Deciphering the introduction and transmission of SARS-CoV-2 in the Colombian Amazon Basin

La pandemia del SARS-CoV-2 ha obligado a las autoridades sanitarias de todo el mundo a tomar importantes decisiones para reducir su propagación. La epidemiología genómica se ha convertido en una herramienta valiosa para comprender las introducciones y la propagación del virus en una ubicación geográfica específica.The SARS-CoV-2 pandemic has forced health authorities across the world to take important decisions to curtail its spread. Genomic epidemiology has emerged as a valuable tool to understand introductions and spread of the virus in a specific geographic location

Deciphering the introduction and transmission of SARS-CoV-2 in the Colombian Amazon Basin.

BackgroundThe SARS-CoV-2 pandemic has forced health authorities across the world to take important decisions to curtail its spread. Genomic epidemiology has emerged as a valuable tool to understand introductions and spread of the virus in a specific geographic location.Methodology/principal findingsHere, we report the sequences of 59 SARS-CoV-2 samples from inhabitants of the Colombian Amazonas department. The viral genomes were distributed in two robust clusters within the distinct GISAID clades GH and G. Spatial-temporal analyses revealed two independent introductions of SARS-CoV-2 in the region, one around April 1, 2020 associated with a local transmission, and one around April 2, 2020 associated with other South American genomes (Uruguay and Brazil). We also identified ten lineages circulating in the Amazonas department including the P.1 variant of concern (VOC).Conclusions/significanceThis study represents the first genomic epidemiology investigation of SARS-CoV-2 in one of the territories with the highest report of indigenous communities of the country. Such findings are essential to decipher viral transmission, inform on global spread and to direct implementation of infection prevention and control measures for these vulnerable populations, especially, due to the recent circulation of one of the variants of concern (P.1) associated with major transmissibility and possible reinfections

Data_Sheet_1_Arbovirus infection in Aedes aegypti from different departments of Colombia.docx

The lack of precise and timely knowledge about the molecular epidemiology of arboviruses of public health importance, particularly in the vector, has limited the comprehensive control of arboviruses. In Colombia and the Americas, entomovirological studies are scarce. Therefore, this study aimed to describe the frequency of natural infection and/or co-infection by Dengue (DENV), Zika (ZIKV), and Chikungunya (CHIKV) in Aedes spp. circulating in different departments of Colombia (Amazonas, Boyacá, Magdalena, and Vichada) and identifying vector species by barcoding. Aedes mosquitoes were collected in departments with reported prevalence or incidence of arbovirus cases during 2020–2021, located in different biogeographic zones of the country: Amazonas, Boyacá, Magdalena, and Vichada. The insects were processed individually for RNA extraction, cDNA synthesis, and subsequent detection of DENV (serotypes DENV1-4 by multiplex PCR), CHIKV, and ZIKV (qRT-PCR). The positive mosquitoes for arboviruses were sequenced (Sanger method) using the subunit I of the cytochrome oxidase (COI) gene for species-level identification. In total, 558 Aedes mosquitoes were captured, 28.1% (n = 157) predominantly infected by DENV in all departments. The serotypes with the highest frequency of infection were DENV-1 and DENV-2 with 10.7% (n = 58) and 14.5% (n = 81), respectively. Coinfections between serotypes represented 3.9% (n = 22). CHIKV infection was detected in one individual (0.2%), and ZIKV infections were not detected. All infected samples were identified as A. aegypti (100%). From the COI dataset (593 bp), high levels of haplotype diversity (H = 0.948 ± 0.012) and moderate nucleotide diversity (π = 0.0225 ± 0.003) were identified, suggesting recent population expansions. Constructed phylogenetic analyses showed our COI sequences’ association with lineage I, which was reported widespread and related to a West African conspecific. We conclude that natural infection in A. aegypti by arbovirus might reflect the country’s epidemiological behavior, with a higher incidence of serotypes DENV-1 and DENV-2, which may be associated with high seroprevalence and asymptomatic infections in humans. This study demonstrates the high susceptibility of this species to arbovirus infection and confirms that A. aegypti is the main vector in Colombia. The importance of including entomovirological surveillance strategy within public health systems to understand transmission dynamics and the potential risk to the population is highlighted herein.</p