P. indicus, both in Chinde and Maganja da Costa was found. The virus was not detected in any of the samples from Zalala and Pebane. Put together, these findings demonstrate that the LAMP assay is a feasible alternative diagnostic tool for the detection of WSSV in Mozambique. The high incidence of WSSV in Chuabo Dembe suggests that either the virus persists long in the environment or has continued to spread from the epicenter over the years.
Key-words: WSSV, white spot syndrome virus, loop-mediated isothermal amplification, LAMP and Shrimp;