Performance of rapid tests for canine visceral leishmaniasis diagnosis in Argentina

To diagnose dogs infected by Leishmania infantum rK39 rapid diagnosis test is widely used in the Americas, while dual path platform (DPP) was recently adopted by Brazil. In this study we assessed the performance of rK39-RDT and DPP tests in recent urban transmission scenarios of Argentina. The sensitivity and specificity were evaluated with a sera panel and field samples, taken as true infected those from parasitological and/or PCR positive tests. Since none of these tests can be taken as a gold standard, the performance was also evaluated using Latent Class Analysis, a statistical modeling technique which allows to estimating sensitivity and specificity defining a latent class variable as the reference standard. The sensitivity of both tests in the panel was around 92% (symptomatic dogs 96%, asymptomatic 83%), while the sensitivity in field samples of rK39-RDT was 77%, and DPP 98% (mean in symptomatic dogs 89%, asymptomatic 82%). The specificity was similar for both tests and samples, around 98%. Therefore, these tests are acceptable for program dog population-based studies, as spatial stratification, focus intervention and follow up, and they could be used for individual screening and confirmation of clinical presumptive diagnosis in polysymptomatic dogs. The inability to discriminate between immunity and actual infectiousness suggest that a combination with other non-immunological based tests will be required for highly sensitive/specific diagnosis in order to targeting control measures in individual reservoirs from public health perspective, as for individual management from animal health perspective.

Para diagnosticar perros infectados por Leishmania infantum, en las Américas se utiliza ampliamente la prueba rápida rK39, mientras que DPP fue adoptado recientemente por Brasil. En este estudio se evaluó el desempeño de las pruebas rK39-RDT y DPP en escenarios de transmisión urbana reciente en Argentina. La sensibilidad y especificidad se evaluaron con un panel de sueros y muestras de campo, considerando muestras infectadas verdaderas aquellas con pruebas parasitológicas y/o de PCR positivas. Como ninguna de estas pruebas puede considerarse estándar de oro, el desempeño también se evaluó mediante análisis de clases latentes, una técnica de modelado estadístico que permite estimar sensibilidad y especificidad definiendo una variable de clase latente como estándar. La sensibilidad de ambas pruebas en el panel fue de alrededor del 92% (perros sintomáticos 96%, asintomáticos 83%), mientras que la sensibilidad en muestras de campo fue rK39-RDT: 77%, y DPP 98% (media en perros sintomáticos 89%, asintomáticos 82%). La especificidad fue similar para ambas pruebas y muestras, cerca de 98%. Por lo tanto, estas pruebas son aceptables para estudios programáticos caninos de base-poblacional, como estratificación espacial, intervención de foco y seguimiento, y podrían utilizarse para el tamizaje individual y la confirmación del diagnóstico clínico presuntivo en perros poli-sintomáticos. La incapacidad de discriminar entre inmunidad e infectividad real sugiere que se requerirá una combinación con otras pruebas, de base no inmunológica, para un diagnóstico suficientemente sensible/específico que permita definir las medidas de control en reservorios individuales, tanto para salud pública, como para la gestión individual en salud animal.

Use of tissue doppler imaging for the early detection of myocardial dysfunction in patients with the indeterminate form of Chagas disease

Abstract INTRODUCTION: Chagas disease is one of the most common diseases in Latin America and heart involvement is the main cause of death. This study aimed to determine differences in tissue Doppler imaging (TDI) parameters in the assessment left and right ventricular function in patients with the indeterminate form of Chagas disease compared to those in healthy controls. METHODS: We compared 194 patients with the indeterminate form of Chagas disease to 72 age-matched healthy individuals. We considered p-values <0.05 to be statistically significant. RESULTS: TDI analysis of the right ventricular (RV) showed lengthened isovolumic relaxation time (IRT) and higher RV index of myocardial performance (RIMP) and left ventricle (LV) index of myocardial performance (LIMP) in the Chagas group than in the control group, indicating RV and LV systolic and diastolic myocardial damage. TDI analysis of the myocardial velocities of the interventricular septum and the lateral wall of the LV also showed a systolic and diastolic myocardial damage. CONCLUSIONS: The study results demonstrated early LV systolic and diastolic myocardial damage in the RV and LV in patients with the indeterminate form of Chagas disease by TDI. These early findings of RV and LV dysfunction may help identify patients who will progress to heart failure during the disease course. TDI should be included in initial patient evaluations because it allows adequate follow-up and treatment.

Chagas cardiomyopathy associated with serological cure after trypanocidal treatment during childhood

Abstract Chagas disease is a chronic parasitological disease, which could cause cardiac manifestations in approximately one-third of affected individuals. Benznidazole and nifurtimox are used to treat this parasitological infection caused by Trypanosoma cruzi. Conventionally, the criterion for cure is consistently negative serological tests after treatment. We report a case of a patient who was treated when she was 13 years old and achieved T. cruzi negative seroconversion but developed Chagas disease cardiomyopathy as an adult.

Pharmacokinetic and pharmacodynamic responses in adult patients with Chagas disease treated with a new formulation of benznidazole

Pharmacological treatment of Chagas disease with benznidazole (BNZ) is effective in children in all stages, but it is controversial in chronically infected adults. We report the pharmacokinetics and pharmacodynamics in six adult patients with Chagas disease treated with the new BNZ formulation (ABARAX®) in doses between 2.5-5.5 mg/Kg/day. All but one patient had plasmatic BNZ concentrations within the expected range. All patients finalised treatment with nondetectable Trypanosoma cruziquantitative polymerase chain reaction, which remained nondetectable at the six month follow-up. Our data suggests parasitological responses with the new BNZ and supports the hypothesis that treatment protocols with lower BNZ doses may be effective.

Leishmaniasis visceral: senderos que confluyen, se bifurcan / Visceral leishmaniasis: paths that converge and divide

La leishmaniasis visceral urbana es una zoonosis emergente en Argentina. En América es producida por Leishmania infantum, con el perro como reservorio principal e insectos flebotomíneos como vectores. En este artículo se presenta el conocimiento acumulado a partir de su emergencia y dispersión en el país, por los referentes del Programa Nacional de Leishmaniasis, en el diagnóstico clínico y de laboratorio, tratamiento, biología de vectores, manejo de reservorio, y el conflicto generado con las acciones recomendadas en relación con los perros infectados. La detección temprana y el tratamiento precoz, con estrategias descentralizadas y horizontales, contribuirán a disminuir la morbimortalidad asociada a la leishmaniasis visceral. El control de su transmisión y dispersión requiere de un manejo ambiental integral y la tenencia responsable de perros. Se discuten los intereses y discursos en conflicto generados por la leishmaniasis visceral en el marco de la relación humano-perro, proponiendo la búsqueda de un discurso consensuado de riesgo.

Urban visceral leishmaniasis is an emerging zoonosis in Argentina. In the Americas the disease is produced by Leishmania infantum, with dogs as the primary reservoir and phlebotomine sandflies as the vectors. This article presents the experience acquired by professionals from the National Leishmaniasis Program in Argentina as visceral leishmaniasis has emerged and spread, especially in clinical and laboratory diagnosis, disease treatment, vector biology, reservoir management, and conflicts regarding recommendations for infected dogs. Early detection and treatment, along with decentralized and horizontal strategies, will contribute to the decrease in morbidity and mortality associated with visceral leishmaniasis. Control over the transmission and spread of the disease requires integral environmental management and responsible dog ownership. The interests and discourses put into conflict by visceral leishmaniasis are discussed in the framework of the human-dog relationship, and the search for a consensus-based risk discourse is proposed.

Reactivación de la enfermedad de Chagas en el sistema nervioso central de pacientes infectados por el virus de la inmunodeficiencia humana / Central nervous system reactivation of Chagas' disease in HIV-infected patients

La reactivación de la enfermedad de Chagas (ECH) en pacientes infectados por el virus de la inmunodeficiencia humana (VIH) puede causar lesiones cerebrales ocupantes. Considerando que el diseño de un algoritmo para el diagnóstico precoz podría reducir la mortalidad, deben considerarse diversos escenarios: 1) ¿Cuándo debe indicarse el examen parasitológico (EP) del frotis de sangre periférica y líquido cefalorraquídeo (LCR)? 2) ¿debe realizarse aún en aquellos pacientes con serología negativa para Trypanosoma cruzi?, 3) ¿en qué casos el tratamiento para la encefalitis por T. gondii puede interrumpirse?

Reactivation of Chagas disease (CHD) in patients infected with Human Immunodeficiency Virus (HIV) can cause brain mass lesions. As the design of an algorithm for early diagnosis could reduce mortality, different secenarios should be considered:1) when the parasitologic examination (PE) of peripheral blood smears and cerebrospinal fluid(CSF) should be indicated? 2) should it de performed even in patients with negative serology for Trypanosoma cruzi? 3) in which cases the treatment for T. gondii encephalitis can be discontinued?

First visceral leishmaniasis focus in Argentina

An eight-year old boy from Posadas (27º 23'S, 55º 54'W) was diagnosed with visceral leishmaniasis (VL) during 2006. Lutzomyia longipalpis was discovered in the backyard of his house, while the spread of canine visceral leishmaniasis was confirmed in Posadas. This is the southernmost report of a VL transmission focus and the first in Argentina.

The activity of azithromycin against Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis in the golden hamster model

New therapeutic alternatives against leishmaniasis remain a priority. The activity of azithromycin against Leishmania (Leishmania) major has been previously demonstrated. Different responses among species of Leishmania make species-specific drug screening necessary. The activity of azithromycin against Leishmania (Viannia) braziliensis and Leishmania (Leishmania) amazonensis was evaluated in golden hamsters infected through footpad injections of metacyclic promastigotes, and compared with untreated controls and animals treated with meglumine antimoniate. Footpad thickness, lesion cultures and dissemination sites were analyzed. Treatment of golden hamsters with oral azithromycin at 450mg/kg had no activity against infections with Leishmania (Leishmania) amazonensis. For infections due to Leishmania (Viannia) braziliensis, azithromycin demonstrated significant activity relative to untreated controls, but inferior to meglumine antimoniate, for controlling lesion size. Neither drug was able to totally eliminate parasites from the lesions. It was concluded that azithromycin has activity against Leishmania (Viannia) braziliensis but not against Leishmania (Leishmania) amazonensis in this model.

Novas alternativas terapêuticas contra a leishmaniose são ainda uma prioridade. A atividade da azitromicina contra a Leishmania (Leishmania) major foi anteriormente demonstrada. Diferentes respostas entre as espécies de Leishmania fazem com que um screening de drogas específicas para espécies seja necessário. A atividade da azitromicina contra a Leishmania (Viannia) braziliensis e a Leishmania (Leishmania) amazonensis foi avaliada em Golden hamsters infectados a través de injeções de promastigotas metacíclicas e comparando com controles sem tratamento e animais tratados com antimoniato de N-metil-glucamina. Foram analisadas a espessura da pata, a cultura das lesões e disseminação para órgãos internos. A azitromicina oral em dose de 450mg/kg não teve atividade contra a infecção por Leishmania ( Leishmania) amazonensis. Para infecções devidas à Leishmania (Viannia) braziliensis, a azitromicina teve uma atividade significativa em relação aos controles sem tratamento, mas foi inferior ao antimoniato de N-metil-glucamina quanto ao controle do tamanho das lesões. Nenhuma das drogas conseguiu eliminar totalmente os parasitos das lesões. Foi concluído que a azitromicina tem atividade contra Leishmania (Viannia) braziliensis, mas não tem atividade contra Leishmania (Leishmania) amazonensis neste modelo.

Resultados alejados del implante miocárdico de células madre en la miocardiopatía chagásica / Late Results in Myocardial Implantation of Stem Cells in Chagasic Myocardial Disease

Objetivo La presente investigación clínica persigue evaluar la seguridad y la factibilidad del cardioimplante de células mononucleares de médula ósea, así como analizar los cambios clínicos y de la función ventricular, en pacientes portadores de insuficiencia cardíaca secundaria a miocardiopatía dilatada de origen chagásico sometidos a este procedimiento. Material y métodos La muestra comprende 5 pacientes consecutivos (3 masculinos) con una edad promedio de 55,8 ± 8,1 años, que presentaban insuficiencia cardíaca secundaria a miocardiopatía chagásica. Los datos preoperatorios promedio de estos pacientes indicaban una clase funcional (NYHA) de 2,6 ± 0,5, mientras que la fracción del ventrículo izquierdo correspondía al 27,6% ± 5,9%, el diámetro diastólico ventricular izquierdo era de 62,9 ± 6,2 mm y el diámetro sistólico del ventrículo izquierdo era de 49,7 ± 7,6 mm. La suspensión celular obtenida de células mononucleares de la médula ósea contenía 10,6 ± 7 ml con un conteo de 1,43 ± 0,6 (E+08) células con una viabilidad mayor del 95%. Correspondían a la fracción CD34+, 5,07 ± 9,51 (E+06) y a la CD133+, 5,11 ± 4,3 (E+06). La suspensión se inyectó por pulsos en cuatro pacientes por vía intracoronaria y en el quinto por vía transepicárdica en el transcurso de una cirugía (reemplazo valvular mitral, revascularización y colocación de matriz bioartificial degradable). Resultados A los 17,2 ± 8,8 meses de seguimiento promedio, 4 enfermos se hallaban vivos y en clase funcional I (p < 0,005). Un paciente falleció de muerte súbita a los 17 meses de seguimiento. En este tiempo de evolución no se observaron efectos adversos en ninguno de los pacientes referidos al implante celular. En relación con la fracción de eyección, se notó un incremento a 36,6% ± 2,3% (p < 0,05). Los datos obtenidos en la medición de los diámetros sistólico y diastólico del ventrículo izquierdo no mostraron cambios estadísticos significativos. Conclusiones Este trabajo representa la segunda comunicación mundial sobre el uso de stem cells en cardiopatía de Chagas-Mazza. El procedimiento resultó factible y seguro y se asoció con mejoría de la capacidad funcional y de la función ventricular en el seguimiento. Estos hallazgos provisorios deberán ser corroborados por estudios clínicos controlados más amplios.

Objective The present clinical study is aimed at assessing the safety and feasibility of cardio implantation of mononuclear bone marrow cells, as well as analyzing the clinical and ventricular function changes in patients with cardiac failure secondary to dilated myocardial disease of chagasic origin that underwent this procedure. Material and Methods The sample included 5 consecutive patients (3 male), mean age 55, 8 ± 8, 1 years that showed cardiac failure secondary to chagasic myocardial disease. Average pre-surgery data in these patients were 2, 6 ± 0, 5 functional class (NYHA), whereas the left ventricle fraction corresponded to 27, 6% ± 5, 9%, the left ventricle diastolic diameter was 49, 7 ± 7, 6 mm. The cellular suspension obtained from mononuclear bone marrow cells contained 10, 6 ± 7 ml with 1, 43 ± 0, 6 (E+08) cell counting with a viability higher than 95%. Corresponding to CD34+, 5, 07 ± 9, 51 (E+06) fraction and CD133+, 5, 11 ± 4, 3 (E+06). Suspension was intracoronary injected in pulses to four patients and transepicardially to the fifth during the course of a surgery (mitral valve replacement, revascularization and degradable bioartificial matrix). Results At 17,2 ± 8,8 average months follow up, 4 patients were alive and with functional class I (p < 0,005). One patient died of sudden death after 17 months of follow up. During this evolution time period no adverse events were observed in none of the patients referred for cellular implantation. In regards to the ejection fraction, a 36,6% ± 2,3% (p < 0,05) increase was observed. Data obtained from the assessment of the left ventricle systolic and diastolic diameters did not show significant statistical changes. Conclusions This study represents the second world communication on the use of stem cells in Chagas-Mazza heart disease. The procedure resulted feasible and safe and was associated to improvement of the functional capacity and ventricular function during follow up. These conditional results should be corroborated by broader controlled clinical trials.

Distribution and pathogenicity of Trypanosoma cruzi isolated from peridomestic populations of Triatoma infestans and Triatoma guasayana from rural Western Argentina

We assessed the distribution of Trypanosoma cruzi infection in peridomestic triatomines collected manually at a district-wide scale in rural villages around Olta, Western Argentina, and typed the isolated strains according to their pathogenicity to laboratory mice. Of 1623 triatomines examined, only 14 (0.9 percent) were infected with T. cruzi based on microscopical examination of feces. The prevalence of T. cruzi infection was 0.8 percent in Triatoma infestans, 2.3 percent in T. guasayana, and nil in T. garciabesi, T. platensis, and T. eratyrusiformis. Local transmission occurred in kitchens, store-rooms and goat corrals or nearby, though at very low levels. T. cruzi was detected by at least one parasitological method in 11 (79 percent) of 14 microscope-positive bugs. Hemoculture was the most sensitive method (67 percent) followed by culture of organ homogenates, histopathology or xenodiagnosis of inoculated suckling mice (55-58 percent), and culture of microscope-positive bug feces (46 percent). The evidence suggests that most of the isolated T. cruzi strains would be myotropic type III. Our study establishes for the first time that peridomestic, microscope-positive T. guasayana nymphs were actually infected with T. cruzi, and may be implicated as a putative secondary vector of T. cruzi in domestic or peridomestic sites.

Caracteristicas clinicas y diagnosticas de la leishmaniasis mucocutanea en pacientes de un area endemica de Salta / Clinical and diagnostic characteristics of mucocutaneous leishmaniasis in patients of an endemic area in Salta

Entre junio de 1990 y diciembre de 1992, en un área endémica para leishmaniasis, de Salta, Argentina, se examinaron 39 pacientes con diagnóstico clínico de leishmaniasis tegumentaria. El 87,2 por ciento (34/39) de los casos presentaron la forma cutánea simple, el 10,3 por ciento la forma cutánea múltiple y en 2.6 por ciento mucosa. La localización corporal más frecuente de las lesiones fue en miembros (71.8 por ciento), seguida de tronco y de la localización múltiple (10.3 por ciento). El 43.6 por ciento eran amas de casa, estudiantes o niños, sugiriendo que la infección pudo ser contraída en el ambiente doméstico o peridoméstico. De los 39 pacientes diagnosticados, en 22 (56.4 por ciento) se realizó la comprobación parasitológica. El examen del frotis, por microscopía directa, permitió el diagnóstico de 13 (59.4 por ciento) de los 22 pacientes. En 5 (22.7 por ciento se encontró leishmanias por cultivos, y por inoculación del hámster en 9 (40.9 por ciento). Se obtuvieron 10 aislamientos parasitarios (45.4 por ciento). Se recomienda, como método de diagnóstico para la vigilancia epidemiológica, la observación micorscópica directa del frotis, dada la sensibilidad demonstrada en este trabajo y la facilidad de su implementación en la endémica. El período de evolución clínica, desde la aparición de la lesión hasta la detección del paciente por el Sistema de Salud, fue de aproximadamente 90 días. Ese período estaría relacionado a la frecuencia de vista del Agente Sanitario a los domicilios, cada 3 meses. Sólo un paciente tratado tuvo una recidiva a los 6 meses, debido al incumplimiento del tratamiento.

A new host of Trypanosoma cruzi from Jujuy, Argentina: octodontomys gliroides (Gervais & D'Orbigny, 1844) (Rodentia, Octodontidae)

To identify wild hosts of Trypanosoma cruzi, surveys were conducted in the subandean valleys of Jujuy Province, Argentina, between June 1986 and March 1987. Seventy two mammals from 13 different species were examined by xenodiagnosis. Fifty two of them were mostly roedents trapped at the localities of Maimará, León and Tilcara, and the remainder had been kept in captivity at the Estación Biológica Experimental, in Jujuy. Trypanosoma cruzi infection was detected only in 2 Octodontomys gliroides (2 pos./8 exam. 25%) from all 72 examined mammals. Isolates were called Octodontomys Argentina 1 and 2 (OA1 and OA2). Both infected animals were caught at the archaelogical ruin of Pucará, at Tilcara. Repeated searches for triatomines in the ruin itself and in neighbour houses rendered negative results. Groups of mice inoculated with either OA1 or OA2 isolates became infected between 7 (OA1) to 12 days (OA2) postinoculation PI. Parasitemia peaks were observed between day 12th - 14th PI. Scarce amastigote nests were found in myocardium and skeletal muscle. Mortality was observed only for mice inoculated with OA1. Isoenzyme patterns of OA1 and OA2 were identical to one found in dogs and slightly different from that of human parasites in Argentina. Bones from Octodontomys sp., were recently found in a cave, dated 10200-8600 BC, in Pumamarca, near Tilcara, Jujuy. There are evidences that O. gliroides cohabited with man in ancient times and was associated to the domestic cycle of T. cruzi transmission, playing a role like that of domestic cavies. in Bolivia

Embryology of Triatoma infestans (Klug), (Hemiptera, Reduviidae), a Chagas' disease vector

This study reports the embryogenesis of T. infestans (Hemiptera, Reduviidae). Morphological parameters of growth sequences from oviposition until hatching (12-14 d 28 degrees C) were established. Five periods, as percent of time of development (TD), were characterized from oviposition until hatching. The most important morphological features were: 1) formation of blastoderm within 7% of TD; 2) germ band and gastrulation within 30% of TD; 3) nerve cord, limb budding, thoracic and abdominal segmentation and formation of body cavity within 50% of TD; 4) nervous system and blastokinesis end, and development of embryonic cuticle within 65% of TD; 5) differentiation of the mouth parts, fat body, and malpighian tubules during final stage and completion of embryo at day 12 to day 14 around hatching. These signals were chosen as appropriate morphological parameters which should enable the evaluation of embryologic modifications due to the action/s of different insecticides

Natural Trypanosoma cruzi infection in dogs of endemic areas of the Argentine Republic

Estudou-se a dinâmica populacional e a prevalência de infecçäo chagásica de 352 cäes vivendo em 108 moradias rurais infectadas por triatomíneos. A área foi dividida em três setores de acordo com suas crescentes distâncias em relaçäo a um povoado urbano. Cada animal foi identificado mediante suas características particulares, e seus donos deram informaçöes a respeito de seus hábitos. As prevalências de infecçäo foram determinadas por sorologia, correlaçäo parasitológica-sorológica, percentual de traçados eletrocardiográficos alterados e o percentual de moradias com cäes parasitados. A área rural mostrou um padräo característico de infecçäo por T. Cruzi e observaram-se diferenças nos parâmetros de populaçäo canina em relaçäo às restantes áreas: maior proporçäo de filhotes, maior populaçäo humana e canina sedentárias, maiores prevalências de infecçäo por xenodiagnóstico em cäes e maior proporçäo de barbeiros ingfectados com T. Cruzi nos cômodos da casa. Supöe-se que as características sedentárias da populaçäo humana desta área rural é fundamental para a oferta de sangue para as populaçöes triatomíneas, e a elevada porcentagem de cäes parasitêmicos dessa área contribui para o aumento de barbeiros infectados com T. Cruzi encontrados nos quartos de dormir

Enfermedad de Chagas en perros experimentalmente infectados con Trypanosoma cruzi / Chagas' disease in dogs experimentally infected with trypanosoma cruzi

Perros mestizos, adultos jóvenes, fueron inoculados con una cepa no letal de T. cruzi. El control de la infección se efectuó durante 620 días e incluyó la obtención del perfil parasitológico, la búsqueda sistemática de anticuerpos específicos y la realización de trazados electrocardiográficos. Durante toda la evolución de la infección, tres de los cuatro perros infectados mostraron una parasitemia sostenida, mientras que en el cuarto animal fue esporádica. Anticuerpos específicos contra T. cruzi fueron detectados a títulos significativos en todos los animales, durante los 620 días. Alteraciones electrocardiográficas inespecíficas fueron observadas en tres perros. Los estudios anatomopatológicos evidenciaron una miocarditis crónica multifocal con lesiones inflamatorias activas, sin nidos de amastigotes tisulares. Los hallazgos observados sugieren la posibilidad de progresión de las lesiones a una miocarditis crónica análoga a la humana