Inventories and concentration profiles of 137Cs in undisturbed soils in the northeast of Buenos Aires Province, Argentina

Inventories and vertical distribution of (137)Cs were determined in La Plata region undisturbed soils, Argentina. A mean inventory value of 891 ± 220 Bq/m(2) was established, which is compatible with the values expected from atmospheric weapon tests fallout. The study was complemented with pH, organic carbon fraction, texture and mineralogical soil analyses. Putting together Southern Hemisphere (137)Cs inventory data, it is possible to correlate these data with the mean annual precipitations. The large differences in (137)Cs concentration profiles were attributed to soil properties, especially the clay content and the pH values. A convection-dispersion model with irreversible retention was used to fit the activity concentration profiles. The obtained effective diffusion coefficient and effective convection velocity parameters values were in the range from 0.2 cm(2)/y to 0.4 cm(2)/y and from 0.23 cm/y to 0.43 cm/y, respectively. These data are in agreement with values reported in literature. In general, with the growth of clay content in the soil, there was an increase in the transfer rate from free to bound state. Finally, the highest transfer rate from free to bound state was obtained for soil pH value equal to 8.

Spatial analysis of the tuberculosis treatment dropout, Buenos Aires, Argentina

OBJECTIVE Identify spatial distribution patterns of the proportion of nonadherence to tuberculosis treatment and its associated factors.METHODS We conducted an ecological study based on secondary and primary data from municipalities of the metropolitan area of Buenos Aires, Argentina. An exploratory analysis of the characteristics of the area and the distributions of the cases included in the sample (proportion of nonadherence) was also carried out along with a multifactor analysis by linear regression. The variables related to the characteristics of the population, residences and families were analyzed.RESULTS Areas with higher proportion of the population without social security benefits (p = 0.007) and of households with unsatisfied basic needs had a higher risk of nonadherence (p = 0.032). In addition, the proportion of nonadherence was higher in areas with the highest proportion of households with no public transportation within 300 meters (p = 0.070).CONCLUSIONS We found a risk area for the nonadherence to treatment characterized by a population living in poverty, with precarious jobs and difficult access to public transportation.

Epidemiological role of humans, dogs and cats in the transmission of Trypanosoma cruzi in a central area of Argentina

Trypanosoma cruzi prevalence rates of human, dog and cat populations from 47 households of 3 rural localities of the phytogeographical Chaqueña area of Argentina were determined both by serological and xenodiagnostic procedures. Human prevalence rates were uniform and ranged from 49.6 to 58.7%. Overall prevalence rate in dogs (75.0%) was significantly higher than in humans (51.0%). The overall proportion of parasitemic individuals assessed by xenodiagnosis was significantly higher in either dog (64.2%) or cat (63.6%) populations than among humans (12.5%). Although both the average number of resident as well as infected individuals per household was higher for people than for dogs (6.5 vs. 3.3, and 3.4 vs. 2.4, respectively), the reverse was recorded when parasitemic individuals were considered (1.0 vs. 2.1). Results are discussed in relation to dog between dogs and people, and dogs and bugs. In the light of present data, dogs must be considered as the major donors of parasites to vector bugs and thus, principal contributors to transmission in this region of Argentina.

Dinâmica da transmissão do Trypanosoma cruzi numa área rural da Argentina. 1 — Os cães como reservatórios: um perfil epidemiológico

Levou-se a cabo numa área rural da Argentina uma pesquisa epidemiológica dos cães associados ao domicílio, com vistas a caracterizar sua dinâmica populacional as infecções naturais pelo T. cruzi empregando técnicas sorológicas e xenodiagnóstico. A estrutura de idades da população mostrou que os indivíduos participam no ciclo doméstico da transmissão uma média de 4 anos; a proporção de sexos por grupos etários sugeriu uma mortalidade diferencial para as fêmeas, especialmente nas cadelas. Achou-se uma prevalência geral de infecção de 84%, crescendo desde 69% em cães 1 ano até 100% nos maiores de 3 anos, indicando alta eficiência de transmissão do T. cruzi aos cães na qual a infecção congênita ou pelo leite pode estar implicada. A sorologia mostrou concordância de 98% com os xenodiagnósticos positivos. A parasitemia não diminuiu com a idade em cães seropositives < 10 anos. Ao menos os 50% dos reservatórios achavam-se estreitamente associados as moradas da gente. A estreita associação trdfica entre os cães e T. infestans; a persistência da parasitemia nos reservatórios; a alta eficiência de transmissão do parasito a este; padrões de exposição do hospedeiro adequados; e altas taxas de recrutamento de indivíduos suscetíveis qualificam o cão como hospedeiro amplificador da doença de Chagas nas áreas rurais do centro e norte da Argentina. Os programas rurais de atenção primária da saúde vieram estimular a introdução de medidas dirigidas a diminuir o contacto cão-barbeiro para ser executadas em conexão à luta química contra os vetores na Argentina.

Dynamics of transmission of Trypanosoma cruzi in a rural area of Argentina: III. Persistence of T. cruzi parasitemia among canine reservoirs in a two-year follow-up

A new cross-sectional survey of household- associated mongrel dogs as well as follow-up of previously parasitemic individuals was carried out in 1984 toy means of xenodiagnosis and serologic techniques to get a deeper insight into the relationship of T. cruzi parasitemia and age among canine hosts in a rural area of Argentina. Persistence of detectable parasitemia was age-independent, or at most, loosely related to age, confirming the pattern observed in 1982. Similarly no significant age-decreasing effect was recorded among seropositive dogs in: a) the probability of detecting parasites in a 2-year follow-up; b) their intensity of infectiousness (=infective force) for T. infestans 3rd-4th instar nymphs, as measured by the percentage of infected bugs observed in each dog xenodiagnosis. Moreover, not only was the infective force of seropositive dogs for bugs approximately constant through lifetime, but it was significantly higher than the one recorded for children in the present survey, and for human people by other researchers. Therefore, and since T. infestans field populations show high feeding frequencies on dogs, the latter are expected to make the greatest contribution to the pool of infected vectors in the rural household of Argentina. This characteristic should be sufficient to involve canine reservoirs definitely as a risk factor for human people residing in the same house. The increased severity of parasitemia observed among dogs in this survey may be related to the acute undernutrition characteristic of canine populations of poor rural areas in our country, which is expected to affect the ability of the host to manage the infection.

Epidemiologic study of bronchopulmonary mycosis in the province of cordoba, argentina

An epidemiological study for histoplasmosis coccidioidomycosis and cryptococcosis made in five areas of the province of Córdoba is presented. The data obtained showed a global positivity of 41.1% for histoplasmin 26.7% for coccidioidin and 14.1% for cryptococcin. In some areas, the Rio III basin and Traslasierra, the histoplasmosis infection indexes were much higher, 53,3% and 73.1% respectively. The index of positive skin tests with Cryptococcus antigen in Traslasierra was also very high: 31.9%.

Evaluación del método de ELISA para detección de antígenos y complejos inmunes circulantes de Trypanosoma cruzi a través de un estudio de campo en una zona endémica de Argentina

En una zona endémica de la República Argentina se llevó a cabo un ensayo de campo de la prueba inmunoenzimática ELISA para la detección de antígenos (cAg) y complejos inmunes circulantes (CIC) en sueros de pacientes chagásicos crónicos. Del total de 215 muestras de sangre analizadas, 51 fueron positivas para ELISA-CIC y 45 lo fueron para ELISA-cAg. De los 74 (34,32% de la población) sujetos considerados infectados con dos reacciones serológicas positivas, 49 (66,21%) presentaron CIC en suero, en tanto que en 43 (58,11%) de ellos se encontró cAg por ELISA. Solo en 2 casos serológicamente no reactivos, se detectaron inespecíficamente CIC y cAg. Dentro del grupo considerado no infectado, se observó reactividad inespecífica de bajo título por una de las pruebas serológicas en 16 (11,35%) de 141 individuos. Estos sueros arrojaron resultados consistentemente negativos por ELISA-CIC y cAg demostrando la utilidad de estos métodos de diagnóstico antigénico en casos de serología conflictiva. La determinación de fracciones antigénicas circulantes por ELISA en individuos chagásicos crónicos permite evidenciar la infección por T. cruzi de manera más directa que midiendo la respuesta inmune humoral en el huésped, presentando además mayor sensibilidad que el diagnóstico parasitológico clásico

Caracteristicas epidemiologicas de 105 casos de criptococosis diagnosticados en la república Argentina entre 1981-1990

Se presentan 105 casos de criptococosis diagnosticados en la República Argentina, entre 1981 y 1990. El número anual de casos fue hasta 1987, de 4 a 8, aumentó desde 1988 por influencia del SIDA y llegó a 35 casos en 1990. La criptococosis no asociada al SIDA se mantuvo entre 3 y 7 casos anuales. Globalmente, el grupo etario más afectado fue el de 20-39 años y la distribución por edad fue diferente en las poblaciones con y sin SIDA. La mediana de la edad de las poblaciones total, asociada al SIDA y a otras causas predisponentes fue de 30, 30 y 45 años, respectivamente. El predominio del sexo masculino fue mucho más evidente entre los pacientes HIV+ que en los que no padecían esta última infección. La causa predisponente fue el SIDA en 57 pacientes, otra en 20 y era desconocida en 28 casos. Estimando indirectamente, el porcentaje de pacientes con SIDA que padecieron criptococosis en este período fue 6,19% (57 casos en 920 HIV+). Cryptococcus neoformans variedad neoformans fue aislado de 101 pacientes y la variedad gattii (serotipo B) de los 4 restantes. Los datos obtenidos son similares a los observados en Europa y Estados Unidos.

Enfermedad de Chagas congenita en la Ciudad de Salta, Argentina

Se estudió la respuesta clínica y serológica a la infección chagásica de 937 embarazadas y sus 929 recién nacidos (RN) vivos, grupo I; 4 RN de origen diverso, grupo II y 35 RN derivados de otros centros, grupo III. Las embarazadas se estudiaron con 3 reacciones serológicas; se definió infección cuando 2 o más reacciones eran positivas. En los RN el diagnóstico se confirmó por observación directa del T. cruzi en una muestra de sangre. Los RN con Chagas congénita (RN-ChC) fueron tratados y seguidos con estudios clínicos y de laboratorio. Se detectaron 149 embarazadas chagásicas (15.9%), de las cuales se diagnosticaron 6 RN-ChC (4%). En el total de 968 RN estudiados se detectaron 12 RN infectados. El micro-hematócrito fue el método parasitológico de lectura rápida más efectivo para el diagnóstico de infección en nuestra serie. El par de reacciones serológicas específicas constituyó un criterio de mayor seguridad para el control y seguimiento de la infección congénita. Las expresiones clínicas más comunes de infección fueron hepatomegalia, esplenomegalia, ictericia, anemia y prematurez, con distintos grados de asociación. Se concluye que dadas las características clínicas de la enfermedad de Chagas congénita en nuestro medio, se impone como estrategia el diagnóstico serológico para la enfermedad de Chagas en todas las embarazadas y el control y seguimiento de sus RN hasta descartar o confirmar infección congénita.

Reporte de un caso de dracunculosis en un canino en la Provincia de Formosa - Argentina

Se comunica el hallazgo de Dracunculus sp. en un canino proveniente de la localidad de Fontana, Departamento Patiño, Provincia de Formosa, Argentina. El hallazgo constituye el cuarto caso de Dracunculosis registrado en animales en una misma área geográfica de Formosa.

Histoplasmosis in the Muñiz Hospital of Buenos Aires

Some epidemiological and immunological characteristics and the methodology of diagnosis of 44 cases of histoplasmosis (HP); 36 (27 males and 9 women) associated with AIDS (HP+AIDS) and 8 (7 males and 1 female) with other predisposing factors (HP+non AIDS), diagnosed in the Muñiz Hospital (MH) during 1994, were retrospectively studied. The median age (MA) of HP+AIDS patients was 28 years; 25.5 (22-40) in the women and 28.5 (20-42) in the men and 50 (22-58) years in the HP+non AIDS patients. The more frequent risk factors for HIV infection were intravenous drug addiction (55%) and homo/bisexuality (19%). The MA of these groups were 28 (20-39) and 41 (26-42) years, respectively. Tobaccoism was a predisposing factor in 83% of HP+non AIDS patients. The muco-cutaneous lesions scraping and blood-cultures established the initial diagnosis in 53% and 36% of HP+AIDS patients, respectively and the muco-cutaneous lesions biopsies in 75% of HP+non AIDS cases. At time of diagnosis, all HP+AIDS patients had <200 while HP+non AIDS patients had > 200 CD4 + lymphocytes/µl. Seventy two per cent of HP+AIDS patients were born in Buenos Aires (Bs As) city and 62% of HP+non AIDS patients were born in provinces of Argentina other than Bs As. At moment of diagnosis, 87.5% of HP+AIDS and 62.5% of HP+non AIDS patients lived in Bs As city and Bs As outskirts.

Species and serovars of enteropathogenic agents associated with acute diarrheal disease in Rosario, Argentina

We report the most frequent species and serovars of enteropathogenic organisms in Rosario from 1985 to 1993. Enteropathogenic Escherichia coli was the most prevalent agent affecting 144/570 (25.2%) children; 0111 represented 41.8%, 055: 13.6%, 0119: 12.7%. Among enterotoxigenic E. coli (ETEC) the most frequent were ETEC-ST 0128:H21 and 0153:H45. Shigella spp were isolated in 8.8%; S.flexneri: 7%, principally type 2 (59.5%); S. sonnei: 1.6%, and S. dysenteriae type 2: 0.2%. Campylobacter spp were found in 6.1% of patients; C.jejuni: 4.6%; C. coli: 1.4% and C. lari: 0.2%; except groups 0 13,50 and 0 4 (2 cases each), no predominant serogroups were found. Salmonella was isolated in 2.8% of cases, being the predominant serovar S. typhimurium until 1986, but a dramatically increase of cases due to S. enteritidis was observed since 1987. There was 1.9% of Aeromonas spp and 2 cases due to Vibrio cholerae non 0-1. No Yersinia was found. In patients with gastroenteritis due to Shigella, Campylobacter, Salmonella, or EPEC as the unique pathogen, leukocytes were observed in the faeces in 70%, 50%, 20%, and 10% of cases respectively.

Norfloxacin monodose use in patients with cholera in Salta, Argentina

The use ofmonodose (800 mg) per os of Norfloxacin was evaluated in 32 patients with cholera at Salvador Mazza's Hospital, Salta, Argentina. It was considered the celerity in negativization of stool culture (100% of cases: 12 hours post administration), its efficiency along time (24/24 controlled patients were negative at 10th day) and MIC of isolated strains (100% of strains were sensitive: range 0.008 to 0.016 mug/ml). It was included oral administration of sorbitol 70% in peanut oil in order to study patients at 10th day's control. This method could be an alternative one in the study of asymptomatic carrier. Norfloxacin monodose shows good performance in early negativization of stool culture and it was also effective along the whole observation period, suggesting it could prevent carriage.