MalariaWorld journal最新文献

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.

Background: The sub-Saharan region of Africa is endemic for malaria, and fever is often assumed to be malaria. In Ghana, about 3.7 million cases were reported in 2011, with 24.4% of these laboratory-confirmed. Other causes of febrile illness, including respiratory syncytial virus (RSV), are prevalent in developing countries like Ghana. There is very little data on the prevalence of this virus in the country. This study determined the proportion of acute febrile illness in an urban paediatric population that was due to malaria or RSV.

Methods: A hospital based surveillance system recruited children below five years of age reporting with fever (axillary temperature ≥ 37.5°C) at the outpatient department of an urban hospital from February 2009 to February 2010. Consenting parents/guardians were interviewed, the medical history of the child was taken and the child clinically examined. Thick blood film from capillary blood taken through a finger prick, was Giemsa-stained and microscopically examined for malaria parasites to confirm malaria diagnosis. Nasopharyngeal aspirate was also examined for RSV by polymerase chain reaction.

Results: Out of 481 febrile children, 51(10.8%) were positive for malaria whilst 75 (15.4%) were positive for RSV. Seven of the 75 RSV-positive cases (9.3%) were co-infected with malaria. Based on judgement by clinicians, over 80% of the febrile children were diagnosed and treated as having malaria either alone or in combination with other diseases.

Conclusion: Not all febrile episodes in malaria-endemic regions are due to malaria. The diagnosis and subsequent treatment of patients based solely on clinical diagnosis leads to an over diagnosis of malaria. Improvement in the guidelines and facilities for the diagnosis of non-malaria febrile illness leads to improved malaria diagnosis. Clinicians should be looking for other causes of fever rather than treating all fevers as malaria.

Over the years, malaria has remained the number one cause of morbidity and mortality in Tanzania. Population based studies have indicated a decline in overall malaria prevalence among under-fives from 18.1% in 2008 to 9.7% in 2012. The decline of malaria infection has occurred in all geographical zones of the country. Malaria mortality and cumulative probability of deaths have also shown a marked decline from 2000 to 2010. During the same period, area specific studies in Muheza, Korogwe, Muleba and Mvomero have also reported a similar declining trend in malaria prevalence and incidence. The decline in malaria prevalence has been observed to coincide with a decline in transmission indices including anopheline mosquito densities. The decline in malaria prevalence has been attributed to a combination of factors including improved access to effective malaria treatment with artemisinin combination therapy and protection from mosquito bites by increased availability of insecticide treated bednets and indoor residual spraying. The objective of this paper was to review the changing landscape of malaria and its implication for disease management, vector control, and livelihoods in Tanzania. It seeks to examine the links within a broad framework that considers the different pathways given the multiplicity of interactions that can produce unexpected outcomes and trade-offs. Despite the remarkable decline in malaria burden, Tanzania is faced with a number of challenges. These include the development of resistance of malaria vectors to pyrethroids, changing mosquito behaviour and livelihood activities that increase mosquito productivity and exposure to mosquito bites. In addition, there are challenges related to health systems, community perceptions, community involvement and sustainability of funding to the national malaria control programme. This review indicates that malaria remains an important and challenging disease that illustrates the interactions among ecosystems, livelihoods, and health systems. Livelihoods and several sectoral development activities including construction, water resource development and agricultural practices contribute significantly to malaria mosquito productivity and transmission. Consequently, these situations require innovative and integrative re-thinking of the strategies to prevent and control malaria. In conclusion, to accelerate and sustain malaria control in Tanzania, the prevention strategies must go hand in hand with an intersectoral participation approach that takes into account ecosystems and livelihoods that have the potential to increase or decrease malaria transmission.

Background: Malaria is prevalent in sub-Saharan Africa, where other concomitant parasitic infections, including intestinal helminths, are common. However, little is known about how concurrent infections affect the expression or pathogenesis of each other. This study aimed to document the prevalence rates of malaria and intestinal helminths individually and as co-infection among asymptomatic children in a rural community in southwest Nigeria.

Materials and methods: Apparently healthy children aged 1-17 years, who were enrolled into a larger study that evaluated the efficacy and safety of two anti-helminthic drugs, were evaluated for intestinal helminths by stool examination using the saline wet mount and Kato-Katz methods. Capillary blood from finger prick samples was used for haematocrit determination and malaria screening by microscopy. Data analysis was conducted using SPSS and significance levels were set at p < 0.05.

Results: Eighty-nine of 178 (50%) enrolees were male. One hundred and fifteen of the 178 (64.6%) children had at least one intestinal helminthic infection while 69 (60%) thereof harboured multiple helminthic infections. Malaria parasites were encountered in 35/178 (19.7%) of the enrolees. Parasite density was ≤500/μl in 51.4% (18/35), 501-1,000/μl in 9 (25.7%) and 1,000-4,720/μl in 8 (22.9%) of the children. Malaria-helminth co-infection was detected in 24/115 (20.9%) of the children. The prevalence [60/115 (52.2%) versus 8/63 (12.7%) p<0.0001] and severity of anaemia were significantly higher among children with worms compared to those without worms. For mild anaemia this was 53/115 (46.8%; with worms) versus 7/63 (11.1%; no worms p<0.0001); for moderate anaemia 2/115 (1.74%; with worms) versus 1/63 (1.59%; without worms; p<0.271).

Conclusion: Malaria and helminths co-infection is common among apparently asymptomatic children in the rural community studied. Co-infections increase the problems associated with anaemia and aggravate the burden of disease in Nigerian children.