Myxobolus opsaridiumi sp. nov. (Cnidaria: Myxosporea) infecting different tissues of an ornamental fish, Opsaridium ubangiensis (Pellegrin, 1901), in Cameroon: morphological and molecular characterization

Guy Benoit Lekeufack-Folefack,Jameel Al-Tamini,Suliman Yousef Al-Omar,Lamjed Mansour,Abraham Fomena,Armandine Estelle Tchoutezo-Tiwa

doi:10.5852/ejt.2021.733.1221

Guy Benoit Lekeufack-Folefack, Jameel Al-Tamini + Show 4 more

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https://doi.org/10.5852/ejt.2021.733.1221

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Abstract

We report a new myxozoan, Myxobolus opsaridiumi sp. nov., infecting the ornamental fish Opsaridium ubangiensis (Pellegrin, 1901) collected from the Anga River near the city of Yaounde, Cameroon. Plasmodia were found in the skin, muscles and spleen. The overall prevalence of infection was 54.7% (288 parasitized fish out of 526 examined). The myxospores were ovoid to subspherical in frontal view and lenticular in lateral view. The valves were symmetrical and relatively thick, without edge markings. The myxospore measurements were 10.7 ± 0.14 (10–11.5) μm long, 9 ± 0.15 (8–10) μm wide and 6.2 ± 0.7 (5.6–7.2) μm thick. The two ovoid polar capsules were equal in size, converging and opening together at the anterior end, measuring 5 ± 0.07 (4.3–6.0) μm long and 2.7 ± 0.07 (2.2–3.0) μm wide. Polar filaments were coiled from 5 to 7 turns. Histopathological analysis revealed no inflammatory reaction associated with the infection. A BLAST search found that the newly obtained 18 rDNA sequence had a low sequence similarity with available sequences for Myxobolus on GenBank. A phylogenetical analysis based on ribosomal DNA partial sequences showed that M. opsaridiumi sp. nov. is closely associated with several species of Myxobolus infecting cyprinid fish.

Highlights

Myxozoa are cosmopolitan microscopic cnidarians that live as endoparasites of invertebrate and vertebrate hosts, primarily in aquatic environments (Kent et al 2001; Lom & Dyková 2006; JiménezGuri et al 2007)
Sampling examination A total of 526 specimens of Opsaridium ubangiensis were caught with a fine-meshed net from September 2014 to July 2017 from the Anga River at Yaounde (3°51′37ʺ N, 11°23′27ʺ E, Centre Region, Cameroon, Central Africa)
Specimens were first examined with the naked eye and with an Olympus BO61 binocular lens to detect the presence of cysts

Summary

Introduction

Myxozoa are cosmopolitan microscopic cnidarians that live as endoparasites of invertebrate and vertebrate hosts, primarily in aquatic environments (Kent et al 2001; Lom & Dyková 2006; JiménezGuri et al 2007). More than 2400 species and 64 genera are recognized (Zhang et al 2013; Atkinson et al 2018; Liu et al 2019; Mathews et al 2020). They are characterized by morphological simplicity and life-cycle complexity (Fiala et al 2015). These parasites are identifiable at the spore stage, as actinospores in invertebrate hosts and myxospores in vertebrates. Most species infect specific organs, but some have been reported to infect several organs in the same host species (Lekeufack & Fomena 2013; Eiras et al 2014)

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