Description of Six Species of Myxobolus Bütschli, 1882 (Myxozoa: Myxosporea) from Freshwater Fish Species in Iraq

Two hundred and fifty-five fishes, belonging to six species, were collected weekly from the Tigris River in the Al-Ataifiya Region, Baghdad City during the period from July 2018 until the end of March 2019. The examination of skin and gills of these fishes showed the occurrence of six Myxobolus species. These included: M. erythrophthalmi, M. fahmii, M. gobiorum, M. ichkeulensis, M. saugati and M. sclerii. The description and measurements, besides the illustrations of these myxozoans parasites are given here for the first time in Iraq. In addition, a list of all Myxobolus species, so far recorded from the six infected fish species is given.

Morphological, histological, and molecular evidence of Myxobolusspinacurvatura(Cnidaria: Myxosporea) from Mugilcephalus in the Turkish Black Sea coast

In the present study, a total of 30 M. cephalus captured from the Samsun coast of the Black Sea, Turkey were examined for myxozoa infections. Different sizes of whitish and rounded cyst-like plasmodia were macroscopically detected in the liver and intestine wall of M. cephalus. Morphological and histological examinations were performed. The SSU rDNA was amplified using nested PCR and myxosporean-specific primers. The present Myxobolus species was identified as M. spinacurvatura based on the spore morphology and host/organ specificity. In the present study, morphological, histological, and molecular data on M. spinacurvatura were presented. Furthermore, BLASTn research showed that SSU rDNA sequences of M. spinacurvatura (accession number MH374629) were identical to that of the reference sequence of M. spinacurvatura (accession from AF378341) recorded previously. The current study includes the first record and molecular evidence of M. spinacurvatura infecting M. cephalus from the Turkish waters. To date, there is no report on comprehensive morphological, histopathological, and molecular data of M. spinacurvatura in M. cephalus as a typical host. Moreover, the new valid SSU rDNA sequence of M. spinacurvatura (accession number MH374629) was the second record in the GenBank. The present SSU rDNA sequence can also be used to construct a phylogenetic tree with other mugiliform-infecting Myxobolus species worldwide.

Prevalence and Mean Intensity of Myxobolus spp. Parasitizing Oreochromis niloticus in Cameroon

Oreochromis niloticus, being one of the most commonly cultured fish on earth constitutes a favorable biotope for myxosporidia. This study provides information concerning the prevalence and mean intensity of Myxobolus species recorded in the kidney and spleen of O. niloticus. O. niloticus were sampled in farming ponds at Bamendou in Cameroon. Classic methods concerning fishing, fish autopsy and search of Myxosporidia were used. Prevalence and mean intensity was calculated. Data analysis based on the chi-square test, Kruskal-Wallis H test and Mann-Whitney U test was done. The study revealed the presence of six Myxobolus species in the kidney and spleen of O. niloticus. All parasites species appeared frequent while their mean intensity was low or very low. The occurrence of M. fotoi was statistically lower (P < 0.05) in the kidney’s anterior portion while the mean intensity of M. agolus was statistically (P < 0.01) higher in the anterior portion of the spleen. Myxobolus cichlidarum was not found in kidney of young fish and occurrence of M. agolus statistically increases (P < 0.05) with host age. Host sex has significant influence (P < 0.05) on: occurrence of M. agolus, M. fotoi, M. agolus, M. brachysporus and M. heterosporus; and mean intensity of M. fotoi. The study revealed that in O. niloticus, the kidney and spleen harboured the same parasites species and there were only few variations in occurrences and mean intensities of parasites species recorded as function of host organs, age and sex.

A new species of myxozoa in the skeletal striated musculature of Rhamdia quelen (Quoy & Gaimard) (Siluriforme: Pimelodidae) Amazonian fish, Marajó island, Brazil

A new myxozoan was found parasitizing the freshwater catfish, Rhamdia quelen (Quoy & Gaimard), in the Marajó island, Amazon region, Brazil. The new species is described based on the results of morphological and molecular analyses. The parasite is approximately 1.5 mm in diameter and develops in the musculature of the host in the form of spherical, whitish cysts, which are visible macroscopically between the epaxial and hypaxial layers. When ruptured, these cysts produced ellipsoidal spores with a mean length of 11.4 μm (10.7–12.6) and width of 7.2 μm (6.4–7.9). Anomalous spores with a caudal elongation, vesicles in the peripheral portion of the spore and ornamentation of the valves were also observed. The results of the phylogenetic analysis of sequences of the 18S rDNA gene using Bayesian Inference indicated clear differences among the Myxobolus species that reinforced the taxonomic position of the parasite, confirming its status as a new species, denominated Myxobolus arariensis n. sp.