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The Parasite that Causes Whirling Disease, M yxobolus cerebralis , is Genetically Variable Within and Across Spatial Scales
Author(s) -
Lodh Nilanjan,
Kerans Billie L.,
Stevens Lori
Publication year - 2011
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2011.00596.x
Subject(s) - biology , tubifex tubifex , parasite hosting , tubifex , haplotype , biological dispersal , 18s ribosomal rna , internal transcribed spacer , host (biology) , ribosomal dna , ribosomal rna , zoology , ecology , genetics , gene , phylogenetics , genotype , population , demography , sociology , world wide web , computer science
Understanding the genetic structure of parasite populations on the natural landscape can reveal important aspects of disease ecology and epidemiology and can indicate parasite dispersal across the landscape. M yxobolus cerebralis ( M yxozoa: M yxosporea), the causative agent of whirling disease in the definitive host T ubifex tubifex, is native to E urasia and has spread to more than 25 states in the USA . The small amounts of data available to date suggest that M . cerebralis has little genetic variability. We examined the genetic variability of parasites infecting the definitive host T . tubifex in the M adison R iver, MT , and also from other parts of N orth A merica and E urope. We cloned and sequenced 18S ribosomal DNA and the internal transcribed spacer‐1 ( ITS ‐1) gene. Five oligochaetes were examined for 18S and five for ITS ‐1, only one individual was examined for both genes. We found two different 18S rRNA haplotypes of M . cerebralis from five worms and both intra‐ and interworm genetic variation for ITS ‐1, which showed 16 different haplotypes from among 20 clones. Comparison of our sequences with those from other studies revealed M . cerebralis from MT was similar to the parasite collected from A laska, O regon, C alifornia, and V irginia in the USA and from M unich, G ermany, based on 18S, whereas parasite sequences from W est V irginia were very different. Combined with the high haplotype diversity of ITS ‐1 and uniqueness of ITS ‐1 haplotypes, our results show that M . cerebralis is more variable than previously thought and raises the possibility of multiple introductions of the parasite into N orth A merica.