Dynamic Distribution of Cyprinid Herpesvirus 3 in Infected Cyprinus carpio and Its Hispathological Changes

Purpose To study the infection process and pathological damage of CyHV-3 infected carp, and provide valuable reference for the effective prevention and cure of koi herpesvirus disease.

Method Carp (Cyprinus carpio) were infected with CyHV-3 and dissected at different time points for detecting the histopathological changes and distribution of virus. And gills and kidney were selected as representative of the external organs and internal organs for dynamic pathological observation.

Result The gill of test fish respiratory epithelial proliferation and a large number of inflammatory cell infiltration. Besides, kidney tissue was significantly inflammatory cell infiltration, showing interstitial nephritis. Then, the gill tissue on the 2^nd day of infection was detected by real-time PCR with the largest viral load, and no virus was detected in the intestine. With the infection time extended, the viral load in organizations gradually increased, and the viral load of gill, kidney and brain tissue reached the highest value on the 10^th day of virus infection, then it remained stable. In addition, the highest amount of virus in the spleen, liver and intestine was detected on the 14^th day of infection.

Conclusion The gills are the first internal invasion sites of CyHV-3, then the virus reached the kidney, spleen and other tissues and organs.