Biologia, Bratislava, 56/Suppl. 9: 97-103, 2001.

ISSN 0006-3088 (Biologia). ISSN 1335-6399 (Biologia. Section Cellular and Molecular Biology).

 

Full Paper

Ticks as important epidemiological indicators of natural foci of tularemia in Slovakia.

 

Vanda Vyrostekova1*, Darina Gurycova1, Elena Kocianova2 & Jozef Rehacek2

1 Department of Epidemiology, Faculty of Medicine, Comenius University, Spitalska 24, SK-81372 Bratislava, Slovakia; tel.: ++ 421 7 59357494, fax: ++ 421 7 59357506, e-mail: vyrostekova@fmed.uniba.sk

2 Institute of Virology, Slovak Academy of Sciences, Dubravska cesta 9, SK-84246, Bratislava, Slovakia

* corresponding author

Received: December 28, 2000 / Accepted: April 23, 2001

 

Abstract

Studies on natural focality of tularemia in Slovakia revealed the role of different species of hosts and their ectoparasites, mainly ticks, in the circulation of Francisella tularensis in our ecological conditions. Foci with a complex structure of reservoirs and vectors, where transmission of the infection is possible via several tick species, have been considered the most important. Geographical distribution of ticks as surveyed in our field studies, as well as their bionomic characteristics were correlated with notified data on the incidence of tularemia in Slovakia. For the known endemic regions of tularemia, the March and the Danube river basin in the west, and the Latorica river basin in the east, the ubiquitary distributed tick Ixodes ricinus, occurring in synusia with Dermacentor reticulatus and Haemaphysalis concinna, was found to be characteristic. Vector competence of I. ricinus, D. reticulatus, D. marginatus and H. concinna was confirmed in our experiments on white mice as a model of hosts highly susceptible to F. tularensis. Surveillance of natural foci of tularemia has shown a long-term and relatively high prevalence of infected D. reticulatus ticks and apparently lower infestation of I. ricinus and H. concinna. Conclusion was made that ticks are important epidemiological markers of the activity of natural foci of tularemia and good indicators of their distribution and persistence. Systematic follow-up of their infestation with F. tularensis is an inevitable part of a modern epidemiological surveillance of the disease in ecological conditions of Slovakia.

 

Key words: ticks, epidemiological markers, tularemia, natural foci.