An Update on the Laboratory Diagnosis of Rickettsia spp. Infection

Abstract

Rickettsia species causing human illness are present globally and can cause significant disease. Diagnosis and identification of this intracellular bacteria are challenging with many available diagnostic modalities suffering from several shortcomings. Detection of antibodies directed against Rickettsia spp. via serological methods remains widely used with a broad range of sensitivity and specificity values reported depending on the assay. Molecular methods, including polymerase chain reaction (PCR) testing, enables species-specific identification with a fast turnaround time; however, due to resource requirements, use in some endemic settings is limited. Reports on the use of next-generation sequencing (NGS) and metagenomics to diagnose Rickettsia spp. infection have been increasing. Despite offering several potential advantages in the diagnosis and surveillance of disease, genomic approaches are currently only limited to reference and research laboratories. Continued development of Rickettsia spp. diagnostics is required to improve disease detection and epidemiological surveillance, and to better understand transmission dynamics.

A forty-year review of Rocky Mountain spotted fever cases in California shows clinical and epidemiologic changes

“…Estimates for serologic test performance suggest that SFG tests have slightly better sensitivity and specificity than tests for R. typhi and differentiation relies on exposure history and potentially stronger reactivity to the specific antigen if both agents suspected. [18]. In California, RMSF cases have been documented since the early 20 th century [19].…”

“…typhi and differentiation relies on exposure history and potentially stronger reactivity to the specific antigen if both agents suspected. [ 18 ]. In California, RMSF cases have been documented since the early 20 th century [ 19 ].…”

Non-negligible seroprevalence of murine typhus and its predictors in Japan: a large-scale seroepidemiological study

“…An epidemiological study of this disease was conducted to assess the epidemic status; however, its diagnostic method relied on the classic WFT (19). The WFT has limited diagnostic accuracy and can cause misclassification between rickettsioses (34,35); therefore, reliable seroprevalence of All rights reserved. No reuse allowed without permission.…”

“…An epidemiological study of this disease was conducted to assess the epidemic status; however, its diagnostic method relied on the classic WFT (19). The WFT has limited diagnostic accuracy and can cause misclassification between rickettsioses (34,35); therefore, reliable seroprevalence of MT based on the assay cannot be obtained. Contrary to a previous study, we could differentiate IgG against R. typhi from that against O. tsutsugamushi using the standard diagnostic test, thereby confirming the estimation of the seroprevalence of MT and indicating its predominance.…”

Discovery of Rickettsia spp. in mosquitoes collected in Georgia by metagenomics analysis and molecular characterization

“…Although rickettsial infections occur worldwide, “hot spot” focal areas of endemicity can present a risk to travelers as well. Rickettsial diseases are difficult to diagnose and can be severe or even fatal when treatment is delayed ( Stewart and Stewart, 2021 ). Therefore, characterizing rickettsiae in mosquitoes and other arthropods from different regions in the world offers significant medical relevance.…”