Pre- and post-insemination episodes of sexual selection in the fowl, Gallus g. domesticus.
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Although much attention has been recently directed to sexual selection arising after insemination from sexual promiscuity, little is known about the mechanisms determining reproductive success after insemination, and the way these mechanisms interact with each other and with selective mechanisms occurring before insemination: mate choice and mate acquisition. Here, we briefly review the findings of an on-going study investigating the mechanisms generating variation in reproductive success at both a pre- and a post-insemination stage in the domestic fowl. Female preference consistently favours socially dominant males before and after insemination. However, although social status mediates the number of sperm that a male inseminates into a female, dominant males may inseminate sperm of lower fertilising quality than their subordinates. We argue that mitochondrial genes may contribute to determine sperm quality, and speculate that the maternal control of mitochondrial genes may prevent sexual selection from operating on males, thus explaining both the lack of a positive correlation between social dominance and sperm quality and the maintenance of variation in male quality in the fowl. (+info)
Outbreak of avian influenza A(H5N1) virus infection in Hong Kong in 1997.
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The first outbreak of avian influenza A(H5N1) virus in humans occurred in Hong Kong in 1997. Infection was confirmed in 18 individuals, 6 of whom died. Infections were acquired by humans directly from chickens, without the involvement of an intermediate host. The outbreak was halted by a territory-wide slaughter of more than 1.5 million chickens at the end of December 1997. The clinical spectrum of H5N1 infection ranges from asymptomatic infection to fatal pneumonitis and multiple organ failure. Reactive hemophagocytic syndrome was the most characteristic pathologic finding and might have contributed to the lymphopenia, liver dysfunction, and abnormal clotting profiles that were observed among patients with severe infection. Rapid diagnosis with the use of reverse-transcription polymerase chain reaction and monoclonal antibody-based immunofluorescent assay were of great clinical value in the management of the outbreak. The experience of the H5N1 outbreak in Hong Kong underscores the importance of continuous surveillance of influenza virus strains in humans and in other animal species. (+info)
The potential impact of flooding on confined animal feeding operations in eastern North Carolina.
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Thousands of confined animal feeding operations (CAFOs) have been constructed in eastern North Carolina. The fecal waste pit and spray field waste management systems used by these operations are susceptible to flooding in this low-lying region. To investigate the potential that flood events can lead to environmental dispersion of animal wastes containing numerous biologic and chemical hazards, we compared the geographic coordinates of 2,287 CAFOs permitted by the North Carolina Division of Water Quality (DWQ) with estimates of flooding derived from digital satellite images of eastern North Carolina taken approximately 1 week after Hurricane Floyd dropped as much as 15-20 inches of rain in September 1999. Three cattle, one poultry, and 237 swine operations had geographic coordinates within the satellite-based flooded area. DWQ confirmed 46 operations with breached or flooded fecal waste pits in the same area. Only 20 of these 46 CAFOs were within the satellite-based estimate of the inundated area. CAFOs within the satellite-based flood area were located in 132 census block groups with a population of 171,498 persons in the 2000 census. African Americans were more likely than whites to live in areas with flooded CAFOs according to satellite estimates, but not according to DWQ reports. These areas have high poverty rates and dependence on wells for drinking water. Our analysis suggests that flood events have a significant potential to degrade environmental health because of dispersion of wastes from industrial animal operations in areas with vulnerable populations. (+info)
Multilocus sequence typing for characterization of clinical and environmental salmonella strains.
(68/1054)
Multilocus sequence typing (MLST) based on the 16S RNA, pduF, glnA, and manB genes was developed for Salmonella, and its discriminatory ability was compared to those of pulsed-field gel electrophoresis (PFGE) and serotyping. PFGE differentiated several strains undifferentiable by serotyping, and 78 distinct PFGE types were identified among 231 Salmonella isolates grouped into 22 serotypes and 12 strains of undetermined serotype. The strains of several PFGE types were further differentiated by MLST, which suggests that the discriminatory ability of MLST for the typing of Salmonella is better than that of serotyping and/or PFGE typing. manB-based sequence typing identified two distinct genetic clusters containing 32 of 54 (59%) clinical isolates whose manB gene sequences were analyzed. The G+C contents and Splitstree analysis of the manB, glnA, and pduF genes of Salmonella indicated that the genes differ in their evolutionary origins and that recombination played a significant role in their evolution. (+info)
Antimicrobial use and resistance in animals.
(69/1054)
Food animals in the United States are often exposed to antimicrobials to treat and prevent infectious disease or to promote growth. Many of these antimicrobials are identical to or closely resemble drugs used in humans. Precise figures for the quantity of antimicrobials used in animals are not publicly available in the United States, and estimates vary widely. Antimicrobial resistance has emerged in zoonotic enteropathogens (e.g., Salmonella spp., Campylobacter spp.), commensal bacteria (e.g., Escherichia coli, enterococci), and bacterial pathogens of animals (e.g., Pasteurella, Actinobacillus spp.), but the prevalence of resistance varies. Antimicrobial resistance emerges from the use of antimicrobials in animals and the subsequent transfer of resistance genes and bacteria among animals and animal products and the environment. To slow the development of resistance, some countries have restricted antimicrobial use in feed, and some groups advocate similar measures in the United States. Alternatives to growth-promoting and prophylactic uses of antimicrobials in agriculture include improved management practices, wider use of vaccines, and introduction of probiotics. Monitoring programs, prudent use guidelines, and educational campaigns provide approaches to minimize the further development of antimicrobial resistance. (+info)
Vancomycin-resistant Enterococcus faecium (VREF) from Norwegian poultry cluster with VREF from poultry from the United Kingdom and The Netherlands in an amplified fragment length polymorphism genogroup.
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The genetic relationship between 197 vancomycin-resistant Enterococcus faecium (VREF) isolates and 21 vancomycin-susceptible E. faecium isolates from Norwegian poultry was analyzed by amplified fragment length polymorphism (AFLP). The isolates were compared to 255 VREF isolates from various sources and countries. The Norwegian isolates constituted a relatively homogeneous population of E. faecium and clustered in a previously defined poultry AFLP genogroup. (+info)
Emergence of multiple genotypes of H5N1 avian influenza viruses in Hong Kong SAR.
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Although A/Hong Kong/156/97 (H5N1/97)-like viruses associated with the "bird flu" incident in Hong Kong SAR have not been detected since the slaughter of poultry in 1997, its putative precursors continue to persist in the region. One of these, Goose/Guangdong/1/96 (H5N1 Gs/Gd)-like viruses, reassorted with other avian viruses to generate multiple genotypes of H5N1 viruses that crossed to chickens and other terrestrial poultry from its reservoir in geese. Whereas none of these recent reassortants had acquired the gene constellation of H5N1/97, these events provide insight into how such a virus may have been generated. The recent H5N1 reassortants readily infect and kill chicken and quail after experimental infection, and some were associated with significant mortality of chickens within the poultry retail markets in Hong Kong. Some genotypes are lethal for mice after intra-nasal inoculation and spread to the brain. On this occasion, the early detection of H5N1 viruses in the retail, live poultry markets led to preemptive intervention before the occurrence of human disease, but these newly emerging, highly pathogenic H5N1 viruses provide cause for pandemic concern. (+info)
Iron indexes and total antioxidant status in response to soy protein intake in perimenopausal women.
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BACKGROUND: Elevated iron stores, oxidative stress, and estrogen deficiency may place postmenopausal women at greater risk of heart disease and cancer than premenopausal women. OBJECTIVE: The objective was to determine the effect of soy-protein isolate (SPI) intake and iron indexes on plasma total antioxidant status (TAS) in perimenopausal women after control for other contributing factors. DESIGN: Perimenopausal women (n = 69) were randomly assigned (double blind) to treatment: isoflavone-rich SPI (SPI+; n = 24), isoflavone-poor SPI (SPI-; n = 24), or whey protein (control; n = 21). Each subject consumed 40 g soy or whey protein daily for 24 wk. Plasma TAS, serum ferritin, serum iron, transferrin saturation, and hemoglobin were measured at baseline, week 12, and week 24. RESULTS: No significant time-by-treatment interactions on iron indexes or TAS were observed, whereas time had an effect on serum ferritin (P < or = 0.0001) and hemoglobin (P = 0.004) but not on TAS. Multiple regression analysis showed that at week 12, 48% (P < or = 0.0001) of the variability in TAS was accounted for by baseline TAS, alcohol intake, soy intake (soy compared with control; P = 0.016), plasma lipoprotein(a), and dietary iron. At week 24, 47% of the variability in TAS was accounted for by baseline TAS, serum ferritin, serum estrone, dietary zinc, and dietary meat, fish, and poultry. CONCLUSIONS: SPI intake had no significant effect on iron status, but our results suggest that dietary soy protein and low iron stores may protect perimenopausal women from oxidative stress. (+info)