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Public policy positions breastfeeding as a key strategy to protect vulnerable children from household food insecurity. (1,2) Using data from a Canadian population-representative survey, Orr and colleagues report that household [...]

Fighting AIDS With Facts and Compassion Sound AIDS policy and employee education are imperatives in today's workplace. Statistics make it painfully clear that almost every employer in the United States [...]

To determine whether the 2011 guidelines for universal routine screening for dyslipidemia in children aged 9 to 11 years, published by the Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents and National Heart, Lung, and Blood Institute, are being followed by pediatric primary-care providers.

ABSTRACTAeromonas salmonicidasubsp. salmonicida, a bacterial pathogen of Atlantic salmon, has no visible pili, yet its genome contains genes for three type IV pilus systems. One system, Tap, is similar to the Pseudomonas aeruginosaPil system, and a second, Flp, resembles the Actinobacillus actinomycetemcomitansFlp pilus, while the third has homology to the mannose-sensitive hemagglutinin pilus of Vibrio cholerae. The latter system is likely nonfunctional since eight genes, including the gene encoding the main pilin subunit, are deleted compared with the orthologous V. choleraelocus. The first two systems were characterized to investigate their expression and role in pathogenesis. The pili of A. salmonicidasubsp. salmonicidawere imaged using atomic force microscopy and Tap- and Flp-overexpressing strains. The Tap pili appeared to be polar, while the Flp pili appeared to be peritrichous. Strains deficient in tapand/or flpwere used in live bacterial challenges of Atlantic salmon, which showed that the Tap pilus made a moderate contribution to virulence, while the Flp pilus made little or no contribution. Delivery of the tapmutant by immersion resulted in reduced cumulative morbidity compared with the cumulative morbidity observed with the wild-type strain; however, delivery by intraperitoneal injection resulted in cumulative morbidity similar to that of the wild type. Unlike the pili of other piliated bacterial pathogens, A. salmonicidasubsp. salmonicidatype IV pili are not absolutely required for virulence in Atlantic salmon. Significant differences in the behavior of the two mutant strains indicated that the two pilus systems are not redundant.

Aeromonas salmonicida subsp. salmonicida, a bacterial pathogen of Atlantic salmon, has no visible pili, yet its genome contains genes for three type IV pilus systems. One system, Tap, is similar to the Pseudomonas aeruginosa Pil system, and a second, Flp, resembles the Actinobacillus actinomycetemcomitans Flp pilus, while the third has homology to the mannose-sensitive hemagglutinin pilus of Vibrio cholerae. The latter system is likely nonfunctional since eight genes, including the gene encoding the main pilin subunit, are deleted compared with the orthologous V. cholerae locus. The first two systems were characterized to investigate their expression and role in pathogenesis. The pili of A. salmonicida subsp. salmonicida were imaged using atomic force microscopy and Tap- and Flp-overexpressing strains. The Tap pili appeared to be polar, while the Flp pili appeared to be peritrichous. Strains deficient in tap and/or flp were used in live bacterial challenges of Atlantic salmon, which showed that the Tap pilus made a moderate contribution to virulence, while the Flp pilus made little or no contribution. Delivery of the tap mutant by immersion resulted in reduced cumulative morbidity compared with the cumulative morbidity observed with the wild-type strain; however, delivery by intraperitoneal injection resulted in cumulative morbidity similar to that of the wild type. Unlike the pili of other piliated bacterial pathogens, A. salmonicida subsp. salmonicida type IV pili are not absolutely required for virulence in Atlantic salmon. Significant differences in the behavior of the two mutant strains indicated that the two pilus systems are not redundant.

Bacterial kidney disease (BKD) in salmonids is caused byRenibacterium salmoninarum(Rs) which is transmitted vertically through salmonid eggs. This study investigated the effect of vertical transmission of one protein of Rs, p57, on the development of the immune system of coho salmon (Oncorhynchus kisutch) and on the susceptibility of the fish to subsequent challenge with Rs. It was shown that exposure of coho salmon at the egg stage to the p57 protein of Rs induces at least partial immunosuppression. Coho salmon eggs were injected with varying amounts of p57. The eggs were fertilized, the progeny were vaccinated against Rs, and then challenged with live, virulent Rs. Fish that had been injected as eggs with 100 ng of p57 demonstrated a significantly higher cumulative percent mortality (50 %) than those from the saline-injected eggs (controls) (14 %). The same fish also produced significantly lower levels of antibodies against p57, although not against whole Rs cells, than those derived from saline-injected eggs. It appeared, therefore, that there was some specificity to the immune suppression. A decreased proportion of phagocytic cells isolated from fish exposed as eggs to 100 ng p57, showed respiratory burst activity (0 ·4 %) compared with the proportion of cells isolated from the saline-injected (control) group (16 ·5 %). These data suggest that early (egg stage) exposure of coho salmon to p57 results in long-term immunosuppression and a decreased ability in the animal to resist subsequent challenges with Rs.