MalariaWorld journal最新文献

Background: Malaria is a devastating disease, particularly in Africa, due to development of resistance by Plasmodium falciparum against all known antimalarial drugs, including artemisinin. Therefore, the search for new antimalarial drugs is urgently needed, especially drugs that can impede the heme detoxification pathway in the malaria parasite, a crucial requirement for parasite survival in host erythrocytes.

Materials and methods: Water infusions of Artemisia annua plants from two different origins, Cameroon and Luxembourg, were used in this study. A semi-quantitative in vitro method, based on the inhibition of ferriprotoporphyrin IX (FP) biomineralisation developed by Deharo et al. [16], was used to reveal the differences in antimalarial activity of both plants. Reversed phase preparative liquid chromatography coupled to a photo diode array (PDA) detector was also used to test for differences in antimalarial activity.

Results: Water extracts from the leaves of the Cameroon plant showed a higher potential antimalarial activity, represented by a higher ability to inhibit β-haematin formation in vitro than A. annua extracts from Luxembourg. Although extracts of the plants of both origins showed comparable efficiencies at high concentrations, the absorbance value at 405 nm of a 10% dilution of the Cameroon plant extract was 0.075, whereas it was 1.515 for the Luxembourg plant extract. The absorbance is inversely proportional to the antimalarial activity. According to the Prep-HPLC chromatogram of the Cameroon crude sample, seven major compounds at 325 nm were found. However, only four much less pronounced compounds appeared in the Luxembourg crude sample under the same chromatographic conditions and concentration. These were preliminarily identified as polyphenolic compounds.

Conclusion: A. annua infusions are widely used by people who cannot afford other treatments. Depending on the cultivation locality different chemical profiles exist. This results in differences in hemozoin formation and will therefore also lead to alterations in antimalarial activity.

Background: Malaria remains a major public health threat in Malawi, affecting mostly children under five and pregnant women. Despite the availability of chemotherapy and chemoprophylaxis, resistance to sulfadoxine pyrimethamine and the high cost and complicated regimen of artemether-lumefantrine have accelerated the use of home-based remedies for the management of malaria in Chikwawa district, Malawi. This study aimed to determine factors that facilitate the use of herbal remedies within communities in the management of malaria in the presence of free health care services, with the intention of assessing the feasibility of developing improved herbal products as anti-malarial prophylaxis.

Materials and methods: Data on factors driving the use of neem-based preparations commonly used in the management of malaria were collected through qualitative interviews and focus group discussions. Qualitative data were analysed drawing on the Framework Analysis approach.

Results: Neem and moringa were identified as the principal plants used for the management of malaria, with neem being the most frequently used. Factors favouring the communal use of neem-based remedies included the habit of resorting to herbal remedies as first aid treatment, lack of drugs and proper medical care in modern health facilities, and the need for preventive anti-malarial remedies during the high-transmission season. The perceived effectiveness of neem-based herbal remedies was based on their fast action against the symptoms of malaria, thereby providing immediate relief to the patient, which might explain their wide-scale use for malaria treatment.

Conclusions: Local communities prefer to use neem and/or moringa remedies for their primary healthcare needs in the management of malaria because of their ease of access, preparation and administration without frequent adverse events, as opposed to ACTs. These remedies are already being used as prophylaxis in unimproved/non-standardised formulation. This suggests that standardised herbal preparations would be culturally acceptable at community level. Evidence-based research is required to validate parasitological and clinical efficacy and determine safety of these anti-malarial herbs.

Background: Sub-Saharan countries have experienced centuries of high morbidity and mortality due to malaria. In addition to insecticide-treated mosquito nets and indoor residual spraying, modern antimalarial medicines have been developed to reduce disease prevalence, although the emergence of drug-resistant strains has compromised their efficacy. The purpose of this study was to evaluate the current status of malaria diagnosis and treatment, and to monitor the therapeutic efficacy of antimalarial drugs.

Materials and methods: A descriptive cross-sectional survey was conducted from 2011 to 2013 at 10 district hospitals in Zambia designated as malaria sentinel sites as well as at the National Malaria Control Centre. District medical officers at each site completed interview questionnaires.

Results: Although basic infrastructure necessary for monitoring antimalarial drug resistance (such as laboratory, dispensary, admission ward, database unit, administration offices, bed space, examination and emergency rooms) was present at all sites, there was a shortage of licensed healthcare personnel. At some sites, antimalarial drugs were prescribed for malaria-like symptoms without diagnostic confirmation by blood smear. There was no regular monitoring of antimalarial drug resistance: only one trial was conducted among all sites in the previous 24 months.

Conclusion: A lack of antimalarial drug resistance monitoring might be associated with personnel and funding shortages. Additional financial support would be necessary to avoid the development and spread of drug-resistant malaria in Zambia.

Background: Suppressing malaria in Africa is costly, but is it a good way for international agencies to use their funds, or alternatively, for the African nations that are the direct beneficiaries? Unfortunately, the current ephemeral methods in the malaria strategy of the World Health Organization have required continuous and rising expenditures by international donors who were beginning to lose interest by 2010. To avoid becoming hostage to international economic limitations, African countries might want to consider suppressing malaria themselves, and might want to add permanent and lasting methods to the WHO strategy. The purpose of this study was to determine whether investments in suppressing malaria might produce significant benefits for African nations.

Materials and methods: Two epidemiologic analyses were used in parallel to evaluate data from Africa: a before-after comparison of countries treated under the US President's Malaria Initiative for Africa (PMI), and a simultaneous comparison of treated-untreated countries.

Results: From 2007 to 2012, relative increases in population and gross domestic product (GDP) were greater in 14 countries treated as part of PMI than in 9 similar, but untreated countries. In the treated countries the relative increase in the GDP of 0.61 before malaria suppression rose to 0.64 afterwards; whereas in the untreated countries it fell from 0.67 to 0.56. The increase in GDP in the 14 treated countries that was attributable to malaria suppression over the 5-year interval was about $4.77 billion. During that period, the mean cost of suppressing malaria had been about $1.43 billion, indicating a return on the investment of 3.4 to 1. However, the costs began rising steeply in 2012.

Conclusions: Malaria suppression might be worthwhile for African countries to undertake themselves, as long as the biocides and drugs in current use remain effective.

Background: Accurate diagnosis of malaria is key to proper management and control and an ideal diagnostic parameter that correlates to disease outcome is required. The former would be helpful in correctly identifying patients that need hospitalisation versus those that can be managed at home. This study determined how well the density estimates by microscopy, qPCR and PfHRP-2 correlate to malaria severity.

Materials and methods: Patients aged ≤ 5 yrs with severe (n = 60, Hb ≤ 6 g/dl) and mild (n = 60, Hb > 6 g/dl) malaria were enrolled to take part in a case control study at Kisumu District Hospital, Western Kenya. Parasite load was determined by microscopy, qPCR targeting the 18s rRNA gene and PfHRP-2 antigen ELISA.

Results: The median parasite load and the 25^th and the 75^th percentile by microscopy in children with severe malaria (SM) was 49,958 parasites/μl (12,013-128,695) compared to 24,233 (6,122-103,886) in the group with mild malaria (MM), P = 0.10. By qPCR, the translated median parasite density was 31,550 parasites/μl (4,106-196,640) in the SM group compared to 24,365 parasites/μl (5,512-93,401) in the MM group (P = 0.73). According to PfHRP-2, the translated median parasite load in children with SM was 628,775 parasites/μl (332,222-1.165x106) compared to 150,453 (94,292-399,100) in children with MM (P < 0.0001).

Conclusions: Unlike microscopy and qPCR, the parasite load detected by PfHRP-2 correlates with disease severity. Because of its unique attributes, PfHRP-2 is able to account for trophozoites and schizonts that are sequestered away from peripheral circulation. Because it persists in circulation, it also serves as an indicator of the magnitude of current and recent infections.

Background: A key to the effective management of malaria is prompt and accurate diagnosis, and the use of malaria rapid diagnostic tests (mRDTs) is becoming relevant in the absence of reliable microscopy. This study explored the phenomenon of using the wrong buffer vial (often a kit from another brand or buffer from HIV rapid test kits), dextrose, saline or distilled water among health care providers who used RDTs for malaria diagnosis in resource poor settings in Enugu South East, Nigeria.

Materials and methods: Laboratory personnel (medical laboratory scientists, technicians, assistants, nurses, community health extension workers (CHEW), community health officers (CHO) and doctors) were interviewed using structured questionnaires and results were checked using the SOP checklist. The selection criterion was a prior experience with using RDTs, and any facility that did not use RDTs was excluded.

Results: Of the 80 study participants that completed their questionnaires, 56.3% reported that malaria diagnosis was positive using non-buffer RDTs detection while others reported negative results. Among the various professionals who used RDTs, 76.2% reported to have run out of RDT buffer stock at least once. Of the study participants that ran out of RDT buffer solution, 73% declared to have used non-RDT alternatives (physiological saline, 0.9% NaCl), distilled water, HIV buffer or ordinary water). Only 30% had received formal training on the proper usage and application of RDTs while 70% had never received any formal training on RDTs but learnt the technique of using RDT on the job.

Conclusions: This study demonstrated that at least three quarters of health care workers in a resource poor setting had run out of buffer when using malaria RDTs and that the majority of them had used buffer substitutes, which are known to generate inaccurate tests results. This has the consequence of misdiagnosis, thus potentially damaging the credibility of malaria control.

Background: Artemisinin based combination therapy (ACT) is the global gold standard for treatment of malaria. In sub-Saharan Africa the majority of malaria cases is treated at home. In rural southwest Nigeria we set out to evaluate the feasibility and acceptability of using artemether-lumefantrine (AL) at the community level to treat acute uncomplicated malaria.

Materials and methods: Following advocacy and community mobilisation in a rural area in south-west Nigeria, 60 community medicine distributors (CMDs: patent medicine sellers, selected mothers from the community and health-care workers) were trained to recognise the signs and symptoms of childhood malaria and to treat febrile children aged 6-59 months with AL, after ruling out certain danger signs. At the end of one year, the programme was evaluated by conducting a 2-week fever recall survey among caregivers, inspection of CMD records to evaluate caregivers' adherence to the treatment schedule, CMDs' performance and the coverage of febrile children with AL. Data was analysed using descriptive statistics.

Results: Based on CMDs' records, 97.6% (1019/1044) of the children treated with AL received the correct dose. Over half (52.3%) of the children (288/551) whose caregivers participated in the 2-week fever recall survey reportedly received AL from a CMD. Reasons for not receiving AL included non-availability of a CMD [35.7%; 94/263] or drug stock out [28.1%; 74/263]. Of the children treated with AL, 80.2% (231/288) received prompt treatment at the correct dose and for the correct length of time. Ninety-eight percent of the caregivers perceived AL to be effective and none reported severe adverse events.

Conclusions: The use of AL at the community level is feasible and acceptable in the home management of malaria in rural southwest Nigeria. Challenges that must be addressed include avoiding stock outs, ensuring adequate number of CMDs and providing incentives to ensure their availability.

Background: To test the assumption that reductions in malaria in Africa will increase economic productivity, a correlation-regression analysis was conducted to evaluate the impact of expenditures by the US President's Malaria Initiative for Africa (PMI), and increases in the economic productivity of countries included in the PMI.

Materials and methods: For the 12 most representative countries the per capita expenditures for malaria suppression in the 2011 budget of the PMI were compared with observed increases in per capita economic productivity. The measure of economic productivity used was the per capita Gross Domestic Product (GDP) for the period 2007 to 2011.

Results: With a mean annual expenditure for suppressing malaria slightly above 1 US dollar per capita (range 0.44-3.40), there was a positive but weak correlation of higher expenditures with increased economic productivity. The correlation coefficient r was 0.5. The increase in per capita GDP in these countries over the 4-year period varied between 60 and 200 USD. The slope of the regression line and thus the ratio of benefits to cost from this programme varied slightly between ecologic zones, but the mean was 6.75 to 1. This meant that there was an increase in per capita GDP of $6.75 for every $1 invested per capita in suppressing malaria.

Conclusions: The high benefits to cost ratio from the PMI makes suppression of malaria by methods used by the initiative potentially an attractive investment, at least for the near future while the biocides and drugs deployed are still effective.

Background: A recovery in chloroquine efficacy following a period of cessation has raised the possibility of its reintroduction for malaria chemotherapy. We investigated the prevalence of the major markers of chloroquine resistance years after the withdrawal of the drug in Nigeria.

Materials and methods: Finger prick blood samples were collected from participants presenting with symptoms of malaria in two selected health centres each representing Lekki and Ijede communities of Lagos, Nigeria. Thick and thin blood smears were prepared for microscopy and dry blood spots made from malaria-positive participants for parasite DNA extraction. The detection of mutations in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multidrug resistance (pfmdr1) genes was performed by nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).

Results: Of the 1527 blood samples that were confirmed by PCR to be P. falciparum positive, 412 and 344 were typed for the molecular detection of pfcrt and pfmdr1 gene mutations, respectively. The mutant alleles of pfcrt were present among 290 (70%) parasite carriers while the pfmdr1 mutant allele was found in 117 (34%) of the total population. There were higher distributions of the mutant alleles for the two loci in Ijede than in Lekki. The observed frequencies of pfcrt mutant alleles in the two parasite populations were in agreement with the expected frequencies predicted by Hardy-Weinberg. In comparing data with studies conducted between 2000 and 2002 in Ijede, we observed an increase in the prevalence of mutant type pfcrt against a marginal decline in the pfmdr1 mutant type.

Conclusion: The high frequencies of pfcrt mutation are suggestive of a persistent drug pressure and continuing inefficacy of chloroquine as an antimalarial drug.

Background: In the era of valuable and costly artemisinin-based combination therapy (ACT) for malaria it has been recommended that the use of ACTs is restricted to only those with confirmed positive malaria diagnosis. The potential benefits of rapid diagnostic tests (RDTs) on anti-malarial drug consumption have been demonstrated in a number of clinical trials. It is unknown if the introduction of RDTs in Nigeria has achieved the desired goal of reducing ACT consumption. This article assesses the impact of a state-wide roll-out of RDTs on ACT prescription in Oyo State, Nigeria.

Materials and methods: ACT prescribing patterns for febrile patients were compared pre- and post-RDT introduction in 106 primary health care facilities. Routine data from the national malaria control programme monthly facility summary forms were extracted for three months before and after the RDT intervention and compared using a 'before and after' design.

Results: RDT testing rates for patients with fever revealed no trend; mean testing rate in the post RDT period was 64.5%. The mean malaria positivity rate was 71.3%, which equalled a proportional morbidity rate of 45.9% of all fever cases. ACT treatment to confirmed case ratio was consistently above the expected value of one and the ratio of treatment to tested patient exceeded one (mean ratio of 1.1) for the three months post RDT. The absolute number of ACT doses prescribed increased remarkably after the introduction of RDTs and ACTs revealing an extra utilisation of 14,199 doses, 5,534 (±517) versus 10,267 (±2,452), p<0.001. Relative Risk of ACT prescription in the post RDT period was 1.71 (1.33-2.25).

Conclusion: There is notable non-adherence to RDT results, with an increase in ACT prescriptions after the initial introductory period for RDTs. This over reliance on ACTs for the management of non-malaria illness could compromise gains from reducing malaria morbidity and mortality and needs to be addressed urgently.