<prompt> tafsiri zifuatazo kutoka kwa swahili hadi kiingereza.angalau virusi 30 ambavyo havikujulikana zamani vimegunduliwa tangu mwaka wa 1973, kutia ndani virusi vya ukimwi, ebola, ugonjwa wa ini, na nipah, na hakuna tiba.  <response>: at least 30 previously unknown disease agents have been identified since 1973, including hiv, ebola, hepatitis c, and nipah virus, for which no cures are available . 