Honey Bee Health in Apiaries in the Vale do Paraiba, Sao Paulo State, Southeastern Brazil

Bee health is a growing global concern due to phenomena with as yet undefined causes, such as the sudden population decline of colonies that has been observed in apiaries in many countries, recently including Brazil. The main objective of this study was to assess the presence and/or prevalence of pathogens that afflict Africanized Apis mellifera bees in the Vale do Paraiba region of Sao Paulo state, Brazil. Three sampling periods were established: period 1 - August and September 2009 (winter/early spring); period 2 - December 2009 and January 2010 (summer); and period 3 - April and May 2010 (autumn). Samples were collected of honeycomb from the brood area, combs containing capped brood, adult bees that cover the brood and foraging bees, to evaluate the presence and prevalence of Paenibacillus larvae, Varroa destructor and Nosema sp. The results indicated that the intensity of infection by Nosema ceranae and infestation rates of V. destructor in the hives were low (mean 637x10 super(3) spores of Nosema ceranae, 5.41% infestation of Varroa in adult bees and 4.17% infestation of Varroa in brood), with no detection of P. larvae spores in the samples. The prevalence of N. ceranae and V. destructor was high, at respective values of 85.2 and 95.7%. All told, 1,668 samples were collected from 438 hives, in 59 apiaries. These results demonstrate that although mites and microsporidia are widespread in the region's colonies, the Africanized bees are apparently tolerant to pathogens and parasites. However, the mechanisms related to defense against pathogens are not completely clear, and monitoring and prophylactic measures are essential to maintain the health of bee colonies.