Influencing factors in the occurrence of injured coliforms in the drinking water distribution system in the city of La Plata, Argentina.

The objective of this study was to evaluate the influencing factors in the occurrence of coliforms in the drinking water in La Plata (Argentina) from June 1999 to June 2001. A total of 180 samples were collected from Rio de La Plata (102 samples) and Puelche Aquifer (78 samples); 45 samples were collected for each of the four seasons. The membrane filter procedure was used for isolating bacteria, and each sample was tested for chlorine and pH. The highest percentage of samples positive for coliforms in the two tested media was obtained in summer while the highest percentage of negative samples was obtained in winter. No Escherichia coli was isolated. The percentage of injured coliforms fluctuated between 70 and 100%. The most frequently isolated bacteria was Enterobacter cloacae in summer, Enterobacter agglomerans in autumn and Klebsiella oxytoca in winter and spring. Significant correlations were observed between coliforms and the distance from the initial treatment point, and with the level of free chlorine. We conclude that drinking water contamination in La Plata occurs in the distribution system due to increased temperatures and reduced disinfectant levels, which result in bacterial regrowth.

Epidemiological survey of Giardia spp. and Blastocystis hominis in an Argentinian rural community.

The aim of this study was to relate personal data, socio-cultural and environmental characteristics, and the presence of symptoms/signs with the frequencies of Giardia spp. and Blastocystis hominis among a rural population in Buenos Aires Province, Argentina. Of the surveyed population (350), 3.7% were infected with only Giardia spp. or 22.9% with B. hominis, and 2.3% were infected with both protozoa. The frequency of infection according to sex; 6.1% of males were infected and 1.6% of females by Giardia spp., 26.7% and 19.5% by B. hominis, and 2.4% and 2.2% by both parasites, respectively. Giardia spp. was detected in only three adults (over 14 years), but B. hominis was more frequent in adults than in children. The prevalences of these protozoa in this community are lower than those reported by other Argentinean studies, which is probably associated with the low density of the studied population (5.95 inhab/km2). Statistical analysis revealed that a male sex, flooding of the home, the use of a latrine, and an abdominal pain were correlated with the presence of these parasites, which indicate the importance of these factors in rural communities.

[Estacionalidad de parásitos intestinales en suelos periurbanos de la ciudad de Neuquén, Patagonia, Argentina]. / Estacionalidad de parásitos intestinales en suelos periurbanos de la ciudad de Neuquén, Patagonia, Argentina.

OBJECTIVE: To determine the presence of eggs, larva, cysts and oocysts of intestinal parasites in the soil of a suburb of Neuquén city during 1 year in order to evaluate their seasonal fluctuations in relation to climatic data and soil characteristics in the studied area. METHODS: A total of 107 soil samples were processed for parasite isolation by sedimentation and flotation methods during the four seasons of the year. Meteorological data were registered and physical, chemical and structural characteristics of the soil were analysed. RESULTS: About 28.9% of the soil samples were positive for at least one parasite form. Six protozoa species (cysts of Entamoeba sp., Enteromonas sp., Endolimax sp., Giardia sp., Iodamoeba sp. and coccidia oocysts) were recovered, but neither larvae nor eggs of human or animal helminths parasites were detected. The percentage of contaminated soil samples and the diversity of species showed a marked decrease in the warm and dry months of the summer. The soil was sandy, without vegetable cover, well drained, and with scarce organic matter content. CONCLUSION: The frequencies of parasite recovery and the number of species show seasonal fluctuations related to the rainfall. The importance of soil as a risk factor for the transmission of intestinal parasites in the studied area is conditioned by its structural characteristics, which prevent retaining the humidity, and by climatic variables. The interrelation of both factors determines unfavourable conditions that could explain the low level of contamination observed in soil as well as the absence of eggs and helminth larvae.

An eco-epidemiological study of contamination of soil with infective forms of intestinal parasites.

The objectives of the present work were to screen topsoil samples collected from public squares in two cities within the Argentine Patagonia for the presence of infective forms of intestinal parasites and to examine the possible relationship between positive findings and the environmental, socioeconomic, and cultural conditions of that region. For this purpose we studied 13 public squares, their 13 custodians, and 44 family groups within their respective surrounding areas. Of the 226 topsoil samples analyzed, 44.3% proved positive for infective forms of intestinal parasites, with 17.3% of these containing more than one species. The frequency of appearance of positive samples was dependent on the season of the year (p < 0.001), while presence of the parasites was related to the soil pH (p < 0.05) but independent of the soil relative humidity (p > 0.05). Some of the organisms detected are associated with zoonoses. We observed the presence of Capillaria spp. and Spirocerca spp. under cool desert climatic conditions. Within the group of custodians we detected hematologic alterations one positive serology for toxoplasmosis and documented behavior conducive to risk of infection with the parasites found in those squares. Within the family group an acquaintance with parasitic zoonoses and their prevention was an inconsistent finding, with toxocarosis and toxoplasmosis being the diseases associated with the greatest degree of ignorance. Furthermore, we consider the failure to de-parasitize pets and the practice of feeding them with raw meat, as typically found in our family survey, to be factors contributing to a greater likelihood of public square contamination. From the results obtained here, we propose a spatial organization approach for the purpose of detecting zones at risk of contracting zoonotic parasitoses within urban environments.

Presencia de parásitos intestinales en paseos públicos urbanos en La Plata Argentina / Presence of intestinal parasities in public places from urban areas from La Plata Argentina

Con el objeto de recuperar e identificar contaminantes parasitarios se estudiaron muestras de suelo de todos los paseos públicos del área urbana de La Plata, Argentina. Se analizaron 23 paseos durante los meses de marzo y abril de 2000 y al mismo tiempo se evaluó el pH y la humedad de cada muestra. Se observaron 552 elementos parasitarios, 98 correspondieron a quistes de protozoos, 106 a huevos de helmintos y 348 a larvas de nematodos. Se demostró que los suelos de los paseos analizados estaban contaminados con parásitos de origen humano y animal

Frecuencia de hallazgo de huevos de helmintos en materia fecal canina recolectada en lugares públicos de la ciudad de La Plata, Argentina / Frequency of helminth eggs finding in canine stool samples collected in public places from La Plata city, Argentina

Frequency of finding helminths eggs in canine stool samples collected in public places from La Plata city, Argentina

Células RK13: influencia de la concentración de suero fetal bovino en el tiempo de duplicación / RK13 cells: influence of fetal bovine serum concentration on doubling time

El objetivo de este trabajo fue analizar el Tiempo de Duplicación (TD) y la Fase de Latencia (Lag) de una línea celular con 2 concentraciones de Suero Fetal Bovino (SFB) y 2 inóculos celulares iniciales. Se realizaron 4 curvas de crecimiento de células adherentes RK13 (rabbit kidney) en Minimal Essential Medium (MEM) suplementado con glutamina, penicilina, estreptomicina y SFB no inactivado al 5 por ciento y 7 por ciento. Los inóculos iniciales fueron de 3 x 10 y 6,8 x 10 células viables/mL. El TD fue de 24 h para el cultivo con 7 por ciento de SFB con ambos inóculos y de 16,36 h para el cultivo con 5 por ciento de SFB con el mayor inóculo. El cultivo con 5 por ciento de SFB y 3 x 10 viables/mL presentó escaso desarrollo. Se observaron diferencias significativas en el TD (p=0,0055) cuando se utilizó el inóculo de 6,8 x 10 viables/mL y se varió el SFB (5 por ciento y 7 por ciento). La diferencia no fue significativa al utilizar los inóculos de 3 x 10 y 6,8 x 10 viables/mL manteniendo constante la concentración de suero fetal (7 por ciento)

Prevalencia de giardia lamblia, su detección en aguas y su relación con factores ambientales en Gualeguaychú, Argentina / Prevalence of giardia lamblia, isolation in water and the relationship with envionmental factors in Gualeguaychú, Argentina

The increasing environmental contamination affects the water quality, and is going to raise the waterborne intestinal infections such as giardiosis. This study determined the prevalence of g. lamblia infection in 1.201 persons of Gualeguaychú, Argentina. It was observed the relationship between giardiosis and the detection of g. lamblia in the recreational and drinking water and with homes environmental factors. General rate of infection was 19,7 percent. The group 2-11 years old was the highest (28,0 percent). No cysts of g. lamblia were found in drinking water, but recreational water was contaminated. Higher rate of infected persons lived in suburban dwellings with dirt floor, latrine, ground-water and close contact with dogs. It is concluded that to drink water is no risk-infection at present, but it will be if this community continues discharging excretsa into the river because this is the source of water for the habitants

Estudio de las infecciones por enteroparásitos en una comunidad periurbana de la provincia de Buenos Aires en Argentina / Study of enteroparasite infections in a periurban community at Buenos Aires, Argentina

A survey for intestinal parasites was performed on 38 individuals within the urban area of La Plata city (province of Buenos Aires, Argentina). This community is composed of brick-factory workers who also live in the factory premises. An analysis for intestinal parasites was done on fecal samples collected serially and by means of anal swabs and there after preserved in formol solution. At the same time, the ocurrence of the parasites under study as well as that of commensal organisms was investigated in water and soil samples within the factory environs. Information was also obtained from the members of this community as their age, sex, birthplace and recent travels, either abroad or to the interior of Argentina. The prevalence of the pathogens and commensal parasites was 89,5 percent. The frecuency of protozoans and helminths was: G. lamblia 26,3 percent; B. hominis 65,8 percent; A. lumbricoides 7,9 percent; H. nana 2,6 percent; uncinaria sp. 7,9 percent; S. stercoralis 2,6 percent and E. vermicularis 42,1 percent. None of these parasite or commensal organisms were present in the water samples investigated. Four out of 20 soil samples analyzed contained parasitic elements T. canis eggs (one); G. liamblia cysts (two) and A. lumbricoides eggs (one). These results indicated that most important factors causing such a high prevalence of coproparasites were the poor conditions of personal and community hygiene in combination with the frequent travels to the north and the northeast of the country, regions which are endemic parasitic areas. The implementation of programs on health education and communal sanitation would contribute in the control of this health problem