Nosema ceranae infection in honeybee samples from Tuscanian Archipelago (Central Italy) investigated by two qPCR methods

Self Cite

Nosema ceranae is a worldwide distributed midgut parasite of western honey bees, leading to dwindling colonies and their collapse. As a treatment, only fumagillin is available, causing issues like resistance and hampered bee physiology. This study aimed to evaluate ApiHerb® and Api-Bioxal® as treatments against N. ceranae. The efficacy was tested using two qPCR methods based on the 16S rRNA and Hsp70 genes. In addition, these methods were compared for their aptitude for the quantification of the infection. For this, 19 colonies were selected based on the presence of N. ceranae infections. The colonies were divided into three groups: treated with ApiHerb, Api-Bioxal with previous queen caging and an untreated control. All colonies were sampled pre- and post-treatment. The bees were analyzed individually and in duplicate with both qPCR methods. All bees in the pre-treatment tested positive for N. ceranae. Both treatments reduced the abundance of N. ceranae, but ApiHerb also decreased the prevalence of infected bees. Analysis with the 16S rRNA method resulted in several orders of magnitude more copies than analysis with the Hsp70 method. We conclude that both products are suitable candidates for N. ceranae treatment. From our analysis, the qPCR method based on the Hsp70 gene results as more apt for the exact quantification of N. ceranae as is needed for the development of veterinary medicinal products.

Section: Discussionmentioning

confidence: 99%

Effect of Api-Bioxal® and ApiHerb® Treatments against Nosema ceranae Infection in Apis mellifera Investigated by Two qPCR Methods

Cilia

Garrido²,

Bonetto

et al. 2020

Self Cite

“…Nowaday, N. ceranae is distributed worldwide and is the microsporidian that is most frequently found in honey bee colonies, even on islands distant from mainland countries [ 6 , 8 , 9 ]. However, information on seasonal variation of N. ceranae infections, prevalence, and spore viability, as well as about its impact on colony conditions and bee survivorship, is particularly scarce for North America.…”

Section: Introductionmentioning

confidence: 99%

Seasonality of Nosema ceranae Infections and Their Relationship with Honey Bee Populations, Food Stores, and Survivorship in a North American Region

Emsen

Mora

Lacey

et al. 2020

Nosema ceranae is an emerging pathogen of the western honey bee (Apis mellifera L.), and thus its seasonality and impact on bee colonies is not sufficiently documented for North America. This study was conducted to determine the infection intensity, prevalence, and viability of N. ceranae in >200 honey bee colonies during spring, summer, and fall, in a North American region. We also determined the relationship of N. ceranae infections with colony populations, food stores, bee survivorship, and overwinter colony mortality. The highest rates of N. ceranae infection, prevalence, and spore viability were found in the spring and summer, while the lowest were recorded in the fall. N. ceranae spore viability was significantly correlated with its prevalence and infection intensity in bees. Threshold to high levels of N. ceranae infections (>1,000,000 spores/bee) were significantly associated with reduced bee populations and food stores in colonies. Furthermore, worker bee survivorship was significantly reduced by N. ceranae infections, although no association between N. ceranae and winter colony mortality was found. It is concluded that N. ceranae infections are highest in spring and summer and may be detrimental to honey bee populations and colony productivity. Our results support the notion that treatment is justified when infections of N. ceranae exceed 1,000,000 spores/bee.

“…The prevalence of Nosema species in A. mellifera populations in Eurasia is currently studied in most European countries [6,25,[40][41][42] and some countries of Southwest Asia as well [29,[43][44][45][46][47]. As the sole causative agent of nosemosis, N. ceranae was detected in Croatia [48], Central Italy [49,50], Iran [43,47], and Saudi Arabia [45]. In South-European countries, such as Italy [6,49,50] and Greece [25], N. ceranae had indeed practically replaced N. apis while this was not observed in Northern Europe (Ireland, Sweden, Norway, and Germany) [30,38].…”

Section: Introductionmentioning

confidence: 99%

“…As the sole causative agent of nosemosis, N. ceranae was detected in Croatia [48], Central Italy [49,50], Iran [43,47], and Saudi Arabia [45]. In South-European countries, such as Italy [6,49,50] and Greece [25], N. ceranae had indeed practically replaced N. apis while this was not observed in Northern Europe (Ireland, Sweden, Norway, and Germany) [30,38]. For example, in Sweden, in the spring of 2007, 89.0% of Nosema-positive bee colonies had N. apis and 10.0% colonies had mixed N. apis/N.…”

Section: Introductionmentioning

confidence: 99%

Prevalence of the Microsporidian Nosema spp. in Honey Bee Populations (Apis mellifera) in Some Ecological Regions of North Asia

Ostroverkhova

Konusova

Кучер

et al. 2020

Two species of microsporidia, Nosema apis and Nosema ceranae, are obligate intracellular parasites that are widespread in the world and cause the infectious disease (Nosemosis) of the Western honey bee Apis mellifera. Information on the prevalence and distribution of Nosema species in North Asia conditions is scarce. The main aim of the present study is to determine the prevalence of Nosema spp. (Nosemosis) in honey bees inhabiting some inland regions of North Asia (Western and Eastern Siberia, Altai Territory, Russia, and northeastern part of Kazakhstan). The objective of the paper is also to assess the influence of climatic factors on the spread of N. ceranae. Eighty apiaries in four ecological regions of North Asia (southern taiga, sub-taiga zone, forest steppe, and mountain taiga forests) were investigated with regard to distribution, prevalence, and diversity of Nosema infection in honey bees using duplex-PCR. Nosema infected bees were found in 65% apiaries of ecoregions studied, and coinfection was predominant (36.3% of Nosema-positive apiaries). Both N. apis and N. ceranae occur across subarctic and warm summer continental climates, but while N. apis predominates in the former, N. ceranae is more predominant in the latter. No statistically significant differences in Nosema distribution were identified in various climatic zones. In the sub-taiga zone (subarctic climate), low presence of colonies with pure N. ceranae and a significantly higher proportion of coinfection apiaries were revealed. Long-term epidemiological study of Nosema spp. prevalence in the sub-taiga zone showed a surprising percentage increase of Nosema-positive apiaries from 46.2% to 74.1% during 2012–2017. From 2012 to 2015, N. apis became a predominant species, but in 2016–2017, the coinfection was mainly detected. In conclusion, the results of this investigation showed that N. ceranae is widespread in all study ecoregions of North Asia where it exists in combination with the N. apis, but there is no replacement of N. apis by N. ceranae in the studied bee populations.