Chronic paralysis is an infectious and contagious disease of adult honeybees caused by the chronic bee paralysis virus (CBPV) (10). CBPV is classified as a positive-sense, single-stranded RNA virus but has not been assigned to a genus or family. Chronic paralysis has been given a variety of names, such as “hairless black syndrome” and “little blacks,” and is the only common viral disease of adult bees that has well-described symptoms, which include abnormal trembling of wings and body. Some individuals become almost hairless and dark in appearance and suffer nibbling attacks from healthy bees of their colony. Affected bees become flightless, often crawling on the ground and on the stems of grass, sometimes in masses of thousands of individuals. The bloated abdomen is caused by distension of the honey sac with fluid, leading to the so-called “dysentery” symptom. Sick individuals die within a few days of the onset of symptoms........................
Knowledge of the mechanism of CBPV spread is crucial to our understanding of the dynamics of the disease. Laboratory experiments show that adult workers are very susceptible to CBPV infection by injection. Inoculated bees usually show symptoms of paralysis at about 5 or 6 days postinoculation (p.i.), appearing feeble and exhibiting the same trembly movements as bees infected naturally in the field. These individuals remain alive for several more days (10). However, despite the efficiency of virus inoculation in laboratory trials, CBPV infections have never been related to Varroa destructor infestations (15), and the virus has not been reported in this parasite
