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Since the first introduction from North America more than a century ago, rainbow trout (Oncorhynchus mykiss) have rapidly established self-sustaining populations in major river basins of Patagonia. Many generations later, only the freshwater resident life history is expressed in the Chubut and Negro rivers of northern Argentinian Patagonia, whereas both the resident and anadromous life histories are found in the Santa Cruz River of southern Argentina. Despite previous studies that have tried to identify the sources of these introduced populations, uncertainty still exists. Here we combined data from many single-nucleotide polymorphisms and microsatellite loci in O. mykiss populations from Argentina and North America to evaluate putative source populations, gene flow between Argentinian river basins, and genetic diversity differences between Argentinian and North American populations. We found that populations from northern and southern Patagonia are highly differentiated and have limited gene flow between them. Phylogeographic analysis also confirmed that they have separate origins, with the northern populations most closely related to the domesticated rainbow trout strains that are raised worldwide and the Santa Cruz River populations most closely related to North American populations from California and Oregon that have an anadromous component. In addition, fish with different life histories in the Santa Cruz River were found to constitute a single interbreeding population. No evidence was found of reduced genetic variation in introduced rainbow trout, suggesting multiple contributing sources. In spite of these advances in understanding, significant questions remain regarding the origins and evolution of the introduced O. mykiss in Patagonia., (© 2024 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Objectives: This study was carried out to evaluate the prevalence of hepatitis delta virus (HDV) among human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infected patients from São Paulo, in the Southeast Region of Brazil., Methods: A total of 3259 HIV patients with serological markers for HBV were initially enrolled in the study. Among these patients, 154 (4.7%) were hepatitis B surface antigen (HBsAg)-reactive. Serum samples were obtained from 86 HBsAg-positive patients and were submitted to anti-HDV serological assay., Results: One (1.2%) HIV/HBV patient was found to be anti-HDV-positive, and the HDV infection was confirmed by PCR. Phylogenetic analysis showed that this HDV sequence grouped with other HDV genotype 1 sequences from Mediterranean European countries, suggesting that this virus has a common ancestor with HDV from that region. This patient was probably infected by sexual transmission, as he reported unprotected sexual intercourse with multiple partners over the course of many years but denied intravenous drug use or any travel to the Brazilian Amazon, an area known to have a high HDV prevalence., Conclusions: HDV infection is infrequent in the Southeast Region of Brazil, however there have been a few cases in this region. HIV/HBV patients are at potential risk for HDV infection, therefore investigations for the presence of HDV infection must be carried out in these patients., (Copyright © 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)