Short communication: Survival of honey bees (Apis mellifera) infected with Crithidia mellificae (Langridge and McGhee: ATCC® 30254™) in the presence of Nosema ceranae

Abstract

Crithidia mellificae, a trypanosomatid parasite of Apis mellifera, has been proposed to be one of the pathogens responsible for the serious honey bee colony losses produced worldwide in the last decade, either alone or in association with Nosema ceranae. Since this pathogenic effect contradicts the results of the experimental infections originally performed by Langridge and McGhee nearly 40 years ago, we investigated the potential linkage of this protozoan with colony decline under laboratory conditions. Nosema-free and trypanosomatid-free honey bees from three different colonies were experimentally infected with fresh C. mellificae spheroid forms (reference strain ATCC30254), with N. ceranae fresh spores and with both parasites at the same time. Replicate cages were kept at 27 °C and used to analyse survival. C. mellificae spheroid forms did not reduce significantly the survival of the worker bees (64.5% at 30 days post-infection vs. 77.8% for the uninfected bees used as controls; differences were non statistically significant) under these experimental conditions. In contrast, the cages infected with N. ceranae exhibited higher rates of mortality from the 20th day post-infection onwards, irrespective of the presence of C. mellificae, suggesting that the spheroid forms of the latter have no pathological effect on A. mellifera.

Trypanosomatid parasite dynamically changes the transcriptome during infection and modifies honey bee physiology

“…This appears to be the case under hive condition as well, since we recovered L. passim-infected honey bees at 37 days after infection. Many parasites share these infection characteristics in order to increase dissemination to other individuals through feces 6,[35][36][37] .…”

Workflow of Lotmaria passim isolation: Experimental infection with a low-passage strain causes higher honeybee mortality rates than the PRA-403 reference strain

“…In the second part of the study, carried out in mid-autumn (2019), the differences in honeybee mortality rates between the L. passim C1 and the ATCC-PRA403 reference strain were determined. To this end, adult worker bees from brood frames kept in an incubator at 34 (±1) °C were caged upon emergence (20 bees/cage; 9 cages) and maintained in incubators (Memmert® IPP500) at 27 °C ( Gómez-Moracho et al, 2020 ; Higes et al, 2016 ). Two days later, the bees were randomly divided into three different treatment groups (3 cages/treatment): L. passim C1 infected bees, ATCC-PRA403 infected bees, and uninfected control bees.…”

Nosema ceranae in Apis mellifera: a 12 years postdetection perspective

“…It was suggested that co‐infection by an iridovirus and N. ceranae was linked with honey bee decline in the USA (Bromenshenk et al ., ), but the presence of iridovirus in both CCD and healthy colonies was not lately confirmed (Tokarz et al ., ). A link was suggested between the presence of C. mellificae and N. ceranae in summer, and the negative synergy between the two was proposed to be a predictive marker of winter mortality (Ravoet et al ., ), although laboratory infection with both parasites did not differ from the group infected with N. ceranae only (Higes et al ., ). The combination of certain pesticides and the effects of N. ceranae on bee colonies have also been studied, such as the treatment of sunflowers with the insecticide fipronil and its effect on honey bee colony loss (Bernal et al ., ).…”