A yellow head virus gene probe: nucleotide sequence and application for insitu hybridization

A portion of the genome of yellow head virus (YHV) of penaeid shrimp was cl oned and the cDNA fragment (1161 bp) was designated clone 3-27. The fragmen t was labeled with digoxigenin and hybridized in situ to tissue sections of YHV-infected Penaeus vannamei. Positively reacting tissues included those of the lymphoid organ, cuticular epithelium, and gills. In addition, connec tive tissue of hepatopancreas, heart, antennal gland, hematopoietic organ, nerve tract, midgut cecum and muscle reacted to the probe. The probe was hi ghly specific since it hybridized only to tissues from YHV-infected shrimp. It did not react to those of uninfected shrimp or shrimp infected with WSS V (white spot syndrome virus), IHHNV (infectious hypodermal and hematopoiet ic necrosis virus), or TSV (Taura syndrome virus). The clone was sequenced, and primers were synthesized for rapid detection of YHV in hemolymph using RT-PCR (reverse transcription-polymerase chain reaction). The strand that constituted the viral sequence in the cDNA was also determined via RT-PCR a nd in situ hybridization with a single-stranded RNA (ssRNA) probe.