Effectiveness of three delivery models for promoting access to pre-exposure prophylaxis in HIV-1 serodiscordant couples in Nigeria.

OBJECTIVES: To evaluate the effectiveness of three models for pre-exposure prophylaxis (PrEP) service delivery to HIV-1 serodiscordant couples in Nigeria. METHODS: 297 heterosexual HIV-1 serodiscordant couples were recruited into three PrEP delivery models and followed up for 18 months. The models were i) Outpatient clinic model providing PreP in routine outpatient care; ii) Antiretroviral therapy (ART) clinic model providing PrEP in ART clinics; and iii) Decentralized care model providing PrEP through primary and secondary care centres linked to a tertiary care centre. The primary effectiveness endpoint was incident HIV-1 infection. The HIV incidence before and after the study was compared and the incidence rate ratio computed for each model. Survival analysis was conducted, Cox regression analysis was used to compare the factors that influenced couple retention in each of the models. Kaplan-Meier survival analysis was used to estimate the median retention time (in months) of the study participants in each of the study models, and log-rank test for equality of survival functions was conducted to test for significant differences among the three models. RESULTS: There was no significant difference (p>0.05) in the couple retention rates among the three models. At months 3, 6 and 9, adherence of the HIV-1-infected partners to ART was highest in the decentralized model, whereas at months 9 and 12, the outpatient model had the highest proportion of HIV-1- uninfected partners adhering to PrEP (p<0.001). The HIV incidence per 100 person-years was zero in the general outpatient clinic and ART clinic models and 1.6 (95% CI: 0.04-9.1) in the decentralized clinic model. The difference in the observed and expected incidence rate was 4.3 (95% CI: 0.44-39.57) for the decentralized clinic model. CONCLUSION: Although incidence of HIV seroconversion was highest in the decentralized clinic model, this difference may be due to the higher sexual risk behavior among study participants in the decentralized model rather than the type of service delivery. The study findings imply that any of the models can effectively deliver PrEP services.

Randomised controlled trial of weekly chloroquine to re-establish normal erythron iron flux and haemoglobin recovery in postmalarial anaemia.

OBJECTIVE: To determine if low-dose weekly chloroquine (CQ) therapy improves recovery from malaria-associated anaemia. DESIGN: Proof of concept randomised clinical trial. SETTING: West Kiang District, Lower River Region, The Gambia. PARTICIPANTS: Children resident in participating communities, aged 12-72 months, with uncomplicated malaria identified using active case detection over two consecutive malaria transmission seasons. INTERVENTIONS: In 2007, eligible children were randomised to chloroquine-sulfadoxine/pyrimethamine (CQ-SP) or co-artemether (ACT) antimalarial therapy, and after parasite clearance on day 3 were subsequently re-randomised (double-blind) to weekly low-dose CQ (5 mg/kg) or placebo. In 2008, all eligible children were treated with ACT and subsequently randomised to CQ or placebo. OUTCOME MEASURES: The primary outcome was a change in haemoglobin from baseline (day 3 of antimalarial treatment) to day 90 in the CQ and placebo treatment arms. Secondary outcomes were changes in urinary neopterin as a marker of macrophage activation, markers of erythropoietic response and prevalence of submicroscopic parasitaemia. Change in haemoglobin in the placebo arm by initial antimalarial treatment was also assessed. RESULTS: In 2007, 101 children with uncomplicated malaria were randomised to antimalarial treatment with CQ-SP or ACT and 65 were subsequently randomised to weekly CQ or placebo. In 2008, all children received ACT antimalarial treatment and 31 were subsequently randomised to receive weekly CQ or placebo. Follow-up to day 90 was 96%. There was no effect of weekly CQ vs placebo on change in haemoglobin at day 90 (CQ+10.04 g/L (95% CI 6.66 to 13.42) vs placebo +7.61 g/L (95% CI 2.88 to 12.35)). There was no effect on the secondary outcomes assessed, or effect of initial antimalarial therapy on haemoglobin recovery. Higher day 90 haemoglobin correlated independently with older age, not being stunted, higher haemoglobin at day 0 and adequate iron status at day 3. CONCLUSIONS: Weekly low-dose CQ after effective antimalarial treatment is not effective in improving recovery from postmalarial anaemia. TRIAL REGISTRATION: The clinical trial registration number is NCT00473837 (ClinicalTrials.gov).

Accelerating the development of a safe and effective HIV vaccine: HIV vaccine case study for the Decade of Vaccines.

Human immunodeficiency virus (HIV), the etiologic agent that causes AIDS, is the fourth largest killer in the world today. Despite the remarkable achievements in development of anti-retroviral therapies against HIV, and the recent advances in new prevention technologies, the rate of new HIV infections continue to outpace efforts on HIV prevention and control. Thus, the development of a safe and effective vaccine for prevention and control of AIDS remains a global public health priority and the greatest opportunity to eventually end the AIDS pandemic. Currently, there is a renaissance in HIV vaccine development, due in large part to the first demonstration of vaccine induced protection, albeit modest, in human efficacy trials, a generation of improved vaccine candidates advancing in the clinical pipeline, and newly defined targets on HIV for broadly neutralizing antibodies. The main barriers to HIV vaccine development include the global variability of HIV, lack of a validated animal model, lack of correlates of protective immunity, lack of natural protective immune responses against HIV, and the reservoir of infected cells conferred by integration of HIV's genome into the host. Some of these barriers are not unique to HIV, but generic to other variable viral pathogens such as hepatitis C and pandemic influenza. Recommendations to overcome these barriers are presented in this document, including but not limited to expansion of efforts to design immunogens capable of eliciting broadly neutralizing antibodies against HIV, expansion of clinical research capabilities to assess multiple immunogens concurrently with comprehensive immune monitoring, increased support for translational vaccine research, and engaging industry as full partners in vaccine discovery and development.

Helicobacter pylori infection and circulating ghrelin levels - a systematic review.

BACKGROUND: The nature of the association between ghrelin, an orexigenic hormone produced mainly in the stomach, and Helicobacter pylori (H pylori), a bacterium that colonises the stomach, is still controversial. We examined available evidence to determine whether an association exists between the two; and if one exists, in what direction. METHODS: We reviewed original English language studies on humans reporting circulating ghrelin levels in H pylori infected and un-infected participants; and circulating ghrelin levels before and after H pylori eradication. Meta-analyses were conducted for eligible studies by combining study specific estimates using the inverse variance method with weighted average for continuous outcomes in a random effects model. RESULTS: Seventeen out of 27 papers that reported ghrelin levels in H pylori positive and negative subjects found lower circulating ghrelin levels in H pylori positive subjects; while 10 found no difference. A meta-analysis of 19 studies with a total of 1801 participants showed a significantly higher circulating ghrelin concentration in H pylori negative participants than in H pylori positive participants (Effect estimate (95%CI) = -0.48 (-0.60, -0.36)). However, eradicating H pylori did not have any significant effect on circulating ghrelin levels (Effect estimate (95% CI) = 0.08 (-0.33, 0.16); Test for overall effect: Z = 0.67 (P = 0.5)). CONCLUSIONS: We conclude that circulating ghrelin levels are lower in H pylori infected people compared to those not infected; but the relationship between circulating ghrelin and eradication of H pylori is more complex.

Determinants of appropriate child health and nutrition practices among women in rural Gambia.

Health education and awareness involves providing knowledge about causes of illness and choices to promote a change in individual behaviour and, thus, improves survival of individuals. Studies have, however, shown that improved knowledge and awareness is not always translated into appropriate actions. This study aimed at exploring the factors determining mothers' choices of appropriate child health and nutrition practices in the Gambia. Eight focus-group discussions (FGDs) were held with 63 women whose children had been seen at the Keneba MRC Clinic within the 12 months preceding the study. The FGDs were analyzed using a thematic framework. Gender inequality, presence or absence of support networks, alternative explanatory models of malnutrition, and poverty were identified as the main factors that would determine the ability of a mother to practise what she knows about child health and nutrition. The findings highlight the need to consider the broader social, cultural and economic factors, including the value of involving men in childcare, when designing nutritional interventions.

Iron delocalisation in the pathogenesis of malarial anaemia.

There is consensus that the pathophysiology of malaria-associated anaemia is multifactorial, but the precise mechanisms behind many of the haematological changes during malaria remain unclear. In this review, we attempt to build a composite picture of the pathophysiology of malarial anaemia using evidence from experimental, human and animal studies. We propose that cytokine- and hepcidin-mediated iron delocalisation, a principal mechanism in the anaemia of inflammation, plays an important role in the aetiology of malarial anaemia, and can explain some of the clinical and laboratory findings. These mechanisms interact with other aetiological determinants, such as dietary iron and micronutrient supply, helminth load, other infections and genetic variation, in determining the severity and associated features of anaemia. We suggest that iron delocalisation as a mechanism for malarial anaemia could be exploited for the development of alternative therapeutic strategies for post-malaria anaemia.

Curbing the menace of antimicrobial resistance in developing countries.

Several reports suggest that antimicrobial resistance is an increasing global problem; but like most pandemics, the greatest toll is in the less developed countries. The dismally low rate of discovery of antimicrobials compared to the rate of development of antimicrobial resistance places humanity on a very dangerous precipice. Since antimicrobial resistance is part of an organism's natural survival instinct, total eradication might be unachievable; however, it can be reduced to a level that it no longer poses a threat to humanity. While inappropriate antimicrobial consumption contributes to the development of antimicrobial resistance, other complex political, social, economic and biomedical factors are equally important. Tackling the menace therefore should go beyond the conventional sensitization of members of the public and occasional press releases to include a multi-sectoral intervention involving the formation of various alliances and partnerships. Involving civil society organisations like the media could greatly enhance the success of the interventions.

Haptoglobin genotype, anaemia and malaria in Gambian children.

OBJECTIVE: To retest our previous finding that the haptoglobin (Hp) 22 genotype is associated with seasonal anaemia, and to investigate the role of malaria in this effect. METHODS: Haemoglobin (Hb) and peripheral parasitaemia were assessed at pre- and post-malarial season cross-sectional surveys in rural Gambian children aged 10-72 months. Between the surveys, active longitudinal surveillance was conducted to detect febrile episodes. RESULTS: Unlike previously, no overall reduction in Hb was observed (Hb = 106.1 vs. 107.2 g/l, P = 0.13, n = 545). However, multi-variable linear regression revealed differences in Hb over the season by Hp and Hb-sickle (HbS) genotype (-2.20 g/l per copy of the Hp2 allele, P = 0.043; HbAS vs. HbAA + 3.13 g/l, P = 0.11, n = 536). There was no effect of malarial episodes during follow-up; this suggests that when effective treatment is given, Hb levels recover. The A61-C Hp promoter SNP, associated with the Hp2 allele, had no effect. CONCLUSION: The effect of the Hp2 allele appears to be independent of effects on malaria incidence but may affect Hb levels through increased oxidant stress and red cell turnover. This may be supported by our previous observations that the effect of Hp22 was independent of markers of iron status and zinc protoporphyrin measured at the cross-sectional surveys and therefore also of iron availability for erythropoiesis.

Haplotype association between haptoglobin (Hp2) and Hp promoter SNP (A-61C) may explain previous controversy of haptoglobin and malaria protection.

BACKGROUND: Malaria is one of the strongest recent selective pressures on the human genome, as evidenced by the high levels of varying haemoglobinopathies in human populations-despite the increased risk of mortality in the homozygous states. Previously, functional polymorphisms of Hp, coded by the co-dominant alleles Hp1 and Hp2, have been variously associated with several infectious diseases, including malaria susceptibility. METHODOLOGY/PRINCIPAL FINDINGS: Risk of a clinical malarial episode over the course of a malarial transmission season was assessed using active surveillance in a cohort of Gambian children aged 10-72 months. We report for the first time that the major haplotype for the A-61C mutant allele in the promoter of haptoglobin (Hp)-an acute phase protein that clears haemoglobin released from haemolysis of red cells-is associated with protection from malarial infection in older children, (children aged >or=36 months, >500 parasites/ul and temperature >37.5 degrees C; OR = 0.42; [95% CI 0.24-0.73] p = 0.002) (lr test for interaction, <36 vs >or=36 months, p = 0.014). Protection was also observed using two other definitions, including temperature >37.5 degrees C, dipstick positive, plus clinical judgement of malaria blinded to dipstick result (all ages, OR = 0.48, [95% CI 0.30-0.78] p = 0.003; >or=36 months, OR = 0.31, [95% CI 0.15-0.62] p = 0.001). A similar level of protection was observed for the known protective genetic variant, sickle cell trait (HbAS). CONCLUSIONS/SIGNIFICANCE: We propose that previous conflicting results between Hp phenotypes/genotypes and malaria susceptibility may be explained by differing prevalence of the A-61C SNP in the populations studied, which we found to be highly associated with the Hp2 allele. We report the -61C allele to be associated with decreased Hp protein levels (independent of Hp phenotype), confirming in vitro studies. Decreased Hp expression may lead to increased oxidant stress and increased red cell turnover, and facilitate the development of acquired immunity, similar to a mechanism suggested for sickle cell trait.

Acceptability of female-controlled HIV/STI prevention options by Nigerian professionals - an exploratory study.

The attitudes of working professionals, particularly in the healthcare sector, may play a large role in the acceptance or otherwise of female-controlled HIV/STI prevention options. In 2002, we conducted an exploratory study on the perceptions surrounding female-controlled HIV/STI prevention options, principally the acceptability of a female condom or a vaginal microbicide, among a small sample of Nigerian professionals. A self-administered structured questionnaire was given to 50 persons representing four professions. The majority of the respondents agreed with a proposition stating a need for female-controlled HIV/STI prevention options. More females than males supported such options; both male and female respondents expressed a higher preference for a vaginal microbicide than for the female condom. The reasons given for unwillingness to use the female condom included social, cultural and religious biases, cumbersomeness and inefficiency. Only a small proportion of the total respondents felt willing to participate in a clinical trial with the vaginal microbicide. Further studies are needed to determine the relevance of these findings to the professional community in Nigeria at large, especially for the purposes of planning better social marketing strategies.