Differentiation of an adult neuron cell line increases susceptibility to rabies infection.

A wide variety of in vitro models have been used for studying rabies infection, however, currently, no central nervous system (CNS) adult neuron cultures are available. The current study determined the susceptibility to rabies infection in an adult CNS neuron cell line (CAD-R1). Cultures of CAD-R1 cells were held for 5 days in medium containing serum (undifferentiated CAD-R1 cells) or in serum-free medium (differentiated CAD-R1 cells). They were then infected with highly neurotropic rabies virus (RV) strain (CVS), obtained from fibroblastic cells (CVS-BHK) or from adult mouse brain (CVS-MB). Undifferentiated and differentiated cells were infected with the two RV strains, but the percentage of infected cells in differentiated cultures was significantly greater (83% and 79%, respectively) than in undifferentiated cells (51% and 60%) (Student's t testUna gran variedad de modelos in vitro se usan para estudiar la infección por virus de rabia, pero hasta el momento no se dispone de una línea neuronal adulta del sistema nervioso central (SNC) para dichos estudios. Por esta razón, nuestro objetivo fue determinar la susceptibilidad de una línea neuronal adulta del SNC (CAD-R1) a la infección por virus de rabia. Para ello, los cultivos se mantuvieron por 5 días en medio con suero (células CAD-R1 indiferenciadas) o sin suero (células CAD-R1 diferenciadas). Luego, se infectaron con una cepa de virus de rabia altamente neurotrópica (CVS) mantenida en células de tipo fibroblástico (CVS-BHK) o en cerebro de ratón (CVS-CR). Los dos tipos de células (indiferenciadas y diferenciadas) se infectaron con ambas cepas de virus de rabia; la proporción de células infectadas en los cultivos diferenciados fue mucho mayor (porcentajes de infección de 83,2% y 78,7% para CVS-BHK y CVS-CR, respectivamente) que en las células indiferenciadas (51,4% y 60,4%) (prueba t de Studen

Spatio-temporal dynamics of Plasmodium falciparum transmission within a spatial unit on the Colombian Pacific Coast

Funder: Newton-Caldas Fund Institutional Links, British Council, award G1854Funder: Newton-Caldas Fund Institutional Links, British Council, award G1854; Faculty of Medicine, Universidad Nacional de Colombia, awards HERMES 35988, 32309Abstract: As malaria control programmes concentrate their efforts towards malaria elimination a better understanding of malaria transmission patterns at fine spatial resolution units becomes necessary. Defining spatial units that consider transmission heterogeneity, human movement and migration will help to set up achievable malaria elimination milestones and guide the creation of efficient operational administrative control units. Using a combination of genetic and epidemiological data we defined a malaria transmission unit as the area contributing 95% of malaria cases diagnosed at the catchment facility located in the town of Guapi in the South Pacific Coast of Colombia. We provide data showing that P. falciparum malaria transmission is heterogeneous in time and space and analysed, using topological data analysis, the spatial connectivity, at the micro epidemiological level, between parasite populations circulating within the unit. To illustrate the necessity to evaluate the efficacy of malaria control measures within the transmission unit in order to increase the efficiency of the malaria control effort, we provide information on the size of the asymptomatic reservoir, the nature of parasite genotypes associated with drug resistance as well as the frequency of the Pfhrp2/3 deletion associated with false negatives when using Rapid Diagnostic Tests

Sentinel network for monitoring in vitro susceptibility of Plasmodium falciparum to antimalarial drugs in Colombia: a proof of concept

Drug resistance is one of the principal obstacles blocking worldwide malaria control. In Colombia, malaria remains a major public health concern and drug-resistant parasites have been reported. In vitro drug susceptibility assays are a useful tool for monitoring the emergence and spread of drug-resistant Plasmodium falciparum. The present study was conducted as a proof of concept for an antimalarial drug resistance surveillance network based on in vitro susceptibility testing in Colombia. Sentinel laboratories were set up in three malaria endemic areas. The enzyme linked immunosorbent assay-histidine rich protein 2 and schizont maturation methods were used to assess the susceptibility of fresh P. falciparum isolates to six antimalarial drugs. This study demonstrates that an antimalarial drug resistance surveillance network based on in vitro methods is feasible in the field with the participation of a research institute, local health institutions and universities. It could also serve as a model for a regional surveillance network. Preliminary susceptibility results showed widespread chloroquine resistance, which was consistent with previous reports for the Pacific region. However, high susceptibility to dihydroartemisinin and lumefantrine compounds, currently used for treatment in the country, was also reported. The implementation process identified critical points and opportunities for the improvement of network sustainability strategies.PAHO [057-1-3144141]; COLCIENCIAS [ID 2229-405-20319]info:eu-repo/semantics/publishedVersio

Baseline in vivo, ex vivo and molecular responses of Plasmodium falciparum to artemether and lumefantrine in three endemic zones for malaria in Colombia

Background: Colombia began using artemisinin-based combination therapies for the treatment of uncomplicated Plasmodium falciparum malaria in 2006. It is necessary to implement resistance surveillance to antimalarial drugs in order to promptly detect changes in parasite susceptibility. The aim of this study was to establish a susceptibility baseline of P. falciparum to artemether-lumefantrine using three monitoring tools. Methods: Patients with uncomplicated malaria treated with artemether-lumefantrine underwent clinical and parasitological follow-up over 28 days. Ex vivo test was performed using the microtest technique for chloroquine, arthemeter, dihydroartemisinin and lumefantrine. Pfmdr1 copy number and polymorphisms in Pfk13, Pfatp6, Pfcrt and Pfmdr1 genes were analyzed. Results: From a total of 150 screened patients, 49 completed follow-up for 28 days. All treated patients had adequate clinical and parasitological responses. Parasitic clearance showed a drastic reduction of parasite biomass at 24 hours and complete elimination at 48 hours. One hundred eleven isolates were processed, all exhibited high susceptibility to artemisinins and a slight decrease in susceptibility to lumefantrine. No genetic polymorphisms associated with resistance to artemisinin were found. Conclusion: This study generated a susceptibility baseline in response to therapy with Coartem (artemetherlumefantrine) with numerical reference values, which will allow data comparison with future studies to systematically monitor changes in the parasite and to provide an early alert to the health authorities

Evaluación de campo de la precisión de la prueba de diagnóstico rápido SD Bioline Malaria Antigen Pf/Pv® en Colombia

Introduction: Rapid diagnostic tests (RDT) have been postulated as a way to ensure access to malaria diagnosis in remote areas. Despite its widespread use, there are no field studies to evaluate the accuracy of the SD Bioline Malaria Antigen Pf/Pv in Colombia RDT.Objective: To evaluate the diagnostic accuracy of the SD Bioline Malaria Antigen Pf/Pv® RDT in two departments endemic for malaria, comparing diagnosis with thick film corrected with PCR.Materials and methods: A retrospective study was carried out to evaluate sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), concordance and sensitivity limits according to parasitemia ranges for the SD Bioline Malaria Antigen Pf/Pv ® test in Cordoba and Choco. The results were compared with microscopy corrected by PCR.Results: A total of 383 samples processed, 121 were positive (75 for P. vivax, 42 for P. falciparum and 4 for mixed infection) and 262 negative samples. P. vivax: sensitivity 92.0% (95% CI: 83.6-96.3), specificity 98.7% ( 95% CI: 96.7-99.5), PPV 94.5% (95% CI: 86.7-97.9), NPV 98.1% (95% CI: 95.8-99.1), Cohen’s kappa coefficient was 0.90 (0.80-1.00). P. falciparum: sensitivity 88.1% (95% CI: 75.0-94.8), specificity 97.9% (95% CI: 95.8-99.0), PPV 84.1% (95% CI: 70.6-92.1), NPV 98.5% (95% IC: 96.6-99.4), Cohen’s kappa coefficient 0.80 (95% CI: 0.70-0.90).Conclusions: The test performed well, being better for P. vivax as compared to P. falciparum. There are still difficulties of RDT to detect low parasitemias. The non amplification of Pfhrp2 and Pfhrp3 genes in two samples diagnosed as mixed infection, suggest a possible deletion of these two genes together. doi: http://dx.doi.org/10.7705/biomedica.v33i4.1464Introducción. Las pruebas de diagnóstico rápido han sido postuladas como una forma de garantizar el diagnóstico de malaria, o paludismo, en zonas de difícil acceso. A pesar de su uso difundido, no hay estudios de campo que evalúen la precisión de la prueba de diagnóstico rápido SD Bioline Malaria Antigen Pf/Pv® en Colombia.Objetivo. Evaluar la precisión diagnóstica de la prueba de diagnóstico rápido SD Bioline Malaria Antigen Pf/Pv ®, en dos departamentos endémicos para malaria, comparando el diagnóstico con la gota gruesa corregida por reacción en cadena de la polimerasa (PCR).Materiales y métodos. Se trata de un estudio retrospectivo para evaluar sensibilidad, especificidad, valor diagnóstico positivo (VPP) y negativo (VPN), concordancia y límites de sensibilidad por rangos de parasitemia, de la prueba SD Bioline Malaria Antigen ® Pf/Pv, en Córdoba y Chocó. Los resultados fueron comparados con la gota gruesa corregida por PCR.Resultados. De 383 muestras procesadas, 121 fueron positivas (75 para Plasmodium vivax, 42 para P. falciparum y 4 para infección mixta) y 262 muestras negativas; los resultados obtenidos fueron los siguientes: P. vivax: sensibilidad, 92,0 % (IC95% 83,6-96,3); especificidad, 98,7 % (IC95% 96,7-99,5); VPP, 94,5 % (IC95% 86,7-97,9); VPN, 98,1 % (IC95% 95,8-99,1); IK, 0,90 (0,80-1,00). P. falciparum: sensibilidad, 88,1 % (IC95% 75,0-94,8); especificidad, 97,9 % (IC95% 95,8-99,0); VPP, 84,1% % (IC95% 70,6-92,1); VPN, 98,5 % (IC95% 96,6-99,4); IK, 0,80 (0,70-0,90).Conclusiones. La prueba tuvo un buen desempeño, siendo mejor para P. vivax en comparación con que para P. falciparum. Persisten dificultades en la detección de bajas parasitemias. La falta de amplificación de los genes Pfhrp2 y Pfhrp3 en dos muestras con diagnóstico de como infección mixta, sugiere una posible deleción conjunta de estos genes.doi: http://dx.doi.org/10.7705/biomedica.v33i4.146

Capacidades do Talento Humano para a Pesquisa na Secretaria Distrital de Saúde e em Empresas Sociais do Estado

La generación de conocimiento aplicado a la resolución de problemas en salud es una necesidad inaplazable para impulsar los procesos de desarrollo competitivo en un país. Por eso, uno de los componentes esenciales dentro de los sistemas de ciencia, tecnología e innovación del mundo es el talento humano. En consecuencia, para fortalecer tales capacidades es necesario conocer suficientemente el estado actual. El objetivo del presente trabajo consiste en explorar las capacidades de investigación del talento humano de la Secretaría Distrital de Salud y la red adherida de empresas sociales del Estado. Esto se hizo a través de una metodología mixta donde se realizaron encuestas virtuales, revisiones del estado de los grupos de investigación en la plataforma ScienTI de Colciencias, grupos focales, y entrevistas para profundizar en una visión general y captar las ideas y estrategias probables de fortalecimiento. Los resultados mostraron un bajo porcentaje de servidores públicos y colaboradores con formación de alto nivel (< 6 %) y experiencia en investigación (27,9 %). Sin embargo, tienen un interés cada vez mayor por adherirse tanto al proceso de investigación (76,4 %) en cuanto a los grupos semillas de investigación (69,56 %). Igualmente, se identificaron ocho grupos de investigación dentro de esas instituciones, de los cuales cuatro fueron reconocidos y clasificados en la convocatoria 640-2013 de Colciencias. Estos hallazgos permitieron plantear algunas estrategias para el fortalecimiento de las capacidades para la investigación del talento humano desde la política, la gestión y la movilización del conocimiento institucional, siendo prioritaria la institucionalización de la investigación como eje de la misión en las organizaciones.Generating knowledge to solve health problems is a pressing need to boost the competitive development processes of a country. For this reason, human talent is one of the vital constituents of the world’s science, technology and innovation systems. Therefore, in order to strengthen such abilities, it is necessary to know the current state of the art. The goal of this study is exploring research competencies of the human talent at District Health Department and their networked State Social Enterprises. This was possible through a mixed methodology where we carried out virtual surveys, status checks of the research groups in Colciencias ScienTI platform, focus group, and interviews to deepen into a general overview and catching insights and probable strengthening strategies. Results showed a low percentage of public servants and collaborators with high-level training (< 6 %) and research experience (27,9 %). Nonetheless, there is an increasing interest to carry out both the research process (76,4 %) and research seedlings (69,56 %). In addition, we could identify eight research groups within these institutions, of which four recognized and classified at call 640-2013 by Colciencias. These findings allowed us to propose some strategies to strength research competencies by human talent taking into account policies, management and involvement where institutionalization of research activities may be a cornerstone for organizations

Sentinel network for monitoring in vitro susceptibility of Plasmodium falciparum to antimalarial drugs in Colombia: a proof of concept

Drug resistance is one of the principal obstacles blocking worldwide malaria control. In Colombia, malaria remains a major public health concern and drug-resistant parasites have been reported. In vitro drug susceptibility assays are a useful tool for monitoring the emergence and spread of drug-resistant Plasmodium falciparum . The present study was conducted as a proof of concept for an antimalarial drug resistance surveillance network based on in vitro susceptibility testing in Colombia. Sentinel laboratories were set up in three malaria endemic areas. The enzyme linked immunosorbent assay-histidine rich protein 2 and schizont maturation methods were used to assess the susceptibility of fresh P. falciparum isolates to six antimalarial drugs. This study demonstrates that an antimalarial drug resistance surveillance network based on in vitro methods is feasible in the field with the participation of a research institute, local health institutions and universities. It could also serve as a model for a regional surveillance network. Preliminary susceptibility results showed widespread chloroquine resistance, which was consistent with previous reports for the Pacific region. However, high susceptibility to dihydroartemisinin and lumefantrine compounds, currently used for treatment in the country, was also reported. The implementation process identified critical points and opportunities for the improvement of network sustainability strategies

Resolving drug selection and migration in an inbred South American Plasmodium falciparum population with identity-by-descent analysis.

Funder: Ministerio de Salud Pública del EcuadorThe human malaria parasite Plasmodium falciparum is globally widespread, but its prevalence varies significantly between and even within countries. Most population genetic studies in P. falciparum focus on regions of high transmission where parasite populations are large and genetically diverse, such as sub-Saharan Africa. Understanding population dynamics in low transmission settings, however, is of particular importance as these are often where drug resistance first evolves. Here, we use the Pacific Coast of Colombia and Ecuador as a model for understanding the population structure and evolution of Plasmodium parasites in small populations harboring less genetic diversity. The combination of low transmission and a high proportion of monoclonal infections means there are few outcrossing events and clonal lineages persist for long periods of time. Yet despite this, the population is evolutionarily labile and has successfully adapted to changes in drug regime. Using newly sequenced whole genomes, we measure relatedness between 166 parasites, calculated as identity by descent (IBD), and find 17 distinct but highly related clonal lineages, six of which have persisted in the region for at least a decade. This inbred population structure is captured in more detail with IBD than with other common population structure analyses like PCA, ADMIXTURE, and distance-based trees. We additionally use patterns of intra-chromosomal IBD and an analysis of haplotypic variation to explore past selection events in the region. Two genes associated with chloroquine resistance, crt and aat1, show evidence of hard selective sweeps, while selection appears soft and/or incomplete at three other key resistance loci (dhps, mdr1, and dhfr). Overall, this work highlights the strength of IBD analyses for studying parasite population structure and resistance evolution in regions of low transmission, and emphasizes that drug resistance can evolve and spread in small populations, as will occur in any region nearing malaria elimination

Spatio-temporal dynamics of Plasmodium falciparum transmission within a spatial unit on the Colombian Pacific Coast.

As malaria control programmes concentrate their efforts towards malaria elimination a better understanding of malaria transmission patterns at fine spatial resolution units becomes necessary. Defining spatial units that consider transmission heterogeneity, human movement and migration will help to set up achievable malaria elimination milestones and guide the creation of efficient operational administrative control units. Using a combination of genetic and epidemiological data we defined a malaria transmission unit as the area contributing 95% of malaria cases diagnosed at the catchment facility located in the town of Guapi in the South Pacific Coast of Colombia. We provide data showing that P. falciparum malaria transmission is heterogeneous in time and space and analysed, using topological data analysis, the spatial connectivity, at the micro epidemiological level, between parasite populations circulating within the unit. To illustrate the necessity to evaluate the efficacy of malaria control measures within the transmission unit in order to increase the efficiency of the malaria control effort, we provide information on the size of the asymptomatic reservoir, the nature of parasite genotypes associated with drug resistance as well as the frequency of the Pfhrp2/3 deletion associated with false negatives when using Rapid Diagnostic Tests

ADMIXTURE groups shown in Fig 3 and sample equivalency to previously reported groups using STRUCTURE.

(A) Elbow method to identify the optimal number of ancestral populations from ADMIXTURE (K) based on cross-validation error. Red line indicates K = 5 ancestral populations selected following best practices. (B) ADMIXTURE results highlighting the three ancestral populations identified in Knudson et al. 2020 with STRUCTURE [19]. (EPS)</p