In primary viremia the virus infects a part of immune system in the liver and spleen, called the reticuloendothelial system, which is made of phagocytic cells.

第一次病毒血症中，病毒入侵肝脾的部分免疫系统，即由巨噬细胞组成的网状内皮系统。

When bacteria or viruses enter the body in sufficient numbers to overcome these phagocytic cells at the site of local infection, the next line of defense consists of lymphocytes.

当细菌或病毒以足够的数量进入体内以克服局部感染部位的这些吞噬细胞时，下一道防线由淋巴细胞组成。