Recent African strains of Zika virus display higher transmissibility and fetal pathogenicity than Asian strains

Abstract

The global emergence of Zika virus (ZIKV) revealed the unprecedented ability for a mosquito-borne virus to cause congenital birth defects. A puzzling aspect of ZIKV emergence is that all human outbreaks and birth defects to date have been exclusively associated with the Asian ZIKV lineage, despite a growing body of laboratory evidence pointing towards higher transmissibility and pathogenicity of the African ZIKV lineage. Whether this apparent paradox reflects the use of relatively old African ZIKV strains in most laboratory studies is unclear. Here, we experimentally compare seven low-passage ZIKV strains representing the recently circulating viral genetic diversity. We find that recent African ZIKV strains display higher transmissibility in mosquitoes and higher lethality in both adult and fetal mice than their Asian counterparts. We emphasize the high epidemic potential of African ZIKV strains and suggest that they could more easily go unnoticed by public health surveillance systems than Asian strains due to their propensity to cause fetal loss rather than birth defects.

Experimental infections with Zika virus strains reveal high vector competence of Aedes albopictus and Aedes aegypti populations from Gabon (Central Africa) for the African virus lineage

“…Additional studies to cover the extent of the African ZIKV lineage diversity are needed to determine whether this observation can be generalized to other ZIKV African strains, and also to better assess the risk of emergence for the strains that are currently circulating silently in enzootic cycles or in African human populations. It was recently suggested that epidemics caused by African ZIKV strains might be less easily detected than those caused by Asian strains due to their propensity to cause foetal loss rather than birth defects [ 49 ].…”

A Method for Repeated, Longitudinal Sampling of Individual Aedes aegypti for Transmission Potential of Arboviruses

“…Traditional vector competence is a cumulative measure, which is monotonically increasing and often described by a logistic function [24,46]. In contrast, our results are highly variable, indicating the process of transmission is likely heterogeneous at the population and individual levels.…”

Possible Emergence of Zika Virus of African Lineage in Brazil and the Risk for New Outbreaks

“…Recently, ZIKV AF circulation in mosquitoes and NHPs in sylvatic areas in Brazil was evidenced (Figure 1) (de Almeida et al, 2019-Preprint publication; Alencar et al, 2021). This lineage displayed higher transmissibility in Aedes aegypti than ZIKV AS , and it was also verified to mosquitoes from South American (Aubry et al, 2021). Alencar et al (2021) found Ae.…”

“…A comparison between the lineages also showed that ZIKV AF induces higher embryo mortality in chicken embryos than ZIKV AS (Willard et al, 2017). Moreover, Aubry et al (2021) observed that ZIKV AF was more pathogenic in immunocompromised adult mice, and in embryos of mice it was observed that intraplacental infection with ZIKV AF caused subcutaneous edema, high levels of infection, and more severe phenotypes, leading to death. A study showed that vertical transmission of ZIKV AF in mice leads to diminished fetal viability and viral RNA can be detected in different fetal tissues, including those related to brain/neurologic development (Vermillion et al, 2017).…”

“…ZIKV AF was identified in non-human primates (NHPs) and mosquitoes in the South and Southeast Brazilian regions, respectively (Figure 1) (de Almeida et al, 2019-Preprint publication;Alencar et al, 2021). At the same time, Aubry et al (2021) showed ZIKV AF being more transmissible in mosquitoes and more lethal in mice when compared to ZIKV AS . In addition, it was suggested that there was a high epidemic potential of ZIKV AF .…”