MalariaWorld journal最新文献

Background: Establishment of an in vitro model to study placental malaria is essential for understanding the biology and pathogenesis of placental malaria. We defined experimental variables for obtaining responses of BeWo cells to placental binding Plasmodium falciparum infected erythrocytes (IE, CS2 parasites).

Materials and methods: Experimental variables included i) concentration of forskolin, a cyclic adenosine monophosphate inducer important in the induction of syncytialisation of BeWo, ii) suitable period of incubating BeWo with forskolin, and iii) ratio of IE to BeWo cells and length of incubation to induce physiological changes in BeWo cells, including the vasculogenic factors vascular endothelial growth factor A (VEGFA), endoglin, and angiopoietin-2; an anti-angiogenic factor (inhibin A); a regulator of cell growth, mammalian target of rapamycin (mTOR); a chemokine (IL-8); and the cytokine macrophage inhibition factor. The human hormone, chorionic gonadotrophin was used as a marker for syncytialisation.

Results: We showed that 72 hrs incubation of BeWo with 10 μm forskolin resulted in higher levels of syncytialisation and hCG secretion. Overall, the best condition was to co-culture syncytialised BeWo with a 10:1 ratio of IE for 48 hours. Under these conditions, when co-cultured with IE, BeWo produced increased amounts of IL-8 (p=0.0001), VEGF (p=0.001) and endoglin (p=0.001).

Conclusion: The model can be used to evaluate the impact of IE, inflammatory cytokines and other factors associated with placental malaria on syncytiotrophoblast function.

Background: We evaluated the association between the use of intermittent preventive treatment with sulphadoxine-pyrimethamine (IPTp-SP) on pregnancy outcomes among women who delivered at a secondary hospital in Nsukka, Enugu State, Nigeria.

Materials and methods: Relevant obstetric data (e.g. IPTp-SP use), matched against pregnancy outcome data such as delivery method, stillbirth, maternal haematocrit test results and babies' birth weights, were collected retrospectively from antenatal care (ANC) case files of women who delivered within a one-year period (2013).

Results: The prevalence of adverse pregnancy outcomes recorded out of the 500 ANC case files analysed were: low birth weight (LBW) 3.6% (15), anaemia 54.3% (114), caesarean section 31.6% (156) and stillbirth 3.6% (67). A total of 342 (68.4%) of the women received IPTp-SP during ANC and the receipt of IPTp-SP was significantly associated with reductions in the following events: LBW [OR = 0.26, 95% CI = 0.09 - 0.75], moderate anaemia [OR = 0.33, 95% CI = 0.17 - 0.63], caesarean section [OR = 0.36, 95% CI = 0.24 - 0.53] and stillbirth [OR = 0.10, 95% CI = 0.06 - 0.18].

Conclusion: In this area of high malaria transmission we demonstrated significant reductions in unfavourable maternal and infant health outcomes when using IPT-SP.

Background: Malaria is the most common life-threatening infectious disease among travellers and chemoprophylaxis is recommended. The overall effectiveness, medication types and cost of malaria chemoprophylaxis in Accra are not well documented. This study investigated the use of chemoprophylaxis for malaria prevention in air travellers departing from Kotoka International Airport (KIA) in Accra, Ghana.

Materials and methods: A cross-sectional study was conducted in the departure lounge of the KIA between February and May 2012. A total of 424 respondents voluntarily completed a semi-structured questionnaire, which included socio-demographic characteristics, duration of stay, nationality, country of permanent residence, chemoprophylaxis used, number of doses missed, cost and side effects experienced, and cost of treatment.

Results: The mean age of respondents was 37 ± 0.84 years with a male:female ratio of 1.2:1.The mean duration of stay in Ghana was 47.9 days [SD 56.8] and 73.5% had made one trip to the country in the preceding year. Of the respondents, 50.7% were from Europe, 24.1% from North America and 17.5% from Africa. The most popular malaria prevention method used was prophylactics (37%) with atovaquone/proguanil used most frequently (34.9%), followed by mefloquine (11.6%) and doxycycline (7.8%). Compliance was high: 73.8% of respondents did not miss a single dose. The most commonly reported side effects were dreams, abdominal discomfort and headaches. Malaria incidence was 7.1% with 80% of them receiving treatment in a hospital or clinic; incurring a cost of up to $30 to treat a person.

Conclusions: Most air travellers from Accr a take atovaquone/pr oguanil. Malaria incidence was low and most travellers were compliant with their chemoprophylaxis with very few side effects. The cost of chemoprophylaxis is low and is thus recommended for all travellers to Accra, Ghana.

Background: Medicine preference, usage and health-seeking behaviour are very important in the treatment of malaria and prevention and management of drug resistance.

Materials and methods: A descriptive cross-sectional study, using a semi-structured questionnaire administered to 135 respondents, was carried out to assess antimalarial drug preference and usage among rural dwellers in Alajue, Ede, Osun State and peri-urban dwellers in Ajara, Badagry, Lagos State, Nigeria.

Results: Loss of appetite, fever, chill and rigour, headache and vomiting were the most frequently reported symptoms (83.3%, 78.6%, 71.4%, 69.0% and 64.3%, respectively). More than half (57.1%) of the respondents had their drugs prescribed by a qualified health practitioner. Sixty-eight (50.3%) respondents treated malaria with Artemisinin-based Combination Therapy (ACT) while Sulphadoxine-Pyrimethamine (SP), paracetamol and herbal medicine usage was reported by 11.9%, 9.6% and 4.4% of the respondents, respectively. Thirty-two respondents (23.7%) took nothing to treat the infection. Of them, only 64.3% completed their drugs regimen during their last episode with 35.7% reporting that fever subsided on/before day 2 of treatment and 64.3% reported that fever subsided two days post treatment. The majority (83.3%) of respondents had no adverse reaction to the drugs used (16.7% reported drowsiness, nausea, headaches and vomiting) with 64% of the respondents reporting that they will use ACT again anytime they have malaria and about 65% reported that the drug was very convenient for them (χ² = 18.192, p = 0.001).

Conclusions: The control of drug resistance in malaria parasites requires reducing the overall drug pressure, improving the ways the drugs are used and prescribing follow-up practices. The use of drug combinations that are not likely to foster resistance like ACT is also a good measure of resistance control. ACT would be expected to remain the key anti-malarial drug for treatment of multidrug resistance P. falciparum since there are no alternative drugs available at present.

Background: Malaria remains a disease of immense clinical and economic significance. Limited research has been carried out to estimate malaria treatment costs at the health care facility level using the patient's perspective. The objectives of this study were therefore to determine the direct and indirect costs of malaria treatment among adult outpatients and to assess the patients' perception of treatment costs.

Materials and methods: A cr oss-sectional study was conducted at the Pharmacy section of the General Practice Clinic, University of Benin Teaching Hospital, Benin City, Edo State, Nigeria. It involved adult outpatients diagnosed with malaria and who received a prescription of one or more anti-malarial medications. A cost-of-illness approach was employed in the assessment of costs of treatment of malaria per sick adult patient. Pre-tested semi-structured questionnaires were used in the study. Furthermore, self-reported incidence of malaria per year was assessed.

Results: The mean direct and indirect cost of tr eating malaria illness per adult outpatient was Nigerian Naira (NGN) 3417.70 ($ 20.34) and NGN 4870 ($ 29.0), respectively, giving a ratio of 0.7:1. Medications and laboratory tests for detection of malaria parasites contributed about 52 and 22% of the total direct cost, respectively. A total of 1592 malaria episodes were self-reported to occur annually, giving a mean value of 3.35 episodes per adult. Having a health care insurance was associated with the response that the cost of malaria treatment was low (P< 0.001).

Conclusion: The mean values of direct cost and indirect cost of treatment of malaria illness per adult outpatient were $ 20.34 and $ 29.0, respectively. Respondents who had health insurance perceived malaria treatment cost to be low, whereas those without such insurance felt otherwise.

Background: Use of insecticide treated bednets (ITNs) was a breakthrough in the fight against malaria. However, ITNs are only effective when properly used. Recent reports indicate low compliance in ITN usage and changes in biting times of malaria vectors with early and late biting cases recorded when people are not sleeping under their nets. Hence, there is a need to develop methods to supplement or replace the use of ITNs for malaria vector control. A field trial was conducted to investigate the effect and longevity of prototypes of long lasting impregnated UV protected eave nets, curtains and door hangers (fully screened houses), compared to houses with bednets only, in traditional East African houses.

Materials and methods: A randomised controlled trial was carried out in the Ahero rice irrigation scheme in Nyando district, Western Kenya. Eighty houses with open eaves were randomly selected. Forty of these houses were fully screened (FSH+LLINs) with long lasting insecticide-treated nets/curtains used to screen the eaves, windows and doors. The FSH materials were produced with anti-UV additives. The other 40 houses served as controls. Long lasting insecticide-treated bednets (LLINs) were suspended over all sleeping areas in the control and intervention houses. Indoor resting Anopheles mosquitoes were collected using pyrethrum spray catches (PSC) during both dry and wet seasons. Indoor population densities of anophelines were compared between intervention (FSH+LLINs) and control (LLINs) houses. Loss of insecticide (deltamethrin) was compared after 12 and 24 months for both the FSH materials and LLINs through bioassays and chemical analyses.

Results: In the FSH+LLINs houses densities of indoor resting Anopheles funestus and An. arabiensis were reduced by 82% (RR=0.18, 95% CI 0.09-0.36, P<0.0001) and 70% (RR=0.30, 95% CI 0.15-0.58, P<0.0001), respectively. No significant difference was recorded for indoor resting Culex spp. (RR=0.95, 95% CI 0.48-1.86, P=0.8). The population of indoor resting bloodfed An. arabiensis and An. funestus was reduced by 72% (RR=0.22, 95% CI 0.09-0.51, P<0.0001) and 84% (RR=0.16, 95% CI 0.07-0.33, P<0.0001) in the FSH+LLINs houses and LLIN houses, respectively. Insecticide loss in eave nets did not depend on the side of the house where the nets were placed. The eave nets showed little loss of bio efficacy over the 12-24 months period.

Conclusions: The study revealed that the use of insecticide-treated nets on the eaves and windows combined with door hangers largely impeded entrance of anopheline mosquitoes into houses and can be used to compliment LLINs for household protection. The eave nets were suspended from wood structures near the eave and remained in place when walls were re-plastered. The nets are therefore not depending on daily compliance behaviour and provide protection for the enti

Background: Widespread dr ug-resistant Plasmodium falciparum strains have challenged the pivotal role played by 4-aminoquinolines, including chloroquine (CQ), which has been delisted for the treatment of malaria in most parts of the world. This study assessed the in vitro sensitivity of P. falciparum clinical isolates (PfCIs) to amodiaquine (AQ) and CQ in Northeast Nigeria.

Materials and methods: PfCIs were collected from subjects with uncomplicated P. falciparum malaria in Azare, Bauchi State and Maiduguri, Borno State following an informed consent. The in vitro sensitivity was assessed by micro-test (MarkIII) method and the IC₅₀ of AQ and CQ was determined using HN-NonLin Version VI.1 software. The reference standard cut-off values for in vitro AQ and CQ resistance of 80 and 160 nmol/l, respectively, were used. Isolates that were inhibited by lower AQ and CQ concentrations were referred to as sensitive.

Results: Valid in vitro assay ^r esults were obtained for 88.9% (80/90) of the PfCIs; Azare had 93.3% (28/30) and Maiduguri had 86.7% (52/60) [χ2 = 0.35; df = 1; p = 0.486]. The geometric mean (GM) IC50 of AQ and CQ were 24.2 nmol/l (95% CI, 10.5 - 49.6 nmol/l) and 39.5 nmol/l (95% CI, 34.5 - 49.6 nmol/l), respectively. The AQ (p = 0.922) and CQ (p = 0.085) GM IC50 were similar between Azare and Maiduguri PfCIs. Only one isolate showed in vitro resistance to AQ giving a sensitivity of 98.8% (79/80) while 17 PfCIs showed in vitro resistance to CQ giving a sensitivity of 78.8% (63/80). The CQ sensitivity was similar between Azare (67.9%; 19/28) and Maiduguri (84.6%; 44/52) PfCIs (χ² = 3.05; df = 1; p = 0.081).

Conclusions: The findings may suggest that the AQ in vitro sensitivity remains high and the isolates in Northeast Nigeria may appear more sensitive to CQ than isolates from other parts. These findings may affect malaria treatment and control policy in Nigeria.

Background: The Roll Back Malaria (RBM) initiative recommended that all pregnant women receive Inter mittent Preventive Treatment (IPTp) and that by 2010 at least 80% of people at risk of malaria (including pregnant women) use insecticide-treated bednets (ITN) in areas with stable transmission. We evaluated ITN/IPTp coverage, explored its associated factors, and estimated the number of pregnancies protected from malaria.

Materials and methods: This analysis was based on data from the 2012 National HIV/AIDS and Reproductive Health Survey (NARHS Plus). To assess ITN coverage, we used the population of women that was pregnant (n=22,438) at the time of the survey. For IPTp coverage, we used women that had a live birth in the 5 years preceding the survey (n= 118,187) and extracted the population of pregnant women that, during their last pregnancy, received drugs for protection against malaria. We estimated the number of live births using the projected population of females in each state, population of women of child -bearing age and the total fertility rate. The estimated number of pregnancies covered/protected by ITN and IPTp was obtained from a product of the estimated live births and the reported coverage. Multivariate logistic regression was used to determine factors associated with ITN and IPTp use.

Results: We estimated that there were 5,798,897 live births in Nigeria in 2012, of which 3,537,327 and 2,302,162 pregnancies were protected by ITN and IPTp, respectively. Four of 36 states achieved the 80% RBM target for ITN coverage. No state achieved the 100% target for IPTp. Education and socio-economic status were associated with IPTp use.

Conclusion: ITN cover age was higher than in previous estimates even though it is still below the RBM targets. However, IPTp coverage remained low in 2012 and was not likely to increase to match the 2015 target coverage of 100%.

Background: In or der to combat the bur den of malaria, different strategies, including Insecticide Treated Nets (ITNs), have been put in place. ITNs have been distributed with support from international donors and this necessitates an increase in monitoring and evaluation efforts in order to determine ITN impact as well as prioritise future programmes. The current standard for estimating impact indicators of ITNs are household surveys. These, however, are expensive and not conducted frequently. Collecting information from school children has been found to be a cheap and fast means for routine monitoring and evaluation of malaria control programmes in sub-Saharan Africa. This study was conducted to explore school children's report of household ownership and use of ITNs in Oyo State, Nigeria.

Materials and methods: A cross-sectional survey was conducted. A three-stage sampling technique was used to select 611 pupils from 15 out of 88 primary schools. Information on pupils' socio-demographics, report of household ownership and use of ITNs were obtained using a semi-structured interviewer-administered questionnaire. Data was analysed using descriptive statistics and Chi-square tests at 5% level of significance.

Results: Respondents' mean age was 10.5±1.7 yrs; 52.7% were females, 84.6% were Yoruba and 65.3% lived with children below 5 yrs of age in their households. Most of the respondents (81.7%) reported household ownership of at least one ITN. The majority (76.4%) obtained nets through mass distribution campaigns. Most of the respondents (89%) reported use of ITNs by a household member the night preceding the survey. More than half of the respondents (51.6%) reported ITN use by children below 5 yrs of age. Class was significantly associated with reported household ownership of ITNs (χ2= 9.217, p <0.010).

Conclusion: The majority of the pupils reported household ownership and use of ITNs. They should be consider ed a potential source of information in monitoring and evaluation activities related to ITN ownership and use.

Background: While environmental factors such as temperature can influence the vector competence of mosquitoes directly, for example by affecting the longevity of the mosquito and the development of the malaria parasite they may also have an indirect impact on the parasite's transmission. By influencing larval development, they may affect the adult traits that are important for the parasite's development and transmission. We studied the influence of two larval environmental factors, food availability and temperature, on the probability that mosquitoes infected with the malaria parasite survived to harbour sporozoites in their salivary glands.

Materials and methods: Anopheles gambiae larvae were reared at 21ºC, 25ºC or 29ºC, and fed either a standard larval diet or half of it. Adults could blood feed on mice harbouring the infectious gametocytic stage of Plasmodium berghei ANKA transformed with green fluorescent protein (GFP). Survival was assessed every 24 hrs up to 21 days post infection, when surviving mosquitoes were dissected to check the salivary glands for sporozoites with a fluorescent microscope sensitive to GFP. Using a binomial GLM we analysed 'vector competence', i.e. if mosquitoes survived until dissection and harboured sporozoites in their salivary glands.

Results: Vector competence dropped by about a third if we fed larvae half the standard food regime. The effect of temperature during the larval period depended strongly on the food regime. At low food, increasing temperature from 21ºC to 29ºC increased vector competence from about 0.18 to 0.48, whereas at standard food, vector competence dropped from about 0.67 at 21ºC to 0.56 at 29ºC.

Conclusions: Thus, perceptions and models about the role of environmental change on the transmission of malaria should include how the environment changes adult life-history by influencing larval development.