| Popis: |
The aim was to study the impact of environmental conditions on seasonal population dynamics of tick species found in southern Croatia with the consequence on rickettsiae vectored by them. Efficiency of DNA extraction from individual ticks was verified by amplifying the portion of mitochondrial 16S rRNA gene of tick origin. By using PCR assays and subsequent sequence analysis of the portion of four rickettsial genes ; gltA, ompA, ompB and gene for 17-kDa protein, the presence and identity of rickettsiae were determined.A total of 192 ticks belonging to five species (Haemaphysalis punctata, D. marginatus, H. marginatum, Rhipicephalus bursa and Rh. turanicus) were collected in May 2001. Comparing the results from the collection in autumn 2000, a major decline was noticed in the adult H. punctata population with no rickettsial DNA detected in this species. Rh. bursa ticks were not competent vectors for SFG rickettsiae. Three of 33 (9.1 %) Rh. turanicus, a newly recognized species in the region, were infected with R. rhipicephali. As previously determined, D. marginatus and H. marginatum ticks were repeatedly infected with R. slovaca and R. aeschlimannii, respectively. An increase in population of adult D. marginatus and H. marginatum ticks was detected over the follow up. However, the percent of infection in ticks was lower (64.7 % in October 2000 and 26.1 % in May 2001) for R. aeschlimannii and higher (36.8 % in October 2000 and 60.0 % in May 2001) for R. slovaca.In conclusion, importance of the climatic impact on seasonal population dynamics of ticks in southern Coratia with consequence on SFG rickettsiae vectored by them was shown in this study. |
