It is speculated that the 1890 flu epidemic may have been caused by this contagious event and not by the influenza virus given the pandemic's timing, neurological symptoms and unknown causative agent.
Inakisiwa kwamba maradhi ya mafua ya mwaka wa 1890 yanaweza kuwa yalisababishwa na tukio hili ya kuruka kwenda kwenye spishi nyine, lakini sio virusi vya mafua, kwa sababu ya muda husika, dalili za nyurolojia, dalili zingine zisizojulikana za ugonjwa huo.