Occurrence of most important Western honey bee (Apis mellifera) parasites (Nosema spp. and Varroa destructor) in Latvia

For the last decades, trend of colony losses in Europe and worldwide is the main topic concerning honey bee health. The life span of honey bees is affected by a combination of a number of biotic and abiotic factors including infections by the mite Varroa destructor, Varroa-associated viruses, Nosema microsporidia, drought, bacteria and/or fungi. In the present study samples were collected from 570 apiaries throuhout Latvia at three times (May/June; July/August and September/October). The results showed that honey bee parasites Nosema spp. and V. destructor occurred in all regions of Latvia. A single species infection of Nosema ceranae was most prevalent in two seasons with low mean intensity. In contrast, mean intensity of Nosema apis was the highest overall. V. destructor prevalence was the highest in autumn and similarly high in most regions of country throughout the year, except in the Kurzeme region where it was the lowest.