West Nile virus infection decreases fecundity of Culex tarsalis females

West Nile virus (family Flaviviridae, genus Flavivirus, WNV) persistently infects many mosquito tissues, and it has been associated with cytopathological changes in midgut muscles and salivary glands. However, the effects of WNV infection on mosquito fitness (survival and reproduction) are not known. We conducted a life table study of individually housed female Culex tarsalis Coquillett. After an initial bloodmeal from a WNV-infected or uninfected chicken, mosquitoes were provided sucrose and offered weekly opportunities to feed on a hanging blood drop. WNV transmission status was determined by testing the remaining blood drop for virus after mosquito feeding. Dead mosquitoes and eggs were collected daily. Mosquito legs and bodies were tested for WNV, and eggs were counted and allowed to hatch. Two replicates of this experiment were performed, with a total of 62 mosquitoes that fed on a WNV-infected chicken (of which 21 became infected) and 43 mosquitoes that fed on an uninfected chicken. Fecundity of WNV-infected mosquitoes was significantly lower than that of uninfected mosquitoes, especially during the first oviposition. WNV infection was associated with smaller egg rafts, whereas increasing wing length and WNV titer in the legs had a positive effect on egg raft size. Additionally, infected mosquitoes had lower egg hatch rates than did uninfected mosquitoes. There were no significant differences in survival between infected and uninfected mosquitoes. Blood feeding rates were higher in infected mosquitoes than in uninfected mosquitoes. A small amount of virus (average, 378; range, 5-5000 plaque-forming units) was transmitted to the blood drops fed upon by infected mosquitoes. Although WNV infection negatively impacts mosquito reproduction, facets of mosquito biology that are critical to virus transmission success were either not affected (survival) or changed in such a way as to result in enhanced vectorial capacity (blood feeding).     

Differences of self-reported osteoarthritis disability and race

BACKGROUND: Differences in self-reported disability may be found for older black and white adults with knee osteoarthritis (OA). METHODS: This secondary analysis of data from a randomized single-blind clinical trial examined race differences in the relationship between self-reports and timed performance tests of walking. Study participants were 518 older adults (131 blacks, 387 whites), including 363 women and 155 men, with an average age of 68.6 years. RESULTS: Older black and white adults with radiographically documented knee OA reported equivalent functional ability and pain severity. However, both blacks' OA severity rating and tested performance were significantly worse than those of whites. Self-report and tested walking performance were significantly less correlated among black older adults than among white older adults. Analyses of potential confounding variables documented that the difference was not due to marital status, gender, education, income, body mass index, comorbidity, pain level, OA severity or general health. CONCLUSIONS: Self-reports of OA disability were less related to tested performance for walking among black older adults. Clinicians' knowledge of black patients' underestimation of their disability has compelling potential for improving clinical treatment and enhancing diagnostic approaches to care of older adults.     

Dynamic association between parental monitoring and communication and adolescent risk involvement among African-American adolescents

PURPOSE: To examine: (1) the relationship between parental monitoring and communication and adolescent risk involvement over time, including consideration of their potential interaction; and (2) the effect of consistent versus inconsistent monitoring and communication over time on adolescent risk behaviors. METHODS: Baseline and follow-up data were collected from 1999-2003. A total of 817 African-American adolescents and their parents were recruited from 35 low-income urban communities in Baltimore, MD. Perceived parental monitoring, parent-adolescent communication and seven risk behaviors were assessed. Logistic general estimating equation (GEE) models were performed to assess the dynamic association. RESULTS: Perceived parental monitoring had protective effects on concurrent adolescent risk involvement over two-year observation. The protective effect on girls' sexual abstinence increased significantly over time. Perceived problem communication was associated with increased risk of concurrent involvement in violent behaviors, but the effect did not change over time. For girls, the probability of engaging in sex increased greatly (from 0.3 to 0.6) for those who perceived problem communication, while it remained stable (about 0.4) for those perceiving less problem communication. CONCLUSIONS: The data confirm the protective effect of perceived parental monitoring on adolescent risk involvement. It also extends previous findings by showing the importance of consistent parental monitoring and communication.     

The International society for developmental psychobiology 39th annual meeting symposium: Alcohol and development: beyond fetal alcohol syndrome

As has been repeatedly demonstrated, alcohol can exert deleterious morphological and physiological effects during early stages in development. The present review examines nonteratological links existing between alcohol and ontogeny. Human and animal studies are taken into consideration for the analysis of fetal, neonatal, infantile, adolescent, and adult responsiveness to the drug. Sensitivity to alcohol's chemosensory and postabsorptive properties, as well as learning and memory processes mediated by such properties, are examined from this developmental perspective. The studies under discussion indicate that, within each stage in development, we can trace alcohol-related experiences capable of determining or modulating alcohol seeking and intake patterns.