Renán Arcadio Poveda Ricalde

Renán Arcadio Poveda Ricalde nace en la ciudad de Mérida Yucatán el 15 de julio de 1930. Durante su niñez, acostumbraba caminar, del lado de su padre, viendo los atardeceres en las playas del puerto de Progreso. Al caer la noche, disfrutaba el maravilloso espectáculo de la bóveda celeste, e incansablemente lo cuestionaba sobre los nombres de las estrellas, de que estaban hechas y que tan lejos se encontraban. Esas caminatas lo marcarían por el resto de su vida y su curiosidad por el universo se transformaría en su pasión

Efectos individuales de la ciclidogiriasis y estreptococosis inducidas en la bioquímica sanguínea de la tilapia Oreochromis niloticus

In this study, we propose to evaluate the blood biochemistry as diagnosis technique of a pathologic process in tilapias Oreochromis niloticus by means of infections induced by Streptococcus sp. or by the activation of the immune response induced by antigens of Cichlidogyrus spp. Specifically, variations of some metabolites from the blood biochemistry were evaluated in experimentally infected tilapia Oreochromis niloticus. The organisms were intraperitoneally challenged (IP) with individual antigenic extracts of Streptococcus sp. (STREP Group, n = 10) and Cichlidogyrus spp. (C-EXP Group, n = 10), respectively, while 10 other tilapia were inoculated with a saline solution buffer (SS Group) and were used as immunization control. Another group of 70 tilapias was maintained in aquaculture conditions included the baseline group (LB). The negative control (CN) included 10 fish free of infection. The blood chemistry (metabolites and ions) were tested in a microplate format. No differences were observed between the LB and the CN groups (p > 0.05). Only fish injected with Streptococcus sp. (STREP) and Cichlidogyrus spp. (C-EXP) were significantly different with the values of glucose, total proteins, albumin, and globulins, when comparing with LB fish (p < 0.05). Furthermore, the cholesterol, calcium and the chlorine changed significantly in the STREP fish (p > 0.05). The results from the induced infections with Streptococcus sp. and Cichlidogyrus spp., respectively, modified some parameters of the blood biochemistry of tilapia that could be used for some preliminary diagnosis of infectious diseases.En este estudio se propone evaluar la posibilidad de utilizar los datos de la bioquímica sanguínea como diagnóstico presuntivo de un proceso infeccioso en tilapias Oreochromis niloticus, mediante infecciones inducidas por Streptococcus sp. o por la activación de la respuesta inmune inducida por antígenos de Cichlidogyrus spp. Específicamente, se evaluó la variabilidad de algunos metabolitos de la bioquímica sanguínea de tilapias O. niloticus, desafiadas de manera individual con inyecciones intraperitoneales (IP) de cultivos celulares de Streptococcus sp. (Grupo STREP, n = 10) y extractos tisulares de Cichlidogyrus spp. (Grupo C-EXP, n = 10). Adicionalmente, a 10 tilapias, se les inyectó búfer salino de fosfato (PBS) (pH = 7), para ser usados como control de inmunizaciones (Grupo solución salina, SS). Además, 70 tilapias se mantuvieron en condiciones acuaculturales usuales y conformaron el grupo línea base (LB). Diez peces más, libres de infección, sirvieron como control negativo (Grupo CN). La bioquímica sanguínea (metabolitos y iones), se analizó por el método de microplaca. Los resultados mostraron que no hubo diferencias entre los grupos LB y CN (p > 0.05). En los peces STREP y C-EXP se encontraron diferencias significativas en las concentraciones de glucosa, proteínas totales, albúmina y globulinas al compararlos con los peces LB (p < 0.05). Asimismo, el colesterol, calcio y cloro variaron significativamente en los peces STREP (p > 0.05). Para esta especie y en las condiciones de cultivo establecidas, las variaciones producidas por la infección con Streptococcus sp. y los antígenos de Cichlidogyrus spp., modificaron algunos parámetros de su bioquímica sanguínea, los cuales pueden servir como indicadores de posibles patologías infecciosas

Eco-bio-social determinants for house infestation by non-domiciliated Triatoma dimidiata in the Yucatan peninsula, Mexico

Background Chagas disease is a vector-borne disease of major importance in the Americas. Disease prevention is mostly limited to vector control. Integrated interventions targeting ecological, biological and social determinants of vector-borne diseases are increasingly used for improved control. Methodology/principal findings We investigated key factors associated with transient house infestation by T. dimidiata in rural villages in Yucatan, Mexico, using a mixed modeling approach based on initial null-hypothesis testing followed by multimodel inference and averaging on data from 308 houses from three villages. We found that the presence of dogs, chickens and potential refuges, such as rock piles, in the peridomicile as well as the proximity of houses to vegetation at the periphery of the village and to public light sources are major risk factors for infestation. These factors explain most of the intra-village variations in infestation. Conclusions/significance These results underline a process of infestation distinct from that of domiciliated triatomines and may be used for risk stratification of houses for both vector surveillance and control. Combined integrated vector interventions, informed by an Ecohealth perspective, should aim at targeting several of these factors to effectively reduce infestation and provide sustainable vector control

Antileishmanial activity of a mixture of

We tested a mixture of Tridax procumbens, known for its direct action against Leishmania mexicana, and Allium sativum, known for its immunomodulatory effect, as an alternative to treat cutaneous leishmaniasis. Acute oral toxicity was tested with the Up-and-Down Procedure (UDP) using a group of healthy mice administered with either T. procumbens or A. sativum extracts and compared with a control group. Liver injury and other parameters of toxicity were determined in mice at day 14. The in vivo assay was performed with mice infected with L. mexicana promastigotes and treated with either a mixture of T. procumbens and A. sativum or each extract separately. The thickness of the mice’s footpads was measured weekly. After the 12-week period of infection, blood samples were obtained by cardiac puncture to determine the total IgG, IgG1 and IgG2a immunoglobulins by a noncommercial indirect ELISA. We showed that the mixture of T. procumbens and A. sativum extracts was better at controlling L. mexicana infection while not being toxic when tested in the acute oral toxicity assay in mice. An increase in the ratio of IgG2a/IgG1 indicated a tendency to raise a Th1-type immune response in mice treated with the mixture. The mixture of T. procumbens and A. sativum extracts is a promising natural treatment for cutaneous leishmaniasis and its healing effects make it a good candidate for a possible new phytomedicine

Antileishmanial activity of a mixture of Tridax procumbens and Allium sativum in mice

We tested a mixture of Tridax procumbens, known for its direct action against Leishmania mexicana, and Allium sativum, known for its immunomodulatory effect, as an alternative to treat cutaneous leishmaniasis. Acute oral toxicity was tested with the Up-and-Down Procedure (UDP) using a group of healthy mice administered with either T. procumbens or A. sativum extracts and compared with a control group. Liver injury and other parameters of toxicity were determined in mice at day 14. The in vivo assay was performed with mice infected with L. mexicana promastigotes and treated with either a mixture of T. procumbens and A. sativum or each extract separately. The thickness of the mice’s footpads was measured weekly. After the 12-week period of infection, blood samples were obtained by cardiac puncture to determine the total IgG, IgG1 and IgG2a immunoglobulins by a noncommercial indirect ELISA. We showed that the mixture of T. procumbens and A. sativum extracts was better at controlling L. mexicana infection while not being toxic when tested in the acute oral toxicity assay in mice. An increase in the ratio of IgG2a/IgG1 indicated a tendency to raise a Th1-type immune response in mice treated with the mixture. The mixture of T. procumbens and A. sativum extracts is a promising natural treatment for cutaneous leishmaniasis and its healing effects make it a good candidate for a possible new phytomedicine

An innovative ecohealth intervention for Chagas disease vector control in Yucatan, Mexico

International audienceBackground: Non-domiciliated (intrusive) triatomine vectors remain a challenge for the sustainability of Chagas disease vector control as these triatomines are able to transiently (re-)infest houses. One of the best-characterized examples is Triatoma dimidiata from the Yucatan peninsula, Mexico, where adult insects seasonally infest houses between March and July. Methods: We focused our study on three rural villages in the state of Yucatan, Mexico, in which we performed a situation analysis as a first step before the implementation of an ecohealth (ecosystem approach to health) vector control intervention. Results: The identification of the key determinants affecting the transient invasion of human dwellings by T. dimidiata was performed by exploring associations between bug presence and qualitative and quantitative variables describing the ecological, biological and social context of the communities. We then used a participa-tory action research approach for implementation and evaluation of a control strategy based on window insect screens to reduce house infestation by T. dimidiata. Conclusions: This ecohealth approach may represent a valuable alternative to vertically-organized insecticide spraying. Further evaluation may confirm that it is sustainable and provides effective control (in the sense of limiting infestation of human dwellings and vector/human contacts) of intrusive triatomines in the region