TABLE 3.

Numbers of animals at risk and death rates (DR) at 117 fur farms responding to the epidemiological questionnaire^a

Age and sex group	Blue fox	Shadow fox	Silver fox	Blue silver fox	Minks	Total
Young females and males
No. of animals at risk	140,274	8,566	1,747	4,513	13,719	168,819
No. of dead animals	30,951	2,364	0	158	87	33,560
DR (%)	22.1	27.6	0	3.5	0.6	19.9
Adult females
No. of animals at risk	27,465	889	557	12	3,111	32,034
No. of dead animals	9,529	240	1	12	142	9,924
DR (%)	34.7	27.0	0.2	100	4.6	31.0
Adult males
No. of animals at risk	1,730	171	222	0	153	2,276
No. of dead animals	539	68	5	0	34	646
DR rate (%)	31.2	39.8	2.3	0	22.2	28.4
Total
No. of animals at risk	169,469	9,626	2,526	4,525	16,983	203,129
No. of dead animals	41,019	2,672	6	170	263	44,130
DR (%)	24.2	27.8	0.2	3.8	1.5	21.7

^aAll minks had been immunized against botulinum toxin type C at the age of 2 months, while foxes were not immunized at all.