Abstract
The study of the genetic polymorphism of pathogens is important for phylogenetic and biogeographic studies and, in the case of foodborne pathogens, to trace the origin of food infection. Since its discovery in 1972, the nonencapsulated species Trichinella pseudospiralis has been detected in mammals and birds, and human infection has occurred, in some cases resulting in death. We studied DNA polymorphism among ten T. pseudospiralis isolates from the Palearctic, Nearctic, and Australian regions, screening the sequences of nine genes [18sRNA, a random amplified polymorphism DNA derived sequence, mitochondrial cytochrome oxidase subunit I (COI), cytochrome P450, cynate lyase, epithelial fusion failure-1, and three unknown genes of Tp3, Tp8, and Tp26]. A high identity of sequence for the nine gene loci was obtained among the seven isolates from the Palearctic region and between the two isolates from the Nearctic region. Genetic identity analysis indicated the distinct polymorphism among the three geographical origins. To easily identify T. pseudospiralis genotypes, a polymerase chain reaction-restriction fragment length polymorphism analysis of COI gene was performed, and the results confirmed the DNA polymorphism within T. pseudospiralis, corresponding to the three regions of origin. We have named the three genotypes as “T. pseudospiralis Palearctic genotype” (code T4P), “Nearctic genotype” (code T4N), and “Australian genotype” (code T4A). To further investigate polymorphism among the nonencapsulated Trichinella species, the sequences of four gene loci (COI, P450, cynate lyase, and SB147D) of T. pseudospiralis, T. papuae, and T. zimbabwensis were analyzed, and the results showed high polymorphism among the three species, strongly supporting their classification as separate species.
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Acknowledgment
The authors wish to thank Simone Mario Cacciò for having performed the phylogenetic analysis with the software MEGA, version 3.1. This work was funded partially by a Grant-in-Aid for Scientific Research (17590370) from the Ministry of Education, Culture, Sports, Science and Technology of Japan and in part by the WP27 Trichimed of the MED-VET-NET Project of the European Union (No. FOODCT-2004-506122), the Slovak Research and Developmental Agency under the contract No. APVV-51-027605, and VEGA agency under the contract No. 2/7186/27. We would also like to thank the Matsumae International Foundation for providing fellowship covering the stay of Dr. Viliam Snabel at Gifu University Graduate School of Medicine during which a part of experiments was carried out.
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Wu, Z., Snabel, V., Pozio, E. et al. Genetic relationships among Trichinella pseudospiralis isolates from Australian, Nearctic, and Palearctic regions. Parasitol Res 101, 1567–1573 (2007). https://doi.org/10.1007/s00436-007-0677-6
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DOI: https://doi.org/10.1007/s00436-007-0677-6