Predominance of Trypanosoma rangeli infection in children from a Chagas disease endemic area in the west-shore of the Panama canal

Abstract

A total of 206 serum samples from children (3-14 years old) Human Trypanosoma cruzi and T. rangeli infections have, for a long time, been recognized as endemic in Panama (Sousa & Johnson 1971, 1973, Sousa & Saldaña 1994. However, currently available, seroepidemiological information is insufficient to convey an acceptable picture of the prevalence of Chagas disease in the country. Of special interest is the unclear role of T. rangeli on human infections. This trypanosome is considered totally benign (Cuba Cuba 1998, Guhl & Vallejo 2003 but with significant immunological consequences on T. cruzi infection (Zuñiga et al. 1997, Palau et al 2003, Basso et al. 2004. It is therefore necessary to update the information concerning human trypanosome infections in endemic regions from Panama.During 2004, a descriptive, parasitological, and seroprevalence study on human trypanosome infections was conducted in the Amador County, La Chorrera District, in the Province of Panama. Four neighboring rural communities, previously recognized as endemic for T. cruzi infection, were selected: Lagartera Grande, Los Hules, Lagarterita, and Las Pavas. The estimated population of these four areas is 1000 inhabitants. In these localities the ecoepidemiological characteristics are favorable for trypanosomes transmission and, at present, no organized vector control measures have been established by the health authorities. The climate in this region is tropical and comprises pasture lands where the presence of the royal palm tree, Attalea butyracea, is abundant. A. butyracea is the primary biotope of Rhodnius pallescens, the main vector of T. cruzi and T. rangeli in Panama. Also, this palm tree is considered a good ecological indicator of Chagas disease risk areas (Romaña et al. 2003).To determine the prevalence of anti-T. cruzi antibodies and blood trypanosomes in these localities, 206 apparently healthy children aged between 3 and 14 years old were investigated. This sample size represents 80% of the total number of children in this age range inhabiting the studied sites. Blood samples were obtained by venipuncture from each child, informed written consent was obtained from all parents or legal guardians. Hemoculture of samples was performed as described by Vasquez et al. (1997). To corroborate and identify the species of trypanosomes isolated, a duplex PCR assay (Chiurillo et al. 2003) followed by dot blot hybridization with radiolabeled oligonucleotide probes specific for T. cruzi and T. rangeli was performed on initially microscopically positive hemocultures.Sera samples were at first screened for the presence of anti-T. cruzi antibodies using an indirect immunofluorescence antibody test (IFAT) with a local T. cruzi isolate (Burunga strain) as antigen, according to the technique described by Guhl and Nicholls (2001). The sensitivity and specificity of this assay is of 95.2 and 96.3%, respectively. Samples with circulating anti-T. cruzi antibodies in the screening test were further submitted to a commercial recombinant ELISA (ELISA, Cha...

Evaluation of Serological Tests To Identify Trypanosoma cruzi Infection in Humans and Determine Cross-Reactivity with Trypanosoma rangeli and Leishmania spp

“…These results, which agree with the findings of other studies, show that human infection with T. rangeli does not cause the production of enough cross-reacting antibodies to interfere with the serodiagnosis of Chagas' disease (13,14). However, this does not exclude the possibility that exposure to T. rangeli may elicit a particular humoral and/or cellular immune response that confers some degree of protection against subsequent infection with T. cruzi (11).…”

“…in the serodiagnosis of Chagas' disease is well documented (2,20). In some areas of endemicity in Central America and Brazil, where T. cruzi and the nonpathogenic protozoan Trypanosoma rangeli can be found infecting the same vectors and vertebrate hosts (12,14), cross-reactivity has been the subject of discussion.…”

Conocimientos y factores de riesgo relacionados con la enfermedad de Chagas en dos comunidades panameñas donde Rhodnius pallescens es el vector principal

“…Vivienda con techo de hojas de palma (2) Vivienda con paredes de madera o cañaza (2) Vivienda con piso de tierra (1) Presencia de chinches dentro de la vivienda (3) Presencia de estructuras anexas a la vivienda (1) Presencia de animales domésticos dentro de la vivienda (2) Presencia de jaulas o corrales con animales cercanos a la vivienda (1) Presencia de gallineros cercanos a la viviendas (2) Presencia frecuente de animales silvestres cerca de la vivienda (1) Presencia de "palmas reales" cercanas (≤50 metros) a la vivienda (3) Almacenar leña o productos agrícolas dentro de la vivienda (1) Acumular diversos materiales de construcción en el peridomicilio (1) Cubrir paredes con calendarios, afiches u otros papeles (1) Habitar en una vivienda con un solo cuarto (1) Haber sido picado (o alguien de la vivienda) por un chinche vector (3) No usar mosquitero frecuentemente (2) No usar con frecuencia repelente cutáneo o mechitas dentro de la vivienda (1) No tener mallas metálicas en puertas o ventanas (2) Tocar los chinches encontrados en la vivienda con las manos desnudas (2)…”

“…Las características clínicas y epidemiológicas particulares que adopta esta zoonosis en el país, han sido estudiadas en los últimos años por varios autores (2)(3)(4)(5)(6)(7). Si bien se han reportado condiciones eco-epidemiológicas apropiadas para su transmisión en casi todas las provincias, la infección humana es más frecuente en las áreas rurales que bordean el Canal de Panamá (1,8), en el distrito de Chepo al este de la provincia de Panamá (9) y en el norte del distrito de Santa Fe en la provincia de Veraguas (7).…”

Prevalencia de autoanticuerpos contra receptores autonómicos en pacientes panameños con cardiopatía chagásica crónica y con otras formas de cardiopatía

“…Para detectar la infección con T. cruzi, a todos los sujetos se les extrajeron 15 ml de sangre y se evaluaron con tres pruebas serológicas de diferente metodología: ELISA (Chagatest, Wiener Lab., Argentina), ImmunoComb II (Orgenics, Israel) y Western Blot con antígeno total de epimastigotes (10,11). Se consideraron chagásicos los sujetos que resultaron positivos en las tres pruebas.…”