Ticks as the main target of human tick-borne disease control: Russian practical experience and its lessons

For several decades, the emphasis in human tick-borne disease control has b een on the epidemiologically-based preventive (non-specific) approach where tick vectors were the main target of control impact. A long-term, large-sc ale campaign for controlling the taiga tick Ixodes persulcatus, the main ve ctor of tick-borne encephalitis, was carried out in Russia in the 1950s to 1970s. The practical experience accumulated during that campaign could be o f great value for the current development of strategies of tick-borne disea se control. A general scheme of human protection from tick-borne diseases i s presented where the required investment into protection is proportional t o the risk of human infection and particular strategies of control and prot ection are differentiated. The critical point in the preventive approach is the necessity of radical tick suppression in the areas with the highest ri sk of human infection that can be successfully achieved only through chemic al treatment directed at the eradication of the entire tick population. The following aspects are considered: the tick population (or a group of popul ations) as a desirable target of any acaricidal impact (biological and geog raphic aspects, the fate of the population after treatment); the advantage of long-term planning for control campaigns; and the influence of acaricida l impact on foci of tick-borne diseases. The conception of losses of potent ial pesticidal impact efficacy provides much room for the improvement of co nventional tick control strategies making them more efficient and safe to t he environment. The current tendency to make humans the main target of cont rol through vaccination and/or medical treatment (specific approach) does n ot fit the objectives of effective human protection from tick-borne disease s, especially because of a tick population's ability to carry and transmit more than one pathogen over the same area.