title: Use of Peptide-Based Enzyme-Linked Immunosorbent Assay followed by Immunofluorescence Assay To Document Ehrlichia chaffeensis as a Cause of Febrile Illness in Nicaragua.
abstract: Ehrlichia chaffeensis, the etiologic agent of human monocytic ehrlichiosis (HME), has been extensively studied as a cause of acute febrile illness and an emerging tick-borne zoonosis in the United States. Limited data suggest its presence in other regions, including Central and South America but not Nicaragua to date. Diagnosis of E. chaffeensis infection by indirect immunofluorescence assay (IFA) is the reference standard due to its presumed high sensitivity and specificity, but IFA is impractical, variably reproducible, and cumbersome for large epidemiologic studies and for clinical diagnosis in resource-poor regions. We evaluated a high-throughput, objective peptide-based enzyme-linked immunosorbent assay (ELISA) for use alone or in combination with IFA. We found that it performed best as a screening test (sensitivity, 100%; specificity, 84%) to reduce the proportion of serum samples that were required by the more cumbersome and subjective IFA testing to <20%. Using a two-step diagnostic approach (IFA is performed if the ELISA is positive), we identified E. chaffeensis or a serologically and antigenically similar organism as a heretofore unrecognized cause of acute febrile illness in humans in Nicaragua and demonstrated the utility of the peptide ELISA as a screening tool for large-scale clinical studies.
authors.affiliation: Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
authors.forename: Ijeuru
authors.initials: I
authors.lastname: Chikeka
authors.affiliation: Hospital Escuela Oscar Danilo Rosales Arguello, Universidad Nacional Autonoma de Nicaragua, León, Nicaragua.
authors.forename: Armando J
authors.initials: AJ
authors.lastname: Matute
authors.affiliation: Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA john.dumler@usuhs.edu mreller1@jhmi.edu.
authors.forename: J Stephen
authors.initials: JS
authors.lastname: Dumler
authors.affiliation: Hubert-Yeargan Center for Global Health, Duke University School of Medicine, Durham, North Carolina, USA.|Division of Infectious Diseases and International Health, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Woods
authors.affiliation: Hospital Escuela Oscar Danilo Rosales Arguello, Universidad Nacional Autonoma de Nicaragua, León, Nicaragua.
authors.forename: Orlando
authors.initials: O
authors.lastname: Mayorga
authors.affiliation: Hubert-Yeargan Center for Global Health, Duke University School of Medicine, Durham, North Carolina, USA john.dumler@usuhs.edu mreller1@jhmi.edu.|Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Reller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D018469:Ehrlichia chaffeensis / Q000276:immunology*; D016873:Ehrlichiosis / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009527:Nicaragua; D012680:Sensitivity and Specificity; D017282:Tick-Borne Diseases / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial