Current assays detect Ebola virus in semen
Diagnostic assays currently used in West Africa efficiently detected the presence of Ebola virus in semen, according to a recent study.
“This study now opens the door to test semen from [Ebola virus] survivors for the presence of residual viral RNA as well as to facilitate epidemiological investigations to rapidly identify sources of new cases as well as potential at-risk contacts,” researchers from the National Institute of Allergy and Infectious Diseases wrote.
The researchers collected six seminal fluid samples and six whole blood samples from healthy donors and spiked them with live Ebola viruses (Ebola virus/H.sapiens-tc/GIN/14/WPG-C05).
The Qiagen QIAamp Viral RNA mini kit extracted RNA samples from the semen and blood specimens. The researchers then used the EZ1 RT-PCR reagents and assay parameters, as well as CRP Ribonuclease P (RNAseP) and Major Goove Binder (MGB) reagents and assay parameters, to test for Ebola virus RNA. They analyzed the data using multiple grouped t tests, and used the Holm-Sidak method to determine significance.
No significant disparities were observed in the extractions using the RNAseP assay, which targeted the housekeeping gene. There was consistency in donor cycle threshold values across the spiked concentrations, which enabled accurate comparisons between sample matrices. There were no significant differences between semen and whole blood sample types.
Spiked samples of RPMI 1640 medium and negative RPMI 1640 medium also were assessed as cell-free controls. All calculated dilutions were significantly higher in the RPMI 1640 medium control samples vs. the semen or whole blood samples.
Moreover, the researchers said RT-PCR using MGB mastermix demonstrated higher assay sensitivity, but more studies will be needed to evaluate any significance between Ebola virus RNA recovery with the MGB-1 assay vs. the EZ1-emergency use authorization (EUA) assays.
“In the future, it would also be desirable to determine the performance of these selected assays with other bodily fluids, especially urine and saliva,” the researchers wrote. “In the interim, public health officials and laboratorians can be confident that the existing EZ1-EUA assay performs as well on semen as they do on whole blood.” – by Jen Byrne
Disclosure: The researchers report no relevant financial disclosures.