Molecular detection and phylogenetic analysis of Anaplasma platys-like and Candidatus Anaplasma boleense strains from Argentina.

The present study aimed at the molecular detection of Anaplasma spp. in different samples obtained from cattle, goats and free-living Rhipicephalus microplus ticks from Argentina. DNA of members of the Anaplasmataceae family was detected by different PCR assays. The phylogenetic analyses of the obtained partial DNA sequences of the 16 S rDNA gene resulted in the identification of two different Anaplasma spp.: (I) Anaplasma platys-like bacteria (in blood sample from cattle and pools of R. microplus larvae and (II) Candidatus Anaplasma boleense (in blood samples from goats and one pool of R. microplus larvae of R. microplus). Candidatus A. boleense was found in two provinces that belong to different biogeographic regions, which leads to the conclusion that this bacterium may be widely distributed in Argentina. Interestingly, both Anaplasma spp. were found in the same R. microplus population in Chaco province, indicating that these two strains of Anaplasma are circulating in the same tick population. The results of this work represent the first report of the circulation of A. platys-like bacteria and Ca. A. boleense in domestic ruminants and free-living R. microplus ticks in Argentina. Further studies to determine the prevalence of infection, dispersion, clinical impact, transmission routes and cross-reactivity in serological tests of both Anaplasma species are needed.

Benznidazole/Poloxamer 407 Solid Dispersion as a New Strategy to Improve the Treatment of Experimental Trypanosoma cruzi Infection.

Benznidazole and nifurtimox are the only drugs specifically approved for the treatment of Chagas disease. Both compounds are given orally in tablets, but occasionally are ineffective and cause adverse effects. Benznidazole, the first-line treatment in many countries, is a compound with low solubility in water that is administered at high doses for long periods of time. To improve its solubility, we developed a new liquid formulation on the basis of solid dispersions (SD) using the amphiphilic polymer poloxamer 407. Herein we present data on its trypanocidal performance in mouse models of acute and chronic Trypanosoma cruzi infection. SD at doses of 60 or 15 mg/kg per day given with different administration schedules were compared with the commercial formulation (CF; 50 mg/kg per day) and vehicle. The SD performance was assessed by direct parasitemia, total anti-T. cruzi antibodies, and parasitic burden in tissues after 4 or 6 mo posttreatment. The efficacy of the SD was equivalent to the CF but without manifest side effects and hepatotoxicity. Considering our previous data on solubility, together with these on efficacy, this new liquid formulation represents a promising alternative for the treatment of Chagas disease, particularly in cases when dosing poses a challenge, as in infants.

Presencia de infección por Trypanosoma cruzi Y Toxoplasma gondii en perros domésticos de localidades rurales en el noroeste argentino / Infection by Trypanosoma cruzi and Toxoplasma gondii in domestic dogs from rural localities in Northwest Argentina

Las zoonosis causadas por los parásitos Trypanosoma cruzi y Toxoplasma gondii son prevalentes en la Argentina y los perros cumplen el papel de reservorio además de padecer las enfermedades. Se considera una buena alternativa conocer la seroprevalencia de estas zoonosis en los perros debido a que son un reflejo de lo que ocurre en la población humana y en el ambiente. Nos propusimos conocer la seroprevalencia de infección por T. gondii y T. cruzi en caninos en cuatro zonas rurales de la provincia de Salta. Para la detección de anticuerpos anti-T. gondii se utilizó Hemaglutinación Indirecta (HAI) y para la detección de anticuerpos anti-T. cruzi, además de HAI, se usó Enzimoinmunoanálisis (ELISA). Fueron muestreados 209 canes y los resultados serológicos indicaron la presencia de anticuerpos anti-T. gondii en la localidad de La Unión, departamento Rivadavia en 18,2% (4/22), en San Carlos con 20,5% (8/39), en Cafayate con 13,1 % (11/84) y en Embarcación departamento General San Martín con 23.4% (15/64). Los anticuerpos anti-T cruzi sólo estuvieron presentes en los perros de la localidad de San Carlos con 28,2% (11/39). La frecuente seroprevalencia a T. gondii, encontrada en los perros de todas las localidades muestreadas sugiere contaminación ambiental por este parásito en la zona. El hallazgo de perros infectados por T. cruzi, en la localidad de San Carlos, nos sugiere la posibilidad de transmisión activa del parásito en un pasado reciente y nos alerta sobre la posibilidad de reservorio

Hepatotoxicity in mice of a novel anti-parasite drug candidate hydroxymethylnitrofurazone: a comparison with Benznidazole.

BACKGROUND: Treatment of Chagas disease, caused by Trypanosoma cruzi, relies on nifurtimox and benznidazole (BZL), which present side effects in adult patients, and natural resistance in some parasite strains. Hydroxymethylnitrofurazone (NFOH) is a new drug candidate with demonstrated trypanocidal activity; however, its safety is not known. METHODS: HepG2 cells dose response to NFOH and BZL (5-100 µM) was assessed by measurement of ROS, DNA damage and survival. Swiss mice were treated with NFOH or BZL for short-term (ST, 21 d) or long-term (LT, 60 d) periods. Sera levels of cellular injury markers, liver inflammatory and oxidative stress, and fibrotic remodeling were monitored. RESULTS: HepG2 cells exhibited mild stress, evidenced by increased ROS and DNA damage, in response to NFOH, while BZL at 100 µM concentration induced >33% cell death in 24 h. In mice, NFOH ST treatment resulted in mild-to-no increase in the liver injury biomarkers (GOT, GPT), and liver levels of inflammatory (myeloperoxidase, TNF-α), oxidative (lipid peroxides) and nitrosative (3-nitrotyrosine) stress. These stress responses in NFOH LT treated mice were normalized to control levels. BZL-treated mice exhibited a >5-fold increase in GOT, GPT and TNF-α (LT) and a 20-40% increase in liver levels of MPO activity (ST and LT) in comparison with NFOH-treated mice. The liver inflammatory infiltrate was noted in the order of BZL>vehicle≥NFOH and BZL>NFOH≥vehicle, respectively, after ST and LT treatments. Liver fibrotic remodeling, identified after ST treatment, was in the order of BZL>vehicle>NFOH; lipid deposits, indicative of mitochondrial dysfunction and in the order of NFOH>vehicle>BZL were evidenced after LT treatment. CONCLUSIONS: NFOH induces mild ST hepatotoxicity that is normalized during LT treatment in mice. Our results suggest that additional studies to determine the efficacy and toxicity of NFOH are warranted.

Congenital Chagas disease involves Trypanosoma cruzi sub-lineage IId in the northwestern province of Salta, Argentina.

Trypanosoma cruzi is genetically classified into six discrete phylogenetic lineages on the basis of different genetic markers. Identifying lineages circulating among humans in different areas is essential to understand the molecular epidemiology of Chagas disease. In the present study, 18 T. cruzi isolates from congenitally infected newborns in the northwestern province of Salta-Argentina were studied by multilocus enzyme electrophoresis (MLEE) and random amplified polymorphic DNA (RAPD). All isolates were typed by MLEE and RAPD as belonging to T. cruzi IId. Analysis of minor variants of TcIId using probes hybridizing with hypervariable domains of kDNA minicircles, detected three variants with a similar distribution among the isolates. Our findings confirm the presence of T. cruzi IId among congenitally infected newborns in northwestern Argentina and support the assumption that human infection by T. cruzi in the Southern Cone countries of Latin America is due principally to T. cruzi II.

Chagas disease in rural areas of Chaco Province, Argentina: epidemiologic survey in humans, reservoirs, and vectors.

We studied the seroprevalence of antibodies against Trypanosoma cruzi in the human population along with domiciliary infestation by triatomine bugs in an area endemic for Chagas disease in the Chaco Province of Argentina. In addition, we carried out parasitologic surveys in patients, dogs, wild mammals, and vectors. The mean seroprevalence in humans was 27.81% (109 of 392) and 24.14% (63 of 261) in 1-15-year-old children. The minimum domiciliary infestation rate was 13.33%, with certain areas reaching 53.85%. The prevalence was 15.09% (16 of 106) in dogs and 35.71% (10 of 28) in opossums. Infection with T. cruzi was detected in 30.10% (59 of 196) of the Triatoma infestans tested. Compared with nationwide studies, our data suggest that 1) there are zones requiring immediate sanitary action, and 2) nationwide estimates are based on very heterogeneous epidemiologic situations. This heterogeneity emphasizes the importance of in-depth studies of restricted areas to provide additional information for a better understanding of the present status of Chagas disease in Argentina.

La transmision de la enfermedad de Chagas en Salta y la deteccion de casos congenitos / The transmission de Chagas disease in Salta and the detection of congenital cases

Se presenta una revisión y actualización de datos sobre las tasas de seroprevalencia para el Trypanosoma cruzi en la Provincia de Salta en las tres últimas décadas, con especial referencia a la detección de casos congénitos y a los beneficios económicos de prevenir la enfermedad de Chagas. Los datos seroepidemiológicos obtenidos en conscriptos de 20 años de edad revelaron una disminución de la seroprevalencia, del 22.7 al 11.1 por ciento entre 1965 y 1985. En estudiantes universitarios, las cifras actuales son más bajas (0.96 por ciento). Las encuestas realizadas en 1996 revelaron seropositividad en más de 15 por ciento de las embarazadas analizadas, sobre todo en la zona Norte de la provincia. Esta situación trae aparejado un alto riesgo de aparición de casos congénitos de infección y, a la vez, una oportunidad para el ensayo de estrategias más adecuadas para su detección. Mediante la aplicación sistemática de Microstrout, Hemocultivo y PCR, se está logrando aumentar la detección temprana de niños con infección congénita. En aborígenes del Chaco salteño encontramos en 1992-94 tasas globales de seroprevalencia del 37 por ciento, con 5 localidades de altísima transmisión, en las que se observó más de un 54 por ciento de infectados. Estas cifras indican que, en vastas zonas del territorio provincial, la lucha contra la vinchuca no sólo debe reducirse a acciones de vigilancia, sino de renovado ataque y nuevas inversiones en rociado, control de bancos de sangre y control de embarazadas para prevenir la transmisión congénita. Un análisis realizado del rédito económico de las operaciones de rociado, sólo para el Departamento de Anta, arroja un valor actual neto que supera los 7 millones de dólares, con tasas internas de retorno de más de 60 por ciento.