Genetic exchange in <i>Trypanosoma brucei</i>: evidence for mating prior to metacyclic stage development

It is well established that genetic exchange occurs between Trypanosoma brucei parasites when two stocks are used to infect tsetse flies under laboratory conditions and a number of such crosses have been undertaken. Both cross and self-fertilisation can take place and, with the products of mating being the equivalent of F1 progeny in a Mendelian system and. Recently, analysis of a large collection of independent progeny using a series of polymorphic micro and minisatellite markers, has formally demonstrated that the allelic segregation at loci on each of the 11-megabase chromosomes conforms to ratios predicted for a classical diploid genetic system involving meiosis as well as independent assortment of markers on different chromosomes. Further extensive analysis of these F1 progeny, using a large panel of micro and minisatellite markers, has led to the construction of a genetic map of one parasite stock A. MacLeod, A. Tweedie and S. McLellan et al., The genetic map of Trypanosoma brucei, Nucleic Acids Res 33 (2005), pp. 6688–6693. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (10)

IMPACTS OF HIGH-SPEED RAIL ON NEW FIRM FORMATION

Using a detailed data set of new firm formation in one city in China the paper provides evidence on the extent to which HSR has facilitated urban economic restructuring. Using location quotients and a probabilistic analysis of the determinants of new firm location, the findings indicate a significant rise of new firm formation after the arrival of HSR and that new firms appear likely to be in places closer to HSR stations, particularly those with a higher frequency of train service and interchange with metro services. The resulting spatial patterns suggest a dynamism of both a reinforced old urban core and a decentralisation process in new urban districts. The paper reinforces the view that more research using disaggregated data is essential to understand the role of HSR in transforming cities and regions in China with implications for other countries using HSR as an instrument of restructuring and transformation

Investment case for eliminating mother-to-child transmission of syphilis: promoting better maternal and child health and stronger health systems

Mother-to-child transmission (MTCT) of syphilis (commonly referred to as “congenital syphilis”) is relatively simple to eliminate and it is inexpensive to detect and treat, making it a possible “easy win” in terms of cost, feasibility and speed of scale-up. Investing in screening and treatment for syphilis in pregnant women ranks as one of the most cost-effective antenatal interventions. Screening all pregnant women, using simple and low-cost technologies, is feasible, even in low-resource settings. Syphilis is easily cured with penicillin, and MTCT of syphilis is easily prevented when pregnant mothers with syphilis infection are identified early and treated promptly. Penicillin is off patent, widely available, on the World Health Organization (WHO) list of essential medicines and, above all, inexpensive

Using hepatitis C prevalence to estimate HIV epidemic potential among people who inject drugs in the Middle East and North Africa.

OBJECTIVES: The objective of this study is to understand the association between HIV and hepatitis C virus (HCV) among people who inject drugs (PWIDs) in the Middle East and North Africa (MENA), and to estimate HIV epidemic potential among PWIDs using HCV prevalence. DESIGN/METHODS: Using data from a systematic review of HIV and HCV among PWID in MENA, we conducted two analyses, stratified by HIV epidemic state: a meta-analysis of the risk ratio of HCV to HIV prevalence (RRHCV/HIV) using DerSimonian-Laird random-effects models, and multivariable linear regression predicting log HIV prevalence. The HCV-HIV association from both analyses was used to estimate HIV prevalence at endemic equilibrium. We compared predicted with current HIV prevalence to classify HIV epidemic potential at country-level as low, medium or high, using predefined criteria. RESULTS: The review identified 88 HCV prevalence measures among PWID in MENA, of which 54 had a paired HIV prevalence measure. The pooled RRHCV/HIV were 16, 4 and 3 in low-level, emerging and established HIV epidemics, respectively. There was a significant linear relationship between HCV and HIV at endemic equilibrium (P = 0.002). The predicted endemic HIV prevalence ranged between 8% (Tunisia) and 22% (Pakistan). Of the nine countries with data, five have high and three medium HIV epidemic potential. Only one country, Pakistan, appears to have reached saturation. CONCLUSION: HCV prevalence could be a predictor of future endemic HIV prevalence. In MENA, we predict that there will be further HIV epidemic growth among PWID. The proposed methodology can identify PWID populations that should be prioritized for HIV prevention interventions

The remittances behaviour of the second generation in Europe: altruism or self-interest?

Whereas most research on remittances focuses on first-generation migrants, the aim of this paper is to investigate the remitting behaviour of the host country-born children of migrants - the second generation - in various European cities. Some important studies found that migrant transnationalism is not only a phenomenon for the first generation, but also apply to the second and higher generations, through, among other things, family visits, elder care, and remittances. At the same time, the maintenance of a strong ethnic identity in the ‘host’ society does not necessarily mean that second-generation migrants have strong transnational ties to their ‘home’ country. The data used in this paper is from “The Integration of the European Second Generation” (TIES) project. The survey collected information on approximately 6,250 individuals aged 18-35 with at least one migrant parent from Morocco, Turkey or former Yugoslavia, in 15 European cities, regrouped in 8 ‘countries’. For the purpose of this paper, only analyses for Austria (Linz and Vienna); Switzerland (Basle and Zurich); Germany (Berlin and Frankfurt); France (Paris and Strasbourg); the Netherlands (Amsterdam and Rotterdam); Spain (Barcelona and Madrid); and Sweden (Stockholm) will be presented.

How large is the gap between present and efficient transport prices in Europe?

In this paper we analyse the gap between present transport prices and efficient transport prices. Efficient transport prices are those prices that maximise economic welfare, including external costs (congestion, air pollution, accidents). The methodology is applied to six urban and interregional case studies using one common optimal pricing model. The case studies cover passenger as well as freight transport and cover all modes. We find that prices need to be raised most for peak urban passenger car transport and to a lesser extent for interregional road transport. Optimal pricing results for public transport are more mixed. We show that current external costs on congested roads are a bad guide for optimal taxes and tolls: the optimal toll that takes into account the reaction of demand is often less than one third of the present marginal external cost.transport pricing; external costs; social costs; congestion pricing

Global population-level association between herpes simplex virus 2 prevalence and HIV prevalence.

BACKGROUND: Our objective was to assess the population-level association between herpes simplex virus 2 (HSV-2) and HIV prevalence. METHODS: Reports of HSV-2 and HIV prevalence were systematically reviewed and synthesized following PRISMA guidelines. Spearman rank correlation ((Equation is included in full-text article.)) was used to assess correlations. Risk ratios (RRHSV-2/HIV) and odds ratios (ORHSV-2/HIV) were used to assess HSV-2/HIV epidemiologic overlap. DerSimonian-Laird random-effects meta-analyses were conducted. RESULTS: In total, 939 matched HSV-2/HIV prevalence measures were identified from 77 countries. HSV-2 prevalence was consistently higher than HIV prevalence. Strong HSV-2/HIV prevalence association was found for all data ((Equation is included in full-text article.) = 0.6, P < 0.001), all data excluding people who inject drugs (PWID) and children ((Equation is included in full-text article.) = 0.7, P < 0.001), female sex workers ((Equation is included in full-text article.) = 0.5, P < 0.001), and MSM ((Equation is included in full-text article.) = 0.7, P < 0.001). No association was found for PWID ((Equation is included in full-text article.) = 0.2, P = 0.222) and children ((Equation is included in full-text article.) = 0.3, P = 0.082). A threshold effect was apparent where HIV prevalence was limited at HSV-2 prevalence less than 20%, but grew steadily with HSV-2 prevalence for HSV-2 prevalence greater than 20%. The overall pooled mean RRHSV-2/HIV was 5.0 (95% CI 4.7-5.3) and ORHSV-2/HIV was 9.0 (95% CI 8.4-9.7). The RRHSV-2/HIV and ORHSV-2/HIV showed similar patterns that conveyed inferences about HSV-2 and HIV epidemiology. CONCLUSION: HSV-2 and HIV prevalence are strongly associated. HSV-2 prevalence can be used as a proxy 'biomarker' of HIV epidemic potential, acting as a 'temperature scale' of the intensity of sexual risk behavior that drive HIV transmission. HSV-2 prevalence can be used to identify populations and/or sexual networks at high-risk of future HIV expansion, and help prioritization, optimization, and resource allocation of cost-effective prevention interventions

Financing essential HIV services: a new economic agenda.

Anna Vassall and colleagues discuss the need for, and challenges facing, innovative and sustainable financing of the HIV response. Please see later in the article for the Editors' Summary