Serological Evidence of Subclinical Rocky Mountain Spotted Fever Infections in Texas

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

“…For R. rickettsii, detectable IgG titers can persist for >1 year after primary infection in some patients (222). In the United States, IgG antibodies reactive with antigens of R. rickettsii at reciprocal titers ≥64 can be found in 5%-10% of the population (273,(281)(282)(283) and might be higher in certain regions. Misinterpretation of serologic data based on single or inappropriately timed samples is problematic and should be avoided, particularly when no other diagnostic techniques are included in patient assessments (279,284).…”

Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts

“…Using these data, some have inferred that mild or subclinical infections with R. rickettsii may occur. For example, serum specimens of 32 (9.1%) of 352 children showed immunoglobulin G (IgG) titers of Ն64 to R. rickettsii antigen when tested by indirect fluorescent-antibody assay (IFA); however, only 8 of these children had experienced a febrile illness accompanied by rash or headache in the previous year, and none had ever been hospitalized or treated for RMSF (335). Another recent study identified IgG titers of Ն64 to R. rickettsii in the sera of 239 (12%) 1999 children 1 to 17 years of age, collected from various medical facilities in six southeastern and south-central states in the United States.…”

Rickettsioses emergentes e reemergentes numa região endêmica do Estado de Minas Gerais, Brasil

“…No que toca à sorologia humana, foram realizados e publicados no Brasil desde o início da década de 80, antecedendo a este trabalho, quatro inquéritos sorológicos para R. rickettsii, encontrando-se os seguintes valores de prevalência na população geral à RIFI com o título mínimo de 1/64: 3,17% (Galvão, 1988);7,14 % (Lemos, 1991) ; 2,16% à RIFI e 4,74% à Prova de Elisa 1:100 (Galvão, 1996) e 18% (Galvão et al, 1999). Taylor trabalhando em uma região do Texas nos Estados Unidos, onde ocorrera um surto epidêmico relacionado à febre das Montanhas Rochosas, encontrou entre 352 estudantes de cinco escolas dessa área, 32 (9,1%) reativos à RIFI num título maior ou igual a 1:64 (Taylor, 1985).…”