A fresh disease could be about to take off right now, as a freak bacterium escapes from an
antibiotic-abusing factory farm, say, or a mutated virus sweeps out of a
laboratory or a forest, as a bat
passes it on to a new host which can infect humans.
请问这两个as都是什么用法？这种一句话里两个as之间只有一个逗号的情况不会造成歧义吗？这种用法多么？
第一个as是连词？
第二个as是引导修饰forest定语从句的先行词？
PS:as adj as里第一个as是副词，第二个as是介词（+名词）或连词（+句子），对吧？
