Expand the range of protection to include other avian viruses such as Newcastle disease virus and Marek's disease. 拓展保护范围，将其它禽类易感病毒如新城疫病毒和马立克氏病病毒等容纳进来。
Marek's disease is an important immunosuppressive disease, which seriously affects the healthy development of the poultry industry. 摘要马立克氏病是一种重要的免疫抑制病，严重影响养鸡业的健康发展。
