Whereas terminological recommendations require authors to use mean intensity or mean abundance to quantify parasites in a sample of hosts, awkward statistical limitations also force them to use either the median or the geometric mean of these measures when making comparisons across different samples. Here, we propose to reconsider this inconsistent practice by giving priority to biological realism in the interpretation of different statistical descriptors and choosing the statistical tools appropriate to our decisions. Prevalence, mean intensity, and indices of parasite distribution (such as median intensity) are suitable descriptors to quantify parasites in a sample of hosts. These measures have different biological interpretations and need different statistical methods to be compared between samples.

Dermacentor reticulatus is a hard tick species with extraordinary biological features. It has a high reproduction rate, a rapid developmental cycle, and is also able to overcome years of unfavourable conditions. Dermacentor reticulatus can survive under water for several months and is cold-hardy even compared to other tick species. It has a wide host range: over 60 different wild and domesticated hosts are known for the three active developmental stages. Its high adaptiveness gives an edge to this tick species as shown by new data on the emergence and establishment of D. reticulatus populations throughout Europe. The tick has been the research focus of a growing number of scientists, physicians and veterinarians. Within the Web of Science database, more than a fifth of the over 700 items published on this species between 1897 and 2015 appeared in the last three years (2013–2015). Here we attempt to synthesize current knowledge on the systematics, ecology, geographical distribution and recent spread of the species and to highlight the great spectrum of possible veterinary and public health threats it poses. Canine babesiosis caused by Babesia canis is a severe leading canine vector-borne disease in many endemic areas. Although less frequently than Ixodes ricinus, D. reticulatus adults bite humans and transmit several Rickettsia spp., Omsk haemorrhagic fever virus or Tick-borne encephalitis virus. We have not solely collected and reviewed the latest and fundamental scientific papers available in primary databases but also widened our scope to books, theses, conference papers and specialists colleagues’ experience where needed. Besides the dominant literature available in English, we also tried to access scientific literature in German, Russian and eastern European languages as well. We hope to inspire future research projects that are necessary to understand the basic life-cycle and ecology of this vector in order to understand and prevent disease threats. We conclude that although great strides have been made in our knowledge of the eco-epidemiology of this species, several gaps still need to be filled with basic research, targeting possible reservoir and vector roles and the key factors resulting in the observed geographical spread of D. reticulatus.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1599-x) contains supplementary material, which is available to authorized users.

Recurring and spontaneously curing spring haemoglobinuria was recently reported in a small sheep flock in a selenium deficient area of northern Hungary. In blood smears of two animals showing clinical signs, Anaplasma-like inclusion bodies were seen in erythrocytes. To extend the scope of the study, 156 sheep from 5 flocks and 26 cattle from 9 farms in the region were examined serologically with a competitive ELISA to detect antibodies to Anaplasma marginale, A. centrale and A. ovis. The seropositivity in sheep was 99.4%, and in cattle 80.8%. A. ovis and A. marginale were identified by PCR and sequence analysis of the major surface protein (msp) 4 gene in sheep and cattle, respectively. Haemoglobinuria, an unusual clinical sign for anaplasmosis might have been a consequence of transient intravascular haemolysis facilitated by selenium deficiency in recently infected sheep, as indicated by the reduction of mean corpuscular haemoglobin concentration (MCHC). Membrane damage was also demonstrated for parenchymal cells, since their enzymes showed pronounced elevation in the plasma. Ticks collected from animals in the affected as well as in neighbouring flocks revealed the presence of Dermacentor marginatus, Ixodes ricinus and D. reticulatus, with the dominance of the first. The present data extend the northern latitude in the geographical occurrence of ovine anaplasmosis in Europe and reveal the endemicity of A. ovis and A. marginale in Hungary.

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