Publications by authors named "Leonardo J Ferreyra"

Surface waters are used by local populations for different purposes, such as recreational activities, water source for human and animal consumption, and irrigation among others, which lead to the need for management strategies on water health and associated risks. During this study, we investigated physicochemical parameters, fecal coliform bacteria, and infectious human enterovirus detection to determine the water quality in different beaches (categorized as an urban area, non-urban areas, and an intermediate position) from San Roque Dam, in Argentina. Multivariate techniques were applied.

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The original publication of this article [1] was missing the below author that made contributions to the research and the published article.

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Human adenoviruses (HAdVs) are uniquely important "model organisms" as they have been used to elucidate fundamental biological processes, are recognized as complex pathogens, and are used as remedies for human health. As pathogens, HAdVs may effect asymptomatic or mild and severe symptomatic disease upon their infection of respiratory, ocular, gastrointestinal, and genitourinary systems. High-resolution genomic data have enhanced the understanding of HAdV epidemiology, with recombination recognized as an important and major pathway in the molecular evolution and genesis of emergent HAdV pathogens.

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Background: On the basis of the published literature, it is still difficult to draw conclusions as to whether picobirnavirus (PBV) circulation is influenced by host species restriction.

Objective: To provide data regarding the genetic relatedness between porcine and human PBV strains present in Argentina as a means of defining the host range and epidemiology of these viruses.

Methods: Fecal specimens (n = 74) collected from kidney transplant patients (n = 55) and piglets (n = 19) were analyzed by RT-PCR using primers designed to amplify the porcine PBV genomic segment 2.

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A study aimed to further understand the biology of porcine picobirnaviruses (PBV) was conducted between November 2003 and January 2008, on a farm located in the outskirts of Córdoba City, Argentina. PBV prevalence was examined by polyacrylamide gel electrophoresis and silver staining (PAGE S/S) on a total of 265 samples collected from pigs divided into four groups, according to age and physiological status. PBV detection rate was highest in the group of sows sampled within the lactogenic period (38.

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Background: Picobirnavirus' (PBV) association with diarrhea in children is not reliably established and the potential role of pathogenic PBV needs further investigations.

Objective: The aim of this study is to clarify the role of PBV in diarrhea illness in children.

Methods: Between January 1977 and December 2002, 2224 stool specimens were collected from children <3 years old with diarrhea illness.

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The persistence of poliovirus-neutralizing antibodies was investigated in 297 individuals residing in Argentina who had completed the vaccination cycle with four or five oral polio vaccine (OPV) doses 1 mo to 19 yr before this study. Seropositivity for the three polio types in individuals who had received four OPV doses remained high and stable, showing rates not less than 94.6, 98.

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In previous research, we concluded that measles virus specific IgG4 antibody titer could be used to differentiate between natural [IgG4 GMT 80 (95% CI, 33 to 191)] and vaccinal source of measles infection [IgG4 GMT 13 (95% CI, 7 to 26)]. The aim of this paper is to show that this new serologic marker (IgG4 measles antibody titer) can be applied to help interpret rare but well documented cases of measles Ig M-positive results in vaccinated individuals who, 1-2 months after vaccination, developed rash and fever and therefore do not meet the criteria for post-vaccinal measles infection. Six measles IgM-positive serum samples obtained from measles vaccinated individuals who developed rash/fever 1 to 2 months post-vaccination were studied by Immunofluorescence assay for the quantification of IgG4 measles specific antibody.

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Background: A variable rate of false-positive results may be observed with commercial assays for the detection of rotavirus and adenovirus antigen in stool specimens, depending on the quality of the reagents and the presence of potentially interfering substances in stool samples.

Objective: The present report analyse the discrepant results that could be obtained by the commercially available diagnostic tests and that can mask the reliable viral diagnosis.

Study Design: One fecal sample was collected from a hospitalized child aged 6 months with acute watery diarrhea and dehydration.

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We studied the occurrence of reovirus infection in children hospitalized with acute gastroenteritis in Argentina during a 20-year interval (1981 through 2001). Three of 2854 (0.10%) stools were positive for reovirus but negative for adenovirus, astrovirus and rotavirus.

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