Severe illness caused by Rickettsia conorii.

An 18-month-old boy presented with a 5-day history of lethargy, fever, vomiting and rash. He required intensive care for inotropic and ventilatory support. He developed a disseminated intravascular coagulopathy and gangrene of his extremities. In addition, he had severe neurological dysfunction and loss of vision, both of which recovered spontaneously with time. The potential severity of tick typhus caused by Rickettsia conorii is described as well as the importance of paired serological tests in the diagnosis of this condition.