AKA Boutonneuse fever, Fievre boutonneuse, Mediterranean fever, Eruptive fever, Marseilles fever, and African tick bite fever.

Mediterranean spotted fever (MSF) is a tick-born rickettsia (Rickettsia conorii), carried by the brown dog tick (Rhipicephalus sanguineus). Humans can catch it from either the tick or from an infected dog or rodent. It is present in Europe, the Middle East, and all countries bordering the Mediterranean and the Black Sea*.

MFS has an incubation period of five to seven days; after this, an ulcer appears at the site of the tick bite, with a black center (tache noire) surrounded by a circle of red. This is followed by fever and then a general maculopapular erythematous rash (small raised red bumps) of the palms, soles, and lower legs. Myalgia, headaches, diarrhoea and weight loss may also be in evidence.

This is usually a comparatively mild disease, but in some cases (about 10% of cases) there can be severe complications, including renal failure, hypocalcemia, hyponatremia, hypoxemia, pneumonia, stupor, purpuric rash, bradycardia, jaundice, coma, and/or gastrointestinal bleeding. In less than 5% of cases it can become fatal. Fatalities are more common among the elderly and those with pre-existing medical conditions. Young children are less likely to have complications; they are also less likely to be infected (or at least diagnosed) with MFS, as the mean age of documented MSF sufferers is about 50.

Treatment and Prevention:
Treatment is most effective if done within ten days of infection. Since this is a bacterial infection, it can be treated effectively with antibiotics. Most patients will be over their infection within about seven days of antibiotic treatment; those with severe infections may take two weeks.

Prevention is mostly just common sense. Check for ticks often, being careful not to crush the tick or leave its head or mouth parts in the flesh when removing them. Since many infections pass directly from canine to human, check your dog for ticks too. A tick repellant may be useful. No vaccination currently exists.

Dogs show much the same symptoms as humans, and can also be treated with antibiotics. Some dogs will recover spontaneously within a few days of infection, and develop a partial immunity to further infection. All breeds of dogs can be infected, and infection is very common in areas in which MSF is present. Dogs that live in endemic areas may be asymptomatic.

* Some sources say that MSF is also present in India; some add Central Asia to the list. I am reasonably confident that MSF is found in these areas, although it may be a slightly different strain than is found in Europe and the Middle East. Since I do not have any real information on these areas, I decided to compromise with a footnote.

Halstead, Scott B. and Kenneth S. Warren, Diseases of Travelers and Immigrants. Scope, 1990.
http://www.provet.co.uk/health/diseases/msfever.htm (dogs)