The landmark HIV Prevention Trials Network (HPTN) 052 trial in HIV-discordant couples demonstrated unequivocally that treatment with antiretroviral therapy (ART) substantially lowers the probability of HIV transmission to the HIV-uninfected partner. However, it has been vigorously debated whether substantial population-level reductions in the rate of new HIV infections could be achieved in “real-world” sub-Saharan African settings where stable, cohabiting couples are often not the norm and where considerable operational challenges exist to the successful and sustainable delivery of treatment and care to large numbers of patients. We used data from one of Africa’s largest population-based prospective cohort studies (in rural KwaZulu-Natal, South Africa) to follow up a total of 16,667 individuals who were HIV-uninfected at baseline, observing individual HIV seroconversions over the period 2004 to 2011. Holding other key HIV risk factors constant, individual HIV acquisition risk declined significantly with increasing ART coverage in the surrounding local community. For example, an HIV-uninfected individual living in a community with high ART coverage (30 to 40% of all HIV-infected individuals on ART) was 38% less likely to acquire HIV than someone living in a community where ART coverage was low (<10% of all HIV-infected individuals on ART).

Objectives To investigate HIV prevalence trends in a rural South African community after the scale-up of antiretroviral treatment (ART) in 2004. Methods We estimated adult HIV prevalence (ages 15–49 years) using data from a large, longitudinal, population-based HIV surveillance in rural KwaZulu-Natal, South Africa, over the period from 2004 (the year when the public-sector ART scale-up started) through 2011. We control for selection effects due to surveillance non-participation using multiple imputation. We further linked the surveillance data to patient records from the local HIV treatment programme to estimate ART coverage. Results ART coverage of all HIV-infected people in this community increased from 0% in 2004 to 31% in 2011. Over the same observation period adult HIV prevalence increased steadily from 21% to 29%. The overall increase in HIV prevalence was largely driven by the prevalence trends in women and men older than 24 years of age, i.e., the age group in which the largest proportions of HIV-infected people received ART. Conclusions The observed dramatic rise in adult HIV prevalence can be largely explained by increased survival of HIV-infected people due to ART. This interpretation is supported by the fact that the overall HIV prevalence trend is mostly due to increases in prevalence in older adults, i.e., in the age groups that currently benefit most from the local ART scale-up. Future studies should decompose HIV prevalence trends into HIV incidence and HIV-specific mortality changes to further improve the causal attribution of prevalence increases to treatment success rather than prevention failure.

Objective:Our study uses sex-specific and age-specific HIV prevalence data from an ongoing population-based demographic and HIV survey to infer HIV incidence and survival in rural KwaZulu-Natal between 2003 and 2011, a period when antiretroviral treatment (ART) was rolled out on a large scale.Design:Catalytic mathematical model for estimating HIV incidence and differential survival in HIV-infected persons on multiple rounds of HIV seroprevalence.Methods:We evaluate trends of HIV incidence and survival by estimating parameters separately for women and men aged 15–49 years during three calendar periods (2003–2005, 2006–2008, 2009–2011) reflecting increasing ART coverage. We compare model-based estimates of HIV incidence with observed cohort-based estimates from the longitudinal HIV surveillance.Results:Median survival after HIV infection increased significantly between 2003–2005 and 2009–2011 from 10.0 [95% confidence interval (CI) 8.8–11.2] to 14.2 (95% CI 12.6–15.8) years in women (P < 0.001) and from 10.0 (95% CI 9.2–10.8) to 14.0 (95% CI 10.6–17.4) years in men (P = 0.02). Our model suggests no statistically significant reduction of HIV incidence in the age-group 15–49 years in 2009–2011 compared with 2003–2005. Age-specific and sex-specific model-based HIV incidence estimates were in good agreement with observed cohort-based estimates from the ongoing HIV surveillance.Conclusion:Our catalytic modelling approach using cross-sectional age-specific HIV prevalence data could be useful to monitor trends of HIV incidence and survival in other African settings with a high ART coverage.

Compared to rural agriculture, urban agriculture (UA) has some distinct features (e.g., the limited land access, alternative growing media, unique legal environments or the non-production-related missions) that encourage the development of new practices, i.e., "novelties" or "innovations". This paper aims to (1) identify the "triggers" for novelty production in UA;(2) characterize the different kinds of novelties applied in UA; (3) evaluate the "innovativeness" of those social, environmental and economic novelties; and, (4) estimate the links between novelties and sustainability. The study was based on the evaluation of 11 case studies in four Western European countries (Italy, Germany, France and Spain). The results show that the trigger and origin of new activities can often be traced back to specific problems that initiators were intended to address or solve. In total, we found 147 novelties produced in the 11 case studies. More novelties are produced in the environmental and social dimensions of sustainability than in the economic. In most cases, external stakeholders played an important role in supporting the projects. The analysis further suggests that innovativeness enhances the overall sustainability in urban agriculture projects.Goldstein et al. [7] defined UA as follows: "Most broadly, urban agriculture refers to growing and raising food crops and animals in an urban setting for the purpose of feeding local populations." Guided by this definition, we focus our research on this type of agricultural or horticultural production that is taking place either within the city or in very close proximity to it. UA as an InnovationDespite the early origin of UA in cities, it has often been considered an "innovative" way to address current urban problems. Therefore, this raises the following question: If UA is not new, why is it so often considered innovative? Pfeiffer et al. [8] indicated that many aspects of urban agricultural production are indeed very similar to those of small-scale rural farms and not entirely new, while other factors set UA apart from traditional agricultural operations. In their study, Pfeiffer et al. also described the distinct features of UA, such as the limited and nontraditional land access, the usage of urban soils and alternative growing media, the unique legal and political environments, the non-production-related missions, and the involvement of nontraditional farmers, which force the development of new practices. Prain and De Zeeuw [9] confirmed and complemented those findings by elaborating that the key factors for innovation in UA are those factors, such as multiple livelihood strategies, lower community cohesion, fewer possibilities for integrated agriculture, and quick market access, which differentiate urban from rural agriculture. They identified a direct correlation between urban settings and innovation processes in UA. Those specific conditions and characteristics drive urban operations to develop unique new practices adapted to the urban context.

BACKGROUNDUnderstanding how the elderly in developing countries spend their time has received little attention. Moreover, the potential of time use data to discern variation in activity patterns has not been fully realized by methods which use a mean added time approach. OBJECTIVESTo uncover patterns of time use among the elderly (60 years and older) in South Africa by applying an innovative methodology that incorporates the timing, duration, and frequency of activities in the analysis. METHODSWe use sequence analysis, which treats the daily series of activities of each individual as a sequence, and cluster analysis, to group these sequences into common clusters of time use behaviour. We then estimate multinomial logit regressions to identify the characteristics of the elderly which predict cluster membership. RESULTSWe find that the time use behaviour of the elderly in South Africa can be divided into five distinct clusters, according to the relative importance in their day of personal care, household maintenance, work, mass media, and social or cultural activities. In comparison to men, women are overrepresented in the cluster where household work dominates, while they are underrepresented in the cluster of the elderly who engage in production work. A range of other individual and household characteristics are also important in predicting cluster membership.