Laboratory evaluation of eleven rapid diagnostic tests for serological diagnosis of Chagas disease in Colombia.

BACKGROUND: Chagas disease is a public health challenge in Colombia, where only an estimated 1.2% of people at risk have accessed diagnosis, while less than 0.5% of affected people have obtained treatment. The development of simplified diagnostic algorithms would enable progress in access to diagnosis; however, the current diagnostic algorithm relies on at least two laboratory-based tests that require qualified personnel, processing equipment, and infrastructure, which are still generally lacking at the primary care level. Rapid diagnostic tests (RDTs) for Chagas disease could simplify diagnosis, but their performance in the epidemiological context of Colombia is not well known. METHODOLOGY: A retrospective analytical observational study of RDTs was performed to estimate the operational characteristics of 11 commercially available RDTs designed for in vitro detection of anti-T. cruzi IgG antibodies. The study was performed under controlled laboratory conditions using human serum samples. PRINCIPAL FINDINGS: Eleven RDTs were assessed, ten using 585 serum samples and one using 551 serum samples. Employing the current national diagnostic algorithm as a reference standard for serological diagnosis of chronic infection, the sensitivity of the assessed RDTs ranged from 75.5% to 99.0% (95% CI 70.5-100), while specificity ranged from 70.9% to 100% (95% CI 65.3-100). Most tests (7/11, 63.6%) had sensitivity above 90%, and almost all (10/11, 90.9%) had specificity above 90%. Five RDTs had both sensitivity and specificity above 90%. CONCLUSIONS/SIGNIFICANCE: The evaluation of these 11 commercially available RDTs under controlled laboratory conditions is a first step in the assessment of the diagnostic performance of RDTs in Colombia. As a next step, field studies will be conducted on available RDTs with sensitivity and specificity greater than 90% in this study, to evaluate performance in real world conditions, with the final goal to allow simplified diagnostic algorithms.

Global variation in force-of-infection trends for human Taenia solium taeniasis/cysticercosis.

Infection by Taenia solium poses a major burden across endemic countries. The World Health Organization (WHO) 2021-2030 Neglected Tropical Diseases roadmap has proposed that 30% of endemic countries achieve intensified T. solium control in hyperendemic areas by 2030. Understanding geographical variation in age-prevalence profiles and force-of-infection (FoI) estimates will inform intervention designs across settings. Human taeniasis (HTT) and human cysticercosis (HCC) age-prevalence data from 16 studies in Latin America, Africa, and Asia were extracted through a systematic review. Catalytic models, incorporating diagnostic performance uncertainty, were fitted to the data using Bayesian methods, to estimate rates of antibody (Ab)-seroconversion, infection acquisition and Ab-seroreversion or infection loss. HCC FoI and Ab-seroreversion rates were also estimated across 23 departments in Colombia from 28,100 individuals. Across settings, there was extensive variation in all-ages seroprevalence. Evidence for Ab-seroreversion or infection loss was found in most settings for both HTT and HCC and for HCC Ab-seroreversion in Colombia. The average duration until humans became Ab-seropositive/infected decreased as all-age (sero)prevalence increased. There was no clear relationship between the average duration humans remain Ab-seropositive and all-age seroprevalence. Marked geographical heterogeneity in T. solium transmission rates indicate the need for setting-specific intervention strategies to achieve the WHO goals.

Spatial distribution and risk factors for human cysticercosis in Colombia.

BACKGROUND: Cysticercosis is a zoonotic neglected tropical disease (NTD) that affects humans and pigs following the ingestion of Taenia solium eggs. Human cysticercosis poses a substantial public health burden in endemic countries. The World Health Organization (WHO) aims to target high-endemicity settings with enhanced interventions in 17 countries by 2030. Between 2008 and 2010, Colombia undertook a national baseline serosurvey of unprecedented scale, which led to an estimated seroprevalence of T. solium cysticercus antibodies among the general population of 8.6%. Here, we use contemporary geostatistical approaches to analyse this unique dataset with the aim of understanding the spatial distribution and risk factors associated with human cysticercosis in Colombia to inform how best to target intervention strategies. METHODS: We used a geostatistical model to estimate individual and household risk factors associated with seropositivity to T. solium cysticercus antibodies from 29,253 people from 133 municipalities in Colombia. We used both independent and spatially structured random effects at neighbourhood/village and municipality levels to account for potential clustering of exposure to T. solium. We present estimates of the distribution and residual correlation of seropositivity at the municipality level. RESULTS: High seroprevalence was identified in municipalities located in the north and south of Colombia, with spatial correlation in seropositivity estimated up to approximately 140 km. Statistically significant risk factors associated with seropositivity to T. solium cysticercus were related to age, sex, educational level, socioeconomic status, use of rainwater, consumption of partially cooked/raw pork meat and possession of dogs. CONCLUSIONS: In Colombia, the distribution of human cysticercosis is influenced by socioeconomic considerations, education and environmental factors related to the spread of T. solium eggs. This information can be used to tailor national intervention strategies, such as targeting spatial hotspots and more highly exposed groups, including displaced people and women. Large-scale seroprevalence surveys accompanied by geospatial mapping are an essential step towards reaching the WHO's 2021‒2030 NTD roadmap targets.

Comparative evaluation of immunoassays to improve access to diagnosis for Chagas disease in Colombia.

OBJECTIVE: Chagas disease affects over six million people, but less than 1% are diagnosed and treated. Complicated diagnostic processes are a major barrier. Colombia's previous diagnostic algorithm, using in-house tests, was difficult to scale up, creating significant access barriers for patients. A new algorithm using commercially manufactured immunoassays would potentially improve access, but these tests' performance in Colombian patients with Chagas disease is not well known. METHODS: We assessed seven commercially available assays. Samples (n=501), 93.8% originating from Colombia, were characterized as positive or negative based on standard procedure at the National Reference Laboratory. Performance characteristics were calculated for individual assays and hypothetical test pairings, then compared to the existing algorithm. RESULTS: Five of seven assays exhibited sensitivity >98% while six showed specificity >97%. A total antigen ELISA paired with a recombinant assay provided similar performance to the current diagnostic process. Six of six assays tested proved capable of detecting different Trypanosoma cruzi genetic lineages. CONCLUSIONS: The study indicated that several commercial assays accurately detect T. cruzi infection in Colombian patients. A simplified testing process with two commercial assays could perform comparably to the previous process, reducing cost and accessibility barriers and facilitating national scale-up.

Cisticercosis en Colombia. Estudio de seroprevalencia 2008 – 2010 / Cysticercosis in Colombia. Seroprevalence study 2008 – 2010

IntroduccIón: el complejo Taeniasis / Cisticercosis (T/C) es una infección parasitaria que en Colombia como en otros países constituye un gran problema de Salud Pública. La prevalencia de cisticercosis en la población general Colombiana no ha sido determinada a la fecha. objetIvo: determinar la prevalencia de cisticercosis en la población general de Colombia e identificar los principales riesgos ambientales, socioeconómicos, culturales y estilos de vida relacionados con la cisticercosis. MaterIales y Métodos: mediante técnica ELISA investigamos la prevalencia de sero positividad de anticuerpos IgG anti cistiercos en población general de 23 departamentos Colombianos incluyendo la ciudad capital. Se analizaron 23.960 muestras sanguíneas. El proceso se realizó en la sección de parasitología del Instituto Nacional de Salud, Bogotá Colombia. resultados: la seroprevalencia general fue de 8.55%, la más alta se presentó en el departamento de Vaupés (40,19%) y la menor en el departamento de Caldas (0,53%). El análisis multivariado de factores de riesgo mostró riesgo incrementado de seropostividad para Mujeres (OR=1,60 IC 1,40 – 1,90) p <0,05, y para personas quienes consumían alimentos sin cocción (OR = 44,80 IC 5,00 – 401,40) p <0,05. No lavarse las manos después de ir al baño y haber utilizado el sanitario (OR = 1,37 IC 0,70 – 2,70) no mostró significancia estadística. conclusIones: Colombia tiene un rango variable de prevalencia de seropositividad de cisticercosis en población general (0.53% to 40.19%). Los principales factores de riesgo fueron el género femenino y el no lavado de manos después de ir al baño.

Factores de riesgo asociados a la seroprevalencia de cisticercosis en el Municipio de Mitú, Colombia / Risk factors associated with seroprevalence of cysticercosis in the municipality of Mitú, Colombia

La cisticercosis es una enfermedad de salud pública que afecta a todas las personas sin discriminación de género ni edad, por eso es necesario considerar estrategias que permitan su erradicación. Una forma de lograrlo es la creación de campañas nacionales, que permitan mejoras en los servicios sanitarios para interrumpir el ciclo de vida de la Taenia solium. También es fundamental incluir aspectos educacionales donde se considere información médica y veterinaria. El objetivo de este estudio fue conocer los posibles factores de riesgo relacionados con la presencia de cisticercosis en la población del municipio de Mitú, Vaupés, Colombia, que ayuden a identificar oportunamente la cadena de transmisión de esta enfermedad. Se encuestaron 1.141 personas de las cuales 441 resultaron positivas para IgG cisticerco mediante la técnica de Elisa. El 56,0% fueron mujeres y principalmente el grupo de 19 a 40 años de edad fue el de mayor porcentaje de seroprevalencia. La falta de hábitos higiénicos, como el lavado de manos después de salir del baño, presentó un mayor riesgo de infección por cisticercosis con respecto aquellos que sí lo realizaban (OR=1,19 IC 95%, 1,03 – 1,38). También se halló un alto porcentaje de falta de hábitos de higiene entre las personas seropositivas con respecto al consumo de carne de cerdo.

Evaluación del equipo FE-5 vs. técnica de Ritchie con muestras fecales de manipuladores de alimentos en cinco ciudades del país / Evaluation of FE-5 team Ritchie vs. technique faecal samples of food handlers in five Colombian cities

El objetivo del trabajo fue evaluar la efectividad del equipo Diasys FE-5, instrumento que sirve como nueva técnica de concentración de parásitos intestinales, que facilita la preparación, centrifugación, concentración y montaje de las muestras para su lectura. Está compuesto de un sistema de Mini Parasep que optimiza la recuperación y concentración de quistes, huevos y larvas en comparación con la técnica tradicional de Ritchie modificada (formol – éter). Se examinaron 764 muestras de materia fecal, procedentes de manipuladores de alimentos de cinco ciudades del país. Las muestras fueron simultáneamente procesadas y analizadas mediante la técnica de Ritchie y el equipo Diasys FE-5. Las dos técnicas permitieron el hallazgo parasitológico de protozoos y helmintos, con una concordancia de índice de kappa de 0.90, aspecto que permite confirmar que el equipo Diasys FE-5 es una herramienta útil y segura en el laboratorio para el diagnóstico de parasitismo intestinal, obteniendo como beneficios la disminución de costos, reactivos, tiempo, y lo más importante, bioseguridad para el profesional y mejoramiento del diagnóstico parasitológico.

Seroprevalencia de la toxoplasmosis y factores relacionados con las enfermedades transmitidas por alimentos en trabajadores de plantas de beneficio animal en cinco ciudades capitales de Colombia, 2008 / Seroprevalence of toxoplasmosis and factors related to foodborne diseases in workers in animal processing plants in five capital cities in Colombia, 2008

El Instituto Nacional de Salud de Colombia, con el fin de conocer la prevalencia de toxoplasmosis en trabajadores de mataderos, realizó la determinación de anticuerpos contra Toxoplasma gondii en la población seleccionada. El objetivo fue determinar la seroprevalencia de toxoplasmosis, mediante la técnica ELFA (Enzyme Linked Fluorescent Assay), en trabajadores de plantas de beneficio animal en cinco ciudades del país durante el año 2008. Se llevó a cabo un estudio de corte transversal en 400 trabajadores de las plantas de beneficio animal que trabajan en el área limpia, quienes fueron seleccionados de forma aleatoria. En los 400 trabajadores encuestados, se encontró una seroprevalencia del 71.8% (287) de anticuerpos anti-IgG contra Toxoplasma gondii y del 2.8% (8) de anticuerpos anti-IgM contra Toxoplasma gondii, estos últimos residentes en las ciudades de Bogotá, Bucaramanga, Medellín (2 casos cada una), Montería y Restrepo (un caso cada una). El mayor porcentaje de positivos para anti-IgG contra Toxoplasma gondii se halló en las ciudades de Restrepo y Villavicencio. Los riesgos de exposición para contraer toxoplasmosis se derivan de no usar los elementos de protección completos, no lavar adecuadamente los alimentos, el consumo de carne mal cocida, exposición a animales y la manipulación de tierra.