title: Kinetics of antibody responses in Rickettsia africae and Rickettsia conorii infections.
abstract: African tick-bite fever, caused by Rickettsia africae, is the most common tick-borne rickettsiosis in sub-Saharan Africa. Mediterranean spotted fever due to Rickettsia conorii also occurs in the region but is more prevalent in Mediterranean countries. Using microimmunofluorescence, we compared the development of immunoglobulin G (IgG) and IgM titers in 48 patients with African tick-bite fever and 48 patients with Mediterranean spotted fever. Doxycycline treatment within 7 days from the onset of disease significantly prevented the development of antibodies to R. africae. In patients with African tick-bite fever, the median times to seroconversion with IgG and IgM were 28 and 25 days, respectively, after the onset of symptoms. These were significantly longer by a median of 6 days for IgG and 9 days for IgM than the times for seroconversion in patients with Mediterranean spotted fever (P < 10(-2)). We recommend that sera collected 4 weeks after the onset of signs of patients with suspected African tick-bite fever should be used for the definitive serological diagnosis of R. africae infections.
authors.affiliation: Unité des Rickettsies, CNRS:UPRESA 6020, Faculté de Médecine, Université de la Méditerranée, 13385 Marseille Cedex 05, France.
authors.forename: Pierre-Edouard
authors.initials: PE
authors.lastname: Fournier
authors.forename: Mogens
authors.initials: M
authors.lastname: Jensenius
authors.forename: Herman
authors.initials: H
authors.lastname: Laferl
authors.forename: Sirka
authors.initials: S
authors.lastname: Vene
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000907:Antibodies, Bacterial / Q000097:blood*; D001907:Boutonneuse Fever / Q000188:drug therapy / Q000276:immunology*; D004318:Doxycycline / Q000627:therapeutic use; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007700:Kinetics; D020114:Rickettsia conorii / Q000276:immunology*; D017282:Tick-Borne Diseases / Q000188:drug therapy / Q000276:immunology*
chemical_list: D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D004318:Doxycycline