Medical Research Council - London Institute of Medical Sciences

Now in our 8th year of bringing you beautiful imagery from biomedical science every day

North South Divide
15 February 2017

North South Divide

Symptoms of Lyme disease, which is caused by Borrelia burgdorferi bacteria transmitted via tick bites, include fever, headache, fatigue, and rash. Without prompt antibiotic treatment, however, Lyme disease can lead to more serious problems, such as heart, joint and nervous system damage. Blacklegged ticks (pictured) are the most common vector of B. burgdorferi and are prevalent throughout the eastern United States. But, inexplicably, northeastern states report more cases of Lyme disease than the south. Now there’s a clue as to why. Ticks die if exposed to extended periods of heat and low humidity, and researchers discovered that in the south, where temperatures are highest, ticks bury themselves under leaves to retain moisture. While northern ticks also stick to shady areas, crucially they don’t go deep into the leaf layer. Thus, it’s thought that by staying buried, southern ticks don’t come into contact with people as often as their northern counterparts.

Written by Ruth Williams

Search The Archive

Submit An Image

What is BPoD?

BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

Read More

BPoD is also available in Catalan at with translations by the University of Valencia.