Borrelia burgdorferi sensu lato infection in Ixodes ricinus ticks in urban green areas in Prague.

Ixodes ricinus ticks are considered as the vector of the Borrelia burgdorferi sensu lato complex in urban areas, including city parks and green recreational areas. The aim of the present study was to determine the prevalence of B. burgdorferi s. l. in urban areas in the city of Prague, Czech Republic. In selected public green areas in Prague, a total of 2819 I. ricinus ticks were collected in spring, from April to June, in 2014-2020. Quantitative real time PCR revealed 28.1% of ticks (31% of males, 33.7% of females and 25.8% of nymphs) to be positive for B. burgdorferi s. l. The prevalence varied significantly (p˂0.01) between collection sites, with the highest numbers of infected ticks found in the central city areas. The places serving people for recreational and sport activities in urban areas are characterized by a lower diversity of reservoir hosts, provide opportunity for exposure to Borrelia infected ticks, and pose a higher infection risk. We have detected seven Borrelia species in ticks: B. garinii, B. afzelii, B. bavariensis, B. burgdorferi sensu stricto, B. valaisiana, B. spielmanii, and B. finlandensis. Most positive ticks were infected by B. garinii (35%) and B. afzelii (36.9%). Our results show that the Borrelia transmission cycle occurs within urban biotops and highlight the need for surveillance of tick-borne pathogens in public green areas.

Changes in osmotic resistance of leucocytes in mental illnesses.

A simple method is described for determining osmotic resistance of leucocytes in peripheral blood: stained leucocytes are counted after 30, 60, 120 and 180 minutes of blood incubation with 0.2% NaCl solution. With this method it was possible to demonstrate a significant decrease in osmotic resistance of leucocytes, primarily granulocytes, in schizophrenics (by about 1/3) and in neurotics (by about 1/5) in comparison to a healthy control sample.