Molecular Diagnosis of White Spot Syndrome Virus (WSSV) and Acute Hepatopancreatic Necrosis Disease (AHPND) Causative Agent in Black Tiger Shrimp Hatcheries

Abstract

Shrimp aquaculture is a very promising and fast-developing industry in Bangladesh that contributes about 3.78% of the national GDP. However, this sector has been suffering from different diseases, especially viral and bacterial diseases. White Spot Disease (WSD) and Acute Hepatopancreatic Necrosis Disease (AHPND) are considered serious intimidation to the commercial tiger shrimp (Penaeus monodon) farming industry. White spot syndrome virus (WSSV), a DNA virus, and Vibrio parahaemolyticus, a bacterium, are the causative agents of WSD and AHPND, respectively. The study aimed to investigate the scenario of viral and bacterial contamination in broods, nauplii, zoea, mysis, post larvae (PL) of shrimp, and other hatchery inputs like Artemia, algae, squid, and mussel in commercial shrimp hatcheries in Cox's Bazar. The prevalence of these dreadful viral and bacterial infections was studied in 10 randomly chosen hatcheries in Cox's Bazar district of Bangladesh. WSSV and AHPND causative agents were detected using nested polymerase chain reaction (PCR). WSSV was detected using nested polymerase chain reaction (PCR) using two pairs of primers, 146F1/146R1 and 146F2/146R2, amplifying the 1447 bp and 941 bp fragments, respectively. AP4F1/AP4R1 and AP4F2/AP4R2 primer pairs were used to detect AHPND causative agent, amplifying the 1269 bp and 230 bp fragments, respectively. Out of 118 randomly selected samples including brood, PL, nauplii, zoea, mysis of shrimp, Artemia, algae, squid, and mussel, 28.81% and 5.08% of the total samples were found positive for WSSV and AHPND, respectively. The study showed that the diseases affected all stages of the life cycle of shrimp, as well as squid, mussel, and other hatchery inputs were also potential hosts for WSSV and AHPND. Hence, the present study suggests focusing on ensuring the production of specific-pathogen-free (SPF) shrimp PL in commercial shrimp hatcheries by maintaining proper biosecurity management. The findings of this study would aid farmers and decision-makers in developing plans to protect the shrimp sector from WSD and AHPND and thereby maintain sustainable shrimp farming in Bangladesh.