RESUMEN
Hasta 1983, cuando alcanzaba la increíble tasa de 118 casos por 100.000 habitantes, la fiebre tifoidea era la peor amenaza infecciosa en Santiago, Chile, ciudad que figuraba junto a Ciudad de México, El Cairo y Bombay, como una de las con mayor endemia en el mundo. El Ministerio de Salud respondió formando el Comité de Tifoidea de Chile, con participación de expertos nacionales y del grupo de Myron Levine, de la Universidad de Maryland, que llevó a cabo ingeniosas investigaciones, culpando al río Mapocho, cuyas aguas contaminadas con Salmonella typhi regaban los predios agrícolas vecinos, conformando así un ciclo largo de infección. Las vacunas antitíficas ensayadas (oral Ty21a atenuada y polisacárido capsular Vi inyectable) no mostraron eficacia, los portadores crónicos no se trataron, pero una campaña sanitaria a través de la televisión contribuyó decisivamente a mejorar los hábitos higiénicos de la población, fortalecida por el pánico que causó la llegada del cólera en 1991, y la fiebre tifoidea prácticamente desapareció del escenario.
Until 1983, when reached the incredible frequency of 118 cases for 100.000 habitants, typhoid fever was the worst infectious threat in Santiago, Chile, city that appeared next to Mexico City, Cairo and Bombay, as one of the most endemic in the world. The Ministry of Health responded with the creation of The Chilean Typhoid Committee, with the participation of national experts and Myron Levine's group, which carried out ingenious investigations blaming the Mapocho River, whose waters contaminated with Salmonella typhi irrigated the neighboring farms, thus conforming a long cycle of infection. Typhoid vaccines tested (strain Ty 21a oral and Vi capsular polysaccharide) did not show efficacy, chronic carriers were not treated, but a health campaign on television made a decisive contribution to improving hygiene habits of the population, strengthened by the panic caused by the arrival of cholera in 1991, and typhoid fever practically disappeared from the stage.
Asunto(s)
Humanos , Historia del Siglo XX , Fiebre Tifoidea/historia , Fiebre Tifoidea/prevención & control , Salmonella/aislamiento & purificación , Microbiología del Agua , Vacunas Tifoides-Paratifoides , Chile , VacunaciónRESUMEN
AIMS: This study evaluated detection methods for Salmonella Typhi (S. Typhi) in the environment, to establish a novel pathway from field sampling to isolation of viable organisms and molecular confirmation from complex environmental samples, thus enabling environmental surveillance of typhoid. METHODS AND RESULTS: Multiple media were assessed using clinical isolates from the Public Health England's (PHE) Culture collection. The culture pathway selected consisted of a primary 2% bile broth and secondary Selenite F broth, followed by modified Chromogenic Agar for Salmonella Esterase (mCASE). A qPCR assay was adapted from a validated S. Typhi PCR panel for confirmation of isolates, with comparison to biochemical and serological tests showing good specificity. Sampling locations in Blantyre, Malawi were used to compare sampling methods. Viable S. Typhi were isolated from a mixture of trap and grab river water samples on six occasions. CONCLUSIONS: Culture of viable S. Typhi from environmental samples was possible using effective capture and culture techniques. SIGNIFICANCE AND IMPACT OF STUDY: Whilst several studies have attempted to detect S. Typhi from the environment, this is the first successful attempt to isolate the organism from river water since the 1980s. Supplementing clinical data with environmental screening offers the potential for enhanced surveillance, which might inform interventions and assess vaccination programmes.