Table 2. Targeted screening for known honey bee pathogens using PCR or RT PCR as appropriate.

Tabular values outside of parentheses are for adult bees, and values inside parentheses are for brood. For 2007, total number of samples for bees was 254 (115 weak, 139 strong), and total number for brood was 101 (33 weak, 68 strong). For 2008, total number of samples for bees was 152 (89 weak, 63 strong), and total number for brood was 80 (28 weak, 52 strong). Calculations for column parameters are as follows:

$$Proportion of weak samples positive=\frac{Number positive and weak}{Number weak}$$

$$Proportion of strong samples positive=\frac{Number positive and strong}{Number strong}$$

$$Positive predictor=\frac{Number positive and weak}{Number positive}$$

$$Sensitivity=\frac{Number positive and weak}{Number weak}$$

$$Specificity=\frac{Number non-positive and strong}{Number strong}.$$

	Weak colonies (≤5 combs of bees)		Strong colonies (>5 combs bees)
Pathogen	No. positive samples	% positive	No. positive samples	% positive	Positive predictor	Sensitivity	Specificity
2007
DWV	65 (17)	56.5 (51.5)	47 (8)	33.8 (11.8)	58 (68.0)	56.5 (51.5)	66.2 (88.2)
N. ceranae	54	47	61	43.9	47	47	56.1
N. apis	23	20	15	10.8	60.5	20	89.2
BQCV	21 (1)	18.3 (3.0)	25 (3)	18 (4.4)	45.7 (25.0)	18.3 (3.0)	82 (95.6)
CBPV	19	16.5	22	15.8	46.3	16.5	84.2
A. woodi	11	9.6	13	9.4	45.8	9.6	90.6
SBV	5	4.3	5	3.6	50	4.3	96.4
KBV	1	0.9	0	0	100	0.9	100
ABPV	0	0	1	0.7	0	0	99.3
AIV	0	0	0	0	-	0	100
IAPV	0	0	0	0	-	0	100
2008
DWV	71 (19)	79.8 (67.9)	31 (21)	49.2 (40.4)	69.6 (47.5)	79.8 (67.9)	50.8 (59.6)
BQCV	57 (16)	64 (57.1)	37 (19)	58.7 (36.5)	60.6 (45.7)	64 (57.1)	41.3 (63.5)
N. apis	48	53.9	37	58.7	56.5	53.9	41.3
N. ceranae	32	36	21	33.3	60.4	36	66.7
SBV	5 (1)	5.6 (3.6)	1 (1)	1.6 (1.9)	83.3 (50.0)	5.6 (3.6)	98.4 (98.1)
M. plutonius	6	6.7	1	1.6	85.7	6.7	98.4
CBPV	2 (1)	2.2 (3.6)	1 (1)	1.6 (1.9)	66.7 (50.0)	2.2 (3.6)	98.4 (98.1)
KBV	1	1.1	1	1.6	50	1.1	98.4
APBV	0	0	1	1.6	0	0	98.4
AIV	0	0	0	0	-	0	100
IAPV	0	0	0	0	-	0	100