Diet, physical activity and substrate oxidation : implications for appetite control, weight loss and body composition

In many countries, governments and health agencies are strongly promoting physical activity as a means to prevent the accumulation of fatness that leads to weight gain and obesity. However, there is often a resistance to respond to health promotion initiatives. For example, in the UK, the Chief Medical Officer has recently reported that 71% of women and 61% of men fail to carry out even the minimal amount of physical activity recommended in the government’s guidelines. Similarly, the Food safety Agency has promoted reductions in the intake of fat, sugar and salt but with very little impact on the pattern of consumption. Why is it that recommendations to improve health are so difficult to implement, and produce the desired outcome?

Spatial and temporal distribution of falciparum malaria in China

Background: Falciparum malaria is the most deadly among the four main types of human malaria. Although great success has been achieved since the launch of the National Malaria Control Programme in 1955, malaria remains a serious public health problem in China. This paper aimed to analyse the geographic distribution, demographic patterns and time trends of falciparum malaria in China. Methods: The annual numbers of falciparum malaria cases during 1992–2003 and the individual case reports of each clinical falciparum malaria during 2004–2005 were extracted from communicable disease information systems in China Center for Diseases Control and Prevention. The annual number of cases and the annual incidence were mapped by matching them to corresponding province- and county-level administrative units in a geographic information system. The distribution of falciparum malaria by age, gender and origin of infection was analysed. Time-series analysis was conducted to investigate the relationship between the falciparum malaria in the endemic provinces and the imported falciparum malaria in non-endemic provinces. Results: Falciparum malaria was endemic in two provinces of China during 2004–05. Imported malaria was reported in 26 non-endemic provinces. Annual incidence of falciparum malaria was mapped at county level in the two endemic provinces of China: Yunnan and Hainan. The sex ratio (male vs. female) for the number of cases in Yunnan was 1.6 in the children of 0–15 years and it reached 5.7 in the adults over 15 years of age. The number of malaria cases in Yunnan was positively correlated with the imported malaria of concurrent months in the non-endemic provinces. Conclusion: The endemic area of falciparum malaria in China has remained restricted to two provinces, Yunnan and Hainan. Stable transmission occurs in the bordering region of Yunnan and the hilly-forested south of Hainan. The age and gender distribution in the endemic area is characterized by the predominance of adult men cases. Imported falciparum malaria in the non-endemic area of China, affected mainly by the malaria transmission in Yunnan, has increased both spatially and temporally. Specific intervention measures targeted at the mobile population groups are warranted.

Genetic analysis of maize streak virus isolates from Uganda reveals widespread distribution of a recombinant variant

Maize streak virus (MSV) contributes significantly to the problem of extremely low African maize yields. Whilst a diverse range of MSV and MSV-like viruses are endemic in sub-Saharan Africa and neighbouring islands, only a single group of maize-adapted variants - MSV subtypes A1 -A6 - causes severe enough disease in maize to influence yields substantially. In order to assist in designing effective strategies to control MSV in maize, a large survey covering 155 locations was conducted to assess the diversity, distribution and genetic characteristics of the Ugandan MSV-A population. PCR-restriction fragment-length polymorphism analyses of 391 virus isolates identified 49 genetic variants. Sixty-two full-genome sequences were determined, 52 of which were detectably recombinant. All but two recombinants contained predominantly MSV-A1-like sequences. Of the ten distinct recombination events observed, seven involved inter-MSV-A subtype recombination and three involved intra-MSV-A1 recombination. One of the intra-MSV-A1 recombinants, designated MSV-A1 UgIII, accounted for >60% of all MSV infections sampled throughout Uganda. Although recombination may be an important factor in the emergence of novel geminivirus variants, it is demonstrated that its characteristics in MSV are quite different from those observed in related African cassava-infecting geminivirus species. © 2007 SGM.

Global genetic diversity and geographical and host-species distribution of beak and feather disease virus isolates

Psittacine beak and feather disease (PBFD) has a broad host range and is widespread in wild and captive psittacine populations in Asia, Africa, the Americas, Europe and Australasia. Beak and feather disease circovirus (BFDV) is the causative agent. BFDV has an ~2 kb single stranded circular DNA genome encoding just two proteins (Rep and CP). In this study we provide support for demarcation of BFDV strains by phylogenetic analysis of 65 complete genomes from databases and 22 new BFDV sequences isolated from infected psittacines in South Africa. We propose 94% genome-wide sequence identity as a strain demarcation threshold, with isolates sharing > 94% identity belonging to the same strain, and strain subtypes sharing> 98% identity. Currently, BFDV diversity falls within 14 strains, with five highly divergent isolates from budgerigars probably representing a new species of circovirus with three strains (budgerigar circovirus; BCV-A, -B and -C). The geographical distribution of BFDV and BCV strains is strongly linked to the international trade in exotic birds; strains with more than one host are generally located in the same geographical area. Lastly, we examined BFDV and BCV sequences for evidence of recombination, and determined that recombination had occurred in most BFDV and BCV strains. We established that there were two globally significant recombination hotspots in the viral genome: the first is along the entire intergenic region and the second is in the C-terminal portion of the CP ORF. The implications of our results for the taxonomy and classification of circoviruses are discussed. © 2011 SGM.

Increasing physical activity among women with young children: Results from the Proactive Mums Project

Context Evidence from the Australian Longitudinal Study of Women's Health suggests that mothers of young children have lower levels of physical activity (PA) than women of similar age without children. Objectives The aim of the ProActive Mums project was to determine the relative efficacy of two strategies designed to increase the proportion of mothers of young children who are meeting current PA guidelines, utilising child care centres (CCCs) as the setting for recruitment. Study Design The project used a randomised (after stratification to ensure even representation of CCCs from differing socio-economic areas) design incorporating repeated data collection from women in three groups, each consisting of 7 childcare centres (CCCs). Baseline surveys were completed by 554 mothers, with follow-up data collection immediately post-Intervention (8 weeks after baseline) and again 5 months later. Women from CCCs in Group 1 (control) received only the surveys throughout the duration of the project. Women from CCCs in Group 2 (information only) were given a print intervention, and women from CCCs in Group 3 were (in addition to being given the same print intervention as women from CCCs in Group 2) invited to to contribute to the development of, and participate in, strategies for the promotion of PA among mothers of young children. The two intervention strategies were extensively evaluated through a series of surveys and interviews. The Intervention The print intervention prescribed for women from CCCs in Group 2 and Group 3 consisted of an 8-page booklet containing motivational messages and information about physical activity. Women from CCCs in Group 3 were also invited to attend meetings at their CCC to identify strategies for increasing their PA. Contacts were made with key stakeholders in the community, including managers of sporting and recreation facilities, childcare service providers, and local councils. A wide range of strategies was developed during the intervention phase of the project, which specifically focused on the need to increase partner support and self-efficacy (or the confidence to be physically active). Results The mean age of participants was 33 (+ 4.8) years, and the mean number of children per family unit was 2.2 (± 0.9). At baseline, fewer than half the women were meeting current guidelines for adequate PA for health benefit, and there were no significant differences between groups in the proportion of women who were adequately active for health benefit. Women in Group 3 were significantly more likely to meet the guidelines at post-intervention follow-up than controls [OR = 1.71 (1.05-2.77)] after controlling for age and PA at baseline. There was no significant effect of the print intervention alone on meeting guidelines at post-intervention follow-up compared with controls, after controlling for age and PA at baseline [OR = 1.15 (0.70-1.89)]. Changes in Partner Support (PS) and Self Efficacy (SE) significantly predicted meeting current PA guidelines at post-intervention follow-up after controlling for baseline PA [∆ PS: OR = 2.29 (1.46-3.58); ∆ SE: OR = 1.86 (1.17- 2.94)]. The intervention effect in Group 3 was not maintained at long-term follow-up. Conclusions The findings indicate that a community participation approach that facilitates increased partner support and self-efficacy can be effective in increasing PA among mothers of young children. Changes in physical activity were found to be mediated by changes in partner support and self-efficacy for physical activity, suggesting that the intervention successfully targeted the individual characteristics it intended to, and that these variables do play an important role in increasing physical activity among women with young children. It is clear that further work needs to be done to explore methods of translating the short-term intervention effect shown in this study into long-term changes in PA behaviour. This study also provided insight into measurement issues in PA research and raised questions about self-report measures of PA and perceived constraints to being physically active. The results from post-study qualitative interviews suggest that many women at this life-stage experience time constraints which, when accompanied by a lack of partner support and financial constraints, make leisure-time PA virtually impossible for many women. Future strategies might focus on targeting this population immediately prior to this life-stage in an attempt to encourage habitual physical activity before women have children. Increasing PA in this population should also address the entire family unit, and consider the way leisure-time is negotiated among the adults within a household. Social change and increased awareness of the range of benefits of PA for women with children are additional strategies to be considered.

Effect of Australia's walk to work day campaign on adults' active commuting and physical activity behavior

Purpose. To determine whether Australia's Walk to Work Day media campaign resulted in behavioural change among targeted groups. Methods. Pre- and postcampaign telephone surveys of a cohort of adults aged 18 to 65 years (n = 1100, 55% response rate) were randomly sampled from Australian major melropolitan areas. Tests for dependent samples were applied (McNemax chi(2) or paired t-test). Results. Among participants who did not usually actively commute to work was a significant decrease in car only use an increase in walking combined with public transport. Among those who were employed was a significant increase in total time walking (+16 min/wk; t [780] = 2.04, p < .05) and in other moderate physical activity (+120 min/wk; t [1087] = 4.76, p < .005), resulting in a significant decrease in the proportion who were inactive (chi(2) (1) = 6.1, p < .05). Conclusion. Although nonexperimental, the Walk to Work Day initiative elicited short-term changes in targeted behaviors among target groups. Reinforcement by integrating worksite health promotion strategies may be required for sustained effects.