Pathogenesis Of Highly Pathogenic Influenza (H5N1) Viruses In Mammal Model Mice

H5N1 subtype highly pathogenic avian influenza viruses (HPAIV) are pathogens of zoonosis that have seriously threaten the public safety. Since the first case that human infected the HPAIV (H5N1) in Hongkong in 1997, the reports about HPAIV infected human beings and caused human dead are never ceased. In 2004, the desease of HPAI in China and eastern-south Asia led to enormous ecnomiclly loss and had influenced the people's confidence in the poultry. In 2005, thousands of wild birds infected the HPAIV (H5N1) and died, which updated people's traditional understanding that the HPAIV can now kill the wild birds. Since now, more than ten countries have reported that the HPAIV infected human beings, the mortality over 60%. The pathogenesis of HPAIV in mammals is an urgent and important tissue in the influenza virus research.To mimic the natural infection of H5N1 avian influenza virus (AIV) in animals, BALB/c mice were inoculated with a low-dosage (10^0.4 EID₅₀) of H5N1 AIV A/bar-headed goose/3/05 (BHG/3/05). The results demonstrated that progress of diseases had great diversity between high dose infection and low dose infection.After that we used 10¹EID₅₀ of the human H5N1 influenza viruses A/Anhui/2/05 (AH/2/05) and avian H5N1 influenza virus A/Sichuan/81/05 (SC/81/05) to inoculate the BALB/c mice. After infection with the AH/2/05, the mice showed significant disease symptom, including bodyweight descent and symptom neurosis. However, there was no disease symptom and death in the mice after infection with SC/81/05. We isolated the organs and tissues of the infected mice after inoculation at day 3,5,7,10,14 to determine the replication ability of the viruses by eggs. The results showed that the replication ability of the AH/2/05 virus was different at each tissue, and the virus can replicate in mice for more than 14 days. We can detect serios lesions of the tissues through the pathological examination. The SC/81/05 virus was only limited in the turbinate and lung, and can be detected only at day 3 post inoculation without apparent lesions in the tissues. These results are useful for a better understanding of the pathogenesis of H5N1 influenza virus infection in nature.