Uso de Trichoderma harzianum y Bacillus subtilis para el control de la Marchitez (Falso Mal de Panamá) por Fusarium en banano (Musa AAA ‘Cavendish’)

Esta investigación tuvo por objetivo evaluar técnica y económicamente la aplicación de Trichoderma harzianum y Bacillus subtilis para el control de Fusarium sp. y microorganismos asociados a este complejo de patógenos, causantes de la enfermedad conocida como marchitez (Falso mal de Panamá) en banano (‘Cavendish’), en la Finca Guacarito, municipio José Ángel Lamas, estado Aragua, Venezuela. En el estudio se aplicaron seis tratamientos con dosis diferenciadas de Trico-plus-A (Trichoderma harzianum), Prophytex (Bacillus subtilis) y una base de arroz con Trichoderma harzianum, además de un testigo sano en la finca referencial El Rodeo de las Flores. Se realizaron mediciones progresivas en todas las plantas por cada tratamiento, evaluándose altura de la planta, número de hojas (quincenal) y la observación de síntomas (semanal) desde su aparición. El análisis técnico económico se realizó estimando los costos por hectárea de las cantidades requeridas para cada biocontrolador y para la mano de obra utilizada en su aplicación. Los tratamientos no tuvieron efectos significativos para altura de planta y número de hojas, para el ANAVAR ; en el análisis de correspondencia múltiple, los tratamientos T4 (98 g/ha Trico-plus-A y 692 cc/ha Prophytex) y T5 ( 197 g/ha Trico-plus-A y 1.730 cc/ha Prophytex), obtuvieron mayor porcentaje de plantas sanas con 55,0 y 60,7%, respectivamente, con relaciones beneficio-costos (B/C) de 5,01 y 2,67, para T4 y T5, generando beneficios netos por tratamiento de 9.072.972,00 y 10.815.409,00 Bs·ha-1,respectivamente. ABSTRACT This research evaluated technical and economically the Trichoderma harzianum and Bacillus subtilis on the biological control of Fusarium sp., and other microorganisms associated to this pathogenic complex. This association induces the disease known as banana wilt (false Panama disease.) in Cavendish banana. The Rev. Fac. Agron. (UCV) 43 (2): 67-75. 2017. experiments were located at the Guacarito farm, Jose Angel Lamas Municipality, Aragua state, Venezuela. Six treatments of different doses of Trico-plus A (Trichoderma harzianum), Prophitex (Bacillus subtilis), and a rice Trichoderma harzianum mix were applied, plus a healthy control, at El Rodeo de las Flores nearby farm. Progressive measurements were made in all the plants in each treatment, evaluating plant height, leaves number (biweekly) and disease symptoms (weekly).The economic and technical analyses costs for one hectare for each biocontroler and for the labor used in its application, were estimated. . The analyses of variance did not showed any statistically difference for plant height and leaves number; but, the analyses of multiple correspondence (AMC) showed that two treatment (T4: 98 g/ha Trico-plus-A y 692 cc/ha Prophytex and T5: 197 g/ha Trico-plus-A y 1.730 cc/ha Prophytex) obtained the higher percentage of healthy plants (55.06 and 60.7%, respectively) with benefit-cost ratios (B / C) of 5.01 and 2.67, for T4 and T5, generating net benefits for treatment of 9,072,972.00 and 10,815,409.00 Bs · ha-1, respectively

Community Risk Factors for Ocular Chlamydia Infection in Niger: Pre-Treatment Results from a Cluster-Randomized Trachoma Trial

Trachoma is one of the most important neglected tropical diseases because it is the leading cause of blindness from an infection in the world. There are about 1.3 million persons blind from the disease and many more at risk of blindness in the future. It is caused by the common bacterium Chlamydia trachomatis and can be treated with mass drug administrations (MDA) of azithromycin. We have begun a clinical trial in Niger, a country with limited resources in Africa, to determine the best treatment strategy. Our study from May to July 2010, which began before MDA's were given, showed that 26% of children aged 0–5 years were infected with the disease. In these children, we found that discharge from the nose, presence of flies on the face, and the number of years of education completed by the head of the household were risk factors for infection in 48 different communities. We hope to use this information about risk factors of infection to help guide future studies for trachoma and also to help with the WHO goal of eliminating the disease worldwide by the year 2020

A rationale for continuing mass antibiotic distributions for trachoma

BACKGROUND: The World Health Organization recommends periodic mass antibiotic distributions to reduce the ocular strains of chlamydia that cause trachoma, the world's leading cause of infectious blindness. Their stated goal is to control infection, not to completely eliminate it. A single mass distribution can dramatically reduce the prevalence of infection. However, if infection is not eliminated in every individual in the community, it may gradually return back into the community, so often repeated treatments are necessary. Since public health groups are reluctant to distribute antibiotics indefinitely, we are still in need of a proven long-term rationale. Here we use mathematical models to demonstrate that repeated antibiotic distributions can eliminate infection in a reasonable time period. METHODS: We fit parameters of a stochastic epidemiological transmission model to data collected before and 6 months after a mass antibiotic distribution in a region of Ethiopia that is one of the most severely affected areas in the world. We validate the model by comparing our predicted results to Ethiopian data which was collected biannually for two years past the initial mass antibiotic distribution. We use the model to simulate the effect of different treatment programs in terms of local elimination of infection. RESULTS: Simulations show that the average prevalence of infection across all villages progressively decreases after each treatment, as long as the frequency and coverage of antibiotics are high enough. Infection can be eliminated in more villages with each round of treatment. However, in the communities where infection is not eliminated, it returns to the same average level, forming the same stationary distribution. This phenomenon is also seen in subsequent epidemiological data from Ethiopia. Simulations suggest that a biannual treatment plan implemented for 5 years will lead to elimination in 95% of all villages. CONCLUSION: Local elimination from a community is theoretically possible, even in the most severely infected communities. However, elimination from larger areas may require repeated biannual treatments and prevention of re-introduction from outside to treated areas

Reduction and Return of Infectious Trachoma in Severely Affected Communities in Ethiopia

Trachoma is one of the leading causes of blindness in the developing world. The World Health Organization has a multi-pronged approach to controlling the ocular chlamydial infection that causes the disease, including distributing antibiotics to entire communities. Even a single community treatment dramatically reduces the prevalence of the infection. Unfortunately, infection returns back into communities after treatment, at least in severely affected areas such as rural Ethiopia. Here, we assess whether additional scheduled treatments in 16 communities in the Gurage area of Ethiopia further reduce infection, and whether the disease returns after distributions are stopped. In communities with the highest levels of trachoma ever studied, we find that repeated mass oral azithromycin distributions gradually reduce the prevalence of trachoma infection in a community, as long as these treatments are given frequently enough and to enough people in the community. Unfortunately, infection returns into the communities after the last treatment. Sustainable changes or complete local elimination of infection will be necessary to stop the return of ocular chlamydial in communities with very high prevalence of the disease

Progress in Characterizing the Endosymbiotic Dinoflagellates of Soritid Foraminifera and Related Studies on Some Stages in the Life Cycle of Marginopora Vertebralis

Foraminifera have developed symbiotic relationships with a wide range of different algae. In all the cases studied, the requirement for a symbiotic relationship with a particular type of alga (not necessarily a particular species of alga) is obligate for the foraminiferal host. Members of one family of larger foraminifera, the Soritidae, are the hosts for endosymbiotic dinoflagellates. Preliminary evidence obtained from ssrRNA sequences, obtained from single samples of endosymbionts from three different hosts, have shown that the endosymbionts are phylogenetically more closely related to coelenterate zooxanthellae than they are to each other. One interpretation is that, over time, the hosts and symbionts have maintained widely flexible relationships. This inference is also supported by data obtained from diatom-bearing and chlorophyte-bearing larger foraminifera, which seem to have exceptionally flexible relationships with their endosymbionts. We speculate that the soritids got their zooxanthellae from environmental pools contributed to by coelentrate host taxa, rather than by co-evolution with their dinoflagellates. These results run contrary to a paradigm based on solid data derived from studies of termites and their parabasalian endosymbionts that shows that hosts and symbionts co-evolved. We suggest that larger foraminifera have taken an alternative symbiotic evolutionary pathway by developing a system of host/symbiont fit that is not finical, but which could have advantages for survival and adaptation in changing habitats

Hemangiomas cavernosos encefalicos: presentacion de dos casos

Dos casos de hemangiomas cavernosos encefálicos intervenidos quirúrgicamente con resultados satisfactorios son relatados. Consideramos necesario la práctica de estudios angiográficos, gammagráficos y sobre todo la tomografía axial computada con el objeto de aproximarse a un diagnóstico cierto. El tratamiento de elección es quirúrgico, siendo el pronóstico reservado en caso de no ser posible la intervención; así recalcamos la necesidad de efectuar un diagnóstico precoz y determinar las posibilidades quirúrgicas, a fin de beneficiar al máximo los pacientes