Table 1.

Haemagglutination activity in houseflies exposed to Newcastle disease (La Sota) virus.

Sample number	Sampling interval, h	Haemagglutination activity
1	0	−
2	0.5	+
3	1	+
4	2	+
5	4	+
6	24	+
7	48	+
8	72	+
9	96	−
10	192	−

+, antibody inhibition; −, no antibody inhibition.