1.1.9. Bee virus X /Bee virus Y

Bee virus X (BVX) is largely symptomless in adult bees and does not multiply in larvae or pupae (Bailey and Ball, 1991). It is associated with the protozoan Malpighamoeba mellificae that causes dysentery in winter bees (Bailey et al., 1983a). Bee virus Y (BVY) is serologically related to BVX and is similarly symptomless in adult bees, larvae or pupae. It is associated in adult bees with the dysentery inducing microsporidium Nosema apis (Bailey et al., 1983a). Both viruses are common, BVY more so than BVX, with strong peaks in late winter for BVX and early summer for BVY (Table 2; Bailey and Ball, 1991).