title: Sexually acquired Zika virus: a systematic review.
abstract: BACKGROUND
  Zika virus (ZIKV) is transmitted to humans primarily by Aedes mosquito bites. However, circumstantial evidence points to a sexual transmission route.
  
  
  OBJECTIVE
  To assess the sexually acquired ZIKV cases and to investigate the shedding of ZIKV in genital fluids.
  
  
  METHODS
  PubMed, Scopus, Pro-MED-mail and WHO ZIKV notification databases from inception to December 2016.
  
  
  METHODS
  Reports describing ZIKV acquisition through sex and studies reporting the detection or isolation of ZIKV in the genital fluids were included.
  The risk of bias was assessed using the National Institute of Health Tool.
  
  
  RESULTS
  Eighteen studies reporting on sex-acquired ZIKV and 21 describing the presence of ZIKV in genital fluids were included. The overall risk of bias was moderate. Sexual transmission was male-female (92.5%), female-male (3.7%) and male-male (3.7%). Modes of sexual transmission were unprotected vaginal (96.2%), oral (18.5%) and anal (7.4%) intercourse. The median time between onset of symptoms in the index partner and presumed sexual transmission was 13 days (range 4-44 days). ZIKV RNA was detected in semen as late as 188 days (range 3-188 days) following symptom onset, and infectious virus was isolated in semen up to 69 days after symptom onset. No study reported ZIKV isolation from female genital samples, but detection did occur up to 13 days after symptom onset.
  
  
  CONCLUSIONS
  ZIKV is potentially sexually transmitted and persists in male genital secretions for a prolonged period after symptom onset. PROSPERO systematic review registration number CRD42016041475.
authors.affiliation: Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil. Electronic address: jose.moreira@ini.fiocruz.br.
authors.forename: J
authors.initials: J
authors.lastname: Moreira
authors.affiliation: Universidade do Grande Rio (Unigranrio), Rio de Janeiro, Brazil.
authors.forename: T M
authors.initials: TM
authors.lastname: Peixoto
authors.affiliation: Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil.
authors.forename: A M
authors.initials: AM
authors.lastname: Siqueira
authors.affiliation: Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil; Universidade do Grande Rio (Unigranrio), Rio de Janeiro, Brazil; Unidade de pesquisa cardiovascular, Instituto Nacional de Cardiologia, Rio de Janeiro, Brazil.
authors.forename: C C
authors.initials: CC
authors.lastname: Lamas
mesh_terms: D000330:Aedes / Q000821:virology; D000818:Animals; D016208:Databases, Factual; D005260:Female; D051516:Hemospermia / Q000175:diagnosis / Q000821:virology; D006801:Humans; D008297:Male; D064887:Observational Studies as Topic; D012463:Saliva / Q000821:virology; D012749:Sexually Transmitted Diseases / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D014621:Vagina / Q000821:virology; D000071244:Zika Virus / Q000302:isolation & purification*; D000071243:Zika Virus Infection / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology
keywords: Febrile illness; Review; Semen; Sex; Zika