Therapy of falciparum malaria in sub-saharan Africa: from molecule to policy

Mapping the flow of veterinary antibiotics in Kenya

Introduction

To effectively regulate and reduce antibiotic use, in the livestock sector, a thorough understanding of the flow of veterinary antibiotics will help to identify key nodes in the chain for targeted interventions. The aim of this study was to understand the flow of antibiotics from import to end-user, and identify relevant governance mechanisms.

Methods

A mixed methods approach was used to collect data in three Kenyan counties (Nairobi, Kiambu, and Kajiado). Focus group discussions (n = 23), individual interviews (n = 148), and key informant interviews (n = 10) were conducted.

Results

The key actors identified include primary wholesalers, secondary wholesalers, retailers, animal health service providers (AHSPs), and farmers. Kenya imports 100% of its veterinary antibiotics: primary wholesalers legally import antibiotics as finished pharmaceutical products (90%) or active pharmaceutical ingredients (10%) after approval by the Veterinary Medicines Directorate. Secondary wholesalers play a major role in the distribution of antibiotics (60% of antibiotics) from importers to farmers, AHSPs, and retailers. Some of the illegal sources of antibiotics include unlicenced/unauthorized middlemen and online platforms that sell directly to retailers, AHSPs, and farmers.

Discussion

Despite the presence of various laws and regulations governing the antibiotic value chain, implementation has been a challenge due to financial and human resource constraints. This contributes to over-the-counter sale of antibiotics without prescription, unlicensed businesses selling antibiotics, illegal importation, and presence of poor-quality drugs. There is a need to review the applicability of existing policies and address policy gaps (e.g., product containing antibiotic combinations, and use of human critically important antibiotics) to ensure the prudent sale and use of antibiotics, pharmacovigilance, antimicrobial use surveillance, and developing a business model that aligns with antibiotic stewardship. Additional interventions include awareness raising and capacity building of the different stakeholders along the antibiotic distribution chain to reduce antibiotic mis- and overuse.

The Malaria Burden: A South African Perspective

Malaria is a deadly disease caused by protozoan pathogens of the Plasmodium parasite. Transmission to humans occurs through the bite of an infected female Anopheles mosquito. According to the World Health Organization (WHO), an estimated 247 million cases of malaria were recorded worldwide in 2021, with approximately 619 000 malaria deaths. The initial signs of malaria can be mild and challenging to diagnose due to the signs and symptoms being similar to those of other illnesses. The malaria burden remains largely concentrated in the WHO sub-Saharan African region and has been recognised as a significant contributor to morbidity and mortality. This review aims to contribute to the existing knowledge on malaria in South Africa, a region within sub-Saharan Africa, focusing on the epidemiology and life cycle of the malaria parasite as well as diagnostic approaches for detecting malaria. In addition, nonpharmacological and pharmacological interventions for treating and preventing malaria infections will also be discussed herein. While there has been a significant reduction in the global burden of this disease, malaria remains a public health issue in South Africa. As such, the implementation of effective preventative measures and strategies, early diagnosis, and appropriate treatment regimens are crucial to reducing the malaria burden in South Africa.

Burden of psoriasis in young adults worldwide from the global burden of disease study 2019

Background

To determine the global burden of psoriasis in young adults, i.e., those aged 15-49, from 1990 to 2019 and predict trends in this burden for 2020 to 2030.

Methods

Age-standardized disease burden indicators and their estimated annual percentage changes were assessed and used to compare the estimated burden between regions. In addition, generalized additive models were used to predict the burden in this population from 2020 to 2030.

Results

From 1990 to 2019, the overall burden of psoriasis in young adults worldwide trended downward, as the age-standardized incidence rate and the age-standardized disability-adjusted life year rate decreased. From 1990 to 2019, there were gender differences in the burden of psoriasis between regions with different Socio-demographic index. Specifically, there was a smaller increase in the burden in young men than in young women in middle- and low-middle-Socio-demographic index areas. In 2019, Western Europe, Australasia, and Southern Latin America had the highest age-standardized incidence rate of psoriasis in young adults, whereas age-standardized disability-adjusted life year rates of psoriasis in young adults were highest in high-income North America. In 2019, the psoriasis burden in young adults was the highest in high-Socio-demographic index areas and the lowest in low-Socio-demographic index regions. We predict that from 2020 to 2030, the incidence rate and disability-adjusted life year rate of psoriasis in all age groups of young adults will continue to decline, but the burden in those aged 30-39 will increase.

Conclusion

From 1990 to 2019, the overall burden of psoriasis in each age group trended downward in this period. We predict that from 2020 to 2030, the burden of psoriasis in those aged 30-39 will increase.

Rational Optimization of Dihydropyrimidoinone-Quinoline Hybrids as Plasmodium falciparum Glutathione Reductase Inhibitors

A series of dihydropyrimidinone-based antimalarial compounds were designed and synthesised based on the previously identified amide-based quinoline hybrids which showed good resistance reversal ability against the resistant strain of Plasmodium falciparum . The aromatic ring on the dihydropyrimidinone of the original hits was exchanged for a methyl group to bring the molecular weights below 500 Da and also determine the effect of the aromatic ring count on the resistance reversal ability of the hybrids. Apart from the previously used amide bond, the hybrid linker was also extended to the triazole linker. Although the triazole linker is synthetically easier to access, the use of an amide linker seems to have an activity advantage. The synthesised compounds in addition to the previously identified hits were subjected to molecular docking particularly targeting the orthosteric site of Plasmodium falciparum glutathione reductase ( Pf GR) protein. The ligand with the best binding interaction was rationally optimised to increase its suitability as a competitive inhibitor against the cofactor of the Pf GR. Two of the optimised ligands showed better binding affinities than the cofactor while one of the two ligands displayed hydrophobically packed correlated hydrogen-bond which is very important in maintaining the ligand stability within the protein. In silico ADME predictions of the synthesised compounds indicate that these compounds possess good pharmacokinetic properties.

Pharmaceutical quality of antimalarial drugs: quinine sulfate and Artemether/Lumefantrine tablets sold on Bukavu Market

Background

Generic antimalarial drugs sold in sub-Saharan Africa require tighter control as counterfeiting has grown more and more out of control. The study aimed to analyze the pharmaceutical quality of quinine sulfate (QS) and Artemether/Lumefantrine(AL) tablets marketed in Bukavu city compared to the current trends in other African cities.

Results

The samples were purchased in community pharmacies or from ambulatory street vendors and analyzed using a set of thirteen simple tests, including visual inspection, UV spectrometry, TLC, and conventional quality control procedures. More than 93% of AL samples had an acceptable global quality score of > 90%. Around 16.6% of QS batches did not satisfy the requirements about hardness, friability, and mass uniformity. Only 33.3% met the disintegration quality; 33.3% did not contain quinine; 8.33% had an active ingredient other than quinine.

Conclusion

The findings strongly alert the circulation of fake antimalarial medicines observed in many countries. Simple TLC procedures may help to detect any low-quality generics to avoid microbial resistance and guarantee the health of the population. Pharmacists and regulatory authorities are alerted to the circulation of low-quality generic quinine preparations in the country.

An insight into the implementation of the global action plan on antimicrobial resistance in the WHO African region: A roadmap for action

INTRODUCTION

The Global Action Plan (GAP) on antimicrobial resistance (AMR) delivers a 'One Health' strategy for the development of the national action plan. It encourages the optimal use of antimicrobials and strengthens the evidence base through surveillance and research.

METHODS

This study evaluated the current status of implementation of the GAP on AMR in World Health Organization (WHO) African countries via a retrospective, cross-sectional analysis of routinely collected data on AMR. A SWOT analysis was used to identify the strengths, weaknesses, opportunities and threats involved in the GAP implementation. A roadmap for action was proposed.

RESULTS

The overall mean GAP performance score across all the countries that were assessed was 32% ± SD12 (95% CI 27-36%). The mean thematic scores were 59% ± 12 (53-65%) for multi-sector and One Health collaboration; 50% ± 22 (42-58%) for developing national AMR action plans; 38% ± 12 (33-42%) for awareness and training; 18% ± 13 (13-23%) for surveillance; 33% ± 13 (29-38%) for infection prevention and control; and 28% ± 23 (20-37%) for optimal use of antimicrobial medicines in human, animal and plant health. The difference in GAP performance scores between African sub-regions and between income categories was not statistically significant (P > 0.05). While seven countries exhibited strengths in two themes, 25 countries exhibited weaknesses across all themes. Six threats and six opportunities were identified to inform a practical roadmap for AMR action.

CONCLUSION

The findings from this study indicate that the overall GAP implementation on AMR in the WHO African region is inadequate. Some thematic GAP scores appeared to be relatively good, but on closer inspection, individual indicators revealed a lack of progress and implementation, requiring action.

Emerging properties of malaria transmission and persistence in urban Accra, Ghana: evidence from a participatory system approach

Background

Several studies that aim to enhance the understanding of malaria transmission and persistence in urban settings failed to address its underlining complexity. This study aims at doing that by applying qualitative and participatory-based system analysis and mapping to elicit the system’s emergent properties.

Methods

In two experts’ workshops, the system was sketched and refined. This system was represented through a causal loop diagram, where the identification of leverage points was done using network analysis.

Results

45 determinants interplaying through 56 linkages, and three subsystems: urbanization-related transmission, infection-prone behaviour and healthcare efficiency, and Plasmodium resistance were identified. Apart from the number of breeding sites and malaria-positive cases, other determinants such as drug prescription and the awareness of householders were identified by the network analysis as leverage points and emergent properties of the system of transmission and persistence of malaria.

Conclusion

Based on the findings, the ongoing efforts to control malaria, such as the use of insecticide-treated bed nets and larvicide applications should continue, and new ones focusing on the public awareness and malaria literacy of city dwellers should be included. The participatory approach strengthened the legitimacy of the recommendations and the co-learning of participants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03851-7.

Chloroquine and Sulfadoxine-Pyrimethamine Resistance in Sub-Saharan Africa-A Review

Malaria is a great concern for global health and accounts for a large amount of morbidity and mortality, particularly in Africa, with sub-Saharan Africa carrying the greatest burden of the disease. Malaria control tools such as insecticide-treated bed nets, indoor residual spraying, and antimalarial drugs have been relatively successful in reducing the burden of malaria; however, sub-Saharan African countries encounter great challenges, the greatest being antimalarial drug resistance. Chloroquine (CQ) was the first-line drug in the 20th century until it was replaced by sulfadoxine–pyrimethamine (SP) as a consequence of resistance. The extensive use of these antimalarials intensified the spread of resistance throughout sub-Saharan Africa, thus resulting in a loss of efficacy for the treatment of malaria. SP was replaced by artemisinin-based combination therapy (ACT) after the emergence of resistance toward SP; however, the use of ACTs is now threatened by the emergence of resistant parasites. The decreased selective pressure on CQ and SP allowed for the reintroduction of sensitivity toward those antimalarials in regions of sub-Saharan Africa where they were not the primary drug for treatment. Therefore, the emergence and spread of antimalarial drug resistance should be tracked to prevent further spread of the resistant parasites, and the re-emergence of sensitivity should be monitored to detect the possible reappearance of sensitivity in sub-Saharan Africa.

An Evaluation of Active Case Detection in Malaria Control Program in Kiyuni Parish of Kyankwanzi District, Uganda

Malaria remains one of the leading health burdens in the developing world, especially in several sub-Saharan Africa countries; and Uganda has some of the highest recorded measures of malaria transmission intensity in the world. It is evident that the prevalence of malaria infection, the incidence of disease, and mortality from severe malaria remain very high in Uganda. Although the recent stable political and economic situation in the last few decades in Uganda supported for a fairly good appreciation of malaria control, the declines in infection, morbidity, and mortality are not sufficient to interrupt transmission and this country is among the top 4 countries with cases of malaria, especially among children under 5 years of age. In fact, Uganda, which is endemic in over 95% of the country, is a representative of challenges facing malaria control in Africa. In this study, we evaluated an active case detection program in 6 randomly selected villages, Uganda. This program covered a potential target population of 5,017 individuals. Our team screened 12,257 samples of malaria by active case detection, every 4 months, from February 2015 to January 2017 in the 6 villages (a total of 6 times). This study assessed the perceptions and practices on malaria control in Kiyuni Parish of Kyankwanzi district, Uganda. Our study presents that the incidence of malaria is sustained high despite efforts to scale-up and improve the use of LLINs and access to ACDs, based on the average incidence confirmed by RDTs.

Cross sectional study to determine chloroquine resistance among Plasmodium falciparum clinical isolates from Khartoum, Sudan

Background:  Malaria continues to present a global health threat; the World Health Organization (WHO) reported 214 million cases of malaria by the year 2015 with a death rate of 438000. Sudan is endemic to malaria with over 95% of malaria cases due to Plasmodium falciparum. Chloroquine is a well-established drug in the treatment of P. falciparum malaria although its use has declined since its introduction as the drug of choice in treatment of malaria in Sudan. The mechanism of resistance has been attributed to mutations in P. falciparum Chloroquine resistance transporter gene coding for a key food vacuole proteins. In current study we aimed at verifying the genetic cause of resistance to Chloroquine in field isolates of P. falciparum. Methods: Twenty P. falciparum cases were diagnosed from East Nile hospital in Khartoum and recruited in the investigation. Nested PCR was conducted to isolate mutation region in the PfCRT gene and the amplicons were sequenced using Sanger sequencing technique (Macrogen, Soule Korea). Results: 16/20 (80%) of the field isolates contained base pair mutation of codon 76 in the pfcrt gene thus being resistant to chloroquine treatment and only 4/20 (20%) did not contain such mutation. Conclusions: High treatment failures associated with Chloroquine treatment is evident of the high prevalence of mutant strains of P. falciparum field isolates thus suggesting the reduced relevance of Chloroquine as a treatment choice in the management of P. falciparum malaria.

The threat of antimicrobial resistance in developing countries: causes and control strategies

The causes of antimicrobial resistance (AMR) in developing countries are complex and may be rooted in practices of health care professionals and patients' behavior towards the use of antimicrobials as well as supply chains of antimicrobials in the population. Some of these factors may include inappropriate prescription practices, inadequate patient education, limited diagnostic facilities, unauthorized sale of antimicrobials, lack of appropriate functioning drug regulatory mechanisms, and non-human use of antimicrobials such as in animal production. Considering that these factors in developing countries may vary from those in developed countries, intervention efforts in developing countries need to address the context and focus on the root causes specific to this part of the world. Here, we describe these health-seeking behaviors that lead to the threat of AMR and healthcare practices that drive the development of AMR in developing countries and we discuss alternatives for disease prevention as well as other treatment options worth exploring.

The threat of antimicrobial resistance in developing countries: causes and control strategies

The causes of antimicrobial resistance (AMR) in developing countries are complex and may be rooted in practices of health care professionals and patients’ behavior towards the use of antimicrobials as well as supply chains of antimicrobials in the population. Some of these factors may include inappropriate prescription practices, inadequate patient education, limited diagnostic facilities, unauthorized sale of antimicrobials, lack of appropriate functioning drug regulatory mechanisms, and non-human use of antimicrobials such as in animal production. Considering that these factors in developing countries may vary from those in developed countries, intervention efforts in developing countries need to address the context and focus on the root causes specific to this part of the world. Here, we describe these health-seeking behaviors that lead to the threat of AMR and healthcare practices that drive the development of AMR in developing countries and we discuss alternatives for disease prevention as well as other treatment options worth exploring.

Knowledge, attitude and practice about malaria in south-western Saudi Arabia: A household-based cross-sectional survey

This study aimed to assess the level of knowledge, attitudes, and practices (KAP) concerning malaria and malaria prevention among rural populations residing in the southwestern region of Saudi Arabia. This was a household-based cross-sectional survey, using structured questionnaire that was developed and distributed among households selected randomly from 19 villages (clusters) located in a southwestern region of Saudi Arabia, north of the border with Yemen. The data collected were analyzed using SPSS version 20. A majority of respondents (98.4%) reported that they had heard about malaria, but only 21.7% reported that they had sufficient information about the disease. Surprisingly, the most popular source of information was the internet and social media (proportion responding positively in parenthesis) (25.5%), followed by family (21.7%), while information from health facilities contributed only 12.4%. A majority of respondents were aware that malaria is a communicable (89.1%) and deadly (70%) disease; however, only 30.2% of the respondents responded that malaria is a treatable disease. Almost all of the aware respondents (97.5%) were inclined to seek treatment from health facilities, and 63.2% preferred to seek treatment within 24h of presenting with symptoms. Regarding personal precautions, the most common practice adopted by respondents was indoor residual spraying IRS (47.3%), followed by anti-mosquito spraying (29.8%), mosquito bed nets (13.2%) and combined anti-mosquito sprays and nets on windows (4.7%). This KAP study did not show any statistically significant differences in KAP due to age; however the practices of preventive measures against malaria differed significantly by nationality (Saudi versus non-Saudi). We conclude that most populations living in the villages have an acceptable level of knowledge and awareness about malaria and seek timely treatment. However, the positive attitudes and practices in relation to personal protection and prevention measures against malaria require marked improvement. The obvious gap between the knowledge and practice related to malaria prevention requires innovative strategies based on local evidence that well suits the local circumstances to promote and encourage the adoption and practice of personal protective measures.

Narrative review of current context of malaria and management strategies in Uganda (Part I)

In accordance with international targets, the Uganda National Malaria Control Strategic Plan established specific targets to be achieved by 2010. For children under five, this included increasing the number of children sleeping under mosquito nets and those receiving a first-line antimalarial to 85%, and decreasing case fatality to 2%. This narrative review offers contextual information relevant to malaria management in Uganda since the advent of artemisinin combination therapy (ACT) as first-line antimalarial treatment in 2004. A comprehensive search using key words and phrases was conducted using the web search engines Google and Google Scholar, as well as the databases of PubMed, ERIC, EMBASE, CINAHL, OvidSP (MEDLINE), PSYC Info, Springer Link, Cochrane Central Register of Controlled Trials (CENTRAL), and Cochrane Database of Systematic Reviews were searched. A total of 147 relevant international and Ugandan literature sources meeting the inclusion criteria were included. This review provides an insightful understanding on six topic areas: global and local priorities, malarial pathology, disease burden, malaria control, treatment guidelines for uncomplicated malaria, and role of the health system in accessing antimalarial medicines. Plasmodium falciparum remains the most common cause of malaria in Uganda, with children under five being most vulnerable due to their underdeveloped immunity. While international efforts to scale up malaria control measures have resulted in considerable decline in malaria incidence and mortality in several regions of sub-Saharan Africa, this benefit has yet to be substantiated for Uganda. At the local level, key initiatives have included implementation of a new antimalarial drug policy in 2004 and strengthening of government health systems and programs. Examples of such programs include removal of user fees, training of frontline health workers, providing free ACT from government systems and subsidized ACT from licensed private outlets, and introduction of the integrated community case management program to bring diagnostics and treatment for malaria, pneumonia and diarrhea closer to the community. However despite notable efforts, Uganda is far from achieving its 2010 targets. Several challenges in the delivery of care and treatment remain, with those most vulnerable and living in rural settings remaining at greatest risk from malaria morbidity and mortality.

Adherence to artemisinin-based combination therapy for the treatment of malaria: a systematic review of the evidence

BACKGROUND

Increasing access to and targeting of artemisinin-based combination therapy (ACT) is a key component of malaria control programmes. To maximize efficacy of ACT and ensure adequate treatment outcomes, patient and caregiver adherence to treatment guidelines is essential. This review summarizes the current evidence base on ACT adherence, including definitions, measurement methods, and associated factors.

METHODS

A systematic search of the published literature was undertaken in November 2012 and updated in April 2013. Bibliographies of manuscripts were also searched and additional references identified. Studies were included if they involved at least one form of ACT and reported an adherence measurement.

RESULTS

The search yielded 1,412 records, 37 of which were found to measure adherence to ACT. Methods to measure adherence focused on self-report, pill counts and bioassays with varying definitions for adherence. Most studies only reported whether medication regimens were completed, but did not assess how the treatment was taken by the patient (i.e. timing, frequency and dose). Adherence data were available for four different ACT formulations: artemether-lumefantrine (AL) (range 39-100%), amodiaquine plus artesunate (AQ + AS) (range 48-94%), artesunate plus sulphadoxine-pyrimethamine (AS + SP) (range 39-75%) and artesunate plus mefloquine (AS + MQ) (range 77-95%). Association between demographic factors, such as age, gender, education and socio-economic status and adherence to ACT regimens was not consistent. Some evidence of positive association between adherence and patient age, caregiver education levels, drug preferences, health worker instructions, patient/caregiver knowledge and drug packaging were also observed.

CONCLUSIONS

This review highlights the weak evidence base on ACT adherence. Results suggest that ACT adherence levels varied substantially between study populations, but comparison between studies was challenging due to differences in study design, definitions, and methods used to measure adherence. Standardising methodologies for both self-report and bioassays used for evaluating adherence of different formulations across diverse contexts would improve the evidence base on ACT adherence and effectiveness; namely, specific and measurable definitions for adherence are needed for both methodologies. Additionally, further studies of the individual factors and barriers associated with non-adherence to ACT are needed in order to make informed policy choices and to improve the delivery of effective malaria treatment.

Impact of inconsistent policies for transfusion-transmitted malaria on clinical practice in Ghana

Background

Policies concerning the prevention of transfusion transmitted malaria (TTM) are the responsibility of blood transfusion services and malaria control programmes. To prevent spreading drug resistance due to over-use of malaria drugs, recent malaria treatment guidelines recommend prompt parasitological confirmation before treatment is started. In contrast, blood safety policies from the World Health Organisation (WHO) recommend presumptive malaria treatment for recipients of blood in endemic countries but evidence supporting this approach is lacking. Our study documented how these conflicting policies relating to malaria transmission through blood transfusion impact on clinical practice in a teaching hospital in West Africa.

Methods/Principal Findings

We randomly selected and reviewed case notes of 151 patients within 24 hours of their receiving a blood transfusion. Transfusion practices including the confirmation of diagnosis and anti-malarial treatment given were compared across three departments; Obstetrics and Gynaecology (O&G), Paediatrics and Medicine. Overall, 66 (44%) of patients received malaria treatment within 24 hrs of their blood transfusion; of which only 2 (3%) received anti-malarials based on a laboratory confirmation of malaria. Paediatric patients (87%) received the most anti-malarials and only 7% and 24% of recipients in medicine and O&G respectively received anti malarials. In 51 patients (78%), the anti-malarials were prescribed at the same time as the blood transfusion and anti-malarials prescriptions exceeded the number of patients with a presumptive diagnosis of malaria.

Conclusions

It is common practice in paediatrics to prescribe anti-malarials routinely with blood transfusions. This contravenes the malaria treatment guidelines of laboratory confirmation before treatment but is in accordance with the less-well evidenced blood safety guidelines. There is an urgent need for more evidence about the clinical impact of transfusion transmitted malaria to enable malaria and blood transfusion programmes to harmonize their policies and give clear guidance to clinicians who prescribe blood transfusions in malaria-endemic areas

Binding modes of 2,4-diaminoquinazoline and 2,4-diaminopteridine analogs to P. falciparum dihydrofolate reductase enzyme: Molecular docking studies

A molecular docking study was carried out on 28 compounds belonging to 2,4-diaminoquinazoline and 2,4-diaminopteridine analogs using Glide, FlexX and GOLD programs and the X-ray crystallographic structures of the quadruple mutant (1J3K:pdb) and wild type (1J3I:pdb) Plasmodium falciparum dihydrofolate reductase enzyme. The experimental conformation the bound ligand WR99210 was precisely reproduced by the docking procedures as demonstrated by low (<2.00 Å) root-mean-square deviations. The results indicated that most of the compounds dock into the active sites of both the wild type and quadruple mutant P. falciparum dihydrofolate reductase enzymes. Visual inspection of the binding modes also demonstrated that most of the compounds could form H-bond interactions with the key amino acid residues (Asp54, Ile14 and Leu/Ile164) and with better docking scores than the bound compound (5). Their long side chains orient in the hydrophobic portion of the active site which is occupied by trichloro aryloxy side chain of WR99210 (5). Thus, avoid potential steric clashes with Asn108 (mutated from Ser108). Such a clash is known to be responsible for the resistance of the P. falciparum to pyrimethamine and cycloguanil.

Anti-malarial drug formulations and novel delivery systems: a review

Artemisinin combination therapies have decreased malaria associated morbidity and mortality in several parts of the world. On the other hand, malaria cases have increased in sub-Saharan Africa largely due to falciparum resistance to the most frequently used drugs (chloroquine and sulphadoxine/pyrimethamine (SP) combination). Therapeutic failure has also been attributed in part to adverse effects of anti-malarial drugs and patients' non-compliance due to inconvenient dosing schedules. We consider that formulation and evaluation of novel drug delivery systems is not only less expensive than developing new drugs, but may also improve delivery of anti-malarials at the desired rates. In this review we evaluate the therapeutic efficacy of existing anti-malarial drugs and assess the feasibility of developing novel formulations and delivery systems.

Coverage of intermittent prevention treatment with sulphadoxine-pyrimethamine among pregnant women and congenital malaria in Côte d'Ivoire

Background

The World Health Organization (WHO) recommends using insecticide-treated mosquito nets (ITNs) and intermittent preventive treatment with sulphadoxine-pyrimethamine (IPT-SP) to prevent malaria in sub-Saharan Africa. Data on IPT-SP coverage and factors associated with placental malaria parasitaemia and low birth weight (LBW) are scarce in Côte d'Ivoire.

Methods

A multicentre, cross-sectional survey was conducted in Côte d'Ivoire from March to September 2008 at six urban and semi-urban antenatal clinics. Standardized forms were used to collect the demographic information and medical histories of women and their offspring. IPT-SP coverage (≥2 doses) as well as placental and congenital malaria prevalence parasitaemia were estimated. Regression logistics were used to study factors associated with placental malaria and LBW (birth weight of alive babies < 2,500 grams).

Results

Overall, 2,044 women with a median age of 24 years were included in this study. Among them 1017 (49.8%) received ≥2 doses of IPT-SP and 694 (34.0%) received one dose. A total of 99 mothers (4.8%) had placental malaria, and of them, four cases of congenital malaria were diagnosed. Factors that protected from maternal placental malaria parasitaemia were the use of one dose (adjusted odds ratio (aOR), 0.32; 95%CI: 0.19-0.55) or ≥2 doses IPT-SP (aOR: 0.18; 95%CI: 0.10-0.32); the use of ITNs (aOR: 0.47; 95%CI: 0.27-0.82). LBW was associated with primigravidity and placental malaria parasitaemia.

Conclusion

IPT-SP decreases the rate of placental malaria parasitaemia and has a strong dose effect. Despite relatively successful IPT-SP coverage in Côte d'Ivoire, substantial commitments from national authorities are urgently required for such public health campaigns. Strategies, such as providing IPT-SP free of charge and directly observing treatment, should be implemented to increase the use of IPT-SP as well as other prophylactic methods.

Case management of severe malaria--a forgotten practice: experiences from health facilities in Uganda

Introduction

Severe malaria is a life-threatening medical emergency and requires prompt and effective treatment to prevent death. There is paucity of published information on current practices of severe malaria case management in sub-Saharan Africa; we evaluated the management practices for severe malaria in Ugandan health facilities

Methods and Findings

We did a cross sectional survey, using multi-stage sampling methods, of health facilities in 11 districts in the eastern and mid-western parts of Uganda. The study instruments were adapted from the WHO hospital care assessment tools. Between June and August 2009, 105 health facilities were surveyed and 181 health workers and 868 patients/caretakers interviewed. None of the inpatient facilities had all seven components of a basic care package for the management of severe malaria consistently available during the 3 months prior to the survey. Referral practices were appropriate for <10% (18/196) of the patients. Prompt care at any health facility was reported by 29% (247/868) of patients. Severe malaria was correctly diagnosed in 27% of patients (233).Though the quinine dose and regimen was correct in the majority (611/868, 70.4%) of patients, it was administered in the correct volumes of 5% dextrose in only 18% (147/815). Most patients (80.1%) had several doses of quinine administered in one single 500 ml bottle of 5% dextrose. Medications were purchased by 385 (44%) patients and medical supplies by 478 patients (70.6%).

Conclusions

Management of severe malaria in Ugandan health facilities was sub-optimal. These findings highlight the challenges of correctly managing severe malaria in resource limited settings. Priority areas for improvement include triage and emergency care, referral practises, quality of diagnosis and treatment, availability of medicines and supplies, training and support supervision.

Factors associated with regional bias of pfcrt (plasmodium falciparum chloroquine resistance transporter) haplotypes in Nepal

Evidences of reappearance of chloroquine sensitive Plasmodium falciparum haplotypes after cessation of chloroquine in many countries provide a rationale for the search of chloroquine sensitive haplotypes in P. falciparum isolates in Nepal where the use of chloroquine for falciparum malaria treatment has been ceased since 1988. P. falciparum chloroquine resistant transporter gene (pfcrt) haplotypes were determined and the factors associated with pfcrt haplotypes in the Eastern and Central regions of Nepal were identified. Blood samples from 106 microscopy-positive falciparum malaria patients (62 from the Eastern and 44 from the Central region) were collected on filter paper. Pfcrt region covering codons 72-76 was amplified by PCR and sequenced. SVMNT haplotype was predominant in the Central region, whereas CVIET haplotype significantly more common in the Eastern region. In multivariable analysis of factors associated with CVIET haplotype, the Eastern region and parasite isolates from patients visiting India within one month are significant at 5% level of significance. These findings suggest that antimalarial pressure is different between Eastern and Central regions of Nepal and there is a need of an effective malaria control program in the border areas between India and Nepal.

Efficacy of intermittent preventive treatment with sulfadoxine-pyrimethamine on placental parasitemia in pregnant women in midwestern Nigeria

OBJECTIVE

To assess the effect of intermittent preventive treatment with sulfadoxine and pyrimethamine (IPT-SP) on placental parasitemia and maternal and perinatal outcome.

METHODS

We compared placental malaria parasitemia during pregnancy and pregnancy outcome in 2 groups of women receiving antenatal care at University of Benin Teaching Hospital. One group was prophylactically treated with IPT-SP and the other was not treated.

RESULTS

The parasitemia rates for peripheral, placental, and cord blood were 11.9%, 11.4%, and 2.7% in the IPT-SP group (n=370) and 19.1%, 22.6%, and 6.2% in the control group (n=371) (P=0.006, P=0.002, and P=0.02, respectively). The treatment reduced the odds of placental parasitemia by 37% (OR 0.63; 95% CI, 0.48-0.81). Peripheral (P=0.002) and placental (P=0.001) parasitemia were significantly reduced in the subgroup of women who took 2 or 3 doses of SP. Fewer women (16.2%) in the IPT-SP group than the control group (23.7%) had symptomatic malaria. Anemia at delivery was significantly lower in the IPT-SP group (10.8 vs 1.6%). The risks of abortion, preterm delivery, and low birth weight were also significantly lower in the IPT-SP group.

CONCLUSION

IPT-SP is effective in preventing placental parasitemia, and reduces rates of malaria, maternal anemia, abortion, preterm delivery and low birth weight among pregnant women.

Malaria

Malaria has had a greater impact on world history than any other infectious disease. More than 300 to 500 million individuals worldwide are infected with Plasmodium spp, and 1.5 to 2.7 million people a year, most of whom are children, die from the infection. Malaria is endemic in over 90 countries in which 2400 million people live; this represents 40% of the world's population. Approximately 90% of malaria deaths occur in Africa. Despite continuing efforts in vaccine development, malaria prevention is difficult, and no drug is universally effective. This article examines malaria caused by the 4 most common Plasmodium spp that infect humans, P vivax, P ovale, P malariae, and P falciparum, as well as mixed infections and the simian parasite P knowlesi. A comprehensive review of the microbiology, clinical presentation, pathogenesis, diagnosis, and treatment of these forms of malaria is given.

Artesunate Plus Amodiaquine (AS+AQ) Versus Artemether -Lumefantrine (AL) for the Treatment of Uncomplicated Plasmodium Falciparum Malaria in Sub-Saharan Africa-A Meta-Analysis

The purpose of this study is to summarize the available data on the efficacy of Artesunate plus Amodiaquine (AS+AQ) versus Artemether -Lumefantrine (AL) for the treatment of uncomplicated Plasmodium falciparum malaria in sub-Saharan Africa using uncorrected parasitaemia as a clinically relevant endpoint. Studies and conference abstracts identified through Pubmed, Medline, Embase, Ansinet, AJOL, Bioline, Cochrane Infectious Diseases Group trials register, The Cochrane Controlled Trials Register, Science Citation Index, Lilacs, African Index Medicus, Clusty, Google, Yahoo and Microsoft search engines. Randomized controlled clinical trials comparing Artesunate-Amodiaquine versus Artemether-Lumefantrine, in Sub-Saharan Africa from January 2004 to June 2009, and which had at least 30 patients per study arm. The authors independently applied the inclusion criteria, assessed methodological quality and extracted data into a predesigned form. The outcome of interest was uncorrected day 28 parasitological failure. Data were then checked for agreement and double entered into RevMan version 5 for further analyses. Fifteen trials (4265 participants) met the inclusion criteria. Day 28 parasitological failure was lower for AL (286 of 2201 participants or 13.0 % failures) when compared with AS+AQ (446 of 2424 participants or 18.4% failures). The relative risk of parasitological failure with AS+AQ was higher when compared with AL (RR 1.65, 95% CI, 1.18-2.32). There were significant heterogeneity and inconsistencies in the studies. AL appears more effective at avoiding parasitological failure at days 28 than AS+AQ.

Drug utilisation study of antimalarials for the treatment of hospitalised children under five in south-eastern Nigeria

PURPOSE

This study aimed at describing the trend in the use of antimalarials for the treatment of malaria in children under 5 years from year 2000 to 2006 in south-eastern Nigeria. Adherence to the 2005 National Antimalarial Treatment Policy was assessed. Quality of drug use was also evaluated. Quality indices studied were the use of international non-proprietary name (INN) in prescription, number antimalarials per episode and use of drugs from essential drug list.

METHODS

The study was retrospective and longitudinal, using data obtained from in-patients folders of children under 5 years, hospitalised for malaria infection in 11 secondary health care centres in south-eastern Nigeria.

RESULTS

The result of the study showed that chloroquine was mostly used for treating severe malaria in children less than 5 years despite the indication of a switch to quinine and parenteral artemisinins by the National Treatment Policy. Prescriptions of drugs were also not by INN names. However, many prescribers do not practice polypharmacy and most of the drugs used in secondary health care centres for treatment of severe malaria were in the essential drug list.

CONCLUSION

There is a need for further studies to establish factors that affect the dissemination and use of treatment guidelines in Nigeria.

Treating malaria in pregnancy in developing countries: priorities in clinical research and drug development

Reducing the burden of falciparum malaria in pregnancy is an urgent international public health priority but one that involves considerable challenges. The rapidly declining effectiveness of agents known to be safe in pregnancy, and the limited efficacy, safety and pharmacokinetic data available for many other antimalarial drugs, mean that current options for the treatment of both severe and uncomplicated falciparum malaria in pregnancy are limited. This report summarizes the literature on this subject and recommends drug combinations for evaluation in Phase II/III treatment trials in pregnancy.

Antimalarial drug quality in Africa

BACKGROUND AND OBJECTIVE

There are several reports of sub-standard and counterfeit antimalarial drugs circulating in the markets of developing countries; we aimed to review the literature for the African continent.

METHODS

A search was conducted in PubMed in English using the medical subject headings (MeSH) terms: 'Antimalarials/analysis'[MeSH] OR 'Antimalarials/standards'[MeSH] AND 'Africa'[MeSH]' to include articles published up to and including 26 February 2007. Data were augmented with reports on the quality of antimalarial drugs in Africa obtained from colleagues in the World Health Organization. We summarized the data under the following themes: content and dissolution; relative bioavailability of antimalarial products; antimalarial stability and shelf life; general tests on pharmaceutical dosage forms; and the presence of degradation or unidentifiable impurities in formulations.

RESULTS AND DISCUSSION

The search yielded 21 relevant peer-reviewed articles and three reports on the quality of antimalarial drugs in Africa. The literature was varied in the quality and breadth of data presented, with most bioavailability studies poorly designed and executed. The review highlights the common finding in drug quality studies that (i) most antimalarial products pass the basic tests for pharmaceutical dosage forms, such as the uniformity of weight for tablets, (ii) most antimalarial drugs pass the content test and (iii) in vitro product dissolution is the main problem area where most drugs fail to meet required pharmacopoeial specifications, especially with regard to sulfadoxine-pyrimethamine products. In addition, there are worryingly high quality failure rates for artemisinin monotherapies such as dihydroartemisinin (DHA); for instance all five DHA sampled products in one study in Nairobi, Kenya, were reported to have failed the requisite tests.

CONCLUSIONS

There is an urgent need to strengthen pharmaceutical management systems such as post-marketing surveillance and the broader health systems in Africa to ensure populations in the continent have access to antimalarial drugs that are safe, of the highest quality standards and that retain their integrity throughout the distribution chain through adequate enforcement of existing legislation and enactment of new ones if necessary, and provision of the necessary resources for drug quality assurance.

Plasmepsins as potential targets for new antimalarial therapy

Malaria is one of the major diseases in the world. Due to the rapid spread of parasite resistance to available antimalarial drugs there is an urgent need for new antimalarials with novel mechanisms of action. Several promising targets for drug intervention have been revealed in recent years. This review addresses the parasitic aspartic proteases termed plasmepsins (Plms) that are involved in the hemoglobin catabolism that occurs during the erythrocytic stage of the malarial parasite life cycle. Four Plasmodium species are responsible for human malaria; P. vivax, P. ovale, P. malariae, and P. falciparum. This review focuses on inhibitors of the haemoglobin-degrading plasmepsins of the most lethal species, P. falciparum; Plm I, Plm II, Plm IV, and histo-aspartic protease (HAP). Previously, Plm II has attracted the most attention. With the identification and characterization of new plasmepsins and the results from recent plasmepsin knockout studies, it now seems clear that in order to achieve high-antiparasitic activities in P. falciparum-infected erythrocytes it is necessary to inhibit several of the haemoglobin-degrading plasmepsins. Herein we summarize the structure-activity relationships of the Plm I, II, IV, and HAP inhibitors. These inhibitors represent all classes which, to the best of our knowledge, have been disclosed in journal articles to date. The 3D structures of inhibitor/plasmepsin II complexes available in the protein data bank are briefly discussed and compared.

Role of cattle treated with deltamethrine in areas with a high population of Anopheles arabiensis in Moshi, Northern Tanzania

Background

Malaria control measures were initiated from in October 2005 to August 2006 in the Lower Moshi irrigation schemes, Tanzania. This manuscript reports on the entomological evaluation of the impact of pyrethroid-treated cattle in reducing the population of the Anopheles arabiensis for selected houses in the Lower Moshi irrigation scheme.

Methods

Cattle were sprayed with the pyrethroid (deltamethrin) acaricide. Grazing and non-grazing cattles were compared and assessed for difference in knockdown resistance (kdr) time using cone or contact bioassay and residual effect (mortality). In experimental huts, mortality was compared between the huts with treated and untreated cattle.

Results

Results from contact bioassays of cattle treated with deltamethrin showed a knockdown effect of 50% within 21 days for grazing cattle and 29 days for non-grazing cattle. Residual effect at 50% was achieved within 17 days for grazing cattle compared to 24 days for inshed cattle. In discussing the results, reference has been made to the exophilic and zoophilic tendencies of An. arabiensis, which are conducive for zooprophylaxis.

Experimental studies in Verandah huts at Mabogini compared An. arabiensis and Culex spp collected from huts with different baits, i e. human, untreated cow and treated cow. Results indicate higher mortality rates in mosquitoes collected from the hut containing the treated cow (mean = 2) compared to huts with untreated cow (mean = 0.3) and human (mean = 0.8). A significantly higher number of Culex spp. was recorded in huts with treated cows compared to the rest.

Conclusion

This study has demonstrated the role of cattle treated with pyrethroid in the control of malaria and reduction of vector density. It showed that, in areas with a predominant An. arabiensis population, cattle should be placed close to dwelling houses in order to maximize the effects of zooprophylaxis. Protective effects of cattle can further be enhanced by regular treatment with pyrethroids at least every three weeks. This paper demonstrates that cattle can be considered as Insecticide-Treated Material (ITM) as long as acaricide treatment is conducted regularly.

Intermittent preventive treatment for malaria in pregnancy in Africa: what's new, what's needed?

Falciparum malaria is an important cause of maternal, perinatal and neonatal morbidity in high transmission settings in Sub-Saharan Africa. Intermittent preventive treatment with sulphadoxine-pyrimethamine (SP-IPT) has proven efficacious in reducing the burden of pregnancy-associated malaria but increasing levels of parasite resistance mean that the benefits of national SP-IPT programmes may soon be seriously undermined in much of the region. Hence, there is an urgent need to develop alternative drug regimens for IPT in pregnancy. This paper reviews published safety and efficacy data on various antimalarials and proposes several candidate combination regimens for assessment in phase II/III clinical trials.

Challenges in the concurrent management of malaria and HIV in pregnancy in sub-Saharan Africa

Approximately one million pregnancies are complicated by both malaria and HIV infection in sub-Saharan Africa annually. Both infections have been associated with maternal and infant morbidity and mortality. Intermittent preventive treatment, usually with sulfadoxine-pyrimethamine, has been shown to prevent pregnancy-related malaria and its complications. Several different regimens of antiretroviral therapy are now available to prevent mother-to-child transmission of HIV and/or progression of maternal HIV infection during pregnancy. However, no published studies have yet shown whether standard intermittent preventive treatment and antiretroviral regimens are medically and operationally compatible in pregnancy. We reviewed existing policies regarding prevention and treatment of HIV and malaria in pregnancy, as well as published literature on adverse effects of antiretrovirals and antimalarials commonly used in pregnancy in developing countries, and found that concurrent prescription of sulfadoxine-pyrimethamine, co-trimoxazole (trimethoprim-sulfamethoxazole), and antiretroviral agents including nevirapine and zidovudine per existing protocols for prevention of malaria and vertical HIV transmission may result in adverse drug interactions or overlapping, diagnostically challenging drug toxicities. Insecticide-treated bednets should be provided for HIV-infected pregnant women at risk for malaria. Sulfadoxine-pyrimethamine should be prescribed cautiously in women concurrently receiving daily nevirapine and/or zidovudine, and should be avoided in women on daily co-trimoxazole. Further research is urgently needed to define safe and effective protocols for concurrent management of HIV and malaria in pregnancy, and to define appropriate interventions for different populations subject to differing levels of malaria transmission and antimalarial drug resistance.

High-efficiency transformation of Plasmodium falciparum by the lepidopteran transposable element piggyBac

Functional analysis of the Plasmodium falciparum genome is restricted because of the limited ability to genetically manipulate this important human pathogen. We have developed an efficient transposon-mediated insertional mutagenesis method much needed for high-throughput functional genomics of malaria parasites. A drug-selectable marker, human dihydrofolate reductase, added to the lepidopteran transposon piggyBac, transformed parasites by integration into the P. falciparum genome in the presence of a transposase-expressing helper plasmid. Multiple integrations occurred at the expected TTAA target sites throughout the genome of the parasite. We were able to transform P. falciparum with this piggyBac element at high frequencies, in the range of 10(-3), and obtain stable clones of insertional mutants in a few weeks instead of 6-12 months. Our results show that the piggyBac transposition system can be used as an efficient, random integration tool needed for large-scale, whole-genome mutagenesis of malaria parasites. The availability of such an adaptable genetic tool opens the way for much needed forward genetic approaches to study this lethal human parasite.

The plastid-derived organelle ofprotozoan human parasites asa target of established and emerging drugs

Human diseases like malaria, toxoplasmosis or cryptosporidiosis are caused by intracellular protozoan parasites of the phylum Apicomplexa and are still a major health problem worldwide. In the case of Plasmodium falciparum, the causative agent of tropical malaria, resistance against previously highly effective drugs is widespread and requires the continued development of new and affordable drugs. Most apicomplexan parasites possess a single plastid-derived organelle called apicoplast, which offers the great opportunity to tailor highly specific inhibitors against vital metabolic pathways resident in this compartment. This is due to the fact that several of these pathways, being of bacterial or algal origin, are absent in the mammalian host. In fact, the targets of several antibiotics already in use for years against some of these diseases can now be traced to the apicoplast and by knowing the molecular entities which are affected by these substances, improved drugs or drug combinations can be envisaged to emerge from this knowledge. Likewise, apicoplast-resident pathways like fatty acid or isoprenoid biosynthesis have already been proven to be the likely targets of the next drug generation. In this review the current knowledge on the different targets and available inhibitors (both established and experimental) will be summarised and an overview of the clinical efficacy of drugs that inhibit functions in the apicoplast and which have been tested in humans so far will be given.