Wasu kwayoyin, kamar Staphylococcus ko Streptococcus, na iya haifar da cututtukan fata, ciwon huhu, meningitis har ma da cututtukan cututtukan cututtukan cututtuka, wanda ke haifar da mummunan cututtuka, da kuma mutuwa. Duk da haka waɗannan kwayoyin suna cikin ɓangaren kwayoyin halitta na al'ada na mutum kuma yawanci suna wanzu a kan fata ko a hanci ba tare da haifar da cutar ba. Wasu kwayoyin suna haifar da cututtuka a cikin mutane, kamar Rickettsia, waɗanda ke da alaƙa da ƙwayoyin cuta na intracellular da ke iya girma da kuma haifuwa kawai a cikin ƙwayoyin sauran kwayoyin. Wani nau'in Rickettsia typhus, yayin da wani ya gano. Wani nau'in ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta na ƙwayo
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