African tick bite fever reported in travelers

NEW YORK (Reuters Health) - Investigators report three cases of African tick bite fever, endemic in sub-Saharan Africa, among international travelers -- two from Germany and one from Kentucky -- in the Archives of Dermatology.

Dr. Amanda Swantje Buchau and colleagues at Heinrich Heine University in Duesseldorf note that African tick bite fever, caused by the microbe Rickettsia africae and transmitted by Amblyomma ticks that feed on cattle and wild game, was unknown outside of endemic areas a decade ago. Now, it is considered the most important rickettsial infection that occurs in international travelers.

Buchau and colleagues describe two patients who were married -- a 67-year-old husband and his 61-year-old wife - was had recently returned from a safari holiday in Swaziland. Both patients had a scabbed over skin ulcer. Both also experienced flu-like symptoms and tender swollen lymph nodes. The man then began to experience frequent nosebleeds among other symptoms.

Microscopic examination of the man's ulcer reveled findings consistent with the diagnosis of tick bite fever.

Usually the diagnosis relies on flu-like symptoms, rash, and crusted ulcers at the site of tick bites with lymph node swelling. Buchau's group points out that "early antibiotic treatment is necessary to avoid systemic involvement, including" kidney failure, inflammation of the heart, and other potentially fatal complications.

Meanwhile, Dr. Carol L. Kulp-Shorten and associates at the University of Louisville School of Medicine treated a 48-year-old woman who developed symptoms 2 weeks after returning from a trip to Zimbabwe. Symptoms included fever, swollen lymph nodes, and fatigue, among others.

Testing of skin lesions once again lead to a diagnosis of tick bite fever.

Kulp-Shorten and colleagues report that the risk factors for tick bite fever include game hunting, safari tourism, travel in the rainy season between November and April, and travel to southern African.

They add: "With the increase in international travel, it is important to recognize the illness in those who have been to endemic countries and to counsel patients regarding preventive measures for planned travel."

SOURCE: Archives of Dermatology, October 2006.