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102 results on '"Guderian, Ronald H."'

8. Chagas Disease in Ecuador: Evidence for Disease Transmission in an Indigenous Population in the Amazon Region

Author

Chico H Martha, Sandoval Carlos, Guevara E Angel, Calvopiña H Manuel, Cooper Philip J, Reed Steve G, and Guderian Ronald H

Subjects
Ecuador, Chagas disease, Trypanosoma cruzi, Amerindian, Amazonia, Microbiology, QR1-502, Infectious and parasitic diseases, RC109-216
Abstract

Two well-defined synthetic peptides TcD and PEP2 were used in a sero-epidemiological study for the detection of Trypanosoma cruzi infections in an indigenous group in the Amazon region of Ecuador. Of the 18 communities studied along the Río Napo, province of Napo, 15 (83.3%) were found to be positive for T. cruzi infection. Of the 1,011 individuals examined 61 (6.03%) resulted positive. A prevalence of infection of 4.8% was found in children aged 1-5 years. The prevalence of infection increased with age, with adults 50 years or older showing a maximum prevalence of 18.8%. Autochthonous transmission of T. cruzi is present among this isolated indigenous population

Published
1997

11. Impact of long-term treatment of onchocerciasis with ivermectin in Ecuador: potential for elimination of infection

Author

Proaño Roberto, Rivera Jorge, Mancero Tamara, Lovato Raquel, Cooper Philip J, Vieira Juan, López Andrea A, Guderian Ronald H, and Guzmán José

Subjects
Medicine
Abstract

Abstract Background Onchocerciasis is a leading cause of blindness worldwide, hence elimination of the infection is an important health priority. Community-based treatment programs with ivermectin form the basis of control programs for the disease in Latin America. The long-term administration of ivermectin could eliminate Onchocerca volvulus infection from endemic areas in Latin America. Methods A strategy of annual to twice-annual treatments with ivermectin has been used for onchocerciasis in endemic communities in Ecuador for up to 14 years. The impact of ivermectin treatment on ocular morbidity, and O. volvulus infection and transmission was monitored in seven sentinel communities. Results Over the period 1990–2003, high rates of treatment coverage of the eligible population were maintained in endemic communities (mean 85.2% per treatment round). Ivermectin reduced the prevalence of anterior segment disease of the eye to 0% in sentinel communities and had a major impact on the prevalence and transmission of infection, with possible elimination of infection in some foci. Conclusion The distribution of ivermectin in endemic communities in Ecuador might have eliminated ocular morbidity and significant progress has been made towards elimination of the infection. A strategy of more frequent treatments with ivermectin may be required in communities where the infection persists to achieve the objective of elimination of the infection from Ecuador. The elimination of the infection from an endemic country in Latin America would be a major public health achievement and could stimulate the implementation of elimination strategies in other endemic countries.

Published
2007
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12. La Oncocercosis en el Ecuador

Author

Guderian Guderian, Ronald H., Swanson Swanson, Daniel, Carrillo, Ramiro, Motea, José, Proaño S., Roberto, and Swanson, Wallace L.

Abstract

Con el reciente descubrimiento de la oncocercosis en Ecuador (3, 7, 2), sabemos que ya existen focos de infección en seis países de Latinoamérica: México, Guatemala, Ecuador, Colombia, Venezuela y Brasil. Con la excepción de Ecuador, los aspectos epidemiológicos de la enfermedad han sido el motivo de algunos cuidadosos estudios realizados (12). La distribución y las manifestaciones clínicas de la enfermedad varían considerablemente en detalle de un sitio geográfico a otro. Así recientemente nos hemos comprometido a realizar un estudio para clasificar la distribución geográfica y los aspectos epidemiológicos de la oncocercosis en Ecuador. Aquí reportamos los resultados sobre la distribución y prevalencia de la infección en la provincia de Esmeraldas, según el estudio realizado en noviembre de 1980 y diciembre de 1982.

Published
2017

13. La oncocercosis en Ecuador. II. Epidemiología de los focos endémicos en la Provincia de Esmeraldas

Author

Guderian, Ronald H., Swanson, Daniel, Carrillo D., Ramiro, Proaño, Roberto, Molea, José, and Swanson, Wallace L.

Abstract

La epidemiología de lá infección fue estudiada en todos los focos endémicos de oncocercosis en la Provincia de Esmeraldas, Ecuador. La prevalencia y la densidad de las microfilarias en la piel, más alta en los hombres que en las mujeres, aumentaban con la edad y en las mujeres que tenían60 años o más de edad. En el área hiperendémica los hombres como las mujeres tenían la misma incidencia de infección, pero la densidad dé las microfilarias en los hombres sobrepasó a la de las mujeres. En las áreas hipoendémicas los hombres tenían una incidencia de infección más alta quelas mujeres, pero las mujeres registraron una densidad más alta de microfilarias en la piel. La incidencia y localización de los nodulos oncocercóticos se correlacionaban estrictamente con la densidad de las microfilarias. Los adultos, con edades de 50—54 años tenían la prevalencia más alta de los nodulos oncocercóticos los cuales se presentaron primariamente en las regiones torácica y pélvica. Los niños en edad de 0 a 14 años, mostraron una baja prevalencia de los nodulos; la mayoría se presentó en la cabeza. De los métodos de diagnóstico usados para detectar la presencia de las microfilarias, la mayoría de los diagnosticados (85.6o/o) fueron realizados con biopsia dé la piel comparando a los que fueron realizados por la prueba de Mazzotti (14.4o/o). (Revista de la Facilitad de Ciencias Médicas, 8:131,1983).

Published
2017

19. Severe digestive pathology associated with chronic Chaga's disease in Ecuador: report of two cases

Author

Guevara,Angel G., Eras,José W., Recalde,Marcelo, Vinueza,Luis, Cooper,Philip J., Ouaissi,Ali, and Guderian,Ronald H.

Subjects
Chagas' disease, PCR, Megaesophagus, parasitic diseases, Megacolon, Ecuador, Megacólon, Megaesôfago, T. cruzi, Doença de Chagas
Abstract

DNA extracted from peripheral blood of two Ecuadorian patients showing severe digestive pathology was amplified by the polymerase chain reaction using a Trypanosoma cruzi specific oligonucleotide primers derived from the primary sequence of a cDNA encoding for a 24 kDa excretory/secretory protein. The positive PCR results together with the clinical findings confirmed that both patients had a digestive pathology due to Chagas' disease. This pathology could be more frequent than previously described in the chagasic endemic regions of Andean countries. DNA obtido do sangue periférico de dois pacientes equatorianos, que apresentavam severa patologia digestiva, foi amplificado pela "polymerase chain reaction" (PCR) utilizando os oligonucleotídoes específicos do Trypanosoma cruzi, derivados de uma seqüência primária de cDNA codificado de 24 kDa proteína excretória/secretória. Os resultados positivos da PCR junto com os achados clínicos confirmam que os dois pacientes tinham uma patologia digestiva de origem chagásica. Esta patologia poderia ser mais freqüente que a descrita previamente nas regiões endêmicas chagásicas das cidades dos Andes.

Published
1997

21. Haemoglobinopathies in black communities living along the banks of the rivers Cayapas and Onzoles, in the Eloy Alfaro canton, in the province of Esmeraldas, Ecuador.

Author

Guevara, Angel, Chico, Martha, Calvopiña, Manuel, Guderian, Ronald H., Guevara, Angel, Chico, Martha, Calvopiña, Manuel, and Guderian, Ronald H.

Abstract

Blood samples from 1,364 individuals of Black race, inhabitants of the area bordering the Cayapas and Onzoles rivers, located in the northwest corner of the Esmeraldas' province, were analysed for haemoglobinopathies by means of haemoglobin electrophoresis using cellulose acetate and citrate agar plates. Of the studied population, 75.7% (1,032) were found to have normal haemoglobin and 24.3% (332) had some homoglobin variant. The rnost frequent variant was Hb.AS with 84.9% (282), followed by Hb.AF 9.6% (32), Hb.SS 2.7% (9), Hb.FS 2.4% (8) and Hb.FF 0.3% (1). The highest prevalence of haemoglobinopathies (31.8%) was detected in young people, 0-9 years of age, and in those aged 10-1 9 (25.8%). A higher prevalence was found in males than females throughout the two river areas studied. On the Cayapas river, cetiain geographical areas were found to have a high prevalence of haemoglobinopathies such as in Trinidad (45.5%) and Santa María (37.9%), while on the Onzoles river the prevalence was more uniform. These findings are discussed, particularly the prevalence of the genotype Hb .SS (2.7%) and the one case (0.3%) with Hb.FF electrophoretic characteristics which requires more detailed study., Se analizaron muestras de sangre de 1.364 individuos de raza negra pura, habitantes de la ribera de los ríos Cayapas y Onzoles, norte de la provincia de Esmeraldas, para hernoglobinopatías mediante electrofóresis de hemoglobina sobre acetato de celulosa y agar de citrato. El 75,7% (1.032) de la población estudiada presenta hemoglobina normal y 24,3% (332) tienevariantes de hemoglobina. La variante más frecuente fue Hb.AS con 84,9% (282), seguida de Hb.AF 9,6% (32), Hb.SS 2,7% (9), Hb.FS 2,4% (8) y Hb.FF 0,3% (1). La prevalencia más elevada se detectó en los grupos de edad jóvenes, 0-9 años (31,8%) y 10-19 años (25,8%). Los hombres presentaron mayor prevalencia que las mujeres en los dos ríos estudiados y existen áreas geográficas características con alta prevalencia en el río Cayapas, Trinidad (45,5%) y Santa María (37,9%), mientras que en el río Onzoles la prevalencia es más uniforme. Se discuten los hallazgos encontrados, principalmente, la prevalencia del genotipo Hb.SS (2,7%) y de un caso (0,3%) con características de Hb.FF que merecen ser estudiados con más detalle.

Published
1998

24. Evaluación del ribósido de alopurinol contra la leishmaniasis cutánea ecuatoriana

Author

Chico, Martha, Armijos, Rodrigo, Mancero, Támara, Guderian, Ronald H., Chico, Martha, Armijos, Rodrigo, Mancero, Támara, and Guderian, Ronald H.

Abstract

In a random study of 75 Ecuadorian patienis with cutaneous leishmaniasis, the objective was to determine the therapeutical index of a new oral antileishmania drug, allopurinol- riboside (AR) plus probenecid. This agent was evaluated by comparing its effect with positive controls treated with pentostam (Sb) and with other controls who received no treatment at all. The lesions mean area reduced rapidly during treatment, allowing determination of percentage healing in the different groups. The AR group was treated with allopurinal-riboside (1500 mg QID) plus probenecid (500 mg QID) for 28 days. 10 (455%) of these 22 patients were found to have healed lesions. Of those patients treated with Sb (20 mg SbIkgIdía, IM for 20 days), al1 28 (100%) patients presented healed lesions. The control group (that which did not receive any treatment) had an elevated percentage of spontaneous healing in 9 (75,0%) of the 12 patients. Patients who failed to respond to treatment or relapsed, were all later treated with pentostam. This study suggests that allopurinol-riboside plus probenecid has a low efficacy against Ecuadorian cutaneous leishmaniasis., Se realizó un estudio randomizado de 75 pacientes con leishmaniasis cutánea ecuatoriana con el fin de determinar el índice terapéutico de una nueva droga oral antileishmania, el ribósido de alopurinol más probenecid. Este agente fue evaluado comparándolo con controles positivos que se trataron con pentostam y con testigos no tratados. Las medidas de las lesiones disminuyeron rápidamente durante la terapia, lo que permitió determinar el porcentaje de cicatrización en los diferentes grupos. En el día 70 se realizó la evaluación de la curación de los pacientes en los diferentes grupos, obteniéndose: alopurinol (1.500 mg/6 h) más probenecid (500 mgI6 h) por 28 días, dió una curación con lesiones cicatrizadas en 10 (45,5%) de los 22 pacientes. Con pentostam (20 mg Sblkgtdía, IM por 20 días) se obtuvo una curación en 28 pacientes siendo esto el 100% de cicatrización. El grupo de no tratamiento presentó un porcentaje muy elevado de curación espontánea en 9 (75,0%) de los 12 pacientes. Todos los pacientes con tratamiento fallido o recidivas recibieron posteriormente tratamiento con pentostam. Este estudio sugiere que el ribósido de alopurinol más probenecid no es una droga con mayor eficacia contra la leishmaniasis cutánea ecuatoriana.

Published
1995

25. El pian en la provincia de Esmeraldas, Ecuador

Author

Guderian, Ronald H., Anselmi, Mariela, Calvopiña, Manuel, Cooper, Philip J., Mancero, Tamara, Guderian, Ronald H., Anselmi, Mariela, Calvopiña, Manuel, Cooper, Philip J., and Mancero, Tamara

Abstract

A clinical and serological epidemiological study in a yaws focus in cantón Eloy Alfaro, in the Santiago basin area of the province of Esmeraldas, showed a prevalence of 11.3% for active skin lesions and seropositivity of 94.9%. The Santiago river was found to be hyperendemic for yaws (prevalence 17.9), while the Zapallito river was rnesoendemic and the Cayapas and Onzole rivers were hypoendemic. Active and latent evidence of yaws was found only in the black race. Children, aged 5-12, were found to have the highest incidence (55.8%) of clinical lesions, the majority being found on the legs (64.2%). The most prevalent lesions (55.4%) were papilloma. Mass treatment of all positive communities, using benzathine penicillin G, was carried out according to WHO recommendations., Se realizó un estudio epidemiológico, clínico y serológico del pian en la cuenca del río Santiago, cantón Eloy Alfaro, provincia de Esmeraldas, el cual demostró una prevalencia del 11,3% con lesiones dérmicas activas y una seropositividad del 94,9%. El área del río Santiago era hiperendémica para el pian (prevalencia 17,9%; seropositividad 98,0%), mientras que el río Zapallito era mesoendémico y los ríos Cayapas y Onzole, hipoendémicos. Se encontró evidencia del pian, activa y latente, solamente en la raza negra. La mayor incidencia de las lesiones clínicas (55,8%) se encontró en los niños de 5-12 años de edad, localizándose el porcentaje superior en las piernas (64,2%). Los papilomas fueron las lesiones más frecuentes (55,4%). Se administró tratamiento masivo con penicilina benzatínica, según las normas de OMS, en todas las comunidades positivas para esta enfermedad.

Published
1995

49. Onchocerca volvulus glycolytic enzyme fructose-1,6-bisphosphate aldolase as a target for a protective immune response in humans.

Author

McCarthy, James S, Wieseman, Moira, Tropea, Joe, Kaslow, David, Abraham, David, Lustigman, Sara, Tuan, Rocky, Guderian, Ronald H, and Nutman, Thomas B

Abstract

To identify potential vaccine candidates for the prevention of infection with the filarial nematode Onchocerca volvulus, we screened an O. volvulus L3 stage cDNA library with sera from putatively immune (PI) subjects, and a prominent immunogenic clone of 1,184 nucleotides was identified. It contained an open reading frame of 363 amino acids encoding the glycolytic enzyme fructose 1,6 bisphosphate aldolase (Ov-fba-1). Immunolocalization experiments demonstrated that the protein was most abundantly expressed in metabolically active tissues, including body wall muscle and the reproductive tract of adult female worms. Immunoelectron microscopy of L3 demonstrated binding in the region where the cuticle separates during molting, in the channels connecting the esophagus to the cuticle, and in the basal lamina surrounding the esophagus and the body cavity. Among subjects from areas where this organism is endemic specific humoral and cellular immune responses to recombinant protein were observed in both PI and infected subjects, whereas responses were not observed among subjects who had not been exposed to O. volvulus. Despite the absence of differential responsiveness in parasite-exposed human populations, when the recombinant was tested for protective efficacy in a mouse chamber model, a reduction in survival of larvae by ca. 50% was seen. This observation provides support for the further study of this parasite enzyme as a vaccine candidate in larger animal models.

Published
2002

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