Kudoa saudiensis sp. n. (Myxosporea: Multivalvulida) infecting oocytes of the Indian mackerel Rastrelliger kanagurta (Perciformes: Scombridae)

Abstract

During a survey the occurrence of Kudoa quraishii Mansour, Harrath, Abd-Elkader, Alwasel, Abdel-Baki et Al Omar, 2014, recently identified in the muscles of the Indian mackerel, Rastrelliger kanagurta (Cuvier), a species of Kudoa Meglitsch, 1947 infecting oocytes of mature females of the same host fish was found. The new species, for which the name Kudoa saudiensis sp. n. is proposed, infects oocytes that are enlarged with a whitish colour. The parasite develops in vesicular polysporous plasmodia within the oocyte. Infection occurs with a mean prevalence of 20% (7/35) of examined females. Mature spores are quadratic in shape in apical view, having four equal valves and four symmetrical polar capsules. Fresh spores are 2.4-3.6 µm long (mean ± SD 3.1 ± 0.3 µm), 4.3-5.4 µm (4.7 ± 0.3 µm) wide and 3.4-4.3 µm (3.8 ± 0.3 µm) in thickness and long. The smaller size of the new Kudoa species was the distinctive feature that separates it from all previously described species. Molecular analysis based on the SSU rDNA sequences shows that the highest percentage of similarity of 98.5% was observed with K. ovivora Swearer et Robertson, 1999, reported from oocytes of labroid fish from the Caribbean coasts of Panama. The percentage of similarity was 98% with K. azevedoi Mansour, Thabet, Chourabi, Harrath, Gtari, Al Omar et Ben Hassine, 2013 and 89% with K. quraishii. Phylogenetic analysis of the SSU and LSU rDNA data revealed a consistent of the new species with K. azevedoi and K. ovivora. Our findings support the creation of Kudoa saudiensis sp. n. that infects oocytes of the Indian mackerel Rastrelliger kanagurta.

Negative impact on the reproductive potential of blue jack mackerel Trachurus picturatus by Kudoa infection of the ovary

“…The Kudoa spores found in the present study are of small size which appears to be characteristic of the Kudoa species infecting ovaries (Mansour et al 2013, Mansour et al 2015. However, the fact that measurements in the present study were made on fixed ovary tissue will certainly bias them negatively, hindering a substantiated comparison of the Kudoa measurements with those reported by other authors.…”

“…samples. Few studies report the occurrence of ovary infection (Swearer & Robertson 1999, Mansour et al 2013, Mansour et al 2015) and all describe a new Kudoa species. Most Kudoa species are host specific, infecting fishes of a particular family or even a single species (Whipps & Kent 2006) and many seem to be also tissue specific.…”

First report of Kudoa species (Myxozoa, Multivalvulida) infection in purple-spotted Bigeye (Priacanthus tayenus) from the Saudi Arabian Gulf

“…infections are a global concern in the fishing sector, often linked to myoliquefaction and the development of multiple plasmodia in fish muscles [ 12 ] . Notably, Kudoa thyrsites , a widely distributed myxosporean species, is known to induce "soft flesh" in affected fish [ 13 ] , leading to reduced market value and significant economic losses [ 14 ].…”

“…Despite its commercial value, P. tayenus has not been extensively studied regarding its parasitological aspects in the Arabian Gulf. Previous studies in Saudi Arabia mainly focused on Kudoidae in marine fish, with no records of their presence in purple-spotted bigeye specimens from the Jubail landing site in the Eastern part of the Saudi Arabian Gulf [13,15]. Therefore, investigating the parasitological aspects of P. tayenus and their histopathological effects on the fish is crucial, especially when Kudoa spp.…”

Morphometric and molecular characterization of Kudoa encrasicoli n. sp. (Myxozoa: Myxosporea) from the European anchovy, Engraulis encrasicolus (L.) (Clupeiformes: Engraulidae)

“…(from Mugil cephalus), which have myxospores with 2 SVs and PCs, have led to amend the genus Kudoa to include myxospores having 2-13 (mostly 4) SVs and PCs (Casal et al, 2019). It comprises more than 100 nominal species, most of them being histozoic myxozoans typically infecting the musculature of a large range of fish species (Moran et al, 1999;Eiras et al, 2014;Kristmundsson & Freeman 2014;Mansour et al, 2014Mansour et al, , 2015Shirakashi et al, 2014;Yokoyama et al, 2014;Abdel-Baki et al, 2016;Azevedo et al, 2016;Shin et al, 2016;Kasai et al, 2016aKasai et al, , 2016bKasai et al, , 2017. Some of these species (e. g. K. thyrsites (Gilchrist, 1923) and others) are economically important because they can form macroscopic cysts in the host's muscle tissues and/or cause the ''soft flesh'', ''milky flesh'' or ''jelly flesh'' syndrome, a postmortem myoliquefactive degeneration negatively affecting the flesh texture of certain severely infected species (Moran et al, 1999;Levsen et al, 2008;Henning & Manley 2012;Eiras et al, 2014;Marshall et al, 2016).…”