RESUMO
Resumen Objetivo: Determinar la circulación de poliovirus en tres municipios considerados como punto transitorio de migrantes en Colombia. Material y método: Se colectaron muestras de aguas residuales (n=36) de municipios fronterizos, seleccionados por mayor tránsito de migrantes regulares como irregulares, en el periodo comprendido entre el 2017-2019. Las muestras fueron concentradas y cultivadas siguiendo el algoritmo de vigilancia ambiental para la circulación de poliovirus de la Organización Mundial de la Salud (OMS). La identificación molecular se realizo mediante reacción en cadena de la polimerasa empleando cebadores específicos de grupo, de serotipo y de cepa vacunal sabin. Resultados y Discusión: Se detectó la presencia de Enterovirus no polio (EVNP) en las muestras ambientales obtenidas y no se hallo circulación de poliovirus deriva dos de la vacuna ni de poliovirus salvaje en los tres municipos evaluados; sin embargo en dos estudios previos publicados por Gonzalez y col con una metodologia similar en el año 2005 y 2015 evaluando las aguas residuales de la ciudad de Armenia-Quindio; se logró identificar la presencia de virus derivado de vacuna, con resultados negativos para la identificación de poliovirus salvaje. Conclusiones: Los hallazgos indican que el sistema de monitoreo de aguas residuales con el fin de determinar la presencia de virus es una herramienta util para realizar vigilancia ambiental.
Abstract Objective: To determine the circulation of poliovirus in three municipalities considered as transitory points for migrants in Colombia. Material and Method: Wastewater samples (n = 36) were collected from border municipalities, selected for greater transit of regular and irregular migrants, in the period between 2017-2019. The samples were concentrated and cultured following the World Health Organization (WHO) environmental surveillance algorithm for poliovirus circulation. Molecular identification was performed by polymerase chain reaction using group-specific, serotype and sabin vaccine strain primers. Results: The presence of non-polio Enterovirus (NPV) was detected in the environmental samples obtained and no circulation of poliovirus derived from the vaccine or wild poliovirus was found in the three evaluated municipalities; However, in two previous studies published by Gonzales et al with a similar methodology in 2005 and 2015 evaluating the wastewater of the city of Armenia-Quindío; It was possible to identify the presence of virus derived from vaccine, with negative results for the identification of wild poliovirus. Conclusions: The findings indicate that the wastewater monitoring system in order to determine the presence of viruses is a useful tool to carry out environmental surveillance.
RESUMO
BACKGROUND: Significant progress has been recently achieved in the development of Plasmodium vivax challenge infections in humans, which are essential for vaccine and drug testing. With the goal of accelerating clinical development of malaria vaccines, the outcome of infections experimentally induced in naïve and semi-immune volunteers by infected mosquito bites was compared. METHODS: Seven malaria-naïve and nine semi-immune Colombian adults (nâ=â16) were subjected to the bites of 2-4 P. vivax sporozoite-infected Anopheles mosquitoes. Parasitemia levels, malaria clinical manifestations, and immune responses were assessed and compared. RESULTS: All volunteers developed infections as confirmed by microscopy and RT-qPCR. No significant difference in the pre-patent period (mean 12.5 and 12.8 days for malaria-naïve and malaria-exposed, respectively) was observed but naïve volunteers developed classical malaria signs and symptoms, while semi-immune volunteers displayed minor or no symptoms at the day of diagnosis. A malaria-naïve volunteer developed a transient low submicroscopic parasitemia that cured spontaneously. Infection induced an increase in specific antibody levels in both groups. CONCLUSION: Sporozoite infectious challenge was safe and reproducible in semi-immune and naïve volunteers. This model will provide information for simultaneous comparison of the protective efficacy of P. vivax vaccines in naïve and semi-immune volunteers under controlled conditions and would accelerate P. vivax vaccine development. TRIAL REGISTRATION: clinicaltrials.gov NCT01585077.