MalariaWorld journal最新文献

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.

Mosquito feeding assays play an important role in quantifying malaria transmission potential in epidemiological and clinical studies. At present, membrane feeding assays are incompletely standardised. This affects our understanding of the precision of the assay and its suitability for evaluating transmission-blocking interventions. Here, we present a detailed protocol for membrane feeding using Anopheles gambiae mosquitoes and naturally P. falciparum infected individuals.

Background: Health education based on understanding community and individual knowledge, attitudes and practices on malaria is gaining momentum as one of the methods for malaria control. The purpose of the survey was to assess peoples' knowledge and perceptions on malaria in order to generate information to contribute to the malaria elimination programme being implemented by the Ministry of Health of Botswana.

Materials and methods: A cross-sectional structured questionnaire-based survey and participatory rural appraisals were conducted to assess the knowledge and practices regarding malaria among all the 71 households of Tubu village, located on the fringes of the Okavango Delta. Relative frequencies were calculated using the SPSS version 20.0 package.

Results: Information dissemination by the Government through different structures, by the media as well as individuals in the community, played a vital role in making the community aware of malaria. Respondents showed some basic knowledge on malaria transmission (95.8%), signs and symptoms (88.7%) and prevention measures (98.6%). They associated malaria with rainfall, floods and harvesting. Respondents indicated that mosquitoes were abundant in grassy areas (60.6%) and stagnant waters (59.2%). 98.6% of the respondents said insecticide-treated bednets were the main method for malaria prevention. As the first option, all respondents who had a history of a malaria episode visited the clinic and not traditional medical practitioners. However, there were few respondents (14.1%) with misconceptions on malaria aspects like where mosquitoes breed.

Conclusions: Generally, the high level of awareness and good practices shown by the community were ideal for sustainable implementation of community-based malaria intervention programmes. Misconceptions on malaria need to be corrected as these may have some detrimental effects on the Ministry of Health's goal of malaria elimination in Botswana by 2016.

Background: Malaria transmission is heterogeneous. Villages close to each other may have very different transmission characteristics. The presence and abundance of malaria vectors is governed by local ecology and microclimate. Knowledge of the dynamics of transmission is important for planning and evaluation of malaria control strategies. This study investigated the heterogeneity of malaria transmission in preparation for a vaccine trial and offers insights into dynamics of malaria incidence in the forest zone of Ghana.

Methods: Malaria transmission was assessed in four villages with different micro-ecological features in the forest zone of the Akwapim-Mampong Range in Ghana, water shed with rivers flowing north to Lake Volta in the south. Human landing catches (HLC) of mosquitoes were conducted and Plasmodium falciparum circumsporozoite rates were assessed by ELISA. Sporozoite prevalence, annual biting rates (ABR) and entomological inoculation rates (EIR) from the four study sites were compared with climatological and ecological data. Regression analysis was used to compare transmission data and blood parasite prevalence, parasite density (PD) and malaria episodes from children in the study area. Additionally we examined trends in confirmed clinical malaria incidence from 2005 -2012.

Results: In total 1307 Anopheles gambiae s.l. and 54 An. funestus females were caught by HLC from November 2003 to August 2005. Sporozoites in Anopheles vectors in four villages ranged from 4.0 to 10.2%, ABR from 371 to 1890 and EIR from 40 to 158. Linear regression on parasitological and clinical data of children from the villages revealed that the ABR significantly influenced the parasite density (PD) of P. falciparum.

Conclusion: Malaria transmission was intense and heterogeneous and corresponded to the micro-ecological differences. Malaria transmission in the early evening hours before people went to sleep was enough to sustain stable malaria. Scaling up preventive measures to reduce exposure to vectors will be effective in reducing parasitemia in children. Variations in transmission intensity must be considered when evaluating impact of control strategies and interventions such as the vaccine trials.

Background: Solomon Islands is a malarious nation in the Pacific with all four human Plasmodium species present. Although chloroquine prophylaxis is recommended for pregnant women, its effectiveness is uncertain because of chloroquine resistance.

Methods: We conducted a parallel-group, open label, individually randomised superiority trial comparing weekly chloroquine prophylaxis (CQ) with intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP) between August 2009- June 2010 among pregnant women aged 15 to 49 years. Participants were randomised at the first antenatal visit using a computer-generated sequence and followed until delivery. Data on mosquito avoidance measures, and pregnancy outcomes were collected.

Results: Because of the low prevalence of malaria, enrolment was prematurely terminated. Among 660 participants (336 in CQ arm, and 324 in IPTp), 68% used a bednet, 53% used window-screens, and 26% lived in a house sprayed in the last 6 months; 91% used at least one of these methods. Peripheral parasitemia at enrolment was 1.5%. At delivery there were no differences between weekly CQ and IPTp in placental parasitemia (0/259 vs. 1/254) or peripheral parasitemia (2/281 vs. 1/267). There were no differences in maternal anaemia, birth outcomes or serious adverse events. A self-reported sulfa-allergy required non-inclusion for 199 of 771 ineligible women (26%).

Conclusions: The use of SP for IPTp is not suitable for prevention of malaria in pregnancy in Solomon Islands, given the low malaria prevalence and the possible high prevalence of sulfa-allergy. Scaling up of transmission-reducing interventions has probably contributed to the malaria reduction in Honiara.

Trial registration: NCT00964691 ClinicalTrials.gov.