Ultrasensitive point-of-care immunoassay for secreted glycoprotein detects Ebola infection earlier than PCR.

Detecting disease with a decoy: Low-cost, rapid diagnostic tests that perform as well as PCR and can be used at the point of need can help contain outbreaks of infectious diseases. Fontes et al. developed an immunoassay to detect Ebola virus secreted glycoprotein (sGP), a decoy antigen present in infected blood. The assay detected sGP-spiked human and nonhuman primate serum samples and human blood samples spiked with Sudan ebolavirus and Bundibugyo ebolavirus. The immunoassay had a lower limit of detection than other lateral flow rapid diagnostic tests for Ebola virus and detected sGP earlier than PCR using samples from infected nonhuman primates. Results support the use of the immunoassay for rapid detection of Ebola virus. Ebola virus (EBOV) hemorrhagic fever outbreaks have been challenging to deter due to the lack of health care infrastructure in disease-endemic countries and a corresponding inability to diagnose and contain the disease at an early stage. EBOV vaccines and therapies have improved disease outcomes, but the advent of an affordable, easily accessed, mass-produced rapid diagnostic test (RDT) that matches the performance of more resource-intensive polymerase chain reaction (PCR) assays would be invaluable in containing future outbreaks. Here, we developed and demonstrated the performance of a new ultrasensitive point-of-care immunoassay, the EBOV D4 assay, which targets the secreted glycoprotein of EBOV. The EBOV D4 assay is 1000-fold more sensitive than the U.S. Food and Drug Administration–approved RDTs and detected EBOV infection earlier than PCR in a standard nonhuman primate model. The EBOV D4 assay is suitable for low-resource settings and may facilitate earlier detection, containment, and treatment during outbreaks of the disease. [ABSTRACT FROM AUTHOR]