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.

Tracking enteric viruses in green vegetables from central Argentina: potential association with viral contamination of irrigation waters.

Consumption of green vegetable products is commonly viewed as a potential risk factor for infection with enteric viruses. The link between vegetable crops and fecally contaminated irrigation water establishes an environmental scenario that can result in a risk to human health. The aim of this work was to analyze the enteric viral quality in leafy green vegetables from Córdoba (Argentina) and its potential association with viral contamination of irrigation waters. During July-December 2012, vegetables were collected from peri-urban green farms (n = 19) and its corresponding urban river irrigation waters (n = 12). Also, urban sewage samples (n = 6) were collected to analyze the viral variants circulating in the community. Viruses were eluted and concentrated by polyethylene glycol precipitation and then were subject to Reverse Transcription Polymerase Chain Reaction to assess the genome presence of norovirus, rotavirus and human astrovirus. The concentrates were also inoculated in HEp-2 (Human Epidermoid carcinoma strain #2) cells to monitor the occurrence of infective enterovirus. The frequency of detection of the viral groups in sewage, irrigation water and crops was: norovirus 100%, 67% and 58%, rotavirus 100%, 75% and 5%, astrovirus 83%, 75% and 32% and infective enterovirus 50%, 33% and 79%, respectively. A similar profile in sewage, irrigation water and green vegetables was observed for norovirus genogroups (I and II) distribution as well as for rotavirus and astrovirus G-types. These results provide the first data for Argentina pointing out that green leafy vegetables are contaminated with a broad range of enteric viruses and that the irrigation water would be a source of contamination. The presence of viral genomes and infective particles in food that in general suffer minimal treatment before consumption underlines that green crops can act as potential sources of enteric virus transmission. Public intervention in the use of the river waters as irrigation source is needed.

Enteric Viruses in Surface Waters from Argentina: Molecular and Viable-Virus Detection.

Water resources contaminated with wastewater are an important source for the dissemination of enteric viruses with an impact on the health of the population. The aim of the study was to assess the viral contamination of freshwater from a dam in Argentina by using infectious enterovirus detection, viral RNA amplification, and a genetic characterization of five enteric viruses associated with diarrhea and hepatitis. Enterovirus infectivity (iEV) was evaluated by cell culture and direct immunofluorescence. The detection of the viral genome of rotavirus (RV), human astrovirus (HAstV), norovirus (NoV), hepatitis A virus (HAV), and hepatitis E virus (HEV) was performed by reverse transcriptase PCR (RT-PCR). A total of 48 water samples from 4 monitoring points on the body of the dam from January to December 2012 and 66 water samples from 3 tourist beaches on the edge of the dam from October 2013 to October 2015 were collected monthly. During the first period, the overall viral frequency detection was 52.1% for group A RV, 50% for HAstV, 60.4% for NoV, 22.9% for HAV, 2.1% for HEV, and 64.6% for iEV. The overall frequency detection for the second sampling was 18.2% for RV and HAstV, 31.8% for NoV, 7.57% for HEV, and 66.7% for iEV. There was no detection of HAV during this period. The genotypes and genogroups detected through the study correlated with the most common genomic variants associated with human gastrointestinal and hepatitis illnesses. The results obtained could alert the health systems and environmental sanitation to make decisions for viral control and prevention in our environment.IMPORTANCE The study shows the impact of anthropic contamination of one of the most important tourist water resources in Argentina. This course of recreational water would be a favorable scenario for infection, as well as a reservoir for the enteric viruses, creating a risk for the population exposed to these waters. The results obtained could alert the health systems and environmental sanitation to make decisions for the control and prevention of viral diseases in this environment.

Quantification of human infection risk caused by rotavirus in surface waters from Córdoba, Argentina.

Fecal contamination of water is a worrying problem because it is associated with the transmission of enteric pathogenic microorganisms that can cause many infectious diseases. In this study, an environmental survey was conducted to assess the level of viral contamination by viable enterovirus and rotavirus genome in two recreational rivers (Suquía and Xanaes) of Córdoba, Argentina. Quantitative microbial risk assessment (QMRA) was calculated to estimate the risk of rotavirus infection. Water sampling was carried out during a one-year period, the presence of total and fecal coliforms was determined and water samples were then concentrated for viral determination. Cell culture and indirect immunofluorescence were applied for enterovirus detection and RT-qPCR for rotavirus quantification. Coliform bacteria levels found in Suquía River often far exceeded the guideline limits for recreational waters. The Xanaes exhibited a lower level of bacterial contamination, frequently within the guideline limits. Enterovirus and rotavirus were frequently detected in the monitoring rivers (percentage of positive samples in Suquía: 78.6% enterovirus, 100% rotavirus; in Xanaes: 87.5% enterovirus, 18.7% rotavirus). Rotavirus was detected at a media concentration of 5.7×10(5) genome copies/L (gc/L) in the Suquía and 8.5×10(0)gc/L in the Xanaes. QMRA revealed high risk of rotavirus infection in the Suquía, at sampling points with acceptable and non-acceptable bacteria numbers. The Xanaes showed significantly lower health risk of rotavirus infection but it proved to be a public health hazard. The viral occurrence was not readily explained by the levels of bacteria indicators, thus viral monitoring should be included to determine microbiological water quality. These findings provide the first data of QMRA for recreational waters in Argentina and reveal the need for public awareness of the health implications of the use of the river waters.

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.

Persistence of measles neutralizing antibody related to vaccine and natural infection acquired before HIV infection.

Little is known about long-lasting measles protective immunity when exposure to wild-type or vaccine measles virus precedes HIV infection. The results obtained suggest that measles immunity wanes and the lowest measles geometric mean titres (GMT) were significantly associated with measles vaccine-induced immunity in individuals that later developed HIV infection (86% prevalence, GMT 164 mIU/ml) compared to naturally induced immunity in HIV-infected adults (100% prevalence, GMT 340 mIU/ml, P = 0·0082) or non-HIV infected adults (100%, GMT 724 mIU/ml, P = 0·0001), and vaccine-induced immunity in non-HIV-infected adults (100%, GMT 347 mIU/ml, P = 0·017). The study was conducted in an area without wild-type virus circulation since 2000. The absence of virus circulating may alter the paradigm of lifelong immunity to measles virus after vaccination. As the proportion of HIV-infected individuals possessing only vaccine-induced immunity continues to grow, checking the status of measles immunity in this group is strongly recommended.

Effect on seroprevalence of anti-poliovirus antibodies and on vaccination coverage of the implementation of a DTwP-IPV-Hib vaccination programme in a South American city.

Vaccination coverage and seroprevalence of poliovirus antibodies were assessed in Argentinean children (aged 8-12 and 19-21 months) living in Cordoba City pre-/post-implementation of a DTwP-IPV-Hib vaccination programme, and compared to those of controls from neighbouring populations receiving a full oral poliovirus vaccine schedule. Vaccination coverage was higher in control areas pre-intervention; this increased post-intervention in Cordoba (>90%) but not in control areas. Poliovirus types 1 and 2 seroprotection rates were >97% in all groups pre-/post-intervention. Type 3 seroprotection rates were generally lower, but increased post-intervention in Cordoba becoming significantly higher than control rates. Anti-type 1 and 3 antibody titres increased twofold and sevenfold, respectively, post-intervention, whereas anti-type 2 antibody titres decreased ~40% in the 8-12 months group. All titres increased in the 19-21 months post-intervention group. The introduction of a three-dose primary DTwP-IPV-Hib schedule maintained protection against poliovirus types 1 and 2, and increased protection against type 3, while vaccine coverage in the study area increased.

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.

Rotavirus VP7-gene selection during coinfections in CaCo-2 cells.

A previous rotavirus epidemiological survey in Córdoba, Argentina, revealed an unusually high frequency of mixed G-type infections (41.5%). The genotype distribution of those mixed infections showed that the most prevalent G-type combinations were G1+G4 (65.0%), G1+G2 (12.5%), G2+G4 (3.1%) and G1+G9 (2.5%). In the present study we analyzed the competitive growth in CaCo-2 cell cultures of strains from the most frequent rotavirus G-type coinfections in order to explain some aspect of the dynamic of G-type replacement along the time. Our results indicated that G1-type was preferentially selected compared with G2 and G9-genotypes, meanwhile, G1-G4 coinfections showed an efficient co-amplification of both types. Interestingly, this mirrored the high detection rates of both genotypes as single and mixed infections (G1+G4, 65.0%) in our region. On the other hand, G2-type revealed a better amplification rate with respect to G4-type. Fluctuant rates in the prevalence of different genotypes usually observed along the time could, in part, be explained by successive replacement of strains with different growth characteristics. We hypothesized that one aspect of these different fitnesses can be measured as differential growth in culture of the strains contained in the sample of a mixed infection. Our findings here provide the first data supporting the validity of the competitive replication in vitro to better understand rotavirus G-type circulation patterns.

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.

Uso de un compuesto a base de gel de hidróxido de bismuto coloidal con pectina en la diarrea aguda / Use of a gel compound with colloidal bismuth hydroxide and pectin in acute diarrhea

El estudio tuvo un año de duración. Se evaluó la eficacia terapéutica de un compuesto a base de un gel de hidróxido de bismuto coloidal al 3% con pectina (Crema de Bismuto Chobet) en la diarrea aguda del lactante. El estudio se realizó en 48 lactantes afectados de diarrea aguda de menos de 24 horas de evolución. La investigación utilizó metodología a doble ciego, fue randomizada y controlada con placebo. Ambos grupos de tratamiento fueron similares en cuanto a características demográficas y etiopatogénicas. El porcentaje de niños mejorados clínicamente a las 24 horas de tratamiento y la reducción del número de deposiciones fue del 45,8% en el grupo placebo y del 83,4% en el grupo tratado con la Crema de Bismuto (p

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.

Loss of maternally derived human herpesvirus-6 immunity and natural infection in Argentinian infants.

BACKGROUND: Human herpesvirus-6 (HHV-6) infection is widespread throughout the world. No data are available in Argentina about the loss of maternally derived HHV-6 immunity and natural infection in infants. METHODS: A population of 100 pregnant women and 407 children between 1 and 15 months of age were assayed by indirect immunofluorescence to detect and quantify specific IgG anti-human herpesvirus-6 (anti-HHV-6) antibodies in Córdoba City, Argentina. RESULTS: There was no significant difference in the positive rate between infants aged 1 to 9 months (range, 43.6 35.5%) and pregnant women (37%). Seropositive ratio dropped in the 10-month group (23.33% seropositive) and rose sharply in the 11-month group (38.89%), 12-month (60.61%), and 13- to 15-month group (63.46%). The geometric mean titer (GMT) for infants in the 12 to 15 months age group (23.4 41.64) was significantly higher than the GMT for infants 10 months of age (11.04) (P < 0.05 with the Tukey-HSD test). CONCLUSIONS: This study shows a significant association between loss of passive HHV-6 antibody and age among infants. The results support evidence that HHV-6 enters the susceptible population at 11 months, leading to a high prevalence of antibodies in children between 13 and 15 months of age.

[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.

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.

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.