Table 1.

Summary of farm and outbreak characteristics and virus types for the 69 mink farms diagnosed with SARS-CoV-2.

Observations	Yes	No	Unknown	Total
Farm characteristics
Farm distance (<3 km) 1	51	18	0	69
Farm distance with the same virus cluster (<3 km) 2	43	25	3	69
Type of housing	Sheds = 39; Halls = 21; Both = 6		3	69
Farm size 3	Small = 27; Medium = 18; Big = 24		0	69
Sharing of materials and vehicles	6	57	6	69
Same owner	32	37	0	69
Shed/hall visitors (≤5)	35	34	0	69
Exchange of employees (≥1)	36	29	4	69
Permanent employees (≤2)	44	25	0	69
Seasonal workers (≤3)	54	15	0	69
Temporary employees (≥1)	18	51	0	69
Symptomatic employees 4	31	20	18	69
Manure	21	39	9	69
Feed supplier 5	A = 45; B = 15; C = 9		0	69
Veterinarian 6	A = 54	B = 15	0	69
Cats	9	51	9	69
Dogs	41	25	3	69
Feral cats or neighbor cats	50	17	2	69
Other animals 7	27	22	20	69
Wildlife including bats and birds	53	1	15	69
Rodents	18	32	19	69
Insects	21	3	45	69
Outbreak characteristics
Date of diagnosis 8	<August = 27	≥August = 42	0	69
Virus type
Virus cluster 9	A = 41; B = 1; C = 15; D = 7; E = 1		4	69

¹ Distance from (an)other infected mink farm(s); ² Distance from (an)other infected mink farm(s) with the same virus cluster; ³ Small ≤ 30,000, medium = 30,000–50,000, big ≥ 50,000; ⁴ Employees reported with signs related to SARS-CoV-2; ⁵ The different letters (A, B, C) stand for the three different feed suppliers; ⁶ The different letters (A, B) stand for the different veterinary practitioners. The majority of the farms were visited by two veterinarians working for the same company. B stands for the other four veterinary practitioners; ⁷ Cattle, sheep or goats, deer, horses, pigs, poultry, rodents, turtles, foxes and wallabies; ⁸ Before or after 1 August 2020; ⁹ Cluster B and E were only detected at one infected mink farm respectively and were not included in the statistical analyses. For four farms the virus cluster could not be determined [15].