Molecular identification and level of infection of Vairimorpha ceranae in Apis mellifera (Hymenoptera: Apidae)

Abstract

There are two species of Vairimorpha spp. that can affect Apis mellifera. Vairimorpha apis and V. ceranae are responsible for causing the disease nosemosis, which is considered one of the most prevalent and economically devastating diseases. This study aimed to record the presence and infection level of Vairimorpha spp. in A. mellifera workers from colonies located in commercial apiaries in the Jacuípe Basin Region, Bahia, Brazil. Bee samples were collected from five apiaries monthly for one year. The samples were transported to the Insecta research laboratory at the Federal University of Recôncavo da Bahia, in the city of Cruz das Almas, Bahia. Analysis was conducted using optical microscopy to detect fungal spores and determine the infection level through spore counting using a Neubauer chamber. Subsequently, samples in which the presence of spores was observed underwent Polymerase Chain Reaction (PCR) for fungus identification at the species level. The results reveal the detection of only V. ceranae species in all five evaluated apiaries through PCR. The infection level ranged from none to semi-strong, although it is not a strong infection. The V. ceranae species was detected throughout all months of the year, and when environmental conditions are favorable, they tend to multiply rapidly.