During the investigation, it was hypothesized that there could be a cross infection since monkeys suspected of illness were typically placed in gang cages containing up to twenty to thirty other monkeys suspected of illness.
Durante a investigación, presentouse a hipótese de que os animais puideron coinfectarse, xa que os monos sospeitosos de estar enfermos eran normalmente situados en gaiolas grandes que contiñan outros 20 a 30 monos sospeitosos de enfermidade.