title: Clinical presentation, convalescence, and relapse of rocky mountain spotted fever in dogs experimentally infected via tick bite.
abstract: Rocky Mountain spotted fever (RMSF) is a tick-borne disease caused by R. rickettsii in North and South America. Domestic dogs are susceptible to infection and canine RMSF can be fatal without appropriate treatment. Although clinical signs of R. rickettsii infection in dogs have been described, published reports usually include descriptions of either advanced clinical cases or experimental infections caused by needle-inoculation of cultured pathogen rather than by tick bite. The natural progression of a tick-borne R. rickettsii infection has not been studied in sufficient detail. Here, we provide a detailed description of clinical, hematological, molecular, and serological dynamics of RMSF in domestic dogs from the day of experimental exposure to infected ticks through recovery. Presented data indicate that neither the height/duration of fever nor detection of rickettsial DNA in dogs' blood by PCR are good indicators for clinical prognosis. Only the apex and subsequent subsidence of neutrophilia seem to mark the beginning of recovery and allow predicting a favorable outcome in Rickettsia-infected dogs, even despite the continuing persistence of mucosal petechiae and skin rash. On the other hand the appropriate (doxycycline) antibiotic therapy of sufficient duration is crucial in prevention of RMSF relapses in dogs.
authors.affiliation: Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Levin
authors.affiliation: Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Lindsay F
authors.initials: LF
authors.lastname: Killmaster
authors.affiliation: Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Galina E
authors.initials: GE
authors.lastname: Zemtsova
authors.affiliation: Infectious Diseases Pathology Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Jana M
authors.initials: JM
authors.lastname: Ritter
authors.affiliation: Animal Resources Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Gregory
authors.initials: G
authors.lastname: Langham
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000097:blood* / Q000188:drug therapy* / Q000382:microbiology; D004285:Dogs; D004318:Doxycycline / Q000627:therapeutic use*; D008297:Male; D011379:Prognosis; D012008:Recurrence; D012284:Rickettsia rickettsii / Q000235:genetics*; D012373:Rocky Mountain Spotted Fever / Q000097:blood / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D064927:Tick Bites / Q000097:blood / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary
chemical_list: D000900:Anti-Bacterial Agents; D004318:Doxycycline