Table 2. Neutralization titers for IQT9646 and Caraparu viruses by using mouse antisera to determine antigenic differences, Peru*.

Strain (virus)	Anti-IQT9646	Anti-BeAn3994
IQT9646 (Itaya)	2,560	80
FPI 2066 (Caraparu)	<40	2,560
BeAn3994 (Caraparu)	40	1,280

*Neutralization titers are expressed as the dilution of mouse immune ascitic fluid antiserum inhibiting 80% of plaque forming units.