Zoonotic transmission (from animal to human) cannot be excluded but is considered most unlikely by the European centre for disease prevention and control (ECDC).
Zoonootilist levikut (loomalt inimesele) ei saa välistada, kuid Haiguste Ennetamise ja Tõrje Euroopa Keskus (ECDC) peab seda väga ebatõenäoliseks.