Preferences of different tick species for human hosts in Turkey.

The ticks removed from the patients who applied to the hospitals in Istanbul and neighboring cities, Turkey, with the complaint of tick bite were examined in this study, on account of their species, biological stages, attachment sites on the body, and the age of the affected patients. A total of 16,969 ticks were identified. Encountered species were as follows: 33.6 % Ixodes spp. immature, 25.3 % Hyalomma spp. immature, 24.3 % I. ricinus, 9.5 % Rhipicephalus sanguineus gr., 3.2 % R. bursa, 2.2 % Hyalomma marginatum, 1.96 % Haemaphysalis adults, 1.66 % Hyalomma aegyptium, 0.52 % Dermacentor marginatus, 0.39 % Rhipicephalus spp. nymphs, 0.12 % Dermacentor spp. nymphs, 0.11 % Haemaphysalis spp. nymphs, 0.09 % Hyalomma scupense, and 0.03 % Hyalomma excavatum. The distribution of attachment sites of the species and instars showed significant differences. Furthermore, age data of the patients also revealed that certain tick species were more common within certain age groups.

The trend towards habitat fragmentation is the key factor driving the spread of Crimean-Congo haemorrhagic fever.

We aimed to characterize an environmental niche driving the distribution of Crimean-Congo haemorrhagic fever (CCHF) in Turkey, using a geo-referenced collection of cases reported between 2003 and 2008 and a set of climate and vegetation features. We used mean monthly air temperatures and Normalized Derived Vegetation Index (NDVI) values, at a resolution of 0.1 degrees , as well as climate features at and below the surface. We computed significant differences in monthly variables between positive and negative sites, within the range of distribution of the tick vector. Seasonal climate (growth season and summer length, accumulated temperatures in winter) and vegetation components (anomalies in NDVI data) were analysed. Fragmentation of habitat was obtained from NDVI monthly data at a resolution of 1 km. Neither single climate or vegetation variables, nor any individual seasonal component, accounted in both space and time for the delineation of areas of disease although accumulated temperatures in winter consistently showed lower values in areas where the disease was reported. Coherent and significant differences between disease-containing and disease-free sites were found when habitat fragmentation and connectivity were examined. High fragmentation and connectivity were unambiguously associated with sites where disease is reported and accounted for the spatial spread of cases in 2003-2008. CCHF cases were always associated with areas of highly fragmented and well-connected patches within the range of the tick vector, while there were no reports from areas with low fragmentation. There was a linear relationship between degree of fragmentation and case incidence. The implications of these findings are discussed with reference to the concept of disease spread through networks of connected spots with high densities of infected vectors and social factors driving different human activities in sites of high fragmentation.

Ticks biting humans in the urban area of Istanbul.

A passive surveillance for tick bites in humans was undertaken in the city of Istanbul (Turkey) in the summer and autumn of 2006. From 1,054 reported tick bites, most were females of Ixodes ricinus (27%) and nymphs of Hyalomma aegyptium (50%). A few adults of Hyalomma m. marginatum, Rhipicephalus sanguineus and Dermacentor marginatus were also recorded. We investigated potential risk factors for I. ricinus and H. aegyptium with spatial statistics. Climate features at 1-km resolution (monthly minimum temperatures in late summer and autumn and rainfall) and vegetation features at high resolution (density and heterogeneity of forest-type vegetation as well as distance of reporting site to these vegetation features) are useful variables explaining high reporting clusters for both Ixodes and Hyalomma. While Ixodes is highly reported in dense highly heterogeneous vegetation patches, Hyalomma is commonly found in areas far from forest-type features and in the small, relatively dry vegetation patches within the urban fabric.

Seroepidemiology of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in wild mice captured in northern Turkey.

An expedition across the Asian part of the Black Sea coast and national parks of Northern Turkey was organized in the summer of 2001 to investigate the presence of Borrelia burgdorferi sensu lato (s.l.), Lyme borreliosis agent, and Anaplasma phagocytophilum, human granulocytic ehrlichiosis, agent, in wild mice. A total of 65 Apodemus flavicollis, Apodemus sylvaticus, Microtus epiroticus, Crocidura suaveolens and Mus macedonicus, were captured. Two out of 22 Apodemus sylvaticus specimens were seropositive for B. afzelii by enzyme-linked immunosorbent assay as confirmed by Western blotting, however cultures of skin and bladder samples from all small mammals in Barbour-Stoenner-Kelly's medium-II remained negative for B. burgdorferi s.l. All sera tested were negative for Anaplasma phagocytophilum by indirect immunofluorescent assay. The prevalence of B. burgdorferi s.l. and Anaplasma phagocytophilum is low in wild mice of the Asian part of Northern Turkey.