We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
LGC Clinical Diagnostics

Download Mobile App




Immunoassay Developed for Lassa Fever Virus

By LabMedica International staff writers
Posted on 12 Apr 2018
Print article
Image: A transmission electron micrograph (TEM) of a number of Lassa virus virions adjacent to some cell debris (Photo courtesy of C. S. Goldsmith/CDC).
Image: A transmission electron micrograph (TEM) of a number of Lassa virus virions adjacent to some cell debris (Photo courtesy of C. S. Goldsmith/CDC).
Lassa fever is a type of viral hemorrhagic fever and is endemic in several West African countries. However, only few hospitals and laboratories in the region have the capacity to conduct molecular or serological Lassa fever diagnostics.

The classical method for detection of Lassa virus-specific antibodies is the immunofluorescence assay (IFA) using virus-infected cells as antigen. However, IFA requires laboratories of biosafety level 4 for assay production and an experienced investigator to interpret the fluorescence signals.

Scientists at the Bernhard Nocht Institute for Tropical Medicine (Hamburg, Germany) and their West African colleagues chose a total of 576 sera from the diagnostic service of the Institute of Lassa Fever Research and Control. Of those, 270 sera tested positive by Lassa virus real-time polymerase chain reaction (RT-PCR) establishing the diagnosis of Lassa fever; 101 sera tested negative by Lassa virus RT-PCR; and 23 had no RT-PCR result. From 47 RT-PCR confirmed Lassa fever patients, 182 (1–9 per patient) follow-up sera were available. From Lassa fever non-endemic areas, 199 samples collected between 2008 and 2011 from patients with suspected viral hemorrhagic fever or viral hepatitis in Ghana, all of whom tested negative by Lassa virus RT-PCR. Another 105 diagnostic leftover samples from German patients with various unknown diseases were included in the study.

The developed immunoglobulin M enzyme-linked immunosorbent assay (IgM ELISA) was based on capturing IgM antibodies using anti-IgM, and the IgG ELISA is based on capturing IgG antibody–antigen complexes using rheumatoid factor or Fc gamma receptor CD32a. Analytical and clinical evaluation was performed with 880 sera from Lassa fever endemic (Nigeria) and non-endemic (Ghana and Germany) areas. The team used the IFA as the reference method, and observed 91.5% to 94.3% analytical accuracy of the ELISAs in detecting Lassa virus-specific antibodies. Evaluation of the ELISAs for diagnosis of Lassa fever on admission to hospital in an endemic area revealed a clinical sensitivity for the stand-alone IgM ELISA of 31% and for combined IgM/IgG detection of 26% compared to RT-PCR. In non-Lassa fever patients from non-endemic areas, the specificity of IgM and IgG ELISA was estimated at 96% and 100%, respectively.

The authors concluded that the ELISAs are not equivalent to RT-PCR for early diagnosis of Lassa fever; however, they are of value in diagnosing patients at later stage. The IgG ELISA may be useful for epidemiological studies and clinical trials due its high specificity, and the higher throughput rate and easier operation compared to IFA. The established assays do not require expensive equipment; ELISA readers are available in many diagnostic laboratories in West Africa. The study was published on March 29, 2018, in the journal PloS Neglected Tropical Diseases.

Related Links:
Bernhard Nocht Institute for Tropical Medicine

Platinum Member
COVID-19 Rapid Test
OSOM COVID-19 Antigen Rapid Test
Specimen Collection & Transport
Complement 3 (C3) Test
GPP-100 C3 Kit
Gold Member
Reagent Reservoirs
Reagent Reservoirs

Print article

Channels

Clinical Chemistry

view channel
Image: Reaching speeds up to 6,000 RPM, this centrifuge forms the basis for a new type of inexpensive, POC biomedical test (Photo courtesy of Duke University)

POC Biomedical Test Spins Water Droplet Using Sound Waves for Cancer Detection

Exosomes, tiny cellular bioparticles carrying a specific set of proteins, lipids, and genetic materials, play a crucial role in cell communication and hold promise for non-invasive diagnostics.... Read more

Molecular Diagnostics

view channel
Image: The study showed the blood-based cancer screening test detects 83% of people with colorectal cancer with specificity of 90% (Photo courtesy of Guardant Health)

Blood Test Shows 83% Accuracy for Detecting Colorectal Cancer

Colorectal cancer is the second biggest cause of cancer deaths among adults in the U.S., with forecasts suggesting 53,010 people might die from it in 2024. While fewer older adults are dying from this... Read more

Hematology

view channel
Image: The Gazelle Hb Variant Test (Photo courtesy of Hemex Health)

First Affordable and Rapid Test for Beta Thalassemia Demonstrates 99% Diagnostic Accuracy

Hemoglobin disorders rank as some of the most prevalent monogenic diseases globally. Among various hemoglobin disorders, beta thalassemia, a hereditary blood disorder, affects about 1.5% of the world's... Read more

Microbiology

view channel
Image: The new platform is designed to perform blood-based diagnoses of nontuberculosis mycobacteria (Photo courtesy of 123RF)

New Blood Test Cuts Diagnosis Time for Nontuberculous Mycobacteria Infections from Months to Hours

Breathing in nontuberculous mycobacteria (NTM) is a common experience for many people. These bacteria are present in water systems, soil, and dust all over the world and usually don't cause any problems.... Read more

Industry

view channel
Image: These new assays are being developed for use on the recently introduced DxI 9000 Immunoassay Analyzer (Photo courtesy of Beckman Coulter)

Beckman Coulter and Fujirebio Expand Partnership on Neurodegenerative Disease Diagnostics

Beckman Coulter Diagnostics (Brea, CA, USA) and Fujirebio Diagnostics (Tokyo, Japan) have expanded their partnership focused on the development, manufacturing and clinical adoption of neurodegenerative... Read more
Copyright © 2000-2024 Globetech Media. All rights reserved.