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The ornate dog tick (Dermacentor reticulatus) can be found in the temperate zones of Eurasia. Its area of occurrence is divided into east and west distributions, although the area as a whole is expanding. The initial east-west division was most probably associated with the varied climatic profile of Europe, for example, the range of specific mean winter and summer temperatures: the region where D. reticulatus is absent is characterized by mean winter temperatures between 0°C and 5°C and thin snow cover. The present expansion may be the effect of climate change. The mean temperatures in Europe have increased, the vegetation season has lengthened and positive trends in the number of wet days can be seen. Consequently, northern Europe has become warmer and wetter over the last century. human activity can also influence the spread of D. reticulatus. The liquidation of habitats suitable for D. reticulatus and the eradication of their hosts can play a role, as can changes in agricultural land use, environmental protection and the spread of international tourism and trade. In summary, the expansion of D. reticulatus into new areas could be the synergistic effect of many favourable factors.
Babesiosis is as one of the emerging human and animal diseases transmitted by ticks. It is caused intraerythrocytic parasites of the genus Babesia. Current evidence of human babesiosis suggests that the majority of cases are involved by Babesia divergens and Babesia microti piroplasms. As zoonotic reservoir of B. microti serve small mammals - insectivores and rodents. The occurrence of this parasite in natural environment in Poland is documented for various regions, in the wide range of mammal hosts. The most important role as Babesia microti reservoir play Microtus voles. The prevalence of infection in Microtus arvalis studied in Mazurian Lakeland is 9-33%; in Microtus agrestis in Katowice agglomeration reach almost 50%, Microtus oeconomus in Białowieża 7.7-50%. The lesser role as zoonotic reservoir play Clethrionomys voles, Apodemus mice and shrews; the prevalence of infections in these mammals don't exceed 2 %. The vectors for B. microti piroplasms in middle-European conditions are Ixodes ricinus, I. trianguliceps and Dermacentor reticulatus. There were recorded the infections of Ixodes ricinus ticks with B. microti in Szczecin and Tri-City, the rate was 6.2-13.3%. The variation in B. microti prevalence in rodents and ticks is very changeable and determined by season, the interaction with other hemoparasites, host's age and local conditions.
Two from three brown rats (Rattus norvegicus) catched in Milanówek near Warsaw, and one catched in the centre of Warsaw were infected with Trypanosoma lewisi. The morphometric features of trypanosomes were in accordance with the features of T. lewisi gived by other authors. This is first note about infection of free living rats with T. lewisi in Poland.
The studies were carried out in Kosewo Górne in the Mazurian District (North-East region of Poland), in September 1995, September 1996 and between May 1997 and June 1998 each month. The animals were trapped in live traps, and after study they were marked and released. The infection of trypanosomes was detected using microhaematocrit centrifugation technique and in blood smears. The intensity of infection had the range from 50 to 150000 individuals in 1ml of blood. The maximal prevalence of infection was in August and September and there were 45% and 38% of infected voles respectively. The infection was detected also in May 1998, in other months the prevalence had low level. There were no individuals of bank vole infected in succecding months. The females of bank vole are more often infected with trypanosomes than males.
Hard-bodied ticks transmit various pathogens, such as Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., and carry numerous other microorganisms with an unknown pathogenic potential. Among them, tick-borne encephalitis virus has great importance. In Central European conditions all developmental stages of ticks participate in the zoonotic cycle of the TBE virus. According to pathogen and tick biology, the roles of larvae, nymphs and adults are different. Larvae and nymphs of Ixodes ricinus ticks are responsible for circulation in rodents and medium sized mammals; adults transfer the infection to ruminants and to next generations via transovarial transmission. All active developmental stages of I. ricinus can play role of the bridge vector, transmitting the infection to humans apart males which don’t feed. The late summer peak of human infectivity is caused by the summer peak of I. ricinus nymphs’ activity. The Dermacentor reticulatus tick attacks humans infrequently, but does participate in the circulation of the virus in the zoonotic foci; larvae and nymphs of the D. reticulatus ticks are responsible for circulation in rodents, mainly Microtinae, while adults transmit the infection to ruminants.
Recent advance in the knowledge of the role of Ixodidae in the epidemiology of human piroplasmosis is reviewed, with special emphasis on Babesia species which cause diseases in man. The problem in Europe came to medical attention since 20 cases have been reported, and most of them due to B. divergens. However, contrary to other European countries, the zoonotic reservoir of Babesia spp. in Poland is unknown and futher research is required to elucidate the importance of Ixodidae in the transmission of piroplasms.
Tick-borne encephalitis virus (TBEV) (Flaviviridae, Flavivirus) is an arthropod-borne virus, an etiologic agent of tick-borne encephalitis (TBE), an infection involving the central nervous system. The disease is endemic in a large region in Eurasia where it is transmitted mainly by Ixodes ricinus in Europe and I. persulcatus ticks in Asia. This is the most important tick-transmitted arbovirus of human pathogenicity in Europe. The Białowieża Primeval Forest is a well-known endemic focus of tick-borne encephalitis. The aim of this study was to identify the prevalence of tickborne encephalitis virus (TBEV) in European bison, the important hosts of ticks in the Białowieża Primeval Forest. In the years 2005–2009, 95 blood samples were collected from European bison and examined for the presence of TBEV using nRT-PCR method. No positive results were obtained. For better understanding of TBEV vertebrate reservoir hosts in Poland, further investigations are needed.
Data about the presence of Trypanosoma evotomys in Poland are presented. Attention is paid to the morphological features of the strain. Biology of the strain, vector species and hosts species are described.
In the present note the first cases of Babesia microti infection of Clethrionomys glareolus in the district of Mazury Lakes is described. Contrary to other European countries, the zoonotic reservoir as well as epidemiological role of parasites from the genus Babesia spp. in Poland is entirely unknown.
Tick-borne pathogens are common in the natural environment, but their occurrence has a focal character. They occur in the natural environment in the form of the enzootic sources of infection. The general components include the animal reservoir, amplifiers and the efficient vector. However, the particular role of components can differ depending on the pathogen, the host range and possible transmission routes. Animal reservoir of pathogen are vertebrate animals, being the hosts of pathogens. In Europe these are small or medium-sized mammals and sometimes birds that feed on the ground. The competence of an animal reservoir is determined by the ability to communicate the infection; long-term persistence of the pathogen in the host; long-duration of infectivity of the animal for ticks; a sufficient number of animals in the endemic region. Amplifiers for ticks are artiodactyls. They are hosts for nymphs and adult ticks, thereby making it possible for ticks to propagate and maintain the proper size of their population. Efficient vector for pathogen are ticks. The first characteristic feature of efficient vectors is feeding duration exceeding 24 hours; the high density of the tick population. The conditions necessary to consider ticks as efficient vectors are met in Central Europe by the Ixodes ricinus, Dermacentor reticulatus and D. marginatus ticks. There are the general differences in biology between Ixodes persulcatus complex ticks and Dermacentor ticks, affecting their different role and ability in pathogens spreading – the range of hosts; the ability to inhabiting of various environments and resistance to unfavourable conditions; the duration of larvae and nymphs activity. The combination of tick’s biology, pathogen ability to transmission, and mammal hosts’ competence, determines the particular role of larvae, nymphs and adults in pathogen circulation in the natural environment, as well as transmission to new hosts.
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