Enhanced mosquito vectorial capacity underlies the Cape Verde Zika epidemic

Abstract

The explosive emergence of Zika virus (ZIKV) across the Pacific and Americas since 2007 was associated with hundreds of thousands of human cases and severe outcomes, including congenital microcephaly caused by ZIKV infection during pregnancy. Although ZIKV was first isolated in Uganda, Africa has so far been exempt from large-scale ZIKV epidemics, despite widespread susceptibility among African human populations. A possible explanation for this pattern is natural variation among populations of the primary vector of ZIKV, the mosquito Aedes aegypti. Globally invasive populations of Ae. aegypti outside of Africa are considered effective ZIKV vectors because they are human specialists with high intrinsic ZIKV susceptibility, whereas African populations of Ae. aegypti across the species’ native range are predominantly generalists with low intrinsic ZIKV susceptibility, making them less likely to spread viruses in the human population. We test this idea by studying a notable exception to the patterns observed across most of Africa: Cape Verde experienced a large ZIKV outbreak in 2015 to 2016. We find that local Ae. aegypti in Cape Verde have substantial human-specialist ancestry, show a robust behavioral preference for human hosts, and exhibit increased susceptibility to ZIKV infection, consistent with a key role for variation among mosquito populations in ZIKV epidemiology. These findings suggest that similar human-specialist populations of Ae. aegypti in the nearby Sahel region of West Africa, which may be expanding in response to rapid urbanization, could serve as effective vectors for ZIKV in the future.

Molecular signature of domestication in the arboviral vectorAedes aegypti

“…The hallmark of domestication in Ae. aegypti is higher attraction to humans than animals, a phenotype that was used to classify Aaa and Aaf mosquitoes, prior to the discovery of Aaf mosquitoes preferentially blood-feeding on humans in Cape Verde and Senegal, and is regulated by chemosensory receptors (6,26,36). Among the 198 Ae.…”

Recovery of Metagenomic Data from theAedes aegyptiMicrobiome using a Reproducible Snakemake Pipeline: MINUUR

“…We selected the data sets to cover a range of sequencing depths, DNA extraction method and sequencing platform (Figure 2C). All raw FASTQ files of published sequencing data were retrieved from the European Nucleotide Archive (ENA) under the project accession numbers PRJEB33044 (37), PRJNA255893 (50), PRJNA385349 (51), PRJNA718905 (35), PRJNA776956 (52) and PRJNA992905 (53).…”

“…For this study, we used five published genome datasets of Aedes aegypti publicly available on the European Nucleotide Archive (35,37,(50)(51)(52)(53). We selected the data sets to cover a range of sequencing depths, DNA extraction method and sequencing platform (Figure 2C).…”

Biology and Behaviour of Aedes aegypti in the Human Environment: Opportunities for Vector Control of Arbovirus Transmission

“…The ancestral form Aaf is not known to have ever occurred outside Africa and today is found in many habitats within Africa, including both forests and urban locations [ 2 , 4 ]. This form is not specialized on human hosts or habitats and may play a less important role in spreading human disease [ 5 , 6 , 7 ], although some populations in West Africa are competent vectors of flaviviruses [ 8 , 9 ] and are found in sympatry with Aaa using human made containers as larval habitats [ 10 , 11 ]. The highly anthropophilic and therefore the most familiar form is Aaa , most likely differentiated from Aaf around 4000–6000 years ago, when the aridification of northern Africa pushed the limit of Aaf further south [ 12 ].…”