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Background. Whether the risk of malaria is increased in infants born to mothers who experience malaria during pregnancy is uncertain. Methods. We investigated malaria incidence among an infant cohort born to 355 primigravidae and 1500 multigravidae with or without placental malaria (PM) in a high malaria transmission area of Ghana. PM was assessed using placental histology. Results. The incidence of all episodes of malaria parasitemia or clinical malaria was very similar among 3 groups of infants: those born to multigravidae without PM, multigravidae with PM, and primigravidae with PM. Infants born to primigravidae without PM experienced a lower incidence of malaria parasitemia or clinical malaria than the other 3 groups: adjusted hazard ratio, 0.64 (95% confidence interval [CI], .48–.86, P < .01) and 0.60 (95% CI, .43–.84, P < .01), respectively. The incidence of malaria parasitemia or clinical malaria was about 2 times higher in most poor infants compared to least poor infants. Conclusions. There was no suggestion that exposure to PM directly increased incidence of malaria among infants of multigravidae. In our study area, absence of placental malaria in primigravidae is a marker of low exposure, and this probably explains the lower incidence of malaria-related outcomes among infants of PM-negative primigravidae.

NO MAS (NM) mosquito repellent was evaluated in two farming villages (4 km apart) in the Kassena Nankana district of northern Ghana. We determined its efficacy against local malaria vectors, degree of user acceptance, and its effect on malaria prevalence in households using insecticide-treated bed nets. The average protective efficacy of NM against Anopheles mosquitoes over 9 hours was 89.6%. Controls averaged 86 bites/person/night versus 9 bites/person/night with the use of NM. Use of repellent was associated with a decrease of absolute malaria prevalence by 19.2% in the repellent village and by 6.5% in the control village (45.5 to 26.3, and 29.5 to 23.0, respectively). The user-acceptance rate of NM repellent was 96.1%. Ten percent (10%) of repellent users reported irritation as the main adverse effect during the period. Eighty-five percent (85%) of the users found the odor of NM appealing and 87% reported no inconvenience in applying the repellent daily.

Introduction: As an increasing number of malaria-endemic countries approach the disease elimination phase, sustenance of control efforts and effective monitoring are necessary to ensure success. Mathematical models that estimate anti-parasite antibody seroconversion rates are gaining relevance as more sensitive transmission intensity estimation tools. Models however estimate yearly seroconversion and seroreversion rates and usually predict long term changes in transmission, occurring years before the time of sampling. Another challenge is the identification of appropriate antigen targets since specific antibody levels must directly reflect changes in transmission patterns. We therefore investigated the potential of antibodies to sporozoite and blood stage antigens for detecting short term differences in malaria transmission in two communities in Northern Ghana with marked, seasonal transmission. Methods: Cross-sectional surveys were conducted during the rainy and dry seasons in two communities, one in close proximity to an irrigation dam and the other at least 20 Km away from the dam. Antibodies against the sporozoite-specific antigens circumsporozoite protein (CSP) and Cell traversal for ookinetes and sporozoites (CelTOS) and the classical blood stage antigen apical membrane antigen 1 (AMA1) were measured by indirect ELISA. Antibody levels and seroprevalence were compared between surveys and between study communities. Antibody seroprevalence data were fitted to a modified reversible catalytic model to estimate the seroconversion and seroreversion rates. Results: Changes in sporozoite-specific antibody levels and seroprevalence directly reflected differences in parasite prevalence between the rainy and dry seasons and hence the extent of malaria transmission. Seroconversion rate estimates from modelled seroprevalence data did not however support the above observation. Conclusions: The data confirms the potential utility of sporozoite-specific antigens as useful markers for monitoring short term/seasonal changes in malaria transmission. It may however be essential to update models to allow for assessment of seasonal changes in malaria transmission, which usually occur within four to six months.

Background Mycobacterium africanum comprises two phylogenetic lineages within the M. tuberculosis complex (MTBC) and is an important cause of human tuberculosis (TB) in West Africa. The reasons for this geographic restriction of M. africanum remain unclear. Here, we performed a prospective study to explore associations between the characteristics of TB patients and the MTBC lineages circulating in Ghana. Method We genotyped 1,211 MTBC isolates recovered from pulmonary TB patients recruited between 2012 and 2014 using single nucleotide polymorphism typing and spoligotyping. Associations between patient and pathogen variables were assessed using univariate and multivariate logistic regression. Results Of the 1,211 MTBC isolates analysed, 71.9 % (871) belonged to Lineage 4; 12.6 % (152) to Lineage 5 (also known as M. africanum West-Africa 1), 9.2 % (112) to Lineage 6 (also known as M. africanum West-Africa 2) and 0.6 % (7) to Mycobacterium bovis. Univariate analysis revealed that Lineage 6 strains were less likely to be isoniazid resistant compared to other strains (odds ratio = 0.25, 95 % confidence interval (CI): 0.05–0.77, P

The incidence density of infection and disease caused by Plasmodium falciparum in children aged six to 24 months living in the holoendemic Sahel of northern Ghana was measured during the wet and dry seasons of 1996 and 1997. At the beginning of each season, a cohort composed of 259 and 277 randomly selected children received supervised curative therapy with quinine and Fansidar and primaquine for those with normal glucose-6-phosphate dehydrogenase activity. The 20 weeks of post-therapy follow-up consisted of three home visits weekly and examination of Giemsa-stained blood films once every two weeks. Blood films were also taken from children brought to clinic with illness. The incidence density of parasitemia after radical cure was 4.7 infections/person-year during the dry season and 7.1 during the wet season (relative risk = 1.51, 95% confidence interval [CI] = 1.25-1.81; P = 0.00001). Although the mean parasitemia count at time of reinfection in the dry season (3,310/microl) roughly equaled that in the wet season (3,056/microl; P = 0.737), the risk ratio for parasitemia > 20,000/microl during the wet season was 1.71 (95% CI = 1.2-2.4; P = 0.0025). The risk ratio for parasitemia > 20,000/microl with fever during the wet season was 2.45 (95% CI = 1.5-4.1; P = 0.0002). The risk ratio for anemia (hemoglobin < 8 g/dl) at first post-radical cure parasitemia showed no difference between seasons (1.0; 95% CI = 0.73-1.4; P = 0.9915). We did not see seasonal differences in anemia known to exist in this region, probably because the longitudinal cohort design using first parasitemia as an end point prevented the subjects from developing the repeated or chronic infections required for anemia induction. These findings bear upon the design of malaria drug and vaccine trials in holoendemic areas.

Adult residents of holoendemic malaria regions in Africa have a naturally acquired immunity (NAI) to malaria that renders them more resistant to new infections, limits parasitemia, and reduces the frequency and severity of illness. Given such attributes, it is not clear how one might evaluate drug or vaccine efficacy in adults without serious confounding. To determine symptomatic and asymptomatic malaria attack rates in adults of northern Ghana, 197 men and women underwent curative therapy for any pre-existing malaria infections at the start of the high transmission (wet) season. They were monitored for first parasitemia and first clinical episode of infection by Plasmodium falciparum over a 20-week period (May-October 1996). The cumulative incidence of primary infection by P. falciparum was 0.98 and incidence density of infection was calculated to be 7.0 cases/person-year. Symptoms were reported by 19.5% of the individuals at the time of first recurrent parasitemia. Incidence of infection, parasite density, and the frequency of symptoms were comparable in males and females. The results suggest that NAI did not provide these adults with significant defense against rapid re-infection and suggest that this population-infection design could serve to demonstrate the efficacy of a drug or vaccine in preventing parasitemia.

Functional studies have demonstrated an interaction between the stimulatory G protein alpha subunit (G-alpha-s) and the malaria parasite at a cellular level. Obstruction of signal transduction via the erythrocyte G-alpha-s subunit reduced invasion by Plasmodium falciparum parasites. We sought to determine whether this signal pathway had an impact at the disease level by testing polymorphisms in the gene encoding G-alpha-s (GNAS) for association with severe malaria in a large multi-centre study encompassing family and case-control studies from The Gambia, Kenya and Malawi, and a case-control study from Ghana. We gained power to detect association using meta-analysis across the seven studies, with an overall sample size approximating 4,000 cases and 4,000 controls. Out of 12 SNPs investigated in the 19 kb GNAS region, four presented signals of association (P < 0.05) with severe malaria. The strongest single-locus association demonstrated an odds ratio of 1.13 (1.05-1.21), P = 0.001. Three of the loci presenting significant associations were clustered at the 5-prime end of the GNAS gene. Accordingly, haplotypes constructed from these loci demonstrated significant associations with severe malaria [OR = 0.88 (0.81-0.96), P = 0.005 and OR = 1.12 (1.03-1.20), P = 0.005]. The evidence presented here indicates that the influence of G-alpha-s on erythrocyte invasion efficacy may, indeed, alter individual susceptibility to disease.

BACKGROUND: Haemoglobin S (HbS) and C (HbC) are variants of the HBB gene which both protect against malaria. It is not clear, however, how these two alleles have evolved in the West African countries where they co-exist at high frequencies. Here we use haplotypic signatures of selection to investigate the evolutionary history of the malaria-protective alleles HbS and HbC in the Kassena-Nankana District (KND) of Ghana. METHODOLOGY/PRINCIPAL FINDINGS: The haplotypic structure of HbS and HbC alleles was investigated, by genotyping 56 SNPs around the HBB locus. We found that, in the KND population, both alleles reside on extended haplotypes (approximately 1.5 Mb for HbS and 650 Kb for HbC) that are significantly less diverse than those of the ancestral HbA allele. The extended haplotypes span a recombination hotspot that is known to exist in this region of the genome SIGNIFICANCE: Our findings show strong support for recent positive selection of both the HbS and HbC alleles and provide insights into how these two alleles have both evolved in the population of northern Ghana.

Background Influenza epidemiology in Africa is generally not well understood. Using syndrome definitions to screen patients for laboratory confirmation of infection is an established means to effectively conduct influenza surveillance. Methods To compare influenza-related epidemiologic data, from October 2010 through March 2013, we enrolled hospitalized severe acute respiratory infection (SARI; fever with respiratory symptoms) and acute febrile illness (AFI; fever without respiratory or other localizing symptoms) patients from three referral hospitals in Ghana. Demographic and epidemiologic data were obtained from enrolled patients after which nasopharyngeal and oropharyngeal swabs were collected, and processed by molecular methods for the presence of influenza viruses. Results Of 730 SARI patients, 59 (8%) were influenza positive; of 543 AFI patients, 34 (6%) were positive for influenza. Both SARI and AFI surveillance yielded influenza A(H3N2) (3% versus 1%), A(H1N1)pdm09 (2% versus 1%), and influenza B (3% versus 4%) in similar proportions. Data from both syndromes show year-round influenza transmission but with increased caseloads associated with the rainy seasons. Conclusions As an appreciable percentage of influenza cases (37%) presented without defined respiratory symptoms, and thus met the AFI but not the SARI definition, it is important to consider broader screening criteria (i.e., AFI) to identify all laboratory-confirmed influenza. The identified influenza transmission seasonality has important implications for the timing of related public health interventions.

Background Health facility data are more readily accessible for operational planning and evaluation of disease control programmes. The importance, potential challenges and limitations of using facility based survey as an alternative tool for monitoring changes in local malaria epidemiology were examined. Methods The study involved six areas within the administrative divisions of The Gambia. The areas were selected to reflect socioeconomic and malaria transmission intensities across the country. The study design involved an age stratified cross sectional surveys that were conducted during the wet season in 2008 and in the 2009 during the dry season. Participants were patients attending clinics in six health centres and the representative populations from the catchment communities of the health centres. Results Overall participants’ characteristics were mostly not comparable in the two methodological approaches in the different seasons and settings. More females than males were enrolled (55.8 vs. 44.2 %) in all the surveys. Malaria infection was higher in the surveys in health centres than in the communities (p

Background Malaria eradication requires a concerted approach involving all available control tools, and an effective vaccine would complement these efforts. An effective malaria vaccine should be able to induce protective immune responses in a genetically diverse population. Identification of immunodominant T cell epitopes will assist in determining if candidate vaccines will be immunogenic in malaria-endemic areas. This study therefore investigated whether class I-restricted T cell epitopes of two leading malaria vaccine antigens, Plasmodium falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1), could recall T cell interferon-γ responses from naturally exposed subjects using ex vivo ELISpot assays. Methods Thirty-five subjects aged between 24 and 43 years were recruited from a malaria-endemic urban community of Ghana in 2011, and their peripheral blood mononuclear cells (PBMCs) were tested in ELISpot IFN-γ assays against overlapping 15mer peptide pools spanning the entire CSP and AMA1 antigens, and 9–10mer peptide epitope mixtures that included previously identified and/or predicted human leukocyte antigen (HLA) class 1-restricted epitopes from same two antigens. Results For CSP, 26 % of subjects responded to at least one of the nine 15mer peptide pools whilst 17 % responded to at least one of the five 9–10mer HLA-restricted epitope mixtures. For AMA1, 63 % of subjects responded to at least one of the 12 AMA1 15mer peptide pools and 51 % responded to at least one of the six 9–10mer HLA-restricted epitope mixtures. Following analysis of data from the two sets of peptide pools, along with bioinformatics predictions of class I-restricted epitopes and the HLA supertypes expressed by a subset of study subjects, peptide pools that may contain epitopes recognized by multiple HLA supertypes were identified. Collectively, these results suggest that natural transmission elicits ELISpot IFN-γ activities to class 1-restricted epitopes that are largely HLA-promiscuous. Conclusions These results generally demonstrate that CSP and AMA1 peptides recalled ELISpot IFN-γ responses from naturally exposed individuals and that both CSP and AMA1 contain diverse class 1-restricted epitopes that are HLA-promiscuous and are widely recognized in this population. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1098-8) contains supplementary material, which is available to authorized users.

BACKGROUND: There is a perception that genomic differences in the species/lineages of the nine species making the Mycobacterium tuberculosis complex (MTBC) may affect the efficacy of distinct control tools in certain geographical areas. We therefore analyzed the prevalence and spatial distribution of MTBC species and lineages among isolates from pulmonary TB cases over an 8-year period, 2007-2014. METHODOLOGY: Mycobacterial species isolated by culture from consecutively recruited pulmonary tuberculosis patients presenting at selected district/sub-district health facilities were confirmed as MTBC by IS6110 and rpos PCR and further assigned lineages and sub lineages by spoligotyping and large sequence polymorphism PCR (RDs 4, 9, 12, 702, 711) assays. Patient characteristics, residency, and risks were obtained with a structured questionnaire. We used SaTScan and ArcMap analyses to identify significantly clustered MTBC lineages within selected districts and spatial display, respectively. RESULTS: Among 2,551 isolates, 2,019 (79.1%), 516 (20.2%) and 16 (0.6%) were identified as M. tuberculosis sensu stricto (MTBss), M. africanum (Maf), 15 M. bovis and 1 M. caprae, respectively. The proportions of MTBss and Maf were fairly constant within the study period. Maf spoligotypes were dominated by Spoligotype International Type (SIT) 331 (25.42%), SIT 326 (15.25%) and SIT 181 (14.12%). We found M. bovis to be significantly higher in Northern Ghana (1.9% of 212) than Southern Ghana (0.5% of 2339) (p = 0.020). Using the purely spatial and space-time analysis, seven significant MTBC lineage clusters (p< 0.05) were identified. Notable among the clusters were Ghana and Cameroon sub-lineages found to be associated with north and south, respectively. CONCLUSION: This study demonstrated that overall, 79.1% of TB in Ghana is caused by MTBss and 20% by M. africanum. Unlike some West African Countries, we did not observe a decline of Maf prevalence in Ghana.

Evaluation of: Greenhouse B, Ho B, Hubbard A et al. Antibodies to Plasmodium falciparum antigens predict a higher risk of malaria but protection from symptoms once parasitemic. J. Infect. Dis. 204, 19–26 (2011).As the research for the development of a malaria vaccine becomes increasingly important, a thorough understanding of the protection afforded by antibodies against parasite antigens is essential. The factors affecting the protective ability of antibodies elicited by highly immunogenic malaria parasite antigens and their interaction have been investigated in a study of Ugandan children by Greenhouse and colleagues. Their interesting finding of the effect of prior exposure on the protection provided against symptomatic malaria and the importance of the results in the immuno-epidemiological studies are discussed in this article.

Human cutaneous leishmaniasis (CL) has previously been reported in West Africa, but more recently, sporadic reports of CL have increased. Leishmania major has been identified from Mauritania, Senegal, Mali, and Burkina Faso. Three zymodemes (MON-26, MON-117, and MON-74, the most frequent) have been found. The geographic range of leishmaniasis is limited by the sand fly vector, its feeding preferences, and its capacity to support internal development of specific species of Leishmania. The risk of acquiring CL has been reported to increase considerably with human activity and epidemics of CL have been associated with deforestation, road construction, wars, or other activities where humans intrude the habitat of the vector. In the Ho Municipality in the Volta Region of Ghana, a localised outbreak of skin ulcers, possibly CL, was noted in 2003 without any such documented activity. This outbreak was consistent with CL as evidenced using various methods including parasite identification, albeit, in a small number of patients with ulcers. This paper reports the outbreak in Ghana. The report does not address a single planned study but rather a compilation of data from a number of ad-hoc investigations in response to the outbreak plus observations and findings made by the authors. It acknowledges that a number of the observations need to be further clarified. What is the detailed epidemiology of the disease? What sparked the epidemic? Can it happen again? What was the causative agent of the disease, L. major or some other Leishmania spp.? What were the main vectors and animal reservoirs?What are the consequences for surveillance of the disease and the prevention of its reoccurrence when the communities see a self-healing disease and may not think it is important? Keywords: cutaneous leishmaniasis; Ghana; Volta Region; West Africa; outbreak; follow-up (Published: 13 July 2011) Citation: Global Health Action 2011, 4 : 5527 - DOI: 10.3402/gha.v4i0.5527

Background. In 2005, Ghana adopted artemisinin-based combination therapy (ACT) for primary treatment of falciparum malaria. A comprehensive study of the drug-resistance–associated mutations and their genetic lineages will lead to a better understanding of the evolution of antimalarial drug resistance in this region. Methods. The pfcrt, pfmdr1, dhps, and dhfr mutations associated with chloroquine (CQ) and sulfadoxinepyrimethamine (SP) resistance and the microsatellite loci flanking these genes were genotyped in Plasmodium falciparum isolates from Ghana. Results. The prevalence of mutations associated with both CQ and SP resistance was high in Ghana. However, we observed a decrease in prevalence of the pfcrt K76T mutation in northern Ghana after the change in drug policy from CQ to ACT. Analysis of genetic diversity and differentiation at microsatellite loci flanking all 4 genes indicated that they have been under strong selection, because of CQ and SP use. The triple-mutant pfcrt and dhfr alleles in Ghana were derived from Southeast Asia, whereas the double-mutant dhfr, dhps, and pfmdr1 alleles were of African lineage. Conclusion. Because of the possible role of pfmdr1 in amodiaquine and mefloquine resistance, demonstrating selection on pfmdr1 and defining lineages of resistant alleles in an African population holds great importance.

Objective/background Mycobacterium africanum (MAF) remains an important TB causing pathogen in West Africa; however, little is known about its population structure and actual diversity which may have implications for diagnostics and vaccines. We carried out comparative genomics analysis of candidate Mycobacterium tuberculosis (MTB) and MAF using whole genome sequencing. Methods Clinical MTB complex strains (n = 187) comprising L4 (n = 22), L5 (n = 126), and L6 (n = 39) isolated over 8 years from Ghana were whole genome sequenced. The reads were mapped onto a reference genome for phylogenetic and functional genomics analysis. A maximum likelihood tree with 100 bootstraps was constructed from the single nucleotide polymorphisms (SNPs) found using RAxML and clustered with hierBAPS. A total of 147 (18 L4, 36 L6, and 93 L5) of the genomes were de novo assembled and annotated for comparative pangenome analysis using Roary. Results The population structure of MAF revealed at least five clusters of L5 as compared to three for L6. We also identified a group of three multi-drug-resistants (MDRs) within a single cluster of L5 strains from Southern Ghana isolated in 2013. Among the global collection of MTB complex, there were four Ghana-specific L5 clusters of which one (L5.1.1) had traits of clonal expansion. From the 5947 pan genes extracted from the collection, 3215 (54.1%) were core to all the 147 genomes whereas 719 (12.1%) were found in single genomes. Most of the variable genes were PE-PGRS/PPE (1,281) duplicates of other genes (431). The genome degradation was more pronounced in Lineages 4 and 6 as compared to Lineage 5. We identified the absence of some unique genes among specific lineages and/or clades with possible clinical implications. For example, mpt64 and mlaD encoding respectively an immunogenic protein and a mammalian cell entry protein were missing from all L6 genomes. In addition, all L5 strains had an amino acid substitution I43 N within the mpt64 gene. Analysis of SNPs within some genes encoding proteins for substrate metabolism, ion transport and secretory systems showed higher proportion of SNPs among L6 compared to L5 and L4. We also identified a number of lineage/sublineage specific SNPs and indels that may be utilized in rapid PCR based genotyping of MTB complex. Conclusion This work emphasizes on the possibility that the mpt64-based rapid diagnostic kit would not be effective in MAF endemic settings. More mutations in ESAT-6 secretory system of MAF compared to MTB sensu stricto can affect efficacy of ESAT-6-based vaccines in the future.

Introduction This study was nested in a prospective cohort of 1010 pregnant women attending antenatal clinics in two public hospitals in Accra, Ghana. Objectives We assessed whether adding the biomarkers Pregnancy Associated Plasma Protein-A (PAPP-A) and Placental Growth Factor (PlGF) to maternal clinical characteristics improved the prediction of a previously developed model for gestational hypertension in a cohort of Ghanaian pregnant women. Methods Pregnant women who were normotensive, at a gestational age at recruitment of between 8 and 13 weeks and provided a blood sample for biomarker analysis were eligible for inclusion. From serum, biomarkers PAPP-A and PlGF concentrations were measured by the AutoDELFIA immunoassay method and multiple of the median (MoM) values corrected for gestational age (PAPP-A and PlGF) and maternal weight (PAPP-A) were calculated. To obtain prediction models, these biomarkers were included with clinical predictors maternal weight,height, diastolic blood pressure, a previous history of gestational hypertension, history of hypertension in parents and parity in a logistic regression to obtain prediction models. The Area Under the Receiver Operating Characteristic Curve (AUC) was used to assess the predictive ability of the models. Results Three hundred and seventy-three women participated in this study. The area under the curve (AUC) of the model with only maternal clinical characteristics was 0.75 (0.64–0.86) and 0.89(0.73–1.00) for multiparous and primigravid women respectively. The AUCs after inclusion of both PAPP-A and PlGF were 0.82 (0.74–0.89) and 0.95 (0.87–1.00) for multiparous and primigravid women respectively. Discussion Adding the biomarkers PAPP-A and PlGF to maternal characteristics in a prediction model for gestational hypertension in a cohort of Ghanaian pregnant women improved predictive ability. Further research using larger sample sizes in similar settings to validate these findings is recommended.

The quest for an effective vaccine as an additional strategy in the control of malaria and to significantly impact the disease burden has progressed tremendously over the past decade and there is a very high probability that a malaria vaccine will be available for use in the near future. The development and deployment of an effective malaria vaccine faces several challenges and the early engagement of endemic country institutions in the entire process will be beneficial to all. It is very likely that the initial vaccine candidates will have to be improved upon, especially as our understanding of the disease processes improves and the number of potential vaccine antigens increase. This will place greater demands on the currently insufficient capacity for trials. Current strategies for testing and deployment of a malaria vaccine, for example those focusing on risk groups such as infants and children and pregnant women, will also need modifications as efforts are moved towards malaria elimination. Also, a successful malaria vaccine development process will need strengthening of the currently weak regulatory framework in endemic countries to enable them have oversight over clinical trials. The introduction of any malaria vaccine will be confronted by some cultural issues and it is essential to understand how these factors will ultimately affect its utilization. These and other challenges related to the development and deployment of an effective malaria vaccine especially as they concern endemic countries are discussed.

Several associations between specific HLA alleles and susceptibility or resistance to Plasmodium falciparum malaria have been previously reported, but no associations have been confirmed in multiple populations. We studied associations between HLA-A, -B, and DRB1 alleles and severe malaria in northern Ghana. We analyzed HLA-DRB1*04 in 4,032 subjects from a severe malaria case-control study, 790 severe malaria cases, 1,611 mild malaria controls, and 1631 asymptomatic controls. The presence of HLA-DRB1*04 was associated with severe malaria (OR = 2.42, 95% CI = 1.64, 3.58). The allele frequency of DRB1*04 was similar in the two major ethnic groups in the study population, Kassem (4.4%) and Nankam (4.7%), and the OR for the association between DRB1*04 and severe malaria was similar in both ethnic groups. These findings are consistent with results from Gabon suggesting that DRB1*04 is a risk factor for severe malaria.

In this review we discuss the different meanings of the term 'malaria' and urge writers and readers to distinguish accurately between them. The distinction is important in clinical practice, clinical trials, epidemiology, and the evaluation of control programs. Both over- and underdiagnosis of malaria as the cause of a disease episode are inevitable; overdiagnosis is common in high-transmission areas and underdiagnosis is common in areas with little or no transmission. Parasite density thresholds, attributable fractions, and clinical algorithms have played important but only partial roles in strengthening diagnosis. Methods by which malaria infection could be confidently identified as the cause, rather than an irrelevant accompaniment, of an illness, are important targets for research. One such 'signature' is a distinctive retinopathy that occurs in severe malaria and not in clinically similar diseases. Other indicators of a malarial etiology of clinical disease are needed to strengthen clinical and scientific approaches to the control of malaria.

Interactions of killer cell immunoglobulin-like receptors (KIRs) with major histocompatibility complex (MHC) class I ligands diversify natural killer cell responses to infection. By analyzing sequence variation in diverse human populations, we show that the KIR3DL1/S1 locus encodes two lineages of polymorphic inhibitory KIR3DL1 allotypes that recognize Bw4 epitopes of protein">HLA-A and HLA-B and one lineage of conserved activating KIR3DS1 allotypes, also implicated in Bw4 recognition. Balancing selection has maintained these three lineages for over 3 million years. Variation was selected at D1 and D2 domain residues that contact HLA class I and at two sites on D0, the domain that enhances the binding of KIR3D to HLA class I. HLA-B variants that gained Bw4 through interallelic microconversion are also products of selection. A worldwide comparison uncovers unusual KIR3DL1/S1 evolution in modern sub-Saharan Africans. Balancing selection is weak and confined to D0, KIR3DS1 is rare and KIR3DL1 allotypes with similar binding sites predominate. Natural killer cells express the dominant KIR3DL1 at a high frequency and with high surface density, providing strong responses to cells perturbed in Bw4 expression.

Background. Usefulness of sulfadoxine-pyrimethamine as first-line therapy for uncomplicated Plasmodium falciparum malaria and intermittent preventive treatment in pregnancy throughout sub-Saharan Africa is compromised by the spread of dhfr alleles associated with pyrimethamine resistance. A predominant haplotype associated with the N51I+C59R+S108N triple-mutant dhfr allele has been reported recently in 4 African countries. A more comprehensive picture of the evolution of this mutant allele in Africa is lacking. Methods. Seventy-five P. falciparum isolates carrying the wild-type dhfr allele and 204 carrying the triple-mutant dhfr allele from 11 African countries were selected. The genetic diversity of the chromosomes bearing these alleles was analyzed with 4 microsatellite markers closely linked to the dhfr gene. Results. Seventy-three different 4-locus haplotypes carrying the wild-type dhfr allele were found. By contrast, 175 (85%) of 204 isolates carrying the triple-mutant dhfr allele shared a unique haplotype, identical to the one identified in Thailand. For the remaining triple-mutant isolates and one isolate with the quadruple-mutant dhfr allele (N51I+C59R+S108N+I164L), haplotypes were closely related to the predominant haplotype by mutation or recombination. Conclusions. Migration of parasites carrying an ancestral triple-mutant dhfr allele drives the spread of dhfr alleles associated with pyrimethamine resistance throughout West and Central Africa.

In Ghana in 2004 (when choroquine was still the nationally recommended drug for the first-line treatment of malaria), the sensitivities, to chloroquine, amodiaquine, quinine, mefloquine, artesunate and halofantrine, of 60 Plasmodium falciparum isolates from two ecologically distinct areas of the country were assessed in vitro. The aim was to make available, to policy-makers, the field-based evidence needed to review the national strategy for malaria treatment. Drug susceptibilities were explored using the standardized protocol of the Antimalarial Drug Resistance Network. Although 32 of the P. falciparum isolates evaluated (56.1% of the 57 isolates successfully investigated for their susceptibility to choroquine) showed resistance to chloroquine and two showed slightly reduced sensitivity to amodiaquine, all the isolates were sensitive to mefloquine, artesunate, quinine and halofantrine. The median inhibitory concentrations (IC(50)) of chloroquine were positively correlated with those of quinine (r=0.4528; P=0.0008) but not those of any of the other drugs investigated. The IC(50) of amodiaquine and artesunate were also positively correlated (r=0.3703; P=0.0067). These results provide evidence of the presence, in Ghana, of P. falciparum isolates that are highly resistant to chloroquine but generally sensitive to most of the other antimalarial drugs commonly used in the country. Partly in consequence of these observations, the recommended first-line treatment for malaria in Ghana was changed to an amodiaquine-artesunate combination in January 2005.

Trypanosoma brucei parasites are kinetoplastid protozoa that devastate the health and economic well-being of millions of people in Africa through the disease human African trypanosomiasis (HAT). New chemotherapy has been eagerly awaited due to severe side effects and the drug resistance issues plaguing current drugs. Recently, there has been an emphasis on the use of medicinal plants worldwide. Morinda lucida Benth. is a popular medicinal plant widely distributed in Africa, and several research groups have reported on the antiprotozoal activities of this plant. In this study, we identified three novel tetracyclic iridoids, molucidin, ML-2-3, and ML-F52, from the CHCl 3 fraction of M. lucida leaves, which possess activity against the GUTat 3.1 strain of T. brucei brucei . The 50% inhibitory concentrations (IC 50 ) of molucidin, ML-2-3, and ML-F52 were 1.27 μM, 3.75 μM, and 0.43 μM, respectively. ML-2-3 and ML-F52 suppressed the expression of paraflagellum rod protein subunit 2, PFR-2, and caused cell cycle alteration, which preceded apoptosis induction in the bloodstream form of Trypanosoma parasites. Novel tetracyclic iridoids may be promising lead compounds for the development of new chemotherapies for African trypanosomal infections in humans and animals.

Human African trypanosomiasis (HAT), commonly known as sleeping sickness has remained a serious health problem in many African countries with thousands of new infected cases annually. Chemotherapy, which is the main form of control against HAT has been characterized lately by the viewpoints of toxicity and drug resistance issues. Recently, there have been a lot of emphases on the use of medicinal plants world-wide. Morinda lucida Benth. is one of the most popular medicinal plants widely distributed in Africa and several groups have reported on its anti-protozoa activities. In this study, we have isolated one novel tetracyclic iridoid, named as molucidin, from the CHCl3 fraction of the M. lucida leaves by bioassay-guided fractionation and purification. Molucidin was structurally elucidated by (1)H and (13)C NMR including HMQC, HMBC, H-H COSY and NOESY resulting in tetracyclic iridoid skeleton, and its absolute configuration was determined. We have further demonstrated that molucidin presented a strong anti-trypanosomal activity, indicating an IC50 value of 1.27 μM. The cytotoxicity study using human normal and cancer cell lines indicated that molucidin exhibited selectivity index (SI) against two normal fibroblasts greater than 4.73. Furthermore, structure-activity relationship (SAR) study was undertaken with molucidin and oregonin, which is identical to anti-trypanosomal active components of Alnus japonica. Overlapping analysis of the lowest energy conformation of molucidin with oregonin suggested a certain similarities of aromatic rings of both oregonin and molucidin. These results contribute to the future drug design studies for HAT.

Background A malaria vaccine that targets the sporozoite/liver stage parasites could potentially prevent blood stage infection and the associated clinical symptoms. Identification of sporozoite/liver stage antigens is, therefore, crucial for the development of effective vaccines. Cell-traversal protein for ookinetes and sporozoites (CelTOS) is a highly conserved antigen involved in sporozoite motility and hepatocyte invasion and has been shown to induce significant IFN-γ production in PBMCs from radiation-attenuated sporozoite-immunized malaria-naïve individuals. The aim of this study was to ascertain whether such CelTOS-specific recall responses are also induced in individuals with natural exposure to Plasmodium falciparum. Methods Ex vivo IFN-γ responses to 15mer overlapping peptide pools covering the entire sequence of CelTOS and five other candidate antigens, CSP, AMA1, MSP1, TRAP and LSA1, were characterized using PBMCs from 35 malaria exposed adults. Responses to four CelTOS peptide pools (CelTp1, CelTp2, CelTp3 and CelTp4), a pool containing peptides from the entire CelTOS antigen (CelTTp), and pools comprised of overlapping peptides from each of the other five malaria antigens were assessed by ex vivo ELISpot assay. A positive IFN-γ response for stimulants was defined by two criteria; a stimulation index of two or greater relative to the unstimulated control, and a difference of 10 or greater in spot forming cells between stimulant and the unstimulated control. Results Of the 35 volunteers tested, five had positive IFN-γ recall responses against the four different CelTOS pools while four volunteers made responses against the CelTTp pool; six volunteers were, therefore, positive with CelTOS. By contrast, six volunteers responded to AMA1, seven to LSA1, 15 to MSP1 and two volunteers responded against CSP and TRAP. Conclusions These results suggest natural malaria transmission induces CelTOS-specific ex vivo IFN-γ in Ghanaian adults and that the frequency of these responses was similar to those of other previously characterized malaria antigens. These findings support the further evaluation of CelTOS as a pre-erythrocytic candidate antigen for inclusion in a potential multi-antigen vaccine. Electronic supplementary material The online version of this article (doi:10.1186/s12936-014-0539-5) contains supplementary material, which is available to authorized users.

We studied socio-cultural determinants of timely appropriate treatment seeking for children under 5 years suspected of having a perceived malaria-related illness. Caretakers of children with suspected malaria were interviewed about illness-related experiences, meanings and behaviour in two endemic villages in southern Ghana. Only 11% of children suspected of having a perceived malaria-related illness received timely appropriate treatment consistent with the Abuja target of treating malaria within 24 h of illness onset; 33% of children received appropriate treatment within 48 h. Reported perceived causes of phlegm predicted timely, appropriate treatment within 24 h of illness onset (P = 0.04) in a multivariate logistic regression model; playing on the ground (P < 0.01) predicted such treatment within 48 h. Two categories of distress, paleness or shortage of blood (P = 0.05) and sweating profusely (P = 0.03), also predicted timely, appropriate treatment within 24 h in a multivariate logistic regression model. Knowing that mosquitoes transmit malaria was not associated with timely, appropriate help seeking for the children, even though such knowledge may promote personal protective measures, especially use of bednets. Patterns of distress and PC were related to timely, appropriate help seeking, but not as expected. Effects on health seeking of illness-related experience and meaning are complex, and explaining their role may strengthen interventions for childhood malaria.

Reported efficacies from vaccine trials may depend heavily on the clinical case definition used in the trial. The dependence may be particularly striking for diseases such as malaria, in which no single case definition is appropriate. We used logistic regression modeling of the relationship between parasitemia and fever in data sets from Ghanaian children to determine the fraction of fevers attributable to malaria and to model how the choice of a threshold parasitemia in the clinical case definition affects the measured efficacy of malaria vaccines. Calculated clinical attack rates varied 10-fold as a function of the threshold parasitemia. Strikingly, measured vaccine efficacies in reducing clinical malaria depended heavily on the threshold parasitemia, varying between 20% and 80% as the threshold varied between 1 and 5000 parasites/ microL. We suggest that clinical case definitions of malaria that incorporate a threshold parasitemia are arbitrary and do not yield stable estimates of vaccine trial end points.

Objective: The study was conducted to determine antimalarial prescribing practices among prescribers in 2 of the 6 sentinel sites established to document antimalarial drug efficacy in Ghana in order to provide some explanation underlying chloroquine treatment failures in the country. Subjects andMethods: The study was descriptive combining both qualitative and quantitative designs. The qualitative design involved in-depth interviews of general prescribers in the Wassa West and Kassena Nankana districts using an interview guide. The quantitative design involved a review of Outpatient Department prescriptions of 100 patients clinically diagnosed as having malaria within the year 2000 in each of the 7 selected health care facilities. Results: The overall number of drugs prescribed per patient encounter was 4.3 in the Wassa West district and 3.0 in the Kassena Nankana district. The number of drugs per patient encounter was 5.4 and 3.7 in private and government health care facilities, respectively. The commonly prescribed antimalarial drug in all the health care facilities visited was chloroquine. However, only 9.8% of prescriptions in private health care facilities contained correct doses of chloroquine compared to 54% in government health care facilities (p = 0.000). Prescriptions containing chloroquine injections were least likely to have correct doses of chloroquine. Conclusion: Thefindings indicate that although chloroquine remained the first-line drug in the treatment of uncomplicated malaria in the two districts, the level of appropriateness of doses prescribed was generally low. Inappropriate doses of chloroquine prescribed were more prevalent in private than government health care facilities, and among prescriptions containing injections.

We compared the VecTestTM dipstick assay for detection of Plasmodium sporozoites in Anopheles vectors of malaria with standard circumsporozoite (CS) microplate ELISA for detection of Plasmodium falciparum circumsporozoite protein (PfCSP) in Anopheles mosquitoes. Mosquitoes were collected from a malaria endemic site (Kassena Nankana district) in northern Ghana. Of 2620 randomly sampled mosquitoes tested, the standard CS-ELISA gave a sporozoite rate of 10.8% compared with 11.2% by VecTestTM, which was not statistically different (P = 0.66). Visual reading of the CS-ELISA results gave a sporozoite rate of 13.4%, which was higher than the other tests (P > 0.05). To allow a more objective evaluation of the sensitivity of the dipstick, an additional 136 known CS-ELISA-positive specimens were analysed. The prevalence of the test (including the additional samples) was 14.6% and 14.7% for CS-ELISA and dipstick, respectively (P > 0.05). The estimated prevalence by visual assessment of the CS-ELISA results was 17.5%. The relative specificity and sensitivity of the VecTestTM dipstick and visually read ELISA were estimated based on the CS-ELISA as a gold standard. The specificities of the dipstick and visual ELISA were high, 98.0% and 96.6%, respectively. However, the sensitivities of the two assays were 88.8% for VecTest and 100% for visual ELISA (P < 0.01). Concordance between VecTest and CS-ELISA was good (kappa = 0.86). Similarly, there was a good concordance between the dipstick and the visually read ELISA (kappa = 0.88). Extrapolating from PfCSP controls (titrated quantities of P. falciparum sporozoites), mean sporozoite loads of CS-ELISA-positive An. gambiae (286 +/- 28.05) and An. funestus (236 +/- 19.32) were determined (P = 0.146). The visual dipstick grades showed high correlation with sporozoite load. The more intense the dipstick colour, the higher the mean sporozoite load (+ = 108, ++ = 207, +++ = 290, r = 0.99, r2 = 1). The VecTest dipstick offers practical advantages for field workers needing rapid and accurate means of detection of sporozoites in mosquitoes.

We conducted all-age point prevalence surveys to profile the severity and seasonality of malaria and anaemia in Kassena-Nankana District of northern Ghana. Random cross-sectional surveys were timed to coincide with the end of low (May 2001) and high (November 2001) malaria transmission seasons and to yield information as to the potential value of haemoglobin (Hb) levels and parasitaemia as markers of malaria morbidity and/or malaria vaccine effect. Parasitaemia was found in 22% (515 of 2286) screened in May (dry-low transmission), and in 61% of the general population (1026 of 1676) screened in November (wet-high transmission). Malaria prevalence in May ranged from 4% (infants

Gender-specific and parity-dependent acquired antibody recognition is characteristic of variant surface antigens (VSA) expressed by chondroitin sulfate A (CSA)-adherent Plasmodium falciparum involved in pregnancy-associated malaria (PAM). However, antibody recognition of recombinant products of a specific VSA gene ( 2O2var1 ) implicated in PAM and transcribed by a CSA-adhering parasite line did not have these characteristics. Furthermore, we could not demonstrate preferential transcription of 2O2var1 in the CSA-adhering line versus the unselected, parental isolate. Our data call for circumspection regarding the molecular identity of the parasite ligand mediating adhesion to CSA in PAM.

In areas of intensePlasmodium falciparumtransmission, protective immunity is acquired during childhood in parallel with acquisition of agglutinating antibodies to parasite-encoded variant surface antigens (VSA) expressed on parasitized red blood cells. In a semi-immune child in such an area, clinical disease is caused mainly by parasites expressing VSA not recognized by preexisting VSA-specific antibodies in that child. Such malaria episodes are known to cause an increase in agglutinating antibodies specifically recognizing VSA expressed by the parasite isolate causing the illness, whereas antibody responses to other parasite isolates are relatively unaffected. However, the detailed kinetics of this VSA antibody acquisition are unknown and hence were the aim of this study. We show thatP. falciparummalaria in Ghanaian children generally caused a rapid and sustained increase in variant-specific VSA antibody levels, while more transient and limited increases in levels of antibodies to VSA expressed by other parasite isolates were also seen. Plasma VSA antibody levels were positively correlated with the age of the healthy plasma donors but negatively correlated with the age of the parasite donors (the malaria patient). The data from this first detailed longitudinal study of acquisition of VSA antibodies support the hypothesis that naturally acquired protective immunity toP. falciparummalaria is mediated, at least in part, by VSA-specific antibodies.

Background : Complete and accurate information on disease occurrence is crucial for effective public health response to disease outbreaks. In response to the 2014 Ebola epidemic in West Africa, Ghana intensified surveillance for the disease across the country. However, the case definition provided by the Ministry of Health was not uniformly applied at all reporting health facilities. Objective : This paper analyses the accompanying Case Record Forms (CRFs) submitted to Noguchi Memorial Institute for Medical Research to determine its completeness and appropriateness for instituting an effective response to the epidemic. Methods : We determined the proportions of completeness in reporting for all criteria provided by the MOH for the clinical diagnosis of Ebola. New indicators were generated to measure the completeness of each variable. Tables and graphs of completeness of indicators were produced and presented. Results : Of the 156 samples, 69% were from males. Approximately 4.5% had no record for age. The date of specimen collection was filled for 96%; 34.6% (54) did not have date of onset of symptoms. In 37.8% (59) of cases, location was blank. In 12% of cases, no symptoms were recorded and about 30% had no record of fever. Travel history, especially to affected areas, was missing for 40.4%. Conclusions : Gaps on CRFs can significantly reduce the utility of results of laboratory analysis for outbreak control. Although all the samples analysed were negative for Ebola Virus, the high proportion of missing data on the forms should be a source of concern. We recommend that frontline health staff be trained on the importance of capturing all information required on the form. Source of funding : The funding for the analysis of suspected samples were provided partially by Ghana Health Servce and research funding from Noguchi Memorial Institute for Medical Research Keywords : Ebola Virus Disease, Data Gaps, Ghana, Ministry of Health, Symptoms

The crude extract of Alnus japonica bark exhibited a strong effect on the growth of Trypanosoma brucei. Subsequent chromatographic separation resulted in the isolation of two novel diarylheptanoids, known as alnuside C (2) and alnuside D (3), and three known compounds, 1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptan-3(R)-O-β-D-glucopyranoside (1), oregonin (4) and hirsutanone (5). The structures of the isolates were elucidated based on the use of extensive spectroscopic and chemical methods. Among the isolated diarylheptanoids, oregonin (4) (a major component of plant bark) and hirsutanone (5) exhibited potent in vitro inhibitory activity against T. brucei growth in the bloodstream with IC50values of 1.14 and 1.78 μM, respectively. We confirmed that oregonin (4) and hirsutanone (5) were not toxic to human normal skin fibroblast cells (NB1RGB) and colon cancer cells (HCT-15) at a concentration of 50 μM; however, lower levels of toxicity were observed for leukemia cells. To determine the structure activity relationships of the isolated components, we performed Conformation Search and found that the 3-oxo function of the heptane chain in the diarylheptanoid molecule is required for their trypanocidal activity.

Background The rising burden of chronic non-communicable diseases in low and middle income countries has major implications on the ability of these countries to achieve universal health coverage. In this paper we discuss the impact of cardiovascular diseases (CVD) on primary healthcare services in urban poor communities in Accra, Ghana. Methods We review the evidence on the evolution of universal health coverage in Ghana and the central role of the community-based health planning services (CHPS) programme and the National Health Insurance Scheme in primary health care. We present preliminary findings from a study on community CVD knowledge, experiences, responses and access to services. Results The rising burden of NCDs in Ghana will affect the achievement of universal health coverage, particularly in urban areas. There is a significant unmet need for CVD care in the study communities. The provision of primary healthcare services for CVD is not accessible, equitable or responsive to the needs of target communities. Conclusions We consider these findings in the context of the primary healthcare system and discuss the challenges and opportunities for strengthening health systems in low and middle-income countries.

Reference values derived from developed countries are used in many countries in Africa for interpretation of laboratory results obtained during routine healthcare and clinical trials. Use of locally derived reference values has been recommended. The purpose of the study was to establish age- and sex-specific reference values for children in the middle belt of Ghana. Reference values were determined for 21 biochemical and 18 hematologic parameters by using Clinical and Laboratory Standards Institute C28-A3 guidelines in a sample of 1,442 healthy children. Hemoglobin, hematocrit, mean cell volume, erythrocytes, urea, and creatinine were lower when compared with values from northern countries but alanine aminotransferase, aspartate aminotransferase, and total bilirubin were higher. A panel of locally relevant age- and sex-specific reference values was established for commonly used biochemical and hematologic tests in children in the middle part of Ghana. This will help in interpretation of laboratory results for clinical management of patients, screening, and safety monitoring during clinical trials.

Background Reported malaria cases continue to decline globally, and this has been attributed to strategic implementation of multiple malaria control tools. Gains made would however need to be sustained through continuous monitoring to ensure malaria elimination and eradication. Entomological inoculation rate (EIR) is currently the standard tool for transmission monitoring but this is not sensitive enough, especially in areas of very low transmission. Transmission estimation models based on seroconversion rates (λ) of antibodies to Plasmodium falciparum blood stage antigens are gaining relevance. Estimates of λ, which is the measure of transmission intensity, correlate with EIR but are limited by long-term persistence of antibodies to blood stage antigens. Seroprevalence of antibodies to sporozoite antigens may be better alternatives since these antigens usually have shorter immune exposure times. The aim of this study was to develop transmission estimation models based on the seroprevalence of antibodies to two P. falciparum sporozoite antigens (CSP, CelTOS) and compare with models based on the classical blood stage antigen AMA1. Methods Antibody levels in archived plasma from three cross-sectional surveys conducted in 2009 in a low transmission area of Southern Ghana were assessed by indirect ELISA. Seroprevalence of antibodies against CSP, CelTOS and AMA1 were fitted to reversible catalytic models to estimate λ and corresponding seroreversion rates (ρ) for each antibody. Results Of the three models developed, the anti-CSP model predicted a 13-fold decrease in λ four years prior to the time of sampling (2009). Anti-AMA1 antibodies formed at a four-fold greater rate compared to that of anti-CelTOS antibodies, and anti-CSP antibodies during the period of decreased λ. In contrast, anti-AMA1 antibodies decayed at a five-fold slower rate relative to that of anti-CSP antibodies while anti-AMA1 and anti-CelTOS antibody decay rates were not significantly different. Anti-CSP antibodies were relatively short-lived as they formed at an 11.6-fold slower rate relative to their decay during the period of decreased λ. Conclusions These features of anti-CSP antibodies can be exploited for the development of models for predicting seasonal, short-term changes in transmission intensity in malaria-endemic areas, especially as the elimination phase of malaria control is approached.

Summary Background Over a decade ago, the Roll Back Malaria Partnership was launched, and since then there has been unprecedented investment in malaria control. We examined the change in malaria transmission intensity during the period 2000–10 in Africa. Methods We assembled a geocoded and community Plasmodium falciparum parasite rate standardised to the age group 2–10 years (PfPR2–10) database from across 49 endemic countries and territories in Africa from surveys undertaken since 1980. The data were used within a Bayesian space–time geostatistical framework to predict PfPR2–10 in 2000 and 2010 at a 1 × 1 km spatial resolution. Population distribution maps at the same spatial resolution were used to compute populations at risk by endemicity class and estimate population-adjusted PfPR2–10 (PAPfPR2–10) for each of the 44 countries for which predictions were possible for each year. Findings Between 2000 and 2010, the population in hyperendemic (>50% to 75% PfPR2–10) or holoendemic (>75% PfPR2–10) areas decreased from 218·6 million (34·4%) of 635·7 million to 183·5 million (22·5%) of 815·7 million across 44 malaria-endemic countries. 280·1 million (34·3%) people lived in areas of mesoendemic transmission (>10% to 50% PfPR2–10) in 2010 compared with 178·6 million (28·1%) in 2000. Population in areas of unstable or very low transmission (

Antibodies against three long synthetic peptides (LSPs) derived from the glutamate-rich protein (GLURP) ofPlasmodium falciparumwere analyzed in three cohorts from Liberia, Ghana, and Senegal. Two overlapping LSPs, LR67 and LR68, are derived from the relatively conserved N-terminal nonrepeat region (R0), and the third, LR70, is derived from the R2 repeat region. A high prevalence of antibody responses to each LSP was observed in all three areas of endemic infection. Levels of cytophilic immunoglobulin G (IgG) antibodies against both GLURP regions were significantly correlated with protection from clinicalP. falciparummalaria. Protected children from the Ghana cohort possessed predominantly IgG1 antibodies against the nonrepeat epitope and IgG3 antibodies against the repeat epitope. T-cell proliferation responses, studied in the cohort from Senegal, revealed that T-helper-cell epitopes were confined to the nonrepeat region. When used as immunogens, the LR67 and LR68 peptides elicited strong IgG responses in outbred mice and LR67 also induced antibodies in mice of differentH-2haplotypes, confirming the presence of T-helper-cell epitopes in these constructs. Mouse antipeptide antisera recognized parasite proteins as determined by immunofluorescence and immunoblotting. This indicates that synthetic peptides derived from relatively conserved epitopes of GLURP might serve as useful immunogens for vaccination againstP. falciparummalaria.

A survey of Plasmodium falciparum infection and clone multiplicity in Ghanaian children was carried out to study the effect of the onset of the malaria transmission season on disease incidence. Fortnightly blood samples were collected from 40 children living in the rural town of Dodowa, between February and August 1998. P. falciparum parasite densities were calculated and PCR genotyping was carried out using the polymorphic MSP-1 and MSP-2 genes as target loci for the estimation of the number of parasite clones in each sample. The average clone number was estimated using maximum likelihood techniques and the minimum number of clones per patient was analysed for the effects of age, sex, season, minimum number of clones per child, level of parasitaemia and parasite genotype. The statistical analysis indicated that the more clones a child carried, the more likely they were to have a clinical malaria episode. This was true after adjusting for age and season effects and for the measured circulating parasitaemia. The probability of clinical disease also increased if the MSP-1 MAD 20 and the MSP-2 FC 27 alleles were present. This longitudinal analysis thus indicates that the probability of a Ghanaian child having a symptomatic malaria episode is positively associated with both increasing numbers and novel types of P. falciparum clones.

Neonates and infants are relatively protected from clinical malaria, but the mechanism of this protection is not well understood. Maternally derived antibodies are commonly believed to provide protection against many infectious diseases, including malaria, for periods of up to 6-9 months but several recent epidemiological studies have produced conflicting results regarding a protective role of passively acquired antimalarial antibodies. In this article, we review the epidemiological evidence for resistance of young infants to malaria, summarize the data on antimalarial antibody levels and specificity and their association with protection from malaria infection or clinical disease, and explore alternative explanations for resistance to malaria in infants.

Background Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. Methods A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator. Results Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy, significant elevation of artesunate IC50 value was observed. The results also suggest the existence of possible cross-resistance among some of the test drugs. Conclusion Ghanaian P. falciparum isolates, to some extent, have become susceptible to chloroquine in vitro, however the increasing trend in artesunate IC50 value observed should be of concern. Continuous monitoring of ACT in Ghana is recommended.

TCR gamma delta(+) cells constitute

A study was conducted in 1997 to compare the accuracy of presumptive diagnosis of malaria in children aged 1–9 years performed by caretakers of the children to that of health centre staff in 2 ecological zones in southern Ghana. Similar symptoms were reported in the children at home and at the health centre. In the home setting, symptoms were reported the same day that they occurred, 77·6% of the children with a report of fever were febrile (axillary temperature ⩾37·5 °C) and 64·7% of the reports of malaria were parasitologically confirmed. In the health centre, the median duration of symptoms before a child was seen was 3 days (range 1–14 days), 58·5% of the children with a report of fever were febrile and 62·6% of the clinically diagnosed cases were parasitologically confirmed. In the 2 settings almost all the infections were due to Plasmodium falciparum . Parasite density was 3 times higher in the health centre cases compared to the home-diagnosed cases. Early and appropriate treatment of malaria detected in children by caretakers may prevent complications that arise as a result of persistence of symptoms and attainment of high parasitaemic levels.

SUMMARYTo assess the eosinophil response to Plasmodium falciparum infection a cohort of initially parasite-free Ghanaian children was followed for 3 months. Seven of nine children who acquired an asymptomatic P. falciparum infection showed increase in eosinophil counts, while a decrease was found in seven of nine children with symptomatic malaria, and no change was observed in 14 children who remained parasite-free. In a hospital-based study, paediatric patients with cerebral malaria (CM), severe anaemia (SA), or uncomplicated malaria (UM) had uniformly low eosinophil counts during the acute illness followed by eosinophilia 30 days after cure. Plasma levels of eosinophil cationic protein (ECP) and eosinophil protein X (EPX) were measured as indicators of eosinophil activation. In spite of the low eosinophil counts, ECP levels were increased on day 0 and significantly higher in patients with CM (geometric mean (95% confidence interval) 8·5 ng/ml (6·8–10·7 ng/ml)) than in SA (4·7 ng/ml (3·0–7·5 ng/ml)) and UM patients (4·3 ng/ml (3·6–5·3 ng/ml), P

We report first-time definitive evidence of human cutaneous leishmaniasis (CL) resulting from L. major infections in Ghana. The evidence is in the form of PCR testing and DNA sequence analysis of skin sample biopsies from residents of the Ho District in the forested Volta Region of southeastern Ghana (Figure 1). The moist semi-deciduous forest of this region of Ghana is atypical for CL. Although two sand fly species with known or suspected potential to transmit L. major were present in communities where human cases of CL originated, they were found in such small numbers that their role in the transmission of CL is uncertain. Twelve million people worldwide are believed to be infected with the parasites that cause leishmaniasis, and 88 different nations report this disease. 1 It is estimated that up to 75% of the 1.5 million new cases of leishmaniasis that occur each year are CL with L. major the responsible etiologic agent of this cutaneous disease in Africa and throughout Eurasia. Over this vast range, CL transmission is typically associated with arid desert and savannah conditions where the parasites are harbored in rodents and vectored by night-biting sand flies of the genus Phlebotomus. For many years, leishmaniasis in Africa and Western Asia has been grossly underestimated; it now appears that the disease is much more prevalent than previously suspected. 1 In Ghana, CL was considered a parasitic disease risk that was limited to the arid sahel-savannah region in the north, but no infections or evidence of transmission had been actually described. Thousands of man-hours of mosquito surveillance have been conducted in northern Ghana 2 for the purpose of quantifying man-biting malaria vectors, but there is no record or report of sand flies in these collections. However, since 1999, an increasing number of suspected CL cases have been reported from the southern Volta Region of Ghana in a moist forest ecosystem where such skin lesions had not been previously reported. The assumption of CL was based subjectively on local microscopy, which identified Leishmania amastigotes in skin lesion biopsies taken from a cluster of local patients. Between 1999 and 2002, the Ghana Health Service recorded 2,426 suspected cases of CL in the Ho, Hohoe, and Kpando Districts (2,348, 2, and 76 cases, respectively). In 2003, the number of suspected cases rose to 6,450 (6,185, 174, and 91 in the same respective districts) with 116 villages affected (Ghana Ministry of Health (MoH), Annual Report, 2003). A limited survey of towns in the Ho district during 2002 identified suspected CL lesions in 12.2–32.3% of local school children. In an effort to determine the cause and extent of the outbreak, the Ghana MoH initiated an epidemiologic study in Ho district with assistance from the U.S. Naval Medical Research Unit No. 3 and the Noguchi Memorial Institute of Medical Research. Initial efforts of our study intended to verify the presence of Leishmania parasites by applying newly developed PCR methods to 5 previously collected, archived biopsy samples

A research infrastructure was established in two ecological zones in southern Ghana to study the variables of malaria transmission and provide information to support the country's Malaria Action Plan (MAP) launched in 1992. Residents' beliefs and practices about causes, recognition, treatment and prevention of malaria were explored in two ecological zones in southern Ghana using epidemiological and social research methods. In both communities females constituted more than 80% of caretakers of children 1-9 years and the illiteracy rate was high. Fever and malaria, which are locally called Asra or Atridi, were found to represent the same thing and are used interchangeably. Caretakers were well informed about the major symptoms of malaria, which correspond to the current clinical case definition of malaria. Knowledge about malaria transmission is, however, shrouded in many misconceptions. Though the human dwellings in the study communities conferred no real protection against mosquitoes, bednet usage was low while residents combatted the nuisance of mosquitoes with insecticide sprays, burning of coils and herbs, which they largely considered as temporary measures. Home treatment of malaria combining herbs and over-the-counter drugs and inadequate doses of chloroquine was widespread. There is a need for a strong educational component to be incorporated into the MAP to correct misconceptions about malaria transmission, appropriate treatment and protection of households. Malaria control policies should recognize the role of home treatment and drug shops in the management of malaria and incorporate them into existing control strategies.

Interactions between HLA class I molecules and killer-cell immunoglobulin-like receptors (KIR) control natural killer cell (NK) functions in immunity and reproduction. Encoded by genes on different chromosomes, these polymorphic ligands and receptors correlate highly with disease resistance and susceptibility. Although studied at low-resolution in many populations, high-resolution analysis of combinatorial diversity of HLA class I and KIR is limited to Asian and Amerindian populations with low genetic diversity. At the other end of the spectrum is the West African population investigated here: we studied 235 individuals, including 104 mother-child pairs, from the Ga-Adangbe of Ghana. This population has a rich diversity of 175 KIR variants forming 208 KIR haplotypes, and 81 HLA-A, -B and -C variants forming 190 HLA class I haplotypes. Each individual we studied has a unique compound genotype of HLA class I and KIR, forming 1–14 functional ligand-receptor interactions. Maintaining this exceptionally high polymorphism is balancing selection. The centromeric region of the KIR locus, encoding HLA-C receptors, is highly diverse whereas the telomeric region encoding Bw4-specific KIR3DL1, lacks diversity in Africans. Present in the Ga-Adangbe are high frequencies of Bw4-bearing HLA-B*53:01 and Bw4-lacking HLA-B*35:01, which otherwise are identical. Balancing selection at key residues maintains numerous HLA-B allotypes having and lacking Bw4, and also those of stronger and weaker interaction with LILRB1, a KIR-related receptor. Correspondingly, there is a balance at key residues of KIR3DL1 that modulate its level of cell-surface expression. Thus, capacity to interact with NK cells synergizes with peptide binding diversity to drive HLA-B allele frequency distribution. These features of KIR and HLA are consistent with ongoing co-evolution and selection imposed by a pathogen endemic to West Africa. Because of the prevalence of malaria in the Ga-Adangbe and previous associations of cerebral malaria with HLA-B*53:01 and KIR, Plasmodium falciparum is a candidate pathogen., Author Summary Natural killer cells are white blood cells with critical roles in human health that deliver front-line immunity against pathogens and nurture placentation in early pregnancy. Controlling these functions are cell-surface receptors called KIR that interact with HLA class I ligands expressed on most cells of the body. KIR and HLA are both products of complex families of variable genes, but present on separate chromosomes. Many HLA and KIR variants and their combinations associate with resistance to specific infections and pregnancy syndromes. Previously we identified basic components of the system necessary for individual and population survival. Here, we explore the system at its most genetically diverse by studying the Ga-Adangbe population from Ghana in West Africa. Co-evolution of KIR receptors with their HLA targets is ongoing in the Ga-Adangbe, with every one of 235 individuals studied having a unique set of KIR receptors and HLA class I ligands. In addition, one critical combination of receptor and ligand maintains alternative forms that either can or cannot interact with their ‘partner.’ This balance resembles that induced by malfunctioning variants of hemoglobin that confer resistance to malaria, a candidate disease for driving diversity and co-evolution of KIR and HLA class I in the Ga-Adangbe.