Varying efficacy of artesunate+amodiaquine and artesunate+sulphadoxine-pyrimethamine for the treatment of uncomplicated falciparum malaria in the Democratic Republic of Congo: a report of two in-vivo studies

BACKGROUND: Very few data on anti-malarial efficacy are available from the Democratic Republic of Congo (DRC). DRC changed its anti-malarial treatment policy to amodiaquine (AQ) and artesunate (AS) in 2005. METHODS: The results of two in vivo efficacy studies, which tested AQ and sulphadoxine-pyrimethamine (SP) monotherapies and AS+SP and AS+AQ combinations in Boende (Equatorial province), and AS+SP, AS+AQ and SP in Kabalo (Katanga province), between 2003 and 2004 are presented. The methodology followed the WHO 2003 protocol for assessing the efficacy of anti-malarials in areas of high transmission. RESULTS: Out of 394 included patients in Boende, the failure rates on day 28 after PCR-genotyping adjustment of AS+SP and AS+AQ were estimated as 24.6% [95% CI: 16.6-35.5] and 15.1% [95% CI: 8.6-25.7], respectively. For the monotherapies, failure rates were 35.9% [95% CI: 27.0-46.7] for SP and 18.3% [95% CI: 11.6-28.1] for AQ. Out of 207 patients enrolled in Kabalo, the failure rate on day 28 after PCR-genotyping adjustment was 0 [1-sided 95% CI: 5.8] for AS+SP and AS+AQ [1-sided 95% CI: 6.2]. It was 19.6% [95% CI: 11.4-32.7] for SP monotherapy. CONCLUSION: The finding of varying efficacy of the same combinations at two sites in one country highlights one difficulty of implementing a uniform national treatment policy in a large country. The poor efficacy of AS+AQ in Boende should alert the national programme to foci of resistance and emphasizes the need for systems for the prospective monitoring of treatment efficacy at sentinel sites in the country

European and Developing Countries Clinical Trials Partnership (EDCTP): the path towards a true partnership

European and Developing Countries Clinical Trials Partnership (EDCTP) was founded in 2003 by the European Parliament and Council. It is a partnership of 14 European Union (EU) member states, Norway, Switzerland, and Developing Countries, formed to fund acceleration of new clinical trial interventions to fight the human immunodeficiency virus and acquired immune deficiency syndrome (HIV/AIDS), malaria and tuberculosis (TB) in the sub-Saharan African region. EDCTP seeks to be synergistic with other funding bodies supporting research on these diseases. EDCTP promotes collaborative research supported by multiple funding agencies and harnesses networking expertise across different African and European countries. EDCTP is different from other similar initiatives. The organisation of EDCTP blends important aspects of partnership that includes ownership, sustainability and responds to demand-driven research. The Developing Countries Coordinating Committee (DCCC); a team of independent scientists and representatives of regional health bodies from sub-Saharan Africa provides advice to the partnership. Thus EDCTP reflects a true partnership and the active involvement and contribution of these African scientists ensures joint ownership of the EDCTP programme with European counterparts. The following have been the major achievements of the EDCTP initiative since its formation in 2003; i) increase in the number of participating African countries from two to 26 in 2008 ii) the cumulative amount of funds spent on EDCTP projects has reached 150 m euros, iii) the cumulative number of clinical trials approved has reached 40 and iv) there has been a significant increase number and diversity in capacity building activities. While we recognise that EDCTP faced enormous challenges in its first few years of existence, the strong involvement of African scientists and its new initiatives such as unconditional funding to regional networks of excellence in sub-Saharan Africa is envisaged to lead to a sustainable programme. Current data shows that the number of projects supported by EDCTP is increasing. DCCC proposes that this success story of true partnership should be used as model by partners involved in the fight against other infectious diseases of public health importance in the region

Plasmodium falciparum: Differential Selection of Drug Resistance Alleles in Contiguous Urban and Peri-Urban Areas of Brazzaville, Republic of Congo

The African continent is currently experiencing rapid population growth, with rising urbanization increasing the percentage of the population living in large towns and cities. We studied the impact of the degree of urbanization on the population genetics of Plasmodium falciparum in urban and peri-urban areas in and around the city of Brazzaville, Republic of Congo. This field setting, which incorporates local health centers situated in areas of varying urbanization, is of interest as it allows the characterization of malaria parasites from areas where the human, parasite, and mosquito populations are shared, but where differences in the degree of urbanization (leading to dramatic differences in transmission intensity) cause the pattern of malaria transmission to differ greatly. We have investigated how these differences in transmission intensity affect parasite genetic diversity, including the amount of genetic polymorphism in each area, the degree of linkage disequilibrium within the populations, and the prevalence and frequency of drug resistance markers. To determine parasite population structure, heterozygosity and linkage disequilibrium, we typed eight microsatellite markers and performed haplotype analysis of the msp1 gene by PCR. Mutations known to be associated with resistance to the antimalarial drugs chloroquine and pyrimethamine were determined by sequencing the relevant portions of the crt and dhfr genes, respectively. We found that parasite genetic diversity was comparable between the two sites, with high levels of polymorphism being maintained in both areas despite dramatic differences in transmission intensity. Crucially, we found that the frequencies of genetic markers of drug resistance against pyrimethamine and chloroquine differed significantly between the sites, indicative of differing selection pressures in the two areas

Investigating the effect of independent blinded digital image assessment on the STOP GAP trial

Background Blinding is the process of keeping treatment assignment hidden and is used to minimise the possibility of bias. Trials at high risk of bias have been shown to report larger treatment effects than low risk studies. In dermatology, one popular method of blinding is to have independent outcome assessors who are unaware of treatment allocation assessing the end point using digital photographs. However, this can be complex, expensive and time-consuming. The objective of this study was to compare the effect of blinded and unblinded outcome assessment on the results of the STOP GAP trial. Methods The STOP GAP trial compared prednisolone to ciclosporin in treating pyoderma gangrenosum. Participants’ lesions were measured at baseline and 6 weeks to calculate the primary outcome, speed of healing. Independent blinded assessors obtained measurements from digital photographs using specialist software. In addition, unblinded treating clinicians estimated lesion area by measuring length and width. The primary outcome was determined using blinded measurements where available, otherwise unblinded measurements were used (method referred to as trial measurements). In this study, agreement between the trial and unblinded measurements was determined using the intraclass correlation coefficient (ICC). The STOP GAP primary analysis was repeated using unblinded measurements only. We introduced differential and non-differential error in unblinded measurements and investigated the effect on the STOP GAP primary analysis. Results 86 (80%) of the 108 patients were assessed using digital images. Agreement between trial and unblinded measurements was excellent (ICC=0.92 at baseline; 0.83 at 6 weeks). There was no evidence that the results of the trial primary analysis differed according to how the primary outcome was assessed (p-value for homogeneity = 1.00). Conclusions Blinded digital image assessment in STOP GAP did not meaningfully alter trial conclusions compared with unblinded assessment. However, as the process brought added accuracy and credibility to the trial it was considered worthwhile. These findings question the usefulness of digital image assessment in a trial with an objective outcome and where bias is not expected to be excessive. Further research should investigate if there are alternative, less complex ways of incorporating blinding in clinical trials

Effect of trimethoprim-sulphamethoxazole on the risk of malaria in HIV-infected Ugandan children living in an area of widespread antifolate resistance

<p>Abstract</p> <p>Background</p> <p>Daily trimethoprim-sulfamethoxazole (TS) protects against malaria, but efficacy may be diminished as anti-folate resistance increases. This study assessed the incidence of falciparum malaria and the prevalence of resistance-conferring <it>Plasmodium falciparum </it>mutations in HIV-infected children receiving daily TS and HIV-uninfected children not taking TS.</p> <p>Materials and methods</p> <p>Subjects were 292 HIV-infected and 517 uninfected children from two cohort studies in Kampala, Uganda observed from August 2006 to December 2008. Daily TS was given to HIV-infected, but not HIV-uninfected children and all participants were provided an insecticide-treated bed net. Standardized protocols were used to measure the incidence of malaria and identify markers of antifolate resistance.</p> <p>Results</p> <p>Sixty-five episodes of falciparum malaria occurred in HIV-infected and 491 episodes in uninfected children during the observation period. TS was associated with a protective efficacy of 80% (0.10 vs. 0.45 episodes per person year, p < 0.001), and efficacy did not vary over three consecutive 9.5 month periods (81%, 74%, 80% respectively, p = 0.506). The prevalences of <it>dhfr </it>51I, 108N, and 59R and <it>dhps </it>437G and 540E mutations were each over 90% among parasites infecting both HIV-infected and uninfected children. Prevalence of the <it>dhfr </it>164L mutation, which is associated with high-level resistance, was significantly higher in parasites from HIV-infected compared to uninfected children (8% vs. 1%, p = 0.001). Sequencing of the <it>dhfr </it>and <it>dhps </it>genes identified only one additional polymorphism, <it>dhps </it>581G, in 2 of 30 samples from HIV-infected and 0 of 54 samples from uninfected children.</p> <p>Conclusion</p> <p>Despite high prevalence of known anti-folate resistance-mediating mutations, TS prophylaxis was highly effective against malaria, but was associated with presence of <it>dhfr </it>164L mutation.</p

Failure to detect Plasmodium vivax in West and Central Africa by PCR species typing

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium vivax </it>is estimated to affect 75 million people annually. It is reportedly absent, however, from west and central Africa due to the high prevalence of the Duffy negative phenotype in the indigenous populations. Despite this, non-African travellers consistently return to their own countries with <it>P. vivax </it>malaria after visiting this region. An attempt was made, therefore, to detect the presence of <it>P. vivax </it>parasites in blood samples collected from the indigenous populations of west and central Africa.</p> <p>Methods</p> <p>Parasite species typing (for all four human malaria parasites) was carried out by PCR on 2,588 blood samples collected from individuals from nine African malaria-endemic countries.</p> <p>Results</p> <p>Most infections (98.5%) were <it>Plasmodium falciparum</it>, <it>Plasmodium malariae </it>was identified in 8.5% of all infections, and <it>Plasmodium ovale </it>in 3.9%. The prevalence of both parasites varied greatly by country. Only one case of <it>P. vivax </it>was detected from Sao Tome, an island off the west coast of Africa, confirming the scarcity of this parasite in Africa.</p> <p>Conclusion</p> <p>The prevalence of <it>P. vivax </it>in local populations in sub-Saharan Africa is very low, despite the frequent identification of this parasite in non-African travellers.</p