Bat and Lyssavirus Exposure among Humans in Area that Celebrates Bat Festival, Nigeria, 2010 and 2013

B ats are vital to many ecosystems and provide benefits to humans (1). However, under certain circumstances, bats may pose a risk to human health, as they host several zoonotic pathogens (2). Humans should therefore avoid bat contact unless appropriate precautions are taken. Among the most concerning batborne pathogens are viruses within the genus Lyssavirus. Previously unimmunized humans exposed to any of the >16 currently recognized and putative lyssaviruses (typically through a bite from an infected animal) will have 1 of 3 outcomes. First is a complete lack of any lyssavirus infection, characterized by the absence of both illness and lyssavirus-neutralizing antibody production. Second is a productive lyssavirus infection, characterized by a fatal encephalitis known as rabies (3). A human with rabies may produce lyssavirus-neutralizing antibodies in the end stages of illness as the disease progresses, although this response is typically inadequate for viral clearance (4). Third is an abortive lyssavirus infection (sometimes termed an exposure) characterized by the absence of frank encephalitis but with production of lyssavirus-neutralizing antibodies. Although