Huyser, Carin, PhD^a,; Richter, Karin, MMed Path^b

Viral incidences in semen are possibly more extensive than currently realized. Salam and Horby¹, summarized literature on the persistence of viruses in genital fluids. They remarked that the absence of conventionally nonsexually transmitted viruses in genital secretions should not be assumed. Although data on virus replication within the testis is scarce, the authors listed 27 viruses from diverse families that were identified in semen. Of these, 17 different viruses showed epidemiological and/or molecular evidence of sexual transmission and/or replication-competent or infection-competent virus were isolated from semen; that is Ebola, Marburg, Lassa, GB virus C, Zika, hepatitis B virus, hepatitis C virus, cytomegalovirus (CMV), Epstein-Barr virus, human herpes virus 8, herpes simplex viruses type 1 and 2 (HSV-1 and HSV-2), mumps virus, adenovirus, adeno-associated virus, human immunodeficiency virus (HIV), and human T-cell lymphotropic virus type I. Vertical and horizontal transmission of a viral infection can have considerable consequences for a partner or offspring, in addition to the direct viral and immune-mediated damages within testicular compartments of the host². Therefore, can semen decontamination have any relevance in the present-day and emerging viral epidemics?

Semen decontamination for HIV-1

Being part of a tertiary infertility Unit (with a diagnostic and therapeutic assisted reproduction laboratory), provides a unique perspective on HIV+ patients seeking assisted reproductive technology (ART) treatment. It is currently the only public health care center active in assisted reproductive technologies situated in the middle to northern part of South Africa.

We have gained experience over time with the robustness of semen decontamination using PureSperm^®, as a 2-step discontinuous gradient^3,4, combined with a ProInsert^TM and a washing step^3,5 to remove selected viruses and bacteria from semen samples. During the research phase of the study, the insert underwent various design changes by the manufacturer (Nidacon International AB), in order to improve efficiency and prevent contamination of the purified sperm sample. Initially, pooled semen samples from healthy student donors (virus-negative) were spiked with selected bacteria, HIV-1, CMV, as well as hepatitis C virus, and tested for technique efficacy to remove microorganisms³. The sperm quality of postprocessed samples was also evaluated. Hereafter, comparisons of blood and semen viral loads from HIV-1 seropositive male patients were performed and semen decontamination ensued. The postprocessed purified sperm sample was submitted for quantitative and qualitative polymerase chain reaction (PCR) validations³. After obtaining encouraging results³, testing then advanced to the clinical application of the procedure for HIV-1 seropositive males seeking ART assistance⁵. The number of HIV+ male patients requesting ART assistance at our Unit increased from 3.09% in 2015 to 10% in 2018 of all male patients. Approximately 90% of the patients who requested the semen decontamination procedure were receiving antiretroviral treatment.

The history of a patient seeking infertility treatment is of the utmost importance, whereby the reproductive profile, regional origin (and travel history), as well as the cost of treatment and resources available will determine fertility screening procedures³. The type and level of viral infection, whether acute or chronic, will determine if density gradient centrifugation and the decontamination procedure can be considered as part of the ART treatment program. The effectiveness of a sperm processing technique to harvest a purified highly motile sperm fraction whilst eliminating all immotile, non-sperm cells and debris, also depends on the etiology of the patient, and hence the quality of the semen sample⁴.

Outcomes

The disparity between blood and seminal viral loads during the technology development phase of the project, where 53.8% of all semen samples from HIV-1 seropositive males were confirmed for HIV-1 DNA, RNA or both^3,5, gave rise to the current management policy for male patients seeking ART treatment. The decontamination procedure is a risk-reducing method. Although we were able to confirm the removal of elevated HIV-1 loads from semen samples from seropositive males³, the focus should be on the health screening and preconception counselling of patients prior to ART; also to ensure stable viral loads (preferably undetected with the lowest limit of PCR detection of 20 copies/mL). We have found that if the blood plasma viral load is <10,000 copies/mL, only 8% of these male patients presented with a positive seminal plasma viral load. With time, experience with preliminary diagnostic spermatology tests was gained, whereby it is advantageous to prepare the male patient in advance that a second semen samples may be requested when the decontamination procedure is scheduled, or when an ordinary swim-up procedure can be accommodated. Progressive sperm motility is a major determinant for the success of density gradient centrifugation⁴. If sperm motility appears to be compromised during an initial evaluation, 2 semen samples are then most likely needed to perform sequential decontamination procedures, where the second semen sample usually contains fewer sperm, but with higher motility (unpublished data). Samples with a high number of particulate debris are processed in parallel, with the splitting of the sample over several gradients. In addition, 1.94% of postprocessed sperm samples previously tested positive for HIV-1 DNA⁵, with current results at <1% testing positive for HIV-1 DNA and 0% for HIV-1 RNA positive (PCR validation).

Discussion and conclusions

The semen decontamination technique was originally developed by researchers from the Omaha Henry Doorly Zoo to protect domestic livestock and conserve or expand the captive population of rare and endangered wildlife. The present report describes the transition of a technique designed for the removal of infectious pathogens from animal semen to a clinical application in males that are HIV-seropositive requesting ART. The semen decontamination procedure has only relevance if the viruses are not attached and/or potentially internalized in the sperm cell of a carrier. Possible attachment and internalization has been suggested (in human) for HSV-1, HSV-2, CMV, human papillomavirus, hepatitis B virus and probably Ebola and Zika viruses^1,6. Semen as a vector in the spreading of viruses, and the association of these viruses with sperm^2,6, is pertinent to the screening of patients requesting ART. The procedure will only be useful as a risk-reduction method during ART treatment if the viral infection/load is known, as in the application for HIV+ males at our Unit. The potential for the testis as a sanctuary and latent reservoir for viruses^1,2, (with protection against antiviral drugs that do not cross the reproductive tract-blood barriers), viral shedding and outbreaks of emerging viruses, lays fertile grounds for ongoing research.

Source of funding

Supported by the Medical Research Council and National Research Foundation (85821/N00414).

Conflict of interest statement

The authors declare that they have no financial conflict of interest with regards to the content of this report.

Acknowledgments

The authors thank Laura Boyd for assistance in proof-reading of the manuscript and collection of referred papers.

References