Exotic myxozoan parasites establish complex life cycles in farm pond aquaculture

Barbara Salti; Stephen D Atkinson; Vera Brekhman; Margarita Smirnov; Tamar Lotan

doi:10.1016/j.jip.2024.108105

Exotic myxozoan parasites establish complex life cycles in farm pond aquaculture

J Invertebr Pathol. 2024 Apr 13:204:108105. doi: 10.1016/j.jip.2024.108105. Online ahead of print.

Authors

Barbara Salti¹, Stephen D Atkinson², Vera Brekhman¹, Margarita Smirnov³, Tamar Lotan⁴

Affiliations

¹ Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, 3498838 Haifa, Israel.
² Department of Microbiology, Oregon State University, Nash Hall 226, Corvallis, OR 97331, USA.
³ Central Fish Health Laboratory, Department of Fisheries and Aquaculture, Ministry of Agriculture and Rural Development, 10803 Nir David, Israel.
⁴ Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, 3498838 Haifa, Israel. Electronic address: lotant@univ.haifa.ac.il.

PMID: 38614293
DOI: 10.1016/j.jip.2024.108105

Abstract

Myxozoans are obligate parasites with complex life cycles, typically infecting fish and annelids. Here, we examined annelids from fish farm pond sediments in the Beit Shean Valley, in the Syrian-African Rift Valley, Israel, for myxozoan infections. We examined 1486 oligochaetes, and found 74 (5 %) were infected with actinospore stages. We used mitochondrial 16S sequencing to infer identity of 25 infected annelids as species of Potamothrix, Psammoryctides, Tubifex and Dero. We identified 7 myxozoan types from collective groups Neoactinomyxum and Sphaeractinomyxon, and characterized them by small subunit ribosomal DNA sequencing. The Neoactinomyxum type was genetically most similar (∼93 %) to cyprinid fish-infecting Myxobolus spp. The six Sphaeractinomyxon types were genetically similar (93-100 %) to Mugilid-infecting Myxobolus spp.; with one being the previously unknown actinospore stage of a myxospore that infects mullet from aquaculture from the Israeli coast of the Mediterranean Sea. As the farm pond system is artificial and geographically isolated from the Mediterranean, the presence of at least seven myxozoans in their annelid hosts demonstrates introduction and establishment of these parasites in a novel, brackish environment.

Keywords: Actinospore; Annelids; Introduced species; Myxosporean; Neoactinomyxum; Sphaeractinomyxon.