Map interpretation guideWorldwide

Why do tick distribution maps change?

Maps change as surveillance improves and as climate, hosts, land use, travel and trade alter where ticks are introduced or can establish.

Reviewed by VuxLore® Knowledge Team For Everyone

Short answer

Maps change as surveillance improves and as climate, hosts, land use, travel and trade alter where ticks are introduced or can establish.

At a glance

A newer coloured area may reflect genuine expansion, better detection or both.

Key takeaways

• Check the map publication date.

• Read the presence definitions.

• Do not interpret uncoloured areas as guaranteed absence.

Biology and observation both move the boundary

Warmer conditions or new host routes may make a site suitable, while additional sampling can reveal a population that was already present but overlooked.

Maps answer defined questions

Some show any record, others established populations, modelled suitability or pathogen detections. The legend and methods determine what the colours mean.