Table 3.
Clinical signs and mortality observed by farmers in 215 2 Danish mink farms tested positive for SARS-CoV-2 in different periods of the epidemic.
| Observations | Period | |||
|---|---|---|---|---|
| 16/7–6/9 | 7/9–4/10 | 5/10–13/11 | Total | |
| Number of mink farms detected 1 in the period | 7 | 56 | 212 | 275 |
| Number of farms with clinical signs | Yes/Total (%) | Yes/Total (%) | Yes/Total (%) | Yes/Total (%) |
| Number of mink on farm, Median (5–95-percentile) | 15,000 (5269–24,745) | 11,550 (2825–36,700) | 12,065 (3323–35,317) | 12,100 (3200–35,788) |
| Clinical signs, in adults | 4/7 (57%) | 30/55 (55%) | 75/145 (52%) | 109/207 (53%) |
| Clinical signs, in young (kits) | 3/7 (43%) | 38/55 (69%) | 83/145 (57%) | 124/207 (60%) |
| No clinical signs | 3/7 (43%) | 16/55 (29%) | 43/145 (30%) | 62/207 (30%) |
| Mortality % (deaths within 30 days/number of mink), Median (5–95-percentile) | 0.39% (0.17–0.49) | 0.38% (0.036–1.04) | 0.5% (0.13–2.3) | 0.45% (0.11–1.9) |
| Increased observed mortality | 4/7 (57%) | 27/55 (49%) | 103/150 (69%) | 134/212 (63%) |
| Nasal discharge | 1/7 (14%) | 16/52 (31%) | 35/141 (25%) | 52/200 (25%) |
| Sneezing | 0/7 (0%) | 13/52 (25%) | 33/141 (23%) | 46/200 (23%) |
| Respiratory symptoms | 2/7 (29%) | 14/52 (27%) | 46/141 (33%) | 62/200 (31%) |
| Depression | 1/7 (14%) | 5/52 (10%) | 8/141 (6%) | 14/200 (7%) |
| Reduced feed intake | 1/7 (14%) | 32/52 (62%) | 74/141 (52%) | 107/200 (54%) |
| Diarrhea | 0/7 (0%) | 5/52 (10%) | 5/141 (4%) | 10/200 (5%) |
1 Date of suspicion is used as detection date, to avoid influence of delayed detection caused by potential limitations in resources for surveillance visits. 2 Not all farmers answered all questions, and therefore the total does not sum to 215.