Ultrasensitive detection of toxocara canis excretory-secretory antigens by a nanobody electrochemical magnetosensor assay.

peer reviewedHuman Toxocariasis (HT) is a zoonotic disease caused by the migration of the larval stage of the roundworm Toxocara canis in the human host. Despite of being the most cosmopolitan helminthiasis worldwide, its diagnosis is elusive. Currently, the detection of specific immunoglobulins IgG against the Toxocara Excretory-Secretory Antigens (TES), combined with clinical and epidemiological criteria is the only strategy to diagnose HT. Cross-reactivity with other parasites and the inability to distinguish between past and active infections are the main limitations of this approach. Here, we present a sensitive and specific novel strategy to detect and quantify TES, aiming to identify active cases of HT. High specificity is achieved by making use of nanobodies (Nbs), recombinant single variable domain antibodies obtained from camelids, that due to their small molecular size (15kDa) can recognize hidden epitopes not accessible to conventional antibodies. High sensitivity is attained by the design of an electrochemical magnetosensor with an amperometric readout with all components of the assay mixed in one single step. Through this strategy, 10-fold higher sensitivity than a conventional sandwich ELISA was achieved. The assay reached a limit of detection of 2 and15 pg/ml in PBST20 0.05% or serum, spiked with TES, respectively. These limits of detection are sufficient to detect clinically relevant toxocaral infections. Furthermore, our nanobodies showed no cross-reactivity with antigens from Ascaris lumbricoides or Ascaris suum. This is to our knowledge, the most sensitive method to detect and quantify TES so far, and has great potential to significantly improve diagnosis of HT. Moreover, the characteristics of our electrochemical assay are promising for the development of point of care diagnostic systems using nanobodies as a versatile and innovative alternative to antibodies. The next step will be the validation of the assay in clinical and epidemiological contexts

Temas de actualidad en salud pública

La salud pública es una disciplina importante para la salud en el mundo. Se define como la ciencia y el arte de prevenir las enfermedades, prolongar la vida y promover la salud a través de los esfuerzos organizados y decisiones con conocimiento de la sociedad, las organizaciones (públicas y privadas), las comunidades y los individuos, esta disciplina se ha renovado con la incorporación de múltiples actores, profesiones, áreas de conocimiento, además de ser afectados y promovido por múltiples tecnologías, en particular los de información. Como un campo cambiante del conocimiento, la salud pública requiere la información basada en la evidencia y actualizaciones regulares, más aún en el contexto de un mundo en transición epidemiológica. "Temas actuales en la salud pública", presenta información actualizada sobre varios temas relacionados con las áreas reales de interés en esta ciencia médica creciente y emocionante, con la concepción y la filosofía que estamos trabajando para mejorar la salud de la población, en lugar que el tratamiento de las enfermedades de los pacientes individuales, la toma de decisiones sobre el cuidado de la salud colectiva que se basan en la mejor evidencia disponible, actualizada, válida y pertinente, y, finalmente, en el contexto de los recursos disponibles. La salud pública debe ser una ciencia compleja, ayudando en las decisiones, acciones y cambios en la salud del mundo. En una sociedad globalizada esto se hizo hincapié no sólo en una nación en particular, sino en todo el mundo.Public health is a major health discipline in the world. Defined as the science and art of preventing diseases, prolonging life and promoting health through the organized efforts and informed choices of the society, organizations (public and private), communities and individuals, this discipline has been renewed by the incorporation of multiple actors, professions, knowledge areas, as well as being impacted and promoted by multiple technologies, particularly information ones. As a changing field of knowledge, public health requires evidence-based information and regular updates, even more in the context of a world in epidemiological transition. Health impacts of climate change are currently in the quest of the Millennium Development Goals, and most of them are related to the activities of public health. “Current Topics in Public Health” presents updated information on multiple topics related to actual areas of interest in this growing and exciting medical science, with the conception and philosophy that we are working to improve the health of the population, rather than treating diseases of individual patients; taking decisions about collective health care that are based on the best available, current, valid and relevant evidence; and finally within the context of available resources. Public health should be a complex science helping in the decision, actions and changes in the health of the world. In a globalized society this is emphasized not just in a particular nation but in the whole world