New research by a team of French and US scientists has identified both the bacterial and the host receptor proteins that enable Rickettsia conorii, the Mediterranean spotted fever pathogen, to enter cells.

Researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, have made the surprising discovery that flaviviruses, which cause such serious diseases as West Nile fever, yellow fever and forms of encephalitis, evade immune system defenses in different ways depending on whether they are transmitted by mosquitoes or ticks. This finding could lead to new approaches to developing vaccines and treatments against these illnesses.

New research on a bacterium that can survive encounters with specific immune system cells has strengthened scientists’ belief that these plentiful white blood cells, known as neutrophils, dictate whether our immune system will permit or prevent bacterial infections. A paper describing the research was released today online in The Journal of Immunology.

When the tick-borne bacterium that causes Lyme disease lacks a specific protein that responds to an incoming meal of blood, it is unable to be transmitted from the tick to a new animal host, researchers at UT Southwestern Medical Center have found.