Seroprevalence of pestivirus in Eurasian tundra reindeer in Finland, Sweden, Norway, Iceland and Russian Federation

Figures & data

Table 1. Details of the 520 serum samples obtained from Eurasian tundra reindeer (Rangifer t. tarandus), including both calves (≤1 year) and adult animals (>1 year) from Finland, Norway, Sweden, Iceland and Russian Federation. Sampling was performed during two consecutive years. Samples from Finland, Norway and Sweden were taken from three geographically separated herds in each country.

	Sampling 1				Sampling 2
Sampling site	Time of sampling	Total no. of samples	No. of calves	No. of adults	Time of sampling	Total no. of samples	No. of calves	No. of adults
Finland, A	2016–12	19	10	9	2017–11	21	13	8
Finland, B	2017–01	21	14	7	2017–10	20	10	10
Finland, C	2017–02	21	10	11	2017–10	20	10	10
Norway, A	2016–11	20	10	10	2017–11	19	10	9
Norway, B	2017–01	20	10	10	2018–04	20	10	10
Norway, C	2017–01	20	10	10	2018–01	20	10	10
Sweden, A	2016–11	19	9	10	2017–12	20	10	10
Sweden, B	2016–12	33^a	14	9	2017–12	20	10	10
Sweden, C	2016–11	20	10	10	2017–11	20	10	10
Iceland	2017–08	25	1	24	2018–09	103	14	89
Russian Federation	2017–12	19	3	16	n/a	n/a	n/a	n/a
Total		237	101	126		283	107	176

^aTen of the sampled animals were of unknown age.

Figure 1. (a) Map showing the sampling sites in Finland, Sweden and Norway (reindeer abattoirs with catchment areas selected to reflect herding conditions at different locations, denoted ‘A’ (■), ‘B’ (●) and ‘C’ (▲) and the sampling sites in Iceland (♦). (b) Map showing the sampling site in Ust–Yanks District, northern Yakutia, Russian Federation (♦).

Figure 1. (Continued.)

Table 2. Results of testing samples from Eurasian tundra reindeer (Rangifer t. tarandus) for anti-pestivirus antibodies in a commercial blocking ELISA: number of samples classified as positive, negative and doubtful (undetermined), and seroprevalence with 95% confidence interval (CI) per country and in sampling year 1 and 2. Doubtful results were not included in calculation of seroprevalence.

Country (year)	Positive	Negative	Doubtful	No. of samples/year	Total no. of samples/country	Seroprevalence, %, [95% CI]
Finland (1)	0	60	1	61	122	0 [0–5]^a
Finland (2)	3	53	5	61		5 [0–10]
Norway (1)	23	36	1	60	119	38 [26–51]
Norway (2)	26	33	0	59		44 [31–57]
Sweden (1)	35	37	0	72	132	49 [37–60]
Sweden (2)	29	26	5	60		48 [36–61]
Iceland (1)	2	23	0	25	128	8 [0–19]
Iceland (2)	0	91	12	103		0 [0–3]^a
Russian Federation (1)	0	19	0	19	19	0 [0–16]^a
Total	118	378	24	520		23 [19–26]

^aConfidence interval approximated by 3/(no. of samplings).

Table 3. Results of testing samples from Eurasian tundra reindeer (Rangifer t. tarandus) for anti-pestivirus antibodies in a commercial blocking ELISA, divided into age groups ‘calves’ (≤1 year) and ‘adults’ (>1 year), shown as number of animals classified as positive out of the total number of animals from each sampling site, and as a percentage.

	Calves		Adults		Total
Sampling site	Positive/Total	%	Positive/Total	%	Positive/Total	%
Finland, A	0/23	0	1/17	5.9	1/40	2.5
Finland, B	0/24	0	0/17	0	0/41	0
Finland, C	2/20	0	0/21	0	2/41	4.9
Norway, A	1/20	5.0	8/19	42.1	9/39	23.0
Norway, B	4/20	20.0	14/20	70.0	18/40	45.0
Norway, C	5/20	25.0	17/20	85.0	22/40	55.0
Sweden, A	5/19	26.3	13/20	65.0	18/39	46.2
Sweden, B	10/24	41.7	14/19	73.7	31/53^a	58.5
Sweden, C	0/20	0	15/20	75.0	15/40	37.5
Iceland	0/15	0	2/113	1.8	2/128	1.6
Russian Federation	0/3	0	0/16	0	0/19	0
Total	27/208	13.0	84/302	27.8	118/520	22.7

^aTen of the sampled animals were of unknown age, and seven of them tested positive.

Table 4. Results of testing a subset of serum samples from Eurasian tundra reindeer (Rangfer t. tarandus) for anti-pestivirus antibodies in a virus neutralisation test (VNT) in herds with ELISA-positive or doubtful animals: presence of neutralising antibodies to pestivirus and titre for two animals (a and b) from one herd as determined in the VNT, compared with competition percentages from the blocking ELISA (22.7% positive, 4.6% doubtful and 72.7% negative).

Sample (site)	Positive/Negative, VNT	Antibody titre result, VNT	Competition %, ELISA
Finland, a (A)	Negative	<1:5	27.9
Norway, a (A)	Positive	1:625	102.3
Norway, b (A)	Positive	1:125	99.3
Norway, a (B)	Positive	1:25	101.4
Norway, b (B)	Positive	1:125	97.5
Norway, a (C)	Positive	1:280	98.1
Norway, b (C)	Positive	1:1400	98.9
Sweden, a (A)	Positive	1:280	87.5
Sweden, b (A)	Positive	1:625	77.0
Sweden, a (B)	Positive	1:56	93.0
Sweden, b (B)	Positive	1:280	88.5
Sweden, a (A)	Positive	1:280	82.5
Sweden, b (B)	Positive	1:625	86.0
Iceland, a	Positive^a	>1:78,125	55.9
Iceland, b	N/D^a	N/D	50.4

^aBoth sera from Iceland caused cytopathogenic effects in the serum controls. In serum Iceland 1a, the cytopathogenic effect disappeared in dilution 1:56 and at higher dilutions the virus was inhibited until >1:78,125.