Aim 1: (A) Determine whether the vertical (brood fish to progeny) transmission of CCV occurs within catfish eggs, on egg surfaces or both, and develop egg disinfection protocols to reduce virus transmission. (1B) Evaluate the efficacy of antiviral agents in preventing viral replication.Aim 2: Immunization of catfish broodstock and assessment of CCV in progeny. (2A) Brood fish will be immunized using attenuated CCV to determine if immunization reduces disease prevalence in eggs, fry, and fingerlings when compared to non-immunized fish. (2B) Vaccinated and non-vaccinated channel and hybrid catfish fingerlings will be challenged with wild type (wt) CCV to compare the virus susceptibility.Aim 3: (A) Test different environmental stress factors (temperature, oxygen, stocking density) that might trigger CCV disease outbreaks. (3B) Evaluate the differential susceptibility of catfish populations (channel, hybrid and blue catfish) towards multiple CCV strains.