传染病发生流行的条件是（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='25399' and id < 2139966 and id<>'2139966' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='25399' and id > 2139966 and id<>'2139966' order by id asc limit 5