• DOI:10.1017/S0031182099006083
• Corpus ID: 2226752

Seasonal synchrony: the key to tick-borne encephalitis foci identified by satellite data

@article{Randolph2000SeasonalST,
  title={Seasonal synchrony: the key to tick-borne encephalitis foci identified by satellite data},
  author={Sarah E. Randolph and Robert Montraville Green and Mick Peacey and David J. Rogers},
  journal={Parasitology},
  year={2000},
  volume={121},
  pages={15 - 23}
}

• S. Randolph, R. M. Green, +1 author D. Rogers
• Published 1 July 2000
• Environmental Science
• Parasitology

A previous analysis of tick infestation patterns on rodents in Slovakia suggested that the key to the focal distribution of western-type tick-borne encephalitis virus (TBEv) in Europe is the geographically variable degree of synchrony in the seasonal activity of larval and nymphal Ixodes ricinus ticks. This prediction is here tested by examining records, from 7 different countries, of the seasonal variation in the abundance of larvae and nymphs feeding on rodents or questing on the vegetation. Larvae consistently started feeding and questing earlier in the year at sites within TBEv foci than elsewhere, so that they appeared in the spring as soon as nymphs were active. Such larval–nymphal synchrony is associated with a rapid fall in ground-level temperatures from August to October as revealed by the satellite-derived index of Land Surface Temperature (LST). Likewise, of 1992 pixels sampled on a grid across Europe, the 418 that fell within TBEv foci were characterized by a higher than average rate of autumnal cooling relative to the peak midsummer LST. It is proposed that such a seasonal temperature profile may cause unfed larvae to pass the winter in quiescence, from which they emerge synchronously with nymphs in the spring.