Eficacia terapéutica de cloroquina más primaquina en malaria vivax no complicada en dos comunidades de la amazonía peruana

Resistance and therapeutic failure to Plasmodium vivax treatment is an increasing problem due to parasite recurrences that sustain transmission. This study aimed to describe clinical and parasitological response after initiation of supervised radical cure treatment in two villages in the Peruvian Amazon follow up by both, molecular tools (qPCR) and thick smear, for 28 days. Thirty-one participants with uncomplicated vivax malaria were recruited from March 2016 to January 2017 in Santa Emilia and San José de Lupuna, river travel is the only way from these endemic rural villages to other places. At the recruitment (day 0), treatment was started with chloroquine 25mg/Kg in 3 days plus primaquine 0.5 mg/Kg/day for 7 days (according to national guidelines in Peru). Clinical and parasitological evaluations were done on days 2, 3, 7, 14, 21 and 28. Although more therapeutic failures were detected by qPCR (n=8) than by microscopy (n=4), such that cumulative incidence efficacy by microscopy was 86.6% (IC95, 75.2 – 99.8%), and 70.8% (IC95, 55.5 – 90.3%) by qPCR, no statistical difference was found between methods (p=0.14). Parasite clearance time by qPCR was longer than by microscopy (14 days vs. 7 days), and longer clearance time was also seen with higher parasitemia (p<0.01). Interpretation of P. vivax parasitemia by qPCR in clinical studies conducted in endemic areas should be done with caution until a reliable laboratory test that clearly distinguishes relapses from reinfections is available.La resistencia y falla terapéutica del tratamiento de Plasmodium vivax son un problema por la recurrencia de parásitos que mantienen la transmisión. El objetivo fue evaluar la evolución clínica y parasitológica durante 28 días desde el inicio del tratamiento supervisado de cura radical en dos comunidades de la Amazonía peruana, usando métodos moleculares (qPCR) y microscopía. Se enroló 31 participantes con malaria vivax no complicada entre marzo del 2016 y enero del 2017 en Santa Emilia y San José de Lupuna, comunidades rurales endémicas accesibles sólo por vía fluvial. En el día de ingreso (día 0), se inició tratamiento con cloroquina 25mg/Kg en tres días más primaquina 0.5 mg/Kg/día por siete días (de acuerdo con las guías nacionales en Perú), luego se hizo evaluaciones clínicas y parasitológicas en los días 2, 3, 7, 14, 21 y 28. Si bien se detectó más fallas terapéuticas por qPCR (8) que por microscopía (4), con una incidencia acumulada de eficacia de 70.8% (95 IC, 55.5 – 90.3%) y 86.6% (95% IC, 75.2 – 99.8%) respectivamente, no se encontró diferencias estadísticas entre los 2 métodos (p=0.14). El qPCR demostró que el tiempo de eliminación de parásitos es mayor al reportado por microscopía (14 versus 7 días) (p<0.01), y también un mayor tiempo de eliminación con mayor parasitemia (p<0.01). Interpretar la parasitemia de P. vivax usando qPCR en estudios clínicos en áreas endémicas debería realizarse con precaución hasta contar con una prueba confiable que diferencie recaídas de reinfecciones

Infection of laboratory-colonized Anopheles darlingi mosquitoes by Plasmodium vivax.

Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector-pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi-Plasmodium interactions

Posesión, retención y uso de mosquiteros tratados con insecticidas de larga duración luego de un año de su distribución en Loreto, Perú

Objectives. To assess long-lasting insecticide - treated bednet (LLITN) ownership, retention and usage one year after their distribution in Loreto, Peru. Materials and methods. from July to September 2007, 26,185 LLITNs Olyset Net ® were delivered in 194 targeted communities in the Peruvian Amazon region, covering 45,331 people. Two cross-sectional community-based surveys in December 2007 and July 2008 were undertaken in a sample of 60 targeted communities (30.9% out of the total). A semi-structured questionnaire was used to collect necessary data to calculate LLITN ownership, retention and usage indicators. Results. High LLITN household ownership was showed in both surveys (99.9% and 98.7%, respectively). LLITN/ person ratio decreased from 0.58 at the end of the LLITN delivery to 0.51 in the second survey, estimating LLITN retention of 87% after 1 year of intervention. In the first survey, 99.0% of all children 5 years and 96,0% of pregnant women slept under a LLITN the previous night, while in the second survey, 77.7% of children 5 years and 66.3% of pregnant women slept under a LLITN the previous night. Big mesh size of LLITN had low people´s acceptability, reaching only 39.0% in the second survey. Conclusions. Although universal LLITN household ownership remained high, their LLITN usage levels have decreased during one-year follow-up period.Objetivos. Evaluar la posesión, retención y uso de mosquiteros tratados con insecticida de larga duración (MTILD) luego de un año de su distribución en Loreto, Perú. Materiales y métodos. De julio a septiembre de 2007 se distribuyeron 26 185 MTILD Olyset Net® en 194 comunidades objetivo de Loreto, que protegieron a 45 331 personas. Posteriormente, se realizaron visitas de monitoreo (primera en diciembre de 2007 y segunda en julio de 2008) a los hogares de una muestra de 60 comunidades objetivo (30,9% del total), colectándose mediante un cuestionario semiestructurado los datos necesarios para el cálculo de indicadores de posesión, retención y uso de los MTILD. Resultados. En ambas visitas, la posesión de MTILD en hogares fue elevada (99,9% y 98,7%, respectivamente). La razón MTILD/persona disminuyó de 0,58 al momento de la distribución a 0,51 en la segunda visita, estimándose una retención al año de MTILD de 87%. En la primera visita, 99,0% de los niños 5 años y 96,0% de las embarazadas durmieron bajo un MTILD la noche anterior, mientras que en la segunda visita, 77,7% de los niños5 años y 66,3% de las embarazadas durmieron bajo un MTILD la noche anterior. El tamaño de los agujeros de la trama de los MTILD tuvo una baja aceptabilidad por parte del a población durante la segunda visita (39,0%). Conclusiones. Si bien la posesión de MTILD en los hogares se ha mantenido elevada, su uso por la población beneficiada ha disminuido durante el año de seguimiento

Tuberculosis meníngea: detección y caracterización de antígenos específicos de mycobacterium tuberculosis en líquido cefalorraquídeo

&lt;p&gt;La tuberculosis meníngea (TBM) es la causa más importante de meningitis crónica mundialmente. Se diagnostica demostrando Mycobacterium tuberculosis en líquido cefalorraquídeo (LCR) por directo y cultivo, ambos poco sensibles (0-25%, 25-86%, respectivamente) (1). Estas dificultades han llevado a buscar métodos diagnósticos más sensibles, de bajo costo y fácil implementación. &lt;/p&gt;&lt;p&gt;Se han caracterizado algunos antígenos específicos de M. tuberculosis: ESAT-6, complejo 85, proteína de 38 kDa, lfacristalina&lt;br /&gt;(2) y CFP-10 (3), los cuales podrían tener potencial iagnóstico detectados en muestras clínicas. Esta estrategia es tractiva como herramienta diagnóstica, pues no se necesita espuesta inmune activa.&lt;/p&gt;&lt;p&gt; &lt;/p&gt

Predominance of asymptomatic and sub-microscopic infections characterizes the <i>Plasmodium</i> gametocyte reservoir in the Peruvian Amazon

<div><p>Malaria transmission requires that <i>Anopheles</i> mosquitoes ingest <i>Plasmodium</i> gametocyte stages circulating in the human bloodstream. In the context of malaria elimination, understanding the epidemiology of gametocytes relative to all <i>Plasmodium</i> infections and the contribution of asymptomatic and sub-microscopic parasite carriers to the gametocyte reservoir is necessary, especially in low endemic settings with predominance of <i>P</i>.<i>vivax</i>. A 13-month longitudinal study was conducted in two communities (n = 1935 individuals) of Loreto Department, Peru, with five active screenings for <i>Plasmodium</i> infections and gametocyte stages by quantitative real-time PCR (qPCR) and reverse transcription (RT)-qPCR, respectively. Parasite prevalence by qPCR was 7.2% for <i>P</i>.<i>vivax</i> (n = 520/7235; range by survey 6.0%-8.1%) and 3.2% for <i>P</i>.<i>falciparum</i> (n = 235/7235; range by survey 0.4%-7.7%). Sub-microscopic infections accounted for 73.5% of <i>P</i>.<i>vivax</i> (range by survey 60%-89%) and almost the totality of <i>P</i>.<i>falciparum</i> cases. Gametocytes were found in 28.4% <i>P</i>.<i>vivax</i> infections (range by survey 18.7%-34.1%), with a peak of 61.5% in one community at the start of the transmission season. About 59.8% of all <i>P</i>.<i>vivax</i> gametocyte carriers were asymptomatic and 31.9% were sub-microscopic. Age patterns for gametocyte prevalence paralleled asexual stage infections and peaked among >15–25 year old individuals. Asexual parasite density was found to be the strongest predictor for <i>P</i>.<i>vivax</i> gametocyte presence in longitudinal multivariate analysis (odds ratio 2.33 [95% confidence interval 1.96, 2.78]; <i>P</i><0.001). Despite significant differences in seasonality patterns and <i>P</i>.<i>vivax</i> prevalence found at the local scale, sub-microscopic and asymptomatic infections predominate and contribute significantly to the gametocyte reservoir in different communities of the Peruvian Amazon. Control and elimination campaigns need sensitive tools to detect all infections that escape routine malaria surveillance, which may contribute to maintain transmission in the region.</p></div

Sub-microscopic and asymptomatic <i>Plasmodium</i> infection rates, by qPCR/RTqPCR.

<p>Sub-microscopic and asymptomatic <i>Plasmodium</i> infection rates, by qPCR/RTqPCR.</p

Multivariate models for <i>P</i>. <i>vivax</i> infection and gametocyte carriage.

<p>Multivariate models for <i>P</i>. <i>vivax</i> infection and gametocyte carriage.</p

Spatial cluster analysis for <i>P</i>.<i>vivax</i> gametocyte carriage.

<p>Regions with higher-than-expected risk and <i>P</i><0.200 are shown, based on SaTScan result. Orange circles indicate spatial clusters; blue circle indicates a spatio-temporal cluster.</p