Effects at Nearctic north-temperate latitudes of indoor versus outdoor overwintering on the microsporidium Nosema ceranae and western honey bees (Apis mellifera)

The stability and effectiveness of fumagillin in controlling Nosema ceranae (Microsporidia) infection in honey bees (Apis mellifera) under laboratory and field conditions

“…In Canada, different efficacy results were recently obtained when applying 8 L of syrup with a total of 190 mg fumagillin (a very diluted mixture) and only testing the colonies the following spring while establishing intensity by mean spore count (Williams et al 2010(Williams et al , 2011, a parameter that is quite unreliable to establish the state of the disease (Meana et al 2010), even when external bees were sampled. However, in this study, neither the quantity consumed, the time needed to consume all the food (medicated or not), nor the conditions of storage were indicated.…”

Infra-Population and -Community Dynamics of the Parasites Nosema apis and Nosema ceranae, and Consequences for Honey Bee (Apis mellifera) Hosts

“…Nonetheless, sympatric honey bee populations, and even individuals, can be co-parasitized by both N. ceranae and Nosema apis [38], [39], the latter being the historical microsporidian species of honey bees [12], [24], [40]. Similar to N. ceranae , N. apis can cause significant tissue damage in the gut that ultimately results in increased winter colony mortality or poor build-up of surviving colonies in spring [40].…”

“…Similar to N. ceranae , N. apis can cause significant tissue damage in the gut that ultimately results in increased winter colony mortality or poor build-up of surviving colonies in spring [40]. Within the last decade, N. ceranae has been detected on all continents where honey bees are maintained, while the occurrence of N. apis has diminished [10], [12], [24], [41]–[43], suggesting a numerical response by N. apis to co-infection that has resulted in decreased prevalence and distribution of the parasite. This apparent exclusion appears to be geographically heterogeneous, and is likely governed by previously discussed genetic and environmental factors influencing dispersal and competition for limited resources during density-dependent parasite regulation [15], [18], [26]–[30], [44].…”

Distribution, epidemiological characteristics and control methods of the pathogen Nosema ceranae Fries in honey bees Apis mellifera L. (Hymenoptera, Apidae)

“…Following this principle Williams et al (2010) studied the effects of the environment on N. ceranae by hibernating a group of hives in controlled conditions as compared to a group in the open air. They concluded that treatment by hibernation does not have a significant effect on the attack intensity N. ceranae in the following spring.…”

“…Its presence was detected recently in Uruguay, although it has not yet caused particular damage in that area and its impact is still unclear (Invernizzi et al 2009, Texeira et al 2013, probably due to the presence of a less virulent strain of the parasite or a resistant feature in the bees (Higes et al 2008, Vandame andPalacio 2010). It is therefore suggested that the parasite is more pathogenic in Europe than in North America , van Engelsdorp et al 2009, making it difficult to assess the real mortality in western colonies (Williams et al 2010). Furthermore, tests carried out in Spain indicated that both N. ceranae and N. apis may be present in hives without causing symptoms of the disease, and that there is no evidence of the replacement of N. apis by N. ceranae, suggesting that nosemosis is not the principal cause of hive collapse and death (Fernández et al 2012).…”