Persistence and Intra-Host Genetic Evolution of Zika Virus Infection in Symptomatic Adults: A Special View in the Male Reproductive System

Abstract

We followed the presence of Zika virus (ZIKV) in four healthy adults (two men and two women), for periods ranging from 78 to 298 days post symptom onset. The patients were evaluated regarding the presence of the virus in different body fluids (blood, saliva, urine and semen), development of immune responses (including antibodies, cytokines and chemokines), and virus genetic variation within samples collected from semen and urine during the infection course. The analysis was focused primarily on the two male patients who shed the virus for up to 158 days after the initial symptoms. ZIKV particles were detected in the spermatozoa cytoplasm and flagella, in immature sperm cells and could also be isolated from semen in cell culture, confirming that the virus is able to preserve integrity and infectivity during replication in the male reproductive system (MRS). Despite the damage caused by ZIKV infection within the MRS, our data showed that ZIKV infection did not result in infertility at least in one of the male patients. This patient was able to conceive a child after the infection. We also detected alterations in the male genital cytokine milieu, which could play an important role in the replication and transmission of the virus which could considerably increase the risk of ZIKV sexual spread. In addition, full genome ZIKV sequences were obtained from several samples (mainly semen), which allowed us to monitor the evolution of the virus within a patient during the infection course. We observed genetic changes over time in consensus sequences and lower frequency intra-host single nucleotide variants (iSNV), that suggested independent compartmentalization of ZIKV populations in the reproductive and urinary systems. Altogether, the present observations confirm the risks associated with the long-term replication and shedding of ZIKV in the MRS and help to elucidate patterns of intra-host genetic evolution during long term replication of the virus.

Safety, Tumor Reduction, and Clinical Impact of Zika Virus Injection in Dogs with Advanced-Stage Brain Tumors

“…In humans, ZIKV particles were detected in blood, saliva, urine, and semen up to 150 days after the initial symptoms, preserving the integrity and infectivity during replication in the male reproductive system. 35 Although the present canine pre-clinical study confirms the ZIKV BR replication and shedding in the male reproductive system, this result does not represent a barrier to human oncolytic therapy since the virus sexual transmission can be physically prevented and ZIKV does not cause infertility in male patients. 35 In short, here we show for the first time significant CNS tumor remission following ZIKV BR intrathecal injections in two dogs bearing spontaneous intracranial tumors with an absence of clinical side effects associated with ZIKV infection.…”

“…35 Although the present canine pre-clinical study confirms the ZIKV BR replication and shedding in the male reproductive system, this result does not represent a barrier to human oncolytic therapy since the virus sexual transmission can be physically prevented and ZIKV does not cause infertility in male patients. 35 In short, here we show for the first time significant CNS tumor remission following ZIKV BR intrathecal injections in two dogs bearing spontaneous intracranial tumors with an absence of clinical side effects associated with ZIKV infection. We also show that the two dogs followed for a longer time had a positive response following a second ZIKV injection, which opens the possibility of a protocol with multiple injections.…”

A Novel Microfluidic Device Integrated with Chitosan-Modified Capillaries for Rapid ZIKV Detection

“…We confirmed that the detection limit of our method was 50 TU/mL or lower, which was approximately 2.5 × 10 3 genome equivalents (ge)/mL (calibration by RNA standard solution, data was not shown). As typical viremia of a patient infected with ZIKV ranges from 4.2 × 10 5 ge/mL to 5.2 × 10 6 ge/mL in saliva samples [33], our method is more than sufficient to detect viremia in patients infected with ZIKV.…”

“…We then analyzed the distribution of RNA on adsorbents through an isotherm model experiment. As a method of electrostatic adsorption, the adsorption of negatively charged nucleic acids by positively charged chitosan in acidic solution, might fit the Langmuir model or Freundlich model, which are two conventional models to describe isotherm equations [33][34][35]. The equations of Langmuir and Freundlich isotherm models are given by the following:…”

Zika virus seroprevalence in blood donors from the Northeastern region of São Paulo State, Brazil, between 2015 and 2017

“…The samples used were obtained from four patients who were confirmed as positive for ZIKV by real-time PCR. 16 Also, we applied used two samples which were only DENV positive and two well-established negative sera for ZIKV and DENV.…”