Description of a new actinosporean type from South African freshwater

Székely, Csaba and Avenant-Oldewage, Annemarie and Molnár, Kálmán (2005) Description of a new actinosporean type from South African freshwater. In: 33rd Annual Congress of the Parasitological Society of Southern Africa (PARSA), 2004. szeptember 12-15., Manyane, Pilansberg National Park.

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Abstract

The 1st report on actinospores described these organisms as parasites related to myxosporeans. For a long time this group of parasites was believed to represent an independent taxonomic entity. Research on actinosporeans became more intensive after it was shown that they corresponded to the intraoligochaete developmental stages of fish-parasitic myxosporeans. The relevant research includes earlier surveys, as well as studies of actinospore infection of oligochaetes in natural waters and fish farms in connection with the life cycle of myxosporeans. Relatively little data areavailable on myxosporean infections of African freshwater fishes and only a single paper appeared in Africa on their actinosporean alternative stages infecting oligochaetes. In September 2003, actinospore infection of oligochaetes collected from the mud of 2 freshwater biotopes in South Africa was studied. Using the ‘cell-well plate method’, a new aurantiactinomyxon type was found in 1.1 % of the examined Branchiura sowerbyi oligochaete specimens from Rietvlei River northwards to Johannesburg, Gauteng. In 1.5 % of Branchiura sowerbyi collected in a pond (Padda Dam), near the Rand Afrikaans University, Johannesburg, the same aurantiactinomyxon type was found. Infected oligochaetes were found only after collection, no actinosporean release was recorded in Branchiura specimens kept alive for several weeks. Actinospore infection showed high intensity in oligochaetes in both positive cases. Until now, no actinosporean stages of myxosporeans have been described from South Africa. The aurantiactinospore type presented in this paper differs from the already known types described in the special literature.

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