Ebola virus disease –how to diagnose it?

The Ebola virus disease outbreak in Africa 5 years ago (2014-2015) showed to the virologists the urgent need for research and development of techniques for rapid and accurate diagnosis of the infection. Since the release of new methods and protocols for detection of the Ebola virus disease, it is crucial for the clinicians to evaluate all pros and cons of each technique and to choose the best procedure based on health care status of the population, standard of living, laboratory inventory, biosafety level and health control.

Despite the new modern accurate methods available nowadays, thegold standard method that proves the presence of Ebola virus is cell culturing of infected Vero E6 cell line, followed by isolation of viral particles and visualization of the viral suspension by electron microscopy or immunofluorescence microscopy.

What is a Serological Ebola analysis (ELISA)?

Enyzyme Linked ImmunoSorbent EBOV Assays are an option for detection of antibodies against Ebola virus in human serum. Most studies showed that the quantity of IgM antibody, secreted as a response to the infection, may vary and follows the symptom onset up to day 30 for weak infections. IgG levels become detectable during the second week of illness and can persist in the next few years which allows the determination of health status and prevalence of the population.

Conventional RT-PCR is characterized as more accurate and sensitive technique for diagnosis of acute Ebola virus disease in comparison with ELISA. In 2000, the Center of disease control and prevention performed RT-PCR analysis for testing of serum samples from patients. The clinicians found that the nested RT-PCR assay for NP gene detects viral RNA up to 72 h before the antigen to become detectable via ELISA.

What is Molecualr Ebola Analysis?

RT-PCR for the EBOV NP gene detects persistent RNA in patients several weeks after the absence of the symptoms. These tests can be utilized for new viral strains, as it was shown in 2007 during the outbreak of BDBV.In comparison with RT-PCR, Real-time RT-PCR provides higher specificity and faster results – only for 2 up to 3 h.

RT-PCR analyses performance was found to vary between the national reference laboratories and it is important to evaluate the potential for false-negative results due to PCR inhibitors and sequence variation in novel viruses.

The collection of more clinical data and practical experience with these detection techniques will help health care agencies to establish an algorithm of activities to reduce the spread of Ebola virus disease in African region and can be a stable basis for stopping the outbreak of novel strains in future.

Lieven Gevaert,

Bio-engineer RUG 1996

Scientific Director of Gentaur Laboratories