Ethnic Comparison of Weight Loss in Trial of Nonpharmacologic Interventions in the Elderly

https://onlinelibrary.wiley.com/doi/epdf/10.1038/oby.2002.1

Reservoirs of Salmonella infection on swine farms in lllinois

An ecological study was conducted to identify possible reservoirs of Salmonella on swine farms in Dlinois. In 1998, 6 single-site farrow-to-finish swine farms with at least 100 sows, identified previously at slaughter as having a high prevalence of Salmonella infection, were selected for study. Between March and October 1998, each farm was visited 4 times. On each visit, 60- 150 pigs were sampled, from various age groups (pre-weaning pigs, nursery, grower, finisher, sows). Overnight trapping was conducted to collect rodents, cats, and arthropods. Fecal samples were obtained from pigs, rodents and cats. Environmental samples of water, feed, boots and pen floor material were also obtained. Samples were cultured for Salmonella using tetrathionate broth, followed by Rappaport\u27s medium for enrichment. Salmonella was detected in every reservoir for which at least 20 samples were available. Salmonella was detected in the feces of sows and finishing pigs on each farm, and in pen floor samples on 5 of the 6 farms. The overall prevalence of Salmonella in swine fecal samples was 2.8%; the prevalence of Salmonella shedding by pigs increased with increasing age (1.4% in suckling pigs, 3.5% in near market weight finishing pigs, 6.2% in sows). Boot samples had the highest prevalence of infection (17% ), suggesting a likely mode of transntission; on one farm, 81% of boot samples were positive. The prevalence of infection also was relatively high in cats (14%), ntice (10%), and flies (7%). The overall prevalence of Salmonella in floor samples was 7%, with one farm having 20% of floor samples positive, thereby implicating pen floors as a source for transntission. Feed samples had a low prevalence of salmonella (2%), suggesting that feed played a lesser role in Salmonella transntission

Spatial and temporal patterns of the distribution of Salmonella on swine farms in Illinois

An ecological study was conducted to identify possible reservoirs of Sa/monelln. From March to November 1998 there were 4 visits to each of 6 selected swine farms in lllinois. Fecal samples were collected from swine in longitudinal and cross-sectional groups on each visit to each farm. Fecal samples were also collected from chickens, cattle, cats, dogs, rodents, and other wildlife. Overnight trapping and hand capture techniques were used to obtain samples from wildlife, cats, and arthropods. Environmental samples including feed, water, pen floor material, bootdebris, and bird feces were collected. All samples were evaluated as Salmonel/n positive or negative by culture. A total of 3564 samples representing 40 sample types were collected and cultured. Of 2442 swine fecal samples, 935 were from longitudinal cohorts, and 1507 were from cross sectional groups. Non-swine fecal samples and environmental samples comprised the remaining 1123 samples. Salmonella was cultured from 157 samples in 19 different sample types. All positive samples are mapped with representation of location and time of collection on the farm

Lung adenocarcinoma originates from retrovirus infection of proliferating type 2 pneumocytes during pulmonary post-natal development or tissue repair

Jaagsiekte sheep retrovirus (JSRV) is a unique oncogenic virus with distinctive biological properties. JSRV is the only virus causing a naturally occurring lung cancer (ovine pulmonary adenocarcinoma, OPA) and possessing a major structural protein that functions as a dominant oncoprotein. Lung cancer is the major cause of death among cancer patients. OPA can be an extremely useful animal model in order to identify the cells originating lung adenocarcinoma and to study the early events of pulmonary carcinogenesis. In this study, we demonstrated that lung adenocarcinoma in sheep originates from infection and transformation of proliferating type 2 pneumocytes (termed here lung alveolar proliferating cells, LAPCs). We excluded that OPA originates from a bronchioalveolar stem cell, or from mature post-mitotic type 2 pneumocytes or from either proliferating or non-proliferating Clara cells. We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection and transformation. On the contrary, healthy adult sheep, which are normally resistant to experimental OPA induction, exhibit a relatively low number of LAPCs and are resistant to JSRV infection of the respiratory epithelium. Importantly, induction of lung injury increased dramatically the number of LAPCs in adult sheep and rendered these animals fully susceptible to JSRV infection and transformation. Furthermore, we show that JSRV preferentially infects actively dividing cell in vitro. Overall, our study provides unique insights into pulmonary biology and carcinogenesis and suggests that JSRV and its host have reached an evolutionary equilibrium in which productive infection (and transformation) can occur only in cells that are scarce for most of the lifespan of the sheep. Our data also indicate that, at least in this model, inflammation can predispose to retroviral infection and cancer

A Reservoir of Drug-Resistant Pathogenic Bacteria in Asymptomatic Hosts

The population genetics of pathogenic bacteria has been intensively studied in order to understand the spread of disease and the evolution of virulence and drug resistance. However, much less attention has been paid to bacterial carriage populations, which inhabit hosts without producing disease. Since new virulent strains that cause disease can be recruited from the carriage population of bacteria, our understanding of infectious disease is seriously incomplete without knowledge on the population structure of pathogenic bacteria living in an asymptomatic host. We report the first extensive survey of the abundance and diversity of a human pathogen in asymptomatic animal hosts. We have found that asymptomatic swine from livestock productions frequently carry populations of Salmonella enterica with a broad range of drug-resistant strains and genetic diversity greatly exceeding that previously described. This study shows how agricultural practice and human intervention may lead and influence the evolution of a hidden reservoir of pathogens, with important implications for human health