Climate warming and changes in habitat suitability for Boophilus microplus(Acari : Ixodidae) in Central America

Remote sensing on the basis of AVHRR (advanced very high resolution radiome ter) satellite imagery was used, together with standard geostatistical. met hods (cokriging), to estimate the distribution of habitat suitability (HS) for the tick Boophilus microplus (Canestrini) in Central America. Most atte ntion was paid to the expected limits of tick, distribution as well as the temperature and vegetation values responsible for different HS zones and th eir variability within the year. The highest HS extended through wide areas of southeastern United States, much of Mexico, and other countries of Cent ral America. Areas with higher HS had relatively stable temperatures (withi n 20-25 C) throughout the year, and had a NDVI (normalized derived vegetati on index) of around 0.4. These areas need to be targeted to ensure acaricid e usage at optimum intervals and to avoid the formation of areas with enzoo tic instability. A seasonal analysis of the climate trend through the study period (1982-1999) revealed a warming cycle, together with a rise in NDVI index values. The main consequence of this trend is the gradual increase in unsuitability in areas where the tick is already established, with the est ablishment of new foci in zones currently too cold to support tick populati ons. The cooling periods of 1-2 yr that were observed between warn-Ling cyc les may also lead to enzootic instability when warm zones cool to within th e suitability range. As the model is remotely sensed, a continuous update o f the B. microplus distribution could be performed, assuring maximum effici ency in developing management strategies.