Molecular Detection and Differentiation of Arthropod, Fungal, Protozoan, Bacterial and Viral Pathogens of Honeybees

The honeybee Apis mellifera is highly appreciated worldwide because of its products, but also as it is a pollinator of crops and wild plants. The beehive is vulnerable to infections due to arthropods, fungi, protozoa, bacteria and/or viruses that manage to by-pass the individual and social immune mechanisms of bees. Due to the close proximity of bees in the beehive and their foraging habits, infections easily spread within and between beehives. Moreover, international trade of bees has caused the global spread of infections, several of which result in significant losses for apiculture. Only in a few cases can infections be diagnosed with the naked eye, by direct observation of the pathogen in the case of some arthropods, or by pathogen-associated distinctive traits. Development of molecular methods based on the amplification and analysis of one or more genes or genomic segments has brought significant progress to the study of bee pathogens, allowing for: (i) the precise and sensitive identification of the infectious agent; (ii) the analysis of co-infections; (iii) the description of novel species; (iv) associations between geno- and pheno-types and (v) population structure studies. Sequencing of bee pathogen genomes has allowed for the identification of new molecular targets and the development of specific genotypification strategies.

Detection of Paenibacillus larvae spores in honey by conventional PCR and its potential for American foulbrood control

The present study attempted to detect Paenibacillus larvae spores in naturally contaminated honeys by conventional PCR and to determine the sensitivity of the reaction with different primer pairs in order to assess its potential for American foulbrood control. For this purpose, duplicated honey samples were collected from 5 bee colonies with clinical American foulbrood and 5 clinically healthy colonies in the same apiary. The samples were analysed for the presence of Paenibacillus larvae spores by culture method and subsequent PCR detection in bacterial colonies. The PCR performed directly with spore DNA failed in 6 out of the 20 honeys investigated with spore load of 10–46 cfu/g. The established sensitivity of 70% of the reaction in the present study shows that the adequate control of American foulbrood by analysis of honeys for Paenibacillus larvae spore contamination should be done by combination of culture method followed by PCR in bacterial colonies, whose sensitivity was 100%.