Free-living ciliates as potential reservoirs for eukaryotic parasites: Occurrence of a trypanosomatid in the macronucleus of Euplotes encysticus

Research output: Contribution to journalResearch articleContributedpeer-review


  • S.I. Fokin - (Author)
  • M. Schrallhammer - , Chair of Limnology, University of Freiburg (Author)
  • C. Chiellini - (Author)
  • F. Verni - (Author)
  • G. Petroni - (Author)


Background: Flagellates of the family Trypanosomatidae are obligate endoparasites, which can be found in various hosts. Several genera infect insects and occur as monoxenous parasites especially in representatives of Diptera and Hemiptera. These trypanosomatid flagellates probably share the worldwide distribution of their hosts, which are often infested by large numbers of endoparasites. Traditionally, their taxonomy was based on morphology, host origin, and life cycle. Here we report the characterization of a trypanosomatid infection detected in a protozoan, a ciliate collected from a polluted freshwater pond in a suburb of New Delhi (India). Methods. Live observations and morphological studies applying light, fluorescence and transmission electron microscopy were conducted. Molecular analyses of host and parasite were performed and used for phylogenetic reconstructions and species (host) or genus level (parasite) identification. Results: Although the morphological characteristics were not revealing, a high similarity of the trypanosomatids 18S rRNA gene sequence to Herpetomonas ztiplika and Herpetomonas trimorpha (Kinetoplastida, Trypanosomatidae), both parasites of biting midges (Culicoides kibunensis and Culicoides truncorum, respectively) allowed the assignment to this genus. The majority of the host population displayed a heavy infection that significantly affected the shape of the host macronucleus, which was the main site of parasite localization. In addition, the growth rate of host cultures, identified as Euplotes encysticus according to cell morphology and 18S rRNA gene sequence, was severely impacted by the infection. Conclusions: The host-parasite system described here represents a recent example of free-living protists acting as environmental reservoirs for parasitic eukaryotic microorganisms. © 2014 Fokin et al.; licensee BioMed Central Ltd.


Original languageEnglish
Article number203
JournalParasites and Vectors
Issue number1
Publication statusPublished - 2014

External IDs

Scopus 84900501626



  • Ciliophora, Endosymbiont, Euplotes encysticus, Herpetomonas, Host range, Leptomonas, Macronucleus, Parasite, Phytomonas, Protozoa