Detection methods, epidemiological investigation, and host ranges of infectious precocity virus (IPV)

Giant freshwater prawn, Macrobrachium rosenbergii, is an important economically aquaculture species widely farmed in tropical and subtropical areas of the world. Infectious precocity virus (IPV) is a virus that results in slow growth and sexual precocity of farmed M. rosenbergii and causes significant economic losses. A TaqMan probe Quantitative Real-time PCR (qPCR) and a nested PCR assay for IPV detection were established in this study. IPV was detected in crustaceans M. rosenbergii, M. nipponense, Procambarus clarkii, Litopenaeus vannamei, Penaeus monodon, and Oratosquilla oratoria and insect Anisops kuroiwae. On the contrary, it was not detected in fishes Misgurnus anguillicaudatus, Carassius auratus, Oreochromis mossambicus, Micropterus salmoides, and Pangasius bocourti; crabs Eriocheir sinensis and Scylla paramamosain; and malacostraca Charybdis feriatus with nested PCR in China. TaqMan probe qPCR was used to study the tissue tropism of IPV in M. rosenbergii. IPV mainly infected the brain, abdominal nerve, integument, and gill. From July 2019 to April 2021, 260 M. rosenbergii from IPV disease (IPVD) outbreak ponds were all IPV positive in nested PCR, and 40 M. rosenbergii from normal ponds without IPVD were all IPV negative in nested PCR. These results could be beneficial to the prevention and control of IPV infection.