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Updated: Sep 21, 2025
Vector Competence Analyses on Aedes aegypti Mosquitoes using Zika Virus
Published on: May 31, 2020
Phenotypic and Genetic Variability of Isolates of ZIKV-2016 in Brazil
Lidiane Menezes Souza Raphael1, Iasmim Silva de Mello1, Mariela Martínez Gómez2
1Laboratory of Molecular Biology of Flavivirus, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro 21040-900, Brazil.
Abstract:
The possibility of a Zika virus epidemic resurgence requires studies to understand its mechanisms of pathogenicity. Here, we describe the isolation of the Zika virus from breast milk (Rio-BM1) and compare its genetic and virological properties with two other isolates (Rio-U1 and Rio-S1) obtained during the same epidemic period. Complete genomic analysis of these three viral isolates showed that they carry characteristics of the American isolates and belong to the Asian genotype. Furthermore, we detected eight non-synonymous single nucleotide variants and multiple nucleotide polymorphisms that reflect phenotypic changes. The new isolate, Rio-BM1, showed the lowest replication rates in mammalian cells, induced lower cell death rates, was more susceptible to treatment with type I IFN, and was less pathogenic than Rio-U1 in a murine model. In conclusion, the present study shows evidence that the isolate Rio-BM1 is more attenuated than Rio-U1, probably due to the impact of genetic alterations in the modulation of virulence. The results obtained in our in vitro model were consistent with the pathogenicity observed in the animal model, indicating that this method can be used to assess the virulence level of other isolates or to predict the pathogenicity of reverse genetic constructs containing other polymorphisms.
Insights
Researchers isolated Zika virus from breast milk, finding the Rio-BM1 strain less pathogenic and more attenuated than other strains. This study offers insights into Zika virus (ZIKV) virulence mechanisms.
Area of Science:
- Virology
- Genomics
- Epidemiology
Background:
- Understanding Zika virus (ZIKV) pathogenicity is crucial due to potential epidemic resurgence.
- ZIKV transmission routes, including via breast milk, require further investigation.
- Genetic diversity among ZIKV isolates influences viral properties.
Purpose of the Study:
- To isolate and characterize Zika virus from breast milk.
- To compare the genetic and virological properties of ZIKV isolates from different sources.
- To assess the pathogenicity and virulence of ZIKV isolates in vitro and in vivo.
Main Methods:
- Complete genomic analysis of three ZIKV isolates (Rio-BM1, Rio-U1, Rio-S1).
- In vitro replication assays in mammalian cells.
- Assessment of cell death rates and susceptibility to type I Interferon (IFN).
- Murine model for in vivo pathogenicity studies.
Main Results:
- All three ZIKV isolates belonged to the Asian genotype, with American isolate characteristics.
- Eight non-synonymous single nucleotide variants and multiple polymorphisms were identified.
- The breast milk isolate (Rio-BM1) exhibited lower replication, reduced cell death, increased IFN susceptibility, and lower pathogenicity in mice compared to Rio-U1.
- In vitro findings correlated with in vivo pathogenicity.
Conclusions:
- The ZIKV isolate Rio-BM1 is more attenuated than Rio-U1, likely due to genetic variations affecting virulence.
- In vitro models can effectively assess ZIKV isolate virulence and predict pathogenicity.
- This research contributes to understanding ZIKV epidemic potential and developing diagnostic/prognostic tools.
