Differential diagnosis of the honey bee trypanosomatids Crithidia mellificae and Lotmaria passim

Jorgen Ravoet*, Ryan S. Schwarz, Tine Descamps, Orlando Yañez, Cansu Ozge Tozkar, Raquel Martin-Hernandez, Carolina Bartolomé, Lina De Smet, Mariano Higes, Tom Wenseleers, Regula Schmid-Hempel, Peter Neumann, Tatsuhiko Kadowaki, Jay D. Evans, Dirk C. de Graaf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)


Trypanosomatids infecting honey bees have been poorly studied with molecular methods until recently. After the description of Crithidia mellificae (Langridge and McGhee, 1967) it took about forty years until molecular data for honey bee trypanosomatids became available and were used to identify and describe a new trypanosomatid species from honey bees, Lotmaria passim (Evans and Schwarz, 2014). However, an easy method to distinguish them without sequencing is not yet available. Research on the related bumble bee parasites Crithidia bombi and Crithidia expoeki revealed a fragment length polymorphism in the internal transcribed spacer 1 (ITS1), which enabled species discrimination. In search of fragment length polymorphisms for differential diagnostics in honey bee trypanosomatids, we studied honey bee trypanosomatid cell cultures of C. mellificae and L. passim. This research resulted in the identification of fragment length polymorphisms in ITS1 and ITS1-2 markers, which enabled us to develop a diagnostic method to differentiate both honey bee trypanosomatid species without the need for sequencing. However, the amplification success of the ITS1 marker depends probably on the trypanosomatid infection level. Further investigation confirmed that L. passim is the dominant species in Belgium, Japan and Switzerland. We found C. mellificae only rarely in Belgian honey bee samples, but not in honey bee samples from other countries. C. mellificae was also detected in mason bees (Osmia bicornis and Osmia cornuta) besides in honey bees. Further, the characterization and comparison of additional markers from L. passim strain SF (published as C. mellificae strain SF) and a Belgian honey bee sample revealed very low divergence in the 18S rRNA, ITS1-2, 28S rRNA and cytochrome b sequences. Nevertheless, a variable stretch was observed in the gp63 virulence factor.

Original languageEnglish
Pages (from-to)21-27
Number of pages7
JournalJournal of Invertebrate Pathology
Publication statusPublished - 1 Sept 2015


  • Apis mellifera
  • Crithidia mellificae
  • Gp63
  • Honey bee
  • ITS1
  • Lotmaria passim

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