Resumen La aplasia pura de células rojas (APCR) es un síndrome definido por anemia normocítica normocrómica, con reticulopenia severa y reducción importante o ausencia absoluta de precursores eritroides en la médula ósea. Ocasionalmente se desencadena en el curso de una colagenopatía o una enfermedad autoinmune. Presentamos el primer caso descripto en la literatura de un varón con APCR como forma de debut de lupus eritematoso sistémico (LES). Se trata de un hombre de 65 años que presentó anemia normocítica normocrómica, ANA 1/5120 y anti-Sm 2,61. Refería úlceras orales, poliartralgias, tumefacción de ambos tobillos y fotosensibilidad. Se realizó estudio de médula ósea con evidencia de hipoplasia de serie roja por paro madurativo a nivel de eritroblasto basófilo, ausencia casi completa de los elementos maduros y contenido muy elevado de proeritroblastos de gran tamaño. Con el diagnóstico de APCR como debut de LES, se lo trató con prednisona con buena respuesta. Podemos concluir que el despistaje de enfermedades sistémicas en pacientes con APCR es esencial para asegurar un correcto manejo y un mejor pronóstico.

Abstract Pure red cell aplasia (PRCA) is a syndrome defined by normocytic normochromic anemia with severe reticulocytopenia and marked reduction or absence of erythroid precursors from the bone marrow. Occasionally it is triggered in the course of collagen or autoimmune diseases. We present the first case reported in the literature of a man with PRCA as the onset form of systemic lupus erythematosus (SLE). A 65-year-old man, who presented normocytic normochromic anemia, ANA 1/5120 and anti-Sm 2,61. He reported oral ulcers, polyarthralgia, swelling of both ankles and photosensitivity. Bone marrow examination showed red cell line hypoplasia due to maturation arrest at the level of the basophilic erythroblast, almost absence of mature cells, and a very high content of large proerythroblasts. With the diagnosis of PRCA as the first manifestation of SLE, he was successfully treated with Prednisone. We can conclude that screening for systemic diseases in patients with PRCA is essential to ensure correct management and a better prognosis.

The aim of this work was to evaluate a dot-enzyme-linked immunosorbent assay (dot-ELISA) using excretory-secretory antigens from the larval stages of Toxocara canis for the diagnosis of toxocariasis. A secondary aim was to establish the optimal conditions for its use in an area with a high prevalence of human T. canis infection. The dot-ELISA test was standardised using different concentrations of the antigen fixed on nitrocellulose paper strips and increasing dilutions of the serum and conjugate. Both the dot-ELISA and standard ELISA methods were tested in parallel with the same batch of sera from controls and from individuals living in the problem area. The best results were obtained with 1.33 µg/mL of antigen, dilutions of 1/80 for the samples and controls and a dilution of 1/5,000 for the anti-human IgG-peroxidase conjugate. All steps of the procedure were performed at room temperature. The coincidence between ELISA and dot-ELISA was 85% and the kappa index was 0.72. The dot-ELISA test described here is rapid, easy to perform and does not require expensive equipment. Thus, this test is suitable for the serological diagnosis of human T. canis infection in field surveys and in the primary health care centres of endemic regions.

In order to evaluate the association between the infection by Toxocara canis and the symptoms of asthma in children from a subtropical region with high prevalence of toxocariasis, 47 asthmatic children and 53 non-asthmatics as a control group were studied. A complete physical examination was performed and clinical and epidemiological data were registered. In asthmatic children the frequency and severity of symptoms were classified in grades I to IV. The presence of anti-Toxocara canis antibodies in both groups was evaluated employing a solid phase ELISA method with excretion/secretion antigens, and total Ig E was also measured. Results showed a total seropositivity of 55%, 57.4% in children with asthma and 52.8% in the control group. Among asthmatics with severe symptoms (grade II, III and IV), there was a 67.7% of seropositivity while in children with symptoms of grade I there was a 37.5% (p = 0.0470). The infection with T. canis could act as a co-factor increasing the severity of the symptoms of bronchial asthma.

A fin de evaluar la relación entre la infección por Toxocara canis y los síntomas del asma bronquial en niños de una región subtropical con alta prevalencia de toxocariosis, se estudiaron 47 niños con asma y 53 sin asma como grupo control. Se efectuó el examen físico completo, registrándose datos clínicos y epidemiológicos. En los niños con asma se categorizó el patrón de presentación, frecuencia y gravedad de los síntomas con una escala de I a IV. Se investigó la presencia de anticuerpos anti-Toxocara canis en ambos grupos mediante el método de ELISA en fase sólida, empleando antígeno de excreción/secreción y se efectuó dosaje de Ig E total. Los resultados muestran una seropositividad del 55% en el total de los niños, del 57.4% en los niños con asma y del 52.8% en los controles. En los niños con sintomatología más grave (grado II, III y IV) hubo un 67.7% de seropositivos, mientras que en los niños con síntomas de grado I la seropositividad fue de 37.5% (p = 0.0470). La infección por T. canis actuaría como un co-factor agravante de los síntomas del asma bronquial.

The presence of Chlamydia trachomatis and human papillomavirus (HPV) was evaluated by PCR technique in 189 sexually active women, between 15 and 58 years old, with cytological abnormalities in their uterine cervical epithelium and belonging to a region of Argentina with high incidence of cervical cancer. Risk factors in relation to chlamydial infection were also analyzed. Total prevalence for C. trachomatis infection was 24.9%, but there was a significant difference between prevalence in low socio-economical level (32.9%) and high or medium socio-economical level (17.7%). Total prevalence for DNA of HPV was 52.9%, but women infected with C. trachomatis showed a higher risk for viral infection than non-infected ones (OR=2.27 / CI 95%=1.10-4.73), with statistical significant difference (p=0.016).

Se estudió mediante técnica de PCR la presencia de Chlamydia trachomatis y de papilomavirus humano (HPV) en 189 mujeres sexualmente activas de entre 15 y 58 años de edad, con alteraciones citológicas del epitelio cérvico-uterino, provenientes de una región con alta incidencia de cáncer de cuello uterino de Argentina, y se analizaron los factores de riesgo. La prevalencia global por C. trachomatis fue de 24.9%; observándose una diferencia significativa de la prevalencia entre las mujeres de bajo nivel socio-económico (32.9%) y las de nivel medio o alto (17.7%). En cuanto a la infección por HPV, la prevalencia fue de 52.9% y se pudo observar que las mujeres infectadas con C. trachomatis presentan un mayor riesgo de infección por este virus que las no infectadas (OR=2.27 / IC 95%=1.10-4.73) con una diferencia estadísticamente significativa (p=0.016).

OBJECTIVES: To evaluate the antibiotic resistance of strains of Shigella spp. isolated from feces samples from northeastern Argentina and to characterize the strains in terms of their molecular epidemiology. METHODS: We studied 132 isolates of Shigella spp. obtained from feces samples from 132 patients with diarrhea who were seen at various private and public laboratories in the Argentine provinces of Chaco and Corrientes during the period of 1998 to 2002. Each strain was characterized according to its serotype, its resistance to 13 individual or combination antibiotics, and its sensitivity to pyocins. With 52 strains selected in relation to their antimicrobial susceptibility profiles we conducted plasmid profile analysis using alkaline lysis, and the repetitive extragenic palindromic sequences were determined by amplifying repetitive DNA segments using polymerase chain reaction. The chi-square test was used to compare proportions, with a level of statistical significance of 0.05. RESULTS: Shigella flexneri was the most common species (78%), followed by S. sonnei (22%). In general, the resistance of S. flexneri to the antibiotics studied was greater than that of S. sonnei, and this difference was statistically significant (P < 0.001) for ampicillin, tetracycline, chloramphenicol, and the combination of ampicillin and sulbactam. The S. flexneri strains also showed multiple resistance more often than S. sonnei strains (84.5% vs. 31.0%; P < 0.001). The strains isolated from S. flexneri were grouped into five pyocin types, three plasmid profiles, and five patterns of repetitive palindromic sequences. The strains of S. sonnei formed three pyocin types, two plasmid profiles, and three patterns of repetitive palindromic sequences. CONCLUSIONS: Given that the Shigella species that were studied showed a high level of resistance to the most frequently used antibiotics, surveillance activities should be implemented in order to detect and control the appearance of new resistant strains. Applying epidemiological typing techniques can provide more precise information about the distribution and evolution of resistant strains of circulating microorganisms.

OBJETIVOS: Evaluar la resistencia a antibióticos de cepas de Shigella spp. aisladas de muestras de heces en el nordeste argentino y caracterizarlas desde el punto de vista de su epidemiología molecular. MÉTODOS: Se estudiaron 132 aislamientos de Shigella spp. obtenidos de las heces de igual número de pacientes con diarrea que asistieron a diferentes laboratorios privados y estatales de las provincias del Chaco y Corrientes, Argentina, durante el período de 1998 a 2002. Cada cepa se caracterizó según su serotipo, su resistencia a 13 antibióticos individuales o combinados y su sensibilidad a las piocinas. A 52 cepas seleccionadas en función de sus perfiles de susceptibilidad antimicrobiana se les determinaron la dotación plasmídica mediante lisis alcalina y las secuencias repetitivas palindrómicas extragénicas mediante la amplificación de segmentos repetitivos de ADN con la reacción en cadena de la polimerasa (REP-RCP). Se aplicó la prueba de ji al cuadrado para comparar proporciones. El nivel de significación estadística fue de 0,05. RESULTADOS: Shigella flexneri fue la especie más frecuente (78%), seguida de S. sonnei (22%). En general, la resistencia de S. flexneri a los antibióticos estudiados fue mayor que la de S. sonnei y esta diferencia fue estadísticamente significativa (P <0,001) frente a ampicilina, tetraciclina, cloramfenicol y la combinación de ampicilina con sulbactama. Las cepas de S. flexneri también mostraron mayor multirresistencia que las de S. sonnei (84,5% frente a 31,0%; P <0,001). Las cepas aisladas de S. flexneri pudieron agruparse según 5 piocinotipos, 3 perfiles plasmídicos y 5 patrones de secuencias repetitivas palindrómicas. Por su parte, las cepas de S. sonnei conformaron 3 piocinotipos, 2 perfiles plasmídicos y 3 patrones de secuencias repetitivas palindrómicas. CONCLUSIONES: Las especies de Shigella estudiadas mostraron una elevada resistencia a los antibióticos de uso más frecuente, por lo que se deben poner en marcha actividades de vigilancia a fin de detectar y controlar la aparición de nuevas cepas resistentes. La aplicación de técnicas de tipificación epidemiológica puede ayudar a conocer con mayor precisión la distribución y evolución de cepas de microorganismos resistentes circulantes.

No período de 1994 a 2000, durante a construção e enchimento da represa Yacyretá, foram estudadas em Ituzaingó e Posadas variáveis infecciosas (diarréias e infecções respiratórias), clínico-cirúrgicas (doenças cardiovasculares e politraumatismos) e ambientais (pluviais, temperatura e umidade). As diarréias, em Ituzaingó, tiveram um aumento 6,5%, 78,3% e 13%, respectivamente em 1995, 1996 e 1997 e nos anos seguintes os valores foram similares aos de 1994 e em Posadas mostraram uma tendência ascendente. As infecções respiratórias, em Ituzaingó em 1995, aumentaram 143% e nos períodos subseqüentes voltaram aos limites de 1994 e, em Posadas tiveram valores ascendentes. No Hospital de Ituzaingó, em 1995, as doenças incrementaram 97,6%, mostraram decréscimo em 1996 e atingiram 127% em 2000; os politraumatismos aumentaram 107% em 1995, declinaram 38% em 1996 nos anos seguintes apresentaram tendência ascendente atingindo 33% em 2000. O impacto das variáveis ambientais foi maior em Ituzaingó do que em Posadas. O aumento das doenças relacionou-se com a temperatura máxima, mas não com a umidade.

Infectious, clinical-surgical and environmental variables were studied in Ituzaingó and Posadas (Argentina) and differences were analyzed from 1994 to 2000, which corresponds to the building of the binational dam Yacyretá (Argentina-Paraguay) and to the resulting reservoir. The chosen infectious variables were diarrhea and respiratory infections and the clinical-surgical variables were cardiovascular diseases and polytraumas. Environmental variables were also investigated. Taking as a baseline the values corresponding to the year 1994, diarrhea in Ituzaingó, increased 6.5% during 1995 and 78.3% in 1996 returned to 1994 values. Posadas showed a rising tendency throughout the period investigated. In Ituzaingó, respiratory infectious rose 143% in 1995, and later returned to 1994 values. In Posadas they increased each year. Cardiovascular diseases reached 97.6% in Ituzaingó during 1995; lowered slightly in 1996 and reached 127% in the year 2000. The impact of the environmental variables was higher in Ituzaingó than Posadas. The negative impact of temperature related with the increased frequency of disease in Ituzaingó is more related to maximum temperature than with changes in humidity.

Toxocarosis is a sanitary problem extended world-wide. Numerous reports dealing with this subject have been published in Argentina, focusing many of them about its impact on human health. However, as toxocarosis is not a disease of compulsory notification and many cases are asymptomatic, actual prevalence rates are unknown and the disease is not recognised as a public health problem. The aim of this work was to determine the extent of the infection among healthy adult population from a subtropical region of Argentina, where high prevalence in children have been previously reported. For this purpose, we selected 355 sera of blood donors (325 men-30 women) aged 18-68 years, from a private-owned blood bank of Resistencia, a city located in Northeast Argentina. All samples tested negative for the infectious diseases routinely investigated for blood donation. Elisa test employing excretion/secretion antigens of larvae L2 Toxocara canis was performed and indeterminate cases were confirmed by Western blot. Out of 355 sera, 138 tested positive (127 men-11 women) which means a global prevalence of 38.9%. There was not significant difference in relation to gender (39.1 % for men - 36.7% for women). The results are consistent with the urban and environmental characteristics of the study area and with socio-cultural habits of its inhabitants, and indicate a strong presence of the ascarid with an important degree of impact on the population

La toxocarosis es un problema sanitario presente en todo el mundo. Sin embargo, por tratarse de una patología que no es de notificación obligatoria y por la existencia de casos asintomáticos, las cifras de prevalencia real en Argentina no son bien conocidas y por ello la toxocariasis tiene un escaso reconocimiento como problema de salud pública. El objetivo del presente trabajo fue determinar la seroprevalencia en adultos sanos de una ciudad subtropical del Nor-Este de Argentina, en la que estudios previos indican que la infección infantil por Toxocara canis es frecuente y que la contaminación de suelos está presente. Se estudiaron 355 sueros de donantes de sangre (325 hombres y 30 mujeres), con edades entre 18 y 68 años, de un Banco de Sangre privado de la ciudad de Resistencia. Se efectuó enzimoinmunoensayo empleando antígenos de excresión/secresión de larvas L2 de T. canis confirmándose mediante Western blot. De los 355 sueros estudiados, 138 fueron positivos (127 hombres y 11 mujeres), lo que significa una prevalencia global de infección del 38,9%; no se encontró diferencia significativa en relación con el género (39,1% en hombres - 36,7% en mujeres). Como el muestreo corres-pondió íntegramente a población adulta, no se consideró de interés discriminar los valores de positividad según franjas etarias. Los resultados encontrados resultan compatibles con las características urbanas y ambientales del área del estudio y con los hábitos socio-culturales de sus habitantes, y señalan una fuerte presencia del ascárido, con un importante grado de exposición por parte de sus pobladores