Table 2.
Summary of the odds ratios (95% CI range) and the percent of positive pathogen detections using PCR for worker bee samples (5 g composite sample) in 2017 and queen samples in 2016 and 2017 from colonies with good-brood or poor-brood patterns. Only pathogens with positive detections are included; chronic bee paralysis virus was not found in any samples. Also included are the comparisons between poor-brood and good-brood colonies with symptoms of the brood disease chalkbrood, and worker bee samples with Varroa destructor mite levels >3 mites per 100 bees, and Nosema spp. levels >1 million spores per bee as determined by microscopy. No pathogen had significantly higher odds of being in a poor-brood pattern colony or queen.
| % of Samples with Positive Detections | ||||
|---|---|---|---|---|
| Sample Type (Year) | Factor | Good-Brood | Poor-Brood | Odds Ratio (95% CI) |
| Queens (2016) | No pathogens detected | 33 | 13 | 0.31 (0.05–1.93) |
| Black Queen Cell Virus | 7 | 0 | 0.31 (0.01–8.29) | |
| Deformed Wing Virus type A | 40 | 60 | 2.25 (0.52–9.70) | |
| Deformed Wing Virus type B | 53 | 73 | 2.41 (0.52–11.1) | |
| Lake Sinai Virus | 13 | 0 | 0.17 (0.01–3.96) | |
| Queens (2017) 1 | No pathogens detected | 79 | 78 | 0.93 (0.2–4.47) |
| Deformed Wing Virus type A | 5 | 11 | 2.25 (0.19–27.22) | |
| Deformed Wing Virus type B | 16 | 17 | 1.07 (0.19–6.13) | |
| Israeli Acute Paralysis Virus | 5 | 0 | 0.33 (0.01–8.73) | |
| Worker bees (2016) | >3 Varroa mites per bee | 6 | 6 | 1.00 (0.06–17.41) |
| >1 million Nosema spores per bee, by microscopy | 12 | 18 | 1.61 (0.23–11.09) | |
| Worker bees (2017) 2 | >3 Varroa mites per bee | 0 | 5 | 3.15 (0.12–81.74) |
| >1 million Nosema spores per bee, by microscopy | 33 | 48 | 1.82 (0.52–6.33) | |
| Acute Bee Paralysis Virus | 10 | 5 | 0.48 (0.04–5.68) | |
| Black Queen Cell Virus | 38 | 19 | 0.38 (0.09–1.55) | |
| Deformed Wing Virus type A | 5 | 14 | 3.33 (0.32–34.99) | |
| Deformed Wing Virus type B | 24 | 43 | 2.40 (0.64–9.03) | |
| Israeli Acute Paralysis Virus | 19 | 5 | 0.21 (0.02–2.09) | |
| Lake Sinai Virus | 100 | 100 | 1.00 (0.02–52.74) | |
| Trypanosomes | 10 | 19 | 2.24 (0.36–13.78) | |
| Nosema spp., by PCR | 90 | 86 | 0.63 (0.09–4.23) | |
| Brood disease (2016) | Chalkbrood | 6 | 0 | 0.31 (0.01–8.27) |
| Brood disease (2017) | Chalkbrood 3 | 52 | 76 | 2.91 (0.78–10.89) |
1 Queens in 2017 were sampled after the queen exchange but classified by their source colony status (before the exchange) of good-brood or poor-brood. 2 Sampled before the queen exchange. 3 Accounts for chalkbrood found before and/or after queen exchange.