ABSTRACT
Arthropods transmit arboviruses via mosquito and tick bites to humans and other animals. The genus flavivirus, which causes diseases, sequelae, and thousands of deaths, mainly in developing and underdeveloped countries, is among the arboviruses of interest to public health. Given the importance of early and accurate diagnosis, this review analyzes the methods of direct detection of flaviviruses, such as reverse transcription loop-mediated isothermal amplification, microfluidics, localized surface plasmon resonance, and surface-enhanced Raman scattering, and presents the advantages, disadvantages, and detection limits identified in studies reported in the literature for each methodology. Among the different methods available, it is essential to balance four fundamental indicators to determine the ideal test: good sensitivity, high specificity, low false positive rate, and rapid results. Among the methods analyzed, reverse transcription loop-mediated isothermal amplification stands out, owing to result availability within a few minutes, with good sensitivity and specificity; in addition, it is the best-characterized methodology.
ABSTRACT
La magnitud del problema mundial de la tuberculosis y su potencial de incremento han conducido a la necesidad de mejorar los métodos de diagnóstico como una de las estrategias conducentes al control de la enfermedad. Los nuevos métodos incluyen pruebas moleculares para la detección directa, medios de cultivo rápido y novedosos procedimientos de identificación. Para la detección directa de micobacterias se dispone hoy de pruebas basadas en la amplificación de los ácidos nucleicos, cuya sensibilidad supera a la de la baciloscopia y es cercana a la de los cultivos, pero con mayores costos que los procedimientos tradicionales.La automatización para detectar el crecimiento en medios de cultivo produjo un cambio radical en la micobacteriología, pues con ella se logró disminuir considerablemente el tiempo requerido para aislar el M. tuberculosis (MTB); la combinación de métodos de detección rápida permite en la actualidad mejores tasas de aislamiento y la demostración más precoz del crecimiento. Las nuevas alternativas han logrado aumentar tanto la sensibilidad como la especificidad y la rapidez diagnósticas; sin embargo, es necesario mejorar aún más los métodos de diagnóstico de esta enfermedad de modo que se combinen el mejor desempeño y la simplicidad de los procedimientos con la disminución de los costos.
The magnitude of the global tuberculosis problem and its potential for increase have led to efforts to improve the diagnostic methods as one of the leadingcontrol strategies. New diagnostic tools have been developed, including direct detection tests, rapid culture media and identification methods. For the direct detection of mycobacteria, tests based on nucleic acid amplification have been implemented, with higher sensitivity than the direct smear, close to that of the cultures; however, they are still expensive methods. Availability of the automated cultures resulted in a radical change in mycobacteriology, reducing the time required for the isolation ofMycobacterium tuberculosis. The combination of rapid methods has increased the rates of isolation and decreased the time required for the detection of growth. Different tools for identifying mycobacteria have also been developed, aimed at improving theperformance of traditional biochemical methods and achieving species identification in a few hours. The new diagnostic alternatives have succeeded in improving the sensitivity, specificity and speed in the diagnosis of tuberculosis; however, the challengeremains to reduce their cost and to make them more accessible in countries where the problem with this disease is still serious.