In recent years Venezuela has faced a severe economic crisis precipitated by political instability and a significant reduction in oil revenue. Public health provision has suffered particularly. Long-term shortages of medicines and medical supplies and an exodus of trained personnel have occurred against the backdrop of a surge in vector-borne parasitic and arboviral infections. Herein, we aim to assess comprehensively the impact of Venezuela's healthcare crisis on vectorborne diseases and the spillover to neighbouring countries. Methods Alongside the ongoing challenges affecting the healthcare system, health-indicator statistics have become increasingly scarce. Official data from the Ministry of Health, for example, are no longer available. To provide and update on vector-borne disease in Venezuela, this study used individualized data from nongovernmental organizations, academic institutions and professional colleges, various local health authorities and epidemiological surveillance programs from neighbouring countries, as well as data available through international agencies. Findings Between 2000-2015 Venezuela witnessed a 365% increase malaria cases followed by a 68% increase (319,765 cases) in late 2017. Neighbouring countries such as Brazil have reported an escalating trend of imported cases from Venezuelan from 1,538 (2014) to 3,129 (2017). Active Chagas disease transmission is reported with seroprevalence in children (<10 years) as high as 12.5% in one community tested (N=64). There has been a nine-fold rise in the mean incidence of dengue between 1990 to 2016. Estimated rates of chikungunya and Zika are 6,975 and 2,057 cases per 100,000 population, respectively, during their epidemic peaks. Interpretation The re-emergence of many arthropod-borne endemic diseases has set in place an epidemic of unprecedented proportions, not only in Venezuela but in the region. Data presented here demonstrates the complex determinants of this situation. National, regional and global authorities must take action to address these worsening epidemics and prevent their expansion beyond Venezuelan borders.
BackgroundMosquitoes belonging to the Albitarsis Group (Anopheles: Nyssorhynchus) are of importance as malaria vectors across the Neotropics. The Group currently comprises six known species, and recent studies have indicated further hidden biodiversity within the Group. DNA barcoding has been proposed as a highly useful tool for species recognition, although its discriminatory utility has not been verified in closely related taxa across a wide geographic distribution.MethodsDNA barcodes (658 bp of the mtDNA Cytochrome c Oxidase - COI) were generated for 565 An. albitarsis s.l. collected in Argentina, Brazil, Colombia, Paraguay, Trinidad and Venezuela over the past twenty years, including specimens from type series and type localities. Here we test the utility of currently advocated barcoding methodologies, including the Kimura-two-parameter distance model (K2P) and Neighbor-joining analysis (NJ), for determining species delineation within mosquitoes of the Neotropical Albitarsis Group of malaria vectors (Anopheles: Nyssorhynchus), and compare results with Bayesian analysis.ResultsSpecies delineation through barcoding analysis and Bayesian phylogenetic analysis, fully concur. Analysis of 565 sequences (302 unique haplotypes) resolved nine NJ tree clusters, with less than 2% intra-node variation. Mean intra-specific variation (K2P) was 0.009 (range 0.002 - 0.014), whereas mean inter-specific divergence were several-fold higher at 0.041 (0.020 - 0.056), supporting the reported "barcoding gap". These results show full support for separate species status of the six known species in the Albitarsis Group (An. albitarsis s.s., An. albitarsis F, An. deaneorum, An. janconnae, An. marajoara and An. oryzalimnetes), and also support species level status for two previously detected lineages - An. albitarsis G &An. albitarsis I (designated herein). In addition, we highlight the presence of a unique mitochondrial lineage close to An. deaneorum and An. marajoara (An. albitarsis H) from Rondônia and Mato Grosso in southwestern Brazil. Further integrated studies are required to confirm the status of this lineage.ConclusionsDNA barcoding provides a reliable means of identifying both known and undiscovered biodiversity within the closely related taxa of the Albitarsis Group. We advocate its usage in future studies to elucidate the vector competence and respective distributions of all eight species in the Albitarsis Group and the novel mitochondrial lineage (An. albitarsis H) recovered in this study.
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