@greenrun, your question is very technical and funny oh but thank God it is an assumption. Apart from rodents to human transmission, the viral participle could also be transferred from person to person, some of these persons are likely to be asymptomatic carriers that could also transfer this pathogen in the active stage of infection. "Killing all the rats" + good community hygiene + standard care when dealing with sick people around us= prevention of Lassa fever. Thank you for reading my post.