Development and Clinical Validation of a Multiplex Real-Time Quantitative PCR Assay for Human Infection by Anaplasma phagocytophilum and Ehrlichia chaffeensis.

Megan Reller,J Dumler

doi:10.3390/tropicalmed3010014

Abstract

Background: Human granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, and human monocytic ehrlichiosis (HME), caused by Ehrlichia chaffeensis, often present as undifferentiated fever but are not treated by typical empiric regimens for acute febrile illness. Their role as agents of vector-borne febrile disease in tropical regions is more poorly studied than for other rickettsial infections. Limitations in diagnosis have impaired epidemiologic and clinical research and needless morbidity and mortality occur due to untreated illness. Methods: We designed and clinically validated a multiplex real-time quantitative PCR assay for Anaplasma phagocytophilum and Ehrlichia chaffeensis using samples confirmed by multiple gold-standard methods. Results: Clinical sensitivity and specificity for A. phagocytophilum were 100% (39/39) and 100% (143/143), respectively, and for E. chaffeensis 95% (20/21) and 99% (159/161), respectively. Conclusions: These assays could support early diagnosis and treatment as well as the high-throughput testing required for large epidemiologic studies.

Highlights

IntroductionHuman granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, and human monocytic ehrlichiosis (HME), caused by Ehrlichia chaffeensis, often present as undifferentiated fever [1,2]
Human granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, and human monocytic ehrlichiosis (HME), caused by Ehrlichia chaffeensis, often present as undifferentiated fever [1,2]. Are these infections difficult to recognize clinically, they are difficult to diagnose. They require specific treatment that is not used for empiric treatment of acute febrile illness.As advanced diagnostic methods are employed to identify etiologic agents of undifferentiated fever, rickettsial infections are increasingly recognized causes of febrile illness in the tropics with substantive morbidity and mortality [3]
HGA and HME are globally-distributed, life-threatening tick-borne rickettsial diseases [13] that present as undifferentiated fever but are not treated by typical empiric regimens for acute febrile illness

Summary

Introduction

Human granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, and human monocytic ehrlichiosis (HME), caused by Ehrlichia chaffeensis, often present as undifferentiated fever [1,2] Are these infections difficult to recognize clinically, they are difficult to diagnose. Human granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, and human monocytic ehrlichiosis (HME), caused by Ehrlichia chaffeensis, often present as undifferentiated fever but are not treated by typical empiric regimens for acute febrile illness. Their role as agents of vector-borne febrile disease in tropical regions is more poorly studied than for other rickettsial infections. Conclusions: These assays could support early diagnosis and treatment as well as the high-throughput testing required for large epidemiologic studies

Methods

Results

Conclusion