Proposal of a pathway for enteric virus groups detection as indicators of faecal contamination to enhance the evaluation of microbiological quality in freshwater in Argentina.

An environmental survey was conducted in order to assess the frequency of detection of picobirnavirus (PBV), human adenovirus (HAdV) and infective enterovirus (iEV) as indicators of faecal contamination in freshwater, and to determine their potential as reporters of the presence of other enteric viruses, such as group A rotavirus (RVA). The study was carried out over a three-year period (2013-2015) in the San Roque Dam, Córdoba, Argentina. The overall frequency detection was 62.9% for PBV, 64.2% for HAdV and 70.4% for iEV. No significant differences were observed in the rates of detection for any of these viruses through the years studied, and a seasonal pattern was not present. Whenever there was RVA detection in the samples analyzed, there was also detection of iEV and/or HAdV and/or PBV. At least one of the viral groups analyzed was demonstrated in the 100% of the samples with faecal coliforms values within the guideline limits. In this setting, especially in those samples which reveal faecal indicator bacteria within the guideline limit, we propose to carry out a pathway, involving PBV, HAdV and iEV detection in order to enhance the evaluation of microbiological quality in freshwater in Argentina. The proposed methodological strategy could report faecal contamination in water, mainly of human origin, and the condition of the matrix to maintain viral viability. In addition, the viral groups selected could report the presence of RV.

Rotavirus seasonality in urban sewage from Argentina: effect of meteorological variables on the viral load and the genetic diversity.

In Argentina, the rotavirus disease exhibits seasonal variations, being most prevalent in the fall and winter months. To deepen the understanding of rotavirus seasonality in our community, the influence of meteorological factors on the rotavirus load and the genetic diversity in urban raw sewage from Córdoba city, Argentina were evaluated. Wastewater samples were collected monthly during a three-year study period and viral particles were concentrated by polyethylene glycol precipitation. RT-nested PCR was applied for rotavirus detection, and VP7/VP4 characterization and real-time PCR for rotavirus quantification. Both molecular techniques showed relatively similar sensitivity rates and revealed rotavirus presence in urban wastewater in cold and warm seasons, indicating its circulation in the local community all year round. However, a slight trend for rotavirus circulation was noted by real-time PCR in the fall and winter seasons, showing a significantly higher peak of rotavirus concentration at mean temperatures lower than 18°C and also higher, although not statistically different during drier weather. VP7 and VP4 gene characterization showed that G1 and P[8] genotypes were dominant, and temporal variations in genotype distribution were not observed. Rotavirus spread is complex and our results point out that weather factors alone cannot explain the seasonal quantitative pattern of the rotavirus disease. Therefore, alternative transmission routes, changes in human behavior and susceptibility, and the stability and survivability of the virus might all together contribute to the seasonality of rotavirus. The results obtained here provide evidence regarding the dynamics of rotavirus circulation and maintenance in Argentina.

Tracking novel adenovirus in environmental and human clinical samples: no evidence of endemic human adenovirus type 58 circulation in Córdoba city, Argentina.

In recent years, several types of human adenovirus (HAdV) have arisen from the recombination between two or more previously known HAdV types, but their epidemiology is poorly understood. In this study, we investigated the circulation of HAdV-58, a recently described HAdV isolated from an HIV-positive patient in Córdoba city, Argentina. For this purpose, a 30-month survey was conducted to study the presence of this type of adenovirus in sewage samples collected at the inlet from a wastewater treatment plant in Córdoba city, Argentina. Complementarily, the virus was sought in stools of HIV-positive patients. Although HAdVs were detected in human stool samples and in a high percentage of sewage samples, no evidence of HAdV-58 circulation was detected. We suggest that there is no endemic circulation of HAdV-58 in the geographical local area. The trend is that the number of identified HAdVs increases over time. In this context, understanding the current circulating HAdVs may be biologically relevant.

Correlation between rotavirus A genotypes detected in hospitalized children and sewage samples in 2006, Córdoba, Argentina.

Routine rotavirus A (RV-A) surveillance is based on clinical cases, so only symptomatic infections are reported. The objective of this study was to determine whether the RV-A genotypes and cold seasonal pattern described in patients with diarrhea is reflected by sewage surveillance, which could be representative of the RV-A genotypes circulating in the population. The genotype distribution of RV-A in effluent samples from a local sewage treatment plant was compared to those from local clinical cases. A total of 52 sewage samples and 70 stool specimens from children with acute non-bacterial diarrhea were collected from January to December 2006. The effluent specimens were concentrated and RNA extracts from concentrated sewage and clinical samples were genotyped for the rotavirus VP7 gene. The proportional distribution of the RV-A G-genotypes in sewage and clinical samples during the cold season was similar: G1 accounted for 26.6% of the typed sewage isolates and 28.8% of the clinical infections; G3 type accounted for 21.9% and 25.8%; G2 type 15.6% and 10.6%; G4 type 17.2% and 21.2%; G8 type 1.6% and 0%; and the G9 type 17.2% and 13.6%, respectively. A similar picture of RV-A genotype detection was obtained in sewage samples collected during the cold and warm seasons. The results indicate that there is a correlation between genotypes of RV-A isolates from human diarrheic patients and of those from sewage samples. In addition, sewage monitoring highlighted the uniform all-year RV-A circulation, which was in contrast to the peak incidence of RV-A infection in the community.

Picobirnavirus (PBV) natural hosts in captivity and virus excretion pattern in infected animals.

A picobirnavirus (PBV) analysis was carried out by polyacrylamide gel electrophoresis of 513 stool samples obtained from 150 animal species collected from the Córdoba city zoo. The purpose of the present study was to determine susceptible species for PBV infection, the viral excretion pattern in infected animals, and the potential association with PBV diarrheic illness. Our findings suggest that PBVs are widespread in animals and could have a similar excretion behavior to that previously detected in infected humans. No disease association with PBV infection could be demonstrated. Thus, infected animals could be persistently infected asymptomatic carriers and could serve as reservoirs of infection.

Detection of group a human rotavirus G9 genotype circulating in Córdoba, Argentina, as early as 1980.

The incidence of human rotavirus G types was determined over a 25-year period (1979-2003) by using reverse transcription-PCR (RT-PCR) to examine 519 stool specimens found to be positive for rotavirus by enzyme linked immunosorbent assay (ELISA) or polyacrylamide gel electrophoresis (PAGE). These stool samples were obtained from children under 3 years old who had been treated for acute diarrhea at public hospitals in Córdoba, Argentina. The present study describes the continued circulation of the common human G types G1 (53.8%), G2 (10.2%), G3 (4.4%), and G4 (27%), and also the detection of the unusual types G8 (0.5%) and G9 (4.2%). Genotype G9 was detected during the 1980-1988 and 1997-2003 periods at relatively low rates. Rotavirus G types distribution was independent of age (1-18 months), gender or out-patient or in-patient status. Unexpectedly, 44.6% of mixed infections were detected, involving common and unusual genotypes. Overall, 95.4% of the typed strains belonged to the most prevalent human serotypes (G1-G4) but the detection of G9 infection throughout this study period highlights the importance of this serotype as a human pathogen.

The epidemiology of acute viral gastroenteritis in hospitalized children in Cordoba City, Argentina: an insight of disease burden.

Information concerning the disease burden of viral gastroenteritis has important implications for the use and monitoring the impact of public health policies. The present study, carried out in Córdoba city, Argentina, documents the epidemiology of severe viral diarrhea as well as the burden of viral gastrointestinal disease in the hospital children admission. A total of 133 stools were collected from hospitalized children (Town Childhood Hospital) suffering from acute diarrhea and studied for the presence of Group A rotavirus, astrovirus and adenovirus 40/41 by enzyme-immuno assay, between November 1997 and October 1998. Enteric viruses accounted for 42.1% of the total diarrheal cases analyzed. Group A rotaviruses, astroviruses, adenoviruses 40/41 and mixed infections were found in 35.3, 4.5, 1.5, and 0.8% studied specimens respectively. We estimated that 1 in 27 children in the 0-35 month-old cohort/range would be annually hospitalized for a viral gastroenteritis illness. The major impact on viral diarrhea lies on rotaviral infection, accounting for 84.0% of the viral diarrheal cases analyzed and for approximately one third of severe diarrheas requiring hospital admission in Córdoba City, Argentina.

[Viral agents related to diarrheic syndrome in kidney transplanted patients]. / Agentes virales asociados al sindrome diarreico en pacientes trasplantados renales.

The aim of this study was to report on the occurrence of conventional and emerging viral agents as well as their etiological link with diarrhea in kidney transplanted subjects from Cordoba, Argentina. A total of 42 stool samples were analysed. They were obtained from both ambulatory and hospitalized kidney transplanted patients with and without diarrhea after transplant. All patients were under immunosuppressive treatment with steroids, azatioprine and cyclosporine or tacrolimus. Results revealed the presence of group A rotavirus and picobimavirus in three patients suffering from severe diarrhea (33.33%). No enteric bacterial agent was isolated from these patients. The presence of viral agents was related to high levels of cyclosporine in blood (> 290 ng/ml) or prolonged immunosuppressive treatment. On the other hand, no virus was detected in any of the samples collected from asymptomatic individuals (p < 0.05). These findings suggest that viruses are implicated in the etiology of diarrheal disease in these patients.

[Resurgence of measles in the province of Cordoba, Argentina, in 2000]. / Resurgimiento de sarampión en ia provincia de Córdoba, Argentina, en 2000.

Since 1993, ministers of health of countries of America established as a goal the eradication of measles by the year 2000. As a consequence of measles eradication vaccination strategy there has been a reduction in the incidence of reported cases. Despite that, measles has continued occurring in epidemic outbreaks in many Argentinian provinces. This paper describes and analyzes the outbreak which occurred at Córdoba province, in 2000. Out of 46 serum samples analyzed from suspected cases, 6 (13.3%) were confirmed as measles by indirect immunofluorescence and enzyme immunoassays. All of them were detected in Cordoba city among both without vaccination data and unvaccinated individuals. The epidemiological links among the measles cases could be established although the geographic source of measles importation as well as the primary infection source remain unknown. The highest measles incidence was observed in the group > or = 20 year old (50%), followed by the pre-school age group (< or = 4 year old, 33.3%). The active vaccination data directed against the suspected case contacts along with a high measles population immunity probably contributed to restrict the 2000 outbreak.

Agentes virales asociados al sindrome diarreico en pacientes trasplantados renales. / [Viral agents related to diarrheic syndrome in kidney transplanted patients]

The aim of this study was to report on the occurrence of conventional and emerging viral agents as well as their etiological link with diarrhea in kidney transplanted subjects from Cordoba, Argentina. A total of 42 stool samples were analysed. They were obtained from both ambulatory and hospitalized kidney transplanted patients with and without diarrhea after transplant. All patients were under immunosuppressive treatment with steroids, azatioprine and cyclosporine or tacrolimus. Results revealed the presence of group A rotavirus and picobimavirus in three patients suffering from severe diarrhea (33.33

). No enteric bacterial agent was isolated from these patients. The presence of viral agents was related to high levels of cyclosporine in blood (> 290 ng/ml) or prolonged immunosuppressive treatment. On the other hand, no virus was detected in any of the samples collected from asymptomatic individuals (p < 0.05). These findings suggest that viruses are implicated in the etiology of diarrheal disease in these patients.

Resurgimiento de sarampión en ia provincia de Córdoba, Argentina, en 2000. / [Resurgence of measles in the province of Cordoba, Argentina, in 2000]

Since 1993, ministers of health of countries of America established as a goal the eradication of measles by the year 2000. As a consequence of measles eradication vaccination strategy there has been a reduction in the incidence of reported cases. Despite that, measles has continued occurring in epidemic outbreaks in many Argentinian provinces. This paper describes and analyzes the outbreak which occurred at Córdoba province, in 2000. Out of 46 serum samples analyzed from suspected cases, 6 (13.3

) were confirmed as measles by indirect immunofluorescence and enzyme immunoassays. All of them were detected in Cordoba city among both without vaccination data and unvaccinated individuals. The epidemiological links among the measles cases could be established although the geographic source of measles importation as well as the primary infection source remain unknown. The highest measles incidence was observed in the group > or = 20 year old (50

), followed by the pre-school age group (< or = 4 year old, 33.3

). The active vaccination data directed against the suspected case contacts along with a high measles population immunity probably contributed to restrict the 2000 outbreak.

Resurgimiento de sarampión en ia provincia de Córdoba, Argentina, en 2000 / [Resurgence of measles in the province of Cordoba, Argentina, in 2000]

Since 1993, ministers of health of countries of America established as a goal the eradication of measles by the year 2000. As a consequence of measles eradication vaccination strategy there has been a reduction in the incidence of reported cases. Despite that, measles has continued occurring in epidemic outbreaks in many Argentinian provinces. This paper describes and analyzes the outbreak which occurred at Córdoba province, in 2000. Out of 46 serum samples analyzed from suspected cases, 6 (13.3

) were confirmed as measles by indirect immunofluorescence and enzyme immunoassays. All of them were detected in Cordoba city among both without vaccination data and unvaccinated individuals. The epidemiological links among the measles cases could be established although the geographic source of measles importation as well as the primary infection source remain unknown. The highest measles incidence was observed in the group > or = 20 year old (50

), followed by the pre-school age group (< or = 4 year old, 33.3

). The active vaccination data directed against the suspected case contacts along with a high measles population immunity probably contributed to restrict the 2000 outbreak.

Mating system parameters in species of genus Prosopis (Leguminosae).

The section Algarobia of genus Prosopis involves important natural resources in arid and semiarid regions of the world. Their rationale use requires a better knowledge of their biology, genetics and mating system. There are contradictory information about their mating system. Some authors claim they are protogynous and obligate outcrosser. However, some evidence have been shown indicating that they might not be protogynous and that they might be somewhat self-fertile. The current paper analyses genetic structure and mating system parameters in populations of seven species of this section from South and North America based on isozyme data. In all species a significant homozygote excess was found in the offspring population but not in mother plant genotypes. Multilocus and mean single locus outcrossing rates (tm, ts) indicated that about 15% selfing can occur in the studied populations. The heterogeneity between pollen and ovule allele frequencies was low suggesting population structuration, in agreement with the estimates of correlation of tm within progeny (rt) and correlation of outcrossed paternity (rp). The difference of FIS estimates between offspring and mother plants suggest some selection favouring heterozygotes between seedling and adult stages.

Unexpected low genetic differentiation among allopatric species of section Algarobia of Prosopis (leguminosae).

The Chaqueña Biogeographic Province, in South America, is the main diversity centre of Prosopis. A group of sympatric species of Section Algarobia in this region constitutes a syngameon, characterised by frequent hybridization and introgression. These processes have been postulated as responsible for the low genetic differentiation observed among species within this group. In this study genetic variability and differentiation among geographically isolated species of the same section was analysed through isoenzyme electrophoresis. Variability parameters and fixation indices were estimated to determine the genetic structure of populations. Two Argentinean, P. ruscifolia ('vinal') and P. flexuosa ('algarrobo amarillo'), and one North American species, P. glandulosa (honey mesquite) were studied. All of them showed, similarly to other species of the same section, high genetic variability and exhibit homozygote excess, probably due to population substructure and low rates of selfing. In contrast to our hypothesis, genetic similarity among species is not related to geographic distance. Genetic distances between P. glandulosa and South American species are similar to those observed among species of this subcontinent. The results obtained suggest that the high genetic similarity among the species of the section Algarobia studied is not due to hybridization.