Rickettsial and Serologic Evidence for Prevalent Spotted Fever Rickettsiosis in Inner Mongolia

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  • * Department of Rickettsiology, Institute of Epidemiology and Microbiology, Chinese Academy of Preventive Medicine, Beijing, People's Republic of China
  • | Department of Pathology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
  • | Inner Mongolia Anti-Epidemic Station, Huhehot, Inner Mongolia, People's Republic of China
  • | § Hulunbeier District Anti-Epidemic Station, Hailaer, Inner Mongolia, People's Republic of China

A field study in northeastern Inner Mongolia, People's Republic of China, in June of 1985 demonstrated a spotted fever group rickettsiosis. Two strains of spotted fever group rickettsiae were isolated. One strain was obtained from the blood of a patient with an eschar, regional lymphadenopathy, and history of a recent tick bite. The other strain originated from ova of ticks, Dermacentor nuttalli. These represent the second isolate of a spotted fever group rickettsia from a human and the first isolate from tick ova in the People's Republic of China. Antibodies to these rickettsiae were demonstrated by indirect immunofluorescence in the sera of 4% of healthy children and 34% of healthy human adults, in 58% of sheep, and in 76% of cattle in the same location. Hemolymph test revealed rickettsiae in 6 of 36 D. nuttalli examined.