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.

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.

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.

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.

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.

Colonization with vancomycin-resistant enterococci (VRE) in intensive care unit patients in Cordoba City, Argentina.

The purpose of this study was to determine the prevalence of colonization with vancomycin-resistant enterococci (VRE) among intensive care unit (ICU) patients in a hospital in Córdoba, Argentina. We collected 235 rectal swab specimens from 147 ICU patients. Resistance to vancomycin was screened with the disk diffusion method, and MICs were determined with the E-test method. Vancomycin-resistant genotypes were determined by PCR. The VRE strains were isolated from 18/147 patients (12.2%). The isolates were identified as Enterococcus faecium (94.4%), and Enterococcus gallinarum (5.6%). PCR showed that the E. faecium strains carried the vanA gene, and the E. gallinarum strain carried the vanC1 gene. Our study indicated that at least 12.2% of ICU patients were VRE carriers.

Suppression of tumorigenicity and anchorage-independent growth of BK virus-transformed mouse cells by human chromosome 11.

Viral transformation models may be useful for detecting and mapping human tumor suppressor genes. BK virus (BKV), a human papovavirus, readily transforms rodent cells but is unable to transform human cells, suggesting that oncosuppressive functions expressed in human cells control BKV oncogenic activity. We have transferred human chromosome 11 to BKV-transformed mouse cells. All of the cell clones were suppressed in the tumorigenic phenotype and anchorage-independent growth, except one clone which was nontumorigenic but maintained the ability to grow in soft agar. Cytogenetic analysis and DNA hybridization with chromosome 11-specific probes showed that all the reverted hybrids had an intact human chromosome 11, except the clone growing in semisolid medium which had lost the short arm. The results suggest that a gene located on 11p controls anchorage independence, whereas a gene on 11q controls the tumorigenicity of BKV-transformed cells. BKV T-antigen was expressed in all the hybrid clones at the same level as in the parental cell line, indicating that the putative human tumor suppressor gene(s) do not inhibit expression of the viral oncogene and must operate by another mechanism in inducing reversion of the oncogenic phenotype. Since BKV-transformed mouse cells are highly susceptible to retrovirus infection, this model can be used for searching and cloning tumor suppressor gene(s) by retrovirus-mediated "insertional mutagenesis".

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.

Culture amplification in human colon adenocarcinoma cell line (CaCo-2) combined with an ELISA as a supplementary assay for accurate diagnosis of rotavirus.

Culture amplification in colon adenocarcinoma cell line (CaCo-2) combined with enzyme immunoassay (Pathfinder ELISA) was developed as a supplementary tool for rotavirus diagnosis. One hundred and thirty stools in which results by polyacrylamide gel electrophoresis (PAGE) were in agreement with those obtained by ELISA were amplified in the CaCo-2 cell line. After the first passage 100% specimens were revealed as positive by ELISA. This result was confirmed by PAGE and direct electron microscopy (EM) which increased the rates of rotavirus detection up to 100% after the third and fifth cell passages, respectively. All of the amplified negative stools were confirmed as negative. Among discordant results, three of the eight specimens positive by ELISA but negative by PAGE were confirmed as true positive after the third cell passage. False positive ELISA results could be discarded when the samples were culture amplified and retested by the same ELISA. Using the CaCo-2 amplification-ELISA as supplementary assay, sensitivity and specificity were 1.000 and 0.953 for ELISA and 0.917 and 1.000 for PAGE, respectively. The combined CaCo-2 cell line amplification-immunoassay method proved to be suitable both to evaluate increase in sensitivity of newly developed rotavirus assays and for rotaviral amplification before antigen assays.

Seroprevalence of human herpesvirus 6 in Andino Puneños (Argentina).

We carried out a seroepidemiological survey to define the prevalence of human herpesvirus 6 (HHV6) infection in an aboriginal population (Andino Puneños) from a remote region in north-west Argentina. Antibodies against HHV6 (total IgG and the 4 subclasses of IgG) were studied in 84 serum samples (collected in 1995 and stored at -70 degrees C), using core blood mononuclear cells infected with HHV6 in an immunofluorescence assay. Of the 84 samples, 70 (83%; 95% confidence interval, 75-91%) exhibited IgG antibodies against HHV6. No significant differences in the frequency of humoral immunity were found among the 4 age-groups studied (mean ages 13, 31, 47 and 70 years) namely, 75%, 89.7%, 79.2% and 100%, respectively. HHV6-specific IgG1 was found in all the positive serum samples tested but none of them contained specific IgG2, IgG3 and IgG4. These results confirmed a high rate of infection with HHV6 within this aboriginal group in Argentina and an IgG1 anti-HHV6 activity compatible with a maintenance of immunity.

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.

Human papillomavirus infection in cyclosporin-induced gingival overgrowth in renal allograft recipients.

BACKGROUND: Host immunity plays an important role in the development of human papillomavirus (HPV)-associated disease. The HPV infection in oral cyclosporin-induced gingival overgrowth in renal transplant recipients has not been investigated previously. The aim of this study was to establish the HPV infection of cyclosporin-induced gingival hyperplasia in renal transplant recipients through morphological changes and use of the in situ hybridization technique. METHODS: We examined 13 renal transplant recipient biopsies with gingival overgrowth lesions and 4 healthy mucosa samples of these patients. The histopathological diagnoses were established on the basis of widely accepted criteria, and the pathologist was not aware of the HPV result. An in situ molecular hybridization was carried out under low stringent conditions to detect HPV species with mixed biotin-labeled probes of HPV 6 and HPV 11, and under high stringent conditions with HPV 6, HPV 11, HPV 16, and HPV 18 probes for HPV typing. RESULTS: The HPV prevalence among the 13 samples studied was 92.31% (12/13), of which 4 tested positive for HPV 6-11 and 1 for HPV 16. The 4 biopsies of normal mucosa from gingival overgrowth patients were also reactive for HPV DNA. In 11/12 (91.7%) HPV-positive cases, koilocytotic atypia was found. CONCLUSIONS: The suppression of T-cell function by cyclosporin therapy can result in an increase of HPV infection, adding to the proliferative activity of cyclosporin in the oral mucosa.

[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.

[Human papillomavirus detection in oral cancer lesions in the city of Córdoba]. / Detección del virus papiloma humano en lesiones cancerosas orales en la ciudad de Córdoba.

Oral cancer is a process that involves different etiological factors and mechanisms in the light of current view of viral cocarcinogenesis. Evidence from histology and DNA hybridization studies suggests that HPV is engaged in oral carcinogenesis. The Pathology Laboratory of the Dentistry School, National University of Córdoba, admits approximately 20% of all patients with cancerous lesions in this city. In the January 1992-December 1997 lapse, we examined 1950 biopsies with oral lesions, 4.77% (93/1950) of which were malignant neoplasms, 79.57% (74/93) were oral carcinomas. Thirty-three oral carcinomas (44.6%; 33/74) were selected at random and included in this study, 33 cells smears of normal oral mucosa of controls individuals were included. They were analyzed by conventional light microscopy and an in situ hybridization technique for the detection of HPV. Data were analyzed with chi square test. The prevalence of HPV among the 33 cancer samples studied was 27.27%, 9/33 tested positive for HPV in low stringent conditions. Only one was positive in high stringent condition for HPV16, a verrugous carcinoma. No HPV-DNA was detected in cells smears of controls. Among the HPV positive, 3/9 (33.33%) were squamous carcinomas and 5/9 (55.56%) were verrugous carcinomas. Only one was a melanoma. Verrugous carcinoma was the carcinoma most associated with the HPV infection (x2 = 20.5; 95% level of confidence). This would indicate a major role of HPV in the pathogenesis of verrucous carcinomas. The viral prevalence found in cancerous lesions reinforces the concept of heterogenic natures of oral cancer. HPV is a circumstance that increase the probability of malignancy, and when reducing, diminish the frequency of cancer.

Induction of senescence and control of tumorigenicity in BK virus transformed mouse cells by human chromosome 6.

Viral transformation models may be useful to detect and map human tumor suppressor genes. BK virus (BKV), a human papovavirus, readily transforms rodent cells but is unable to transform human cells, suggesting that oncosuppressive functions expressed in human cells control BKV oncogenic activity. We have transferred human chromosome 6 to BKV-transformed mouse pRPcT1ss1 cells. The great majority of the colonies growing in selective medium degenerated by senescence. Only five hybrid pRPcT1ss1/H6 clones maintained the immortalized phenotype of the recipient cell line. All the immortalized clones had two common regions of deletion involving bands 6q21-22 and the SOD2 gene in 6q25. Senescent colonies carried an intact chromosome 6. A specific human sequence in 6q21-22 was amplified by PCR in senescent cells, suggesting that this region harbors a gene inducing senescence. The SOD2 deletion confirms recent data on the role of the Mn-dependent superoxide dismutase in inhibition of proliferation. The monochromosomic hybrids bearing a deleted chromosome 6 showed a reverted phenotype in vitro and a significantly longer latency period before they were tumorigenic in nude mice, indicating the presence of a tumor suppressor gene in the residual regions of chromosome 6. Molecular mapping suggests that this gene is located in 6q27. The BKV transformation model detects genes inducing senescence and tumor suppressor genes on human chromosome 6 and may represent a useful system to isolate and clone such genes.