Anaplasma phagocytophilum is a Gram-negative, tick-transmitted, obligate intracellular bacterium that elicits acute febrile diseases in humans and domestic animals. In contrast to the United States, human granulocytic anaplasmosis seems to be a rare disease in Europe despite the initial recognition of A. phagocytophilum as the causative agent of tick-borne fever in European sheep and cattle. Considerable strain variation has been suggested to occur within this species, because isolates from humans and animals differed in their pathogenicity for heterologous hosts. In order to explain host preference and epidemiological diversity, molecular characterization of A. phagocytophilum strains has been undertaken. Most often the 16S rRNA gene was used, but it might be not informative enough to delineate distinct genotypes of A. phagocytophilum. Previously, we have shown that A. phagocytophilum strains infecting Ixodes ricinus ticks are highly diverse in their ankA genes. Therefore, we sequenced the 16S rRNA and ankA genes of 194 A. phagocytophilum strains from humans and several animal species. Whereas the phylogenetic analysis using 16S rRNA gene sequences was not meaningful, we showed that distinct host species correlate with A. phagocytophilum ankA gene clusters.

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BackgroundQ fever, a worldwide zoonotic disease caused by Coxiella burnetii, is endemic in northern Spain where it has been reported as responsible for large series of human pneumonia cases and domestic ruminants' reproductive disorders. To investigate pathogen exposure among domestic ruminants in semi-extensive grazing systems in northern Spain, a serosurvey was carried out in 1,379 sheep (42 flocks), 626 beef cattle (46 herds) and 115 goats (11 herds). Serum antibodies were analysed by ELISA and positive samples were retested by Complement Fixation test (CFT) to detect recent infections.ResultsELISA anti-C. burnetii antibody prevalence was slightly higher in sheep (11.8 ± 2.0%) than in goats (8.7 ± 5.9%) and beef cattle (6.7 ± 2.0%). Herd prevalence was 74% for ovine, 45% for goat and 43% for bovine. Twenty-one percent of sheep flocks, 27% of goat and 14% of cattle herds had a C. burnetii seroprevalence ≥ 20%. Only 15 out of 214 ELISA-positive animals reacted positive by CFT. Age-associated seroprevalence differed between ruminant species with a general increasing pattern with age. No evidence of correlation between abortion history and seroprevalence rates was observed despite the known abortifacient nature of C. burnetii in domestic ruminants.ConclusionsResults reported herein showed that sheep had the highest contact rate with C. burnetii in the region but also that cattle and goats should not be neglected as part of the domestic cycle of C. burnetii. This work reports basic epidemiologic patterns of C. burnetii in semi-extensive grazed domestic ruminants which, together with the relevant role of C. burnetii as a zoonotic and abortifacient agent, makes these results to concern both Public and Animal Health Authorities.

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Wildlife can act as reservoir of different tick-borne pathogens of veterinary and zoonotic importance. To investigate the role of wild ruminants as reservoir of piroplasm infection, 28 red deer, 69 roe deer and 38 chamois from Northern Spain were examined by reverse line blot (RLB) hybridization. The survey detected a prevalence of 85.7% in red deer, 62.3% in roe deer and 28.9% in chamois. Four different piroplasms were identified: Theileria sp. OT3 (previously described in sheep) as the most prevalent (85.7% in red deer, 46.4% in roe deer and 26.3% in chamois); Theileria sp. 3185/02 (previously described in a red deer in Central Spain) more abundant in red deer (53.6%) than in roe deer (10.1%) but absent from chamois; Babesia divergens detected in 6 roe deer; Theileria ovis present in 1 chamois. Mixed infections (Theileria sp. OT3 and Theileria sp. 3185/02) were only found in red and roe deer. Sequencing analysis of the 18S rRNA gene confirmed the RLB results and showed 99.7% identity between Theileria sp. 3185/02 and T. capreoli, suggesting that they are the same species. Tick distribution and contact of wild ruminants with domestic animals are discussed in terms of piroplasm infection. The results suggest that a considerable number of wildlife ruminants are asymptomatic carriers that may serve as reservoirs of the infection posing a serious concern in terms of piroplasmosis control.

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Explanations for the dynamics of tick-borne disease systems usually focus on changes in the transmission potential in natural enzootic cycles. These are undoubtedly important, but recent analyses reveal that they may not be quantitatively the most significant side of the interaction between infected ticks and humans. Variation in human activities that may impact inadvertently but positively on both the enzootic cycles and the degree of human exposure to those cycles, provide more robust explanations for recent upsurges in tick-borne encephalitis in Europe. This can account for long-term increases in incidence that coincided with post-soviet political independence, for small-scales spatial variation in incidence within a country, and for short-scale fluctuations such as annual spikes in incidence. The patterns of relevant human activities, typically those related to the use of forest resources, are evidently driven and/or constrained by the cultural and socioeconomic circumstances of each population, resulting in contrasting national epidemiological outcomes.