Influence of dengue virus serotypes on the abundance of Aedes aegypti insect-specific viruses (ISVs).

A comprehensive understanding of the virome in mosquito vectors is crucial for assessing the potential transmission of viral agents, designing effective vector control strategies, and advancing our knowledge of insect-specific viruses (ISVs). In this study, we utilized Oxford Nanopore Technologies metagenomics to characterize the virome of Aedes aegypti mosquitoes collected in various regions of Colombia, a country hyperendemic for dengue virus (DENV). Analyses were conducted on groups of insects with previous natural DENV infection (DENV-1 and DENV-2 serotypes), as well as mosquito samples that tested negative for virus infection (DENV-negative). Our findings indicate that the Ae. aegypti virome exhibits a similar viral composition at the ISV family and species levels in both DENV-positive and DENV-negative samples across all study sites. However, differences were observed in the relative abundance of viral families such as Phenuiviridae, Partitiviridae, Flaviviridae, Rhabdoviridae, Picornaviridae, Bromoviridae, and Virgaviridae, depending on the serotype of DENV-1 and DENV-2. In addition, ISVs are frequently found in the core virome of Ae. aegypti, such as Phasi Charoen-like phasivirus (PCLV), which was the most prevalent and showed variable abundance in relation to the presence of specific DENV serotypes. Phylogenetic analyses of the L, M, and S segments of the PCLV genome are associated with sequences from different regions of the world but show close clustering with sequences from Brazil and Guadeloupe, indicating a shared evolutionary relationship. The profiling of the Ae. aegypti virome in Colombia presented here improves our understanding of viral diversity within mosquito vectors and provides information that opens the way to possible connections between ISVs and arboviruses. Future studies aimed at deepening our understanding of the mechanisms underlying the interactions between ISVs and DENV serotypes in Ae. aegypti could provide valuable information for the design of effective vector-borne viral disease control and prevention strategies.IMPORTANCEIn this study, we employed a metagenomic approach to characterize the virome of Aedes aegypti mosquitoes, with and without natural DENV infection, in several regions of Colombia. Our findings indicate that the mosquito virome is predominantly composed of insect-specific viruses (ISVs) and that infection with different DENV serotypes (DENV-1 and DENV-2) could lead to alterations in the relative abundance of viral families and species constituting the core virome in Aedes spp. The study also sheds light on the identification of the genome and evolutionary relationships of the Phasi Charoen-like phasivirus in Ae. aegypti in Colombia, a widespread ISV in areas with high DENV incidence.

Molecular Surveillance Detects High Prevalence of the Neglected Parasite Mansonella ozzardi in the Colombian Amazon.

BACKGROUND: Mansonellosis is an undermapped insect-transmitted disease caused by filarial nematodes that are estimated to infect hundreds of millions of people. Despite their prevalence, there are many outstanding questions regarding the general biology and health impacts of the responsible parasites. Historical reports suggest that the Colombian Amazon is endemic for mansonellosis and may serve as an ideal location to pursue these questions. METHODS: We deployed molecular and classical approaches to survey Mansonella prevalence among adults belonging to indigenous communities along the Amazon River and its tributaries near Leticia, Colombia. RESULTS: Loop-mediated isothermal amplification (LAMP) assays on whole-blood samples detected a much higher prevalence of Mansonella ozzardi infection (approximately 40%) compared to blood smear microscopy or LAMP performed using plasma, likely reflecting greater sensitivity and the ability to detect low microfilaremias and occult infections. Mansonella infection rates increased with age and were higher among men. Genomic analysis confirmed the presence of M. ozzardi that clusters closely with strains sequenced in neighboring countries. We successfully cryopreserved M. ozzardi microfilariae, advancing the prospects of rearing infective larvae in controlled settings. CONCLUSION: These data suggest an underestimation of true mansonellosis prevalence, and we expect that these methods will help facilitate the study of mansonellosis in endemic and laboratory settings.

Malaria at international borders: challenges for elimination on the remote Brazil-Peru border.

Understanding local epidemiology is essential to reduce the burden of malaria in complex contexts, such as Brazilian municipalities that share borders with endemic countries. A descriptive study of malaria in the period 2003 to 2020 was conducted using data from the Malaria Epidemiological Surveillance Information System related to a remote municipality with an extensive border with Peru to understand the disease transmission, focusing on the obstacles to its elimination. The transmission increases at the end of the rainy season. During the period of 18 years, 53,575 malaria cases were reported (Mean of API 224.7 cases/1,000), of which 11% were imported from Peru. Thirteen outbreaks of malaria were observed during the studied period, the last one in 2018. The highest burden of cases was caused by P. vivax (73.2%), but P. falciparum was also prevalent at the beginning of the study period (50% in 2006). Several changes in the epidemiological risk were observed: (1) the proportion of international imported cases of malaria changed from 30.7% in 2003 to 3.5% in 2020 (p<0.05); (2) indigenous people affected increased from 24.3% in 2003 to 89.5% in 2020 (p<0.0001); (3) infected children and adolescents < 15 years old increased from 50.2% in 2003 to 67.4% in 2020 (p<0.01); (4) the proportion of men decreased from 56.7% in 2003 to 50.4% in 2020 (p<0.01); (5) the likelihood of P. falciparum malaria has significantly declined (p<0.01). The number of cases and the incidence of malaria in 2019 and 2020 were the lowest in the period of 18 years. The burden of malaria in indigenous areas and its determinants, seasonality, geographical access and the long international border are obstacles for the elimination of malaria that must be overcome.

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

BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: Here, 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/SIGNIFICANCE: This 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.

Epidemiologia da Malária no Município de Atalaia do Norte, Amazonas, Brasil / Epidemiology of Malaria in the Municipality of Atalaia do Norte, Amazonas, Brazil

INTRODUÇAO: A malária é uma doença complexa de elevada morbidade na região Amazônica brasileira. Nos últimos anos o número de casos vem aumentando na região e para estabelecer estratégias mais adequadas para controle é preciso conhecer a epidemiologia local em cada uma das áreas onde a malária está presente. Com isso, o objetivo desse estudo foi investigar a presença de casos de malária e/ou infecção assintomática por Plasmodium spp. nos habitantes do município de Atalaia do Norte estado do Amazonas e determinar os principais determinantes demográficos associados. METODOLOGIA: O estudo foi realizado no município de Atalaia do Norte e em duas comunidades rurais desse município situado no estado do Amazonas. Foi realizado um estudo epidemiológico misto composto por uma analise retrospectivo e um estudo seccional. Para o estudo retrospectivo foram analisados os casos positivos de malária por local provável de infecção obtidos do SIVEP-Malária, no período de 2003 até 2018 para o município. O estudo seccional foi realizado em duas comunidades rurais do município, durante dois períodos do tempo, um na estação seca e outro na estação das chuvas. No total participaram do inquérito 190 indivíduos. Cada indivíduo foi submetido a um questionário e coleta de sangue para a realização dos testes de gota espessa e PCR para a confirmação do diagnóstico de infecção plasmodial.

RESULTADOS: Entre 2003-2018 foram confirmados 50.097 (IPA= 256,1 casos por mil habitantes) casos de malária no município de Atalaia do Norte com 60,7% ocorrendo em área indígena (n=29.867). Entre os casos confirmados 12,7% foram casos importados. Predominaram infecções em indivíduos do sexo masculino (n=55,1%) e em menores de 15 anos. (n=55,6%). O P. vivax foi a espécie parasitária mais prevalente sendo responsável do 72% dos casos notificados. O estudo seccional mostrou que dos indivíduos participantes, quatro (3,6%) indivíduos na estação seca e três (3,7%) na estação das chuvas foram positivos na gota espessa para infecção pelo P. vivax. Enquanto na PCR 19 (17,4%) foram identificados na estação seca e 21 (25,9%) na estação das chuvas. Foi identificada uma prevalência de infecção assintomática na estação seca de 19,2% e na estação das chuvas de 24,6%. Na área indígena 94% das infecções foram assintomáticas. Conclusões: Atalaia do norte é um município endêmico para malária com transmissão estável da doença durante todo o ano e com presença de portadores assintomáticos que podem atuar como reservatórios do Plasmodium. A maioria de casos ocorrem na área indígena sendo a população mais vulnerável devido as dificuldades de acesso à saúde nesta área do país. Ainda o controle e a eliminação da malária são um desafio para esta região que requer de intervenções imediatas para a eliminação da doença. (AU)

Caracterização da diversidade genética de amostras clínicas de Plasmodium falciparum isoladas de indivíduos de Barcelos - Amazonas utilizando o gene que codifica para a proteína de superfície do merozoíta 2 (msp2) / Characterization of the genetic diversity of Plasmodium falciparum isolated from clinical samples of individuals from Barcelos - Amazonas using the gene encoding the merozoite surface protein (msp2)

INTRODUCÃO: A complexa diversidade genética do Plasmodium falciparum é emparte responsável pela evasão da resposta imune do hospedeiro, pelo surgimentoda resistência aos fármacos e pela dificuldade no desenvolvimento de uma vacinaanti-malárica eficaz. Estudos sobre a biologia deste parasito se concentramfundamentalmente em áreas holo e hiperendêmicas de malária na Áfricasubsaariana. Trabalhos realizados na região Amazônica, ainda são escassos no quese refere à diversidade genética de populações naturais de P. falciparum. Esteestudo analisou a diversidade genética de P. falciparum isolados de indivíduosprovenientes da região do médio rio Negro, Amazonas utilizando como alvo o geneque codifica para a proteína de superfície do merozoíta 2. METODOLOGIA: Oestudo foi realizado em Barcelos, um município de alto risco epidemiológico paramalária com uma média anual de 5.000 casos nos últimos cinco anos (IPAmédio=156,4/1000). Foram avaliadas 79 amostras isoladas de indivíduos queapresentaram malária clínica ou infecção assintomática. Os DNAs genômicosextraídos foram submetidos à reação em cadeia da polimerase (PCR) para aconfirmação do diagnóstico de infecção pelo P. falciparume em seguida foi feita umaPCR-nested, para amplificação da região do bloco 3 do gene msp2 paradiferenciação das famílias alélicas (3D7 e FC27) e a diversidade intra-família foiobservada após digestão com a enzima HinfI. RESULTADOS: Só foi encontrada afamilia 3D7 nas amostras estudadas. Dois diferentes genótipos foram encontradoscirculando na área, caracterizados pela combinação dos fragmentos 16 pb, 108 pb,349 (genotipo 1) e 16 pb, 108 pb, 400pb (genotipo 2). Foi observado que só doisindivíduos com malária clinica portavam os dois genótipos simultaneamente...

INTRODUCTION: The complex genetic diversity of Plasmodium falciparum is partlyresponsible for the evasion of the host immune response, the emergence of drugresistance and the difficulty in developing an effective anti-malarial vaccine. Studieson the biology of this parasite are mainly concentrated in holo and hyperendemicmalaria areas in sub-Saharan Africa. Research in the Amazon region, is scarce inrelation to the genetic diversity of natural populations of P. falciparum. This studyanalyzed the genetic diversity of P. falciparum isolates from individuals of the MiddleRio Negro, Amazon in Brazil, using the gene coding for the merozoite surface protein2 (MSP2). METHODOLOGY: The study was conducted in Barcelos, a malaria highepidemiological risk municipality, with an annual average of 5,000 cases in the lastfive years (mean IPA = 156.4 / 1000). We evaluated 79 samples isolated fromsubjects presenting clinical malaria or asymptomatic infection. The extracted genomicDNA was subjected to polymerase chain reaction (PCR) to confirm the diagnosis ofinfection with P. falciparum. A PCR-nested was made for amplification of the genemsp2 block 3 region for differentiation of allelic families (3D7 and FC27); intrafamilydiversity was observed after digestion with the enzyme HinfI. RESULTS: Only family3D7 was observed in the samples. Two different genotypes were found circulating inthe area, characterized by the combination of fragments 16 bp, 108 bp, 349(genotype 1) and 16 bp, 108 bp, 400bp (genotype 2). It was observed that only twoindividuals with clinical malaria carried two genotypes simultaneously...