[Prevelance of the etiological agent of human ehrlichiosis (HGE) in ticks from west-north Poland]

Abstract

Ehrlichias occur in ticks in the cells of their haemolymph-hematocytes. They enter the vertebrate host organism with the saliva of the tick, during a blood meal. Humans can also be the hosts for this pathogen. Two pathogens cause a humane disease-monocytic ehrlichiasis (E. chaffensis) or granulocytic ehrlichiasis (HGE factor). The above disease units are difficult to diagnose because of their non-specific symptoms. A preliminary study has been conducted on the prevalence of the HGE factor in the ticks, Ixodes ricinus in the recreational areas of the West-Pomeranian Province. All forms of I. ricinus were collected from 3 sites. All the sites are known to be frequented by hikers and gatherers of forest mushrooms and berries. The site selection involved also careful consideration of the tree- and underbrush type. The ticks were collected twice a year in spring (May/June) and in autumn (August\September), which was associated with the biological activity of the collected acarines. A total of 1159 Ixodes ricinus ticks were collected, in this number 172 females, 167 males, 597 nymphs, and 223 larvae. Using the PCR technique, the 16SrRNA-gene fragment was amplified using primers specific for the HGE factor: EHR 790 and EHR 521. The studied population contained 3.7% infected females in spring and 2.7% in autumn, 0.68% infected males in spring, no infected in autumn. The nymphs were infected in spring (2.17%) and in autumn too (0.73%), but the larvae were not infected in both seasons. Analysing the above-mentioned results it can be concluded that the decisive majority of the individuals transmitting the HGE factor are the adult forms. The present study was only a preliminary one. In the future much more sites will be monitored, in the recreational areas of both the city of Szczecin and the entire province.