The proportion of asymptomatic infections and spectrum of disease among pregnant women infected by Zika virus: systematic monitoring in French Guiana, 2016

Abstract

Zika virus (ZIKV) infection has been associated with complications during pregnancy. Although the presence of symptoms might be a risk factor for complication, the proportion of ZIKV-infected pregnant women with symptoms remains unknown. Following the emergence of ZIKV in French Guiana, all pregnancies in the territory were monitored by RT-PCR and/or detection of ZIKV antibodies. Follow-up data collected during pregnancy monitoring interviews were analysed from 1 February to 1 June 2016. We enrolled 3,050 pregnant women aged 14–48 years and 573 (19%) had laboratory-confirmed ZIKV infection. Rash, arthralgia, myalgia and conjunctival hyperaemia were more frequently observed in ZIKV-positive women; 23% of them (95% confidence interval (CI): 20–27) had at least one symptom compatible with ZIKV infection. Women 30 years and older were significantly more likely to have symptoms than younger women (28% vs 20%). The proportion of symptomatic infections varied from 17% in the remote interior to 35% in the urbanised population near the coast (adjusted risk ratio: 1.6; 95% CI: 1.4–1.9.). These estimates put findings on cohorts of symptomatic ZIKV-positive pregnant women into the wider context of an epidemic with mainly asymptomatic infections. The proportion of symptomatic ZIKV infections appears to vary substantially between populations.

Zika virus during pregnancy: From maternal exposure to congenital Zika virus syndrome

“…37,38 However, pregnancy is not associated with more frequent or more severe maternal complications. 32 The presence and the severity of maternal symptoms are not associated with a higher risk of birth defects or fetal loss. 39,40 Although a persistent viremia was initially associated with a higher risk of birth defects, no recent studies have been able to determine if viral load or prolonged viremia represented risk factors for adverse fetal or neonatal outcomes.…”

“…Pregnant women were symptomatic in 17% to 56% of cases of ZIKV infection . Symptom onset may appear from the second day after infection and may last up to 2 weeks.…”

“…Rare severe neurological complications might occur, particularly Guillain‐Barré syndrome, which may be a life‐threatening condition in pregnant women (prevalence of 1.23% (95% CI, 1.17%‐1.29%) in general infected‐population) . However, pregnancy is not associated with more frequent or more severe maternal complications . The presence and the severity of maternal symptoms are not associated with a higher risk of birth defects or fetal loss .…”

“…Pregnant women were symptomatic in 17% to 56% of cases of ZIKV infection. 16,23,32,33 Symptom onset may appear from the second day after infection and may last up to 2 weeks. Symptomatic infections are characterized by a maculopapular rash, mild fever, asthenia, pruritus, arthralgia, retro-orbital cephaleas, myalgia, conjunctivitis or conjunctival hyperemia, and/or edema of the extremities.…”

Genetic diversity of Collaborative Cross mice controls viral replication, clinical severity and brain pathology induced by Zika virus infection, independently of Oas1b

“…However, during recent epidemics, ZIKV infection triggered severe complications including Guillain-Barré syndrome and encephalitis in adults (3, 4), and congenital malformations in fetuses of infected pregnant women (5, 6). Viral mutations may have contributed to ZIKV enhanced pathogenicity (7, 8) but only partly explain the variable proportions of symptomatic infections (9) and the increased incidence of congenital Zika syndrome (CZS) in Polynesia (10) and Brazil (11), suggesting a role for host genetic variants. Recent evidence indicates that the regulation of innate immunity genes is driven by host genetic background in human fetal brain-derived neural stem cells (hNSCs) infected in vitro with ZIKV (12).…”