Different Sensitivity of Japanese Native-Bred Chickens to H5 Subtypes of Highly Pathogenic Avian Influenza Viruses

The aim of this study was to investigate the sensitivity of three breeds of Japanese native chickens, commercial broilers, and specific-pathogen-free (SPF) white leghorns to three strains of the H5 subtype of highly pathogenic avian influenza viruses (HPAIVs). Chickens were experimentally inoculated with doses of 10(2), 10(4), and 10(6) 50% egg infective dose of A/mandarin duck/Miyazaki/22M-765/2011 (duck-11), A/chicken/Miyazaki/7/2014 (chicken-14), and A/chicken/Kumamoto/1-2C/2016 (chicken-16). The 50% chicken lethal dose of each virus, mean death time, and viral shedding patterns were compared. The Japanese native chickens showed varied susceptibility to the three H5 HPAIV isolates. Although two of the breeds showed some degree of resistance to duck-11 and chicken-14, all three were more sensitive to chicken-16 than commercial broiler chickens. We have shown that Japanese native chickens do not necessarily have resistance to HPAIV and that the pathogenic characteristics of HPAIVs are quite different between native and commercial chickens.

Automated summary

The study found that Japanese native chickens exhibit varying susceptibility to different strains of H5 highly pathogenic avian influenza viruses, with two breeds showing some degree of resistance to certain viruses while being more sensitive to others compared to commercial broiler chickens. This suggests that the pathogenic characteristics of HPAIVs differ significantly between native and commercial chickens.