Persistence of Zika Virus in Semen After Acute Infection
Condition: Zika Virus; Zika Virus Disease; Virus Shedding; Transmission
MeSH terms: Virus Diseases; Zika Virus Infection
Study type: Observational

Summary: 
      This is a prospective observational laboratory evaluation of the persistence rate of zika
      virus (ZIKV) infection in semen by real-time Reverse Transcriptase Polymerase Chain Reaction
      (RT-PCR), and assessment of ZIKV replication-competence in semen by isolation of ZIKV.
      Evaluation of the persistence of ZIKV and its replication-competence in semen samples will
      increase the understanding of the risk of sexual transmission of ZIKV infection in the
      post-viremic phase in non-epidemic settings.
    

Detailed description: 
      Objectives

        1. To assess the duration of persistence of zika virus (ZIKV) in semen samples by means of
           RT-PCR, after acute ZIKV infection.

        2. To assess replication fitness of ZIKV in semen, by isolation of ZIKV virions in culture.

      Study design, population, materials and methods: Prospective cohort study of persistence of
      zika virus (ZIKV) in semen samples of adult male patients who attend the outpatient clinic of
      the Institute of Tropical Medicine in Antwerp and who have a confirmed ZIKV infection
      (positive RT-PCR for ZIKV in a serum or urine sample at the time of inclusion). Clinical and
      epidemiological data will be recorded in a standardized Case Record Form (CRF). Baseline
      serum, blood and urine samples will be collected as required for routine clinical evaluation
      of an individual case and for arbovirus antibody detection assays; sampling of serum and
      urine collection for RT-PCR will be scheduled weekly until 2 consecutive semen samples test
      negative in ZIKV RT-PCR. ZIKV isolation will be attempted from each available semen sample
      with a positive PCR result. The semen analyses will include: sperm count, morphology,
      motility, leukocyte and erythrocyte count and pH of the semen. Serum at 4 weeks will be
      collected for ZIKV antibody detection assay.

      Sample size : panel of 20 ZIKV confirmed cases Endpoints: Proportion of ZIKV positive RT-PCR
      on semen samples over time after confirmation of acute ZIKV infection, positivity rates of
      ZIKV isolation from semen samples over time after acute ZIKV infection.

      Expected results and relevance : Evaluation of the persistence of ZIKV and its
      replication-competence in semen samples will increase the understanding of the risk of sexual
      transmission of ZIKV infection in the post-viremic phase in non-epidemic settings. This
      evidence will contribute to a more rational advice on preventing sexual transmission of ZIKV
      infection.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        men of 18 years or older, with confirmed ZIKV infection, residing in areas without
        epidemiologically important arthropod-borne ZIKV transmission
      
Biospecimen description: 
      sera urine semen
    
Keywords: zika virus; semen analysis; sexual transmission