An international inter-laboratory study on Nosema spp. spore detection and quantification through microscopic examination of crushed honey bee abdomens

Véronique Duquesne (1) , Cristina Gastaldi (1) , Aurélie del Cont (1) , Nicolas Cougoule (1) , Andrzej Bober (2) , Marleen Brunain (3) , Gabriela Chioveanu (4) , Noel Demicoli (5) , Petra Deakne Paulus , Pilar Fernandez Somalo (6) , Miriam Filipova (7) , Eva Forsgren (8) , Anna Granato (9) , Kalinka Gurgulova (10) , Sirpa Heinikainen (11) , Age Kärssin (12) , Irena Kinduriene (13) , Hemma Köglberger (14, 15) , Konstantinos Oureilidis (16) , Zanda Ozolina , Martin Pijacek , Metka Pislak Ocepek , Marc Oliver Schäfer , Ivana Tlak Gajger , Maria José Valerio , Maureen Wakefield , Stéphanie Franco (1)

1 Laboratoire de Sophia Antipolis
2 NVRI - National Veterinary Research Institute [Pulawy, Pologne]
3 UGENT - Universiteit Gent = Ghent University
4 IDAH - Institutul de Diagnostic şi Sănătate Animală = Institute for Diagnosis and Animal Health
5 NVL - National Veterinary Laboratory
6 Laboratorio Central de Veterinaria
7 Department of Molecular Biology and Epizootiology, Veterinary and Food Institute in Dolny Kubin, State Veterinary and Food Institute, NRL for Honeybee Health, 026 01 Dolny Kubin, Slovakia
8 EBC - Department of Ecology and Genetics [Uppsala]
9 IZSVe - Istituto Zooprofilattico Sperimentale delle Venezie
10 National Diagnostic and Research Veterinary Medical Institute, Aquaculture, Fish and Bee Diseases, NRL for Bee Diseases, 1040 Sofia, Bulgaria
11 Finnish Food Safety Authority Evira
12 Estonian Veterinary and Food Laboratory
13 National Food and Veterinary Risk Assessment Institute of Lithuania
14 Department for Apiculture and Bee protection, Ages-Austrian Agency for Health and Food Safety, 1220 Vienna, Austria
15 Austrian Agency for Health and Food Safety (AGES)
16 BIOR - Institute of Food Safety, Animal Health and Environment

Nosemosis is a microsporidian disease causing mortality and weakening of honey bee colonies, especially in the event of co-exposure to other sources of stress. As a result, the disease is regulated in some countries. Reliable and harmonised diagnosis is crucial to ensure the quality of surveillance and research results. For this reason, the first European Interlaboratory Comparison (ILC) was organised in 2017 in order to assess both the methods and the results obtained by National Reference Laboratories (NRLs) in counting Nosema spp. spores by microscopy. Implementing their own routine conditions of analysis, the 23 participants were asked to perform an assay on a panel of ten positive and negative samples of crushed honey bee abdomens. They were asked to report results from a qualitative and quantitative standpoint. The assessment covered specificity, sensitivity, trueness and precision. Quantitative results were analysed in compliance with international standards NF ISO 13528 (2015) and NF ISO 5725-2 (1994). Three results showed a lack of precision and five a lack of trueness. However, overall results indicated a global specificity of 98% and a global sensitivity of 100%, thus demonstrating the advanced performance of the microscopic methods applied to Nosema spores by the NRLs. Therefore, the study concluded that using microscopy to detect and quantify spores of Nosema spp. was reliable and valid.

Mots clés: Diagnosis; Interlaboratory comparison; Microscopic counting; Microsporidia; Nosema spp.

Domaines: Sciences du Vivant [q-bio]

Véronique Duquesne, Cristina Gastaldi, Aurélie del Cont, Nicolas Cougoule, Andrzej Bober, et al.. An international inter-laboratory study on Nosema spp. spore detection and quantification through microscopic examination of crushed honey bee abdomens. Journal of Microbiological Methods, 2021, 184, pp.106183. ⟨10.1016/j.mimet.2021.106183⟩. ⟨anses-03627158⟩