Study of Phenotypic Variability and Borrelia Infectivity in Different Populations of Ornithodoros Tholozani in Zanjan Province

Bakground and Objective: The soft tick, Ornithodoros tholozani, is of major medical importance due to biting humans and taking blood-meal. Despite the medical importance of this tick, no in-depth studies have been carried out to distinguish different forms and their capability in transmitting the disease. To this end, this study was carried out to identify phenotypic diversity, and contamination of the different strains of this tick to Borrelia persica in Zanjan province. Materials and Methods: In this descriptive study, microscopic examination was carried out with ۰.۱ micrometer precision, and ۲۰ quantitative morphometric indexes were measured alongside the assessment of qualitative factors. The contamination to Borrelia was investigated through feeding on three-day-old neonate mice, and injection of squashed suspension into the peritoneum of the mice. Results: laboratory investigation revealed that the contamination by Borrelia in tick samples was ۰.۰۰۴-۰.۰۰۸. Morphologic traits examination revealed that body size of the ticks from Khodabandeh and Mahneshan cities was ۶.۸۱× ۳.۹۳ mm. The two strains of Khodabandeh and Mahneshan had different capitulum widths, and genital opening sizes. Males of Ornithodoros tholozani were smaller than females reaching a size of ۴.۶ × ۲.۶ mm. Apart from the length and width of capitulum which were higher in Mahneshan samples than in Khodabandeh, the other indexes were not significantly different. The nymphs in the two strains differed in the body size, the length and width of capitulum, the lengths of the second and fourth segments of the palp however, they were identical in other indexes. Conclusion: Regarding the morphologic distinction between samples in the study sites and their contamination by Borrelia and lack of comprehensive knowledge in analyzing the data, it seems necessary to conduct extensive research in order to review description of the species, express taxonomic position of different strains and provide molecular identification protocol in order to prioritize the application sites, and monitor the administration plans to precisely determine the infection rate of the ticks to Borrelia in diverse geographical regions.

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Keywords: Ornithodoros tholozani ، Zanjan province ، Borrelia persica ، Morphometric indexes