Malaria Research and Treatment最新文献

Background: Thrombocytopenia is a most commonly observed complication during malaria infections. Inflammatory cytokines such as IL-1, IL-6, and IL-10 have been documented in malaria induced thrombocytopaenia. This study was aimed to understand the possible relationship between inflammatory cytokines across varying degrees of thrombocytopenia during P. vivax, P. falciparum, and mixed infections.

Methods: A hospital-based cross sectional study was conducted at District Wenlock Hospital in Mangaluru, a city situated along the south-western coastal region of Arabian Sea in India. In this study, blood samples from 627 malaria patients were analyzed for infected parasite species, clinical conditions, platelet levels, and key cytokines that are produced in response to infection; samples from 176 uninfected healthy individuals were used as controls.

Results: The results of our study showed a high prevalence of malarial thrombocytopenia (platelets <150 ×10³/μl) in this endemic settings. About 62.7% patients had mild-to-moderate levels of thrombocytopenia and 16% patients had severe thrombocytopenia (platelets <50 × 10³/μl). Upon comparison of cytokines across varying degrees of thrombocytopenia, irrespective of infecting species, the levels of TNF-α and IL-10 were significantly higher during thrombocytopenia, whereas IL-6 levels were considerably lower in severe thrombocytopenia patients suffering from P. vivax or P. falciparum infections. The severe clinical complications observed in patients with malarial thrombocytopenia included severe anemia (17.5%), acute renal failure (12.7%), jaundice (27.0%), metabolic acidosis (36.5%), spontaneous bleeding (3.2%), hypoglycemia (25.4%), hyperparasitemia (4.8%), acute respiratory distress syndrome (1.6%), pulmonary edema (19.0%), and cerebral malaria (1.6%) in various combinations.

Conclusion: Overall, the results of our study suggest that inflammatory cytokines influence the transformation of mild forms of thrombocytopenia into severe forms during malarial infections. Further studies are needed to understand the association of inflammatory cytokine responses with severe malaria complications and thrombocytopenia.

Background: Malaria is one of the most important life-threatening infectious diseases in the tropics. In spite of the effectiveness of artemisinin-based combination therapy, reports on reduced sensitivity of the parasite to artemisinin in Cambodia and Thailand warrants screening for new potential antimalarial drugs for future use. Ghanaian herbalists claim that Polyalthia longifolia has antimalarial activity. Therefore, antiplasmodial activity, cytotoxic effects, and antioxidant and phytochemical properties of P. longifolia leaf extract were investigated in this study.

Methodology/principal findings: Aqueous, 70% hydroethanolic and ethyl acetate leaf extracts were prepared using standard procedures. Antiplasmodial activity was assessed in vitro by using chloroquine-sensitive malaria parasite strain NF54. The SYBR® Green and tetrazolium-based calorimetric assays were used to measure parasite growth inhibition and cytotoxicity, respectively, after extract treatment. Total antioxidant activity was evaluated using a free radical scavenging assay. Results obtained showed that extracts protected red blood cells against Plasmodium falciparum mediated damage. Fifty percent inhibitory concentration (IC₅₀) values were 24.0±1.08 μg/ml, 22.5±0.12 μg/ml, and 9.5±0.69 μg/ml for aqueous, hydroethanolic, and ethyl acetate extracts, respectively. Flavonoids, tannins, and saponins were present in the hydroethanolic extract, whereas only the latter was observed in the aqueous extract. Aqueous and hydroethanolic extracts showed stronger antioxidant activities compared to the ethyl acetate extract.

Conclusions/significance: The extracts of P. longifolia have antiplasmodial properties and low toxicities to human red blood cells. The extracts could be developed as useful alternatives to antimalarial drugs. These results support claims of the herbalists that decoctions of P. longifolia are useful antimalarial agents.

Introduction: Insecticide treated bed net (ITN) is one type of cost-effective vector control approach for the prevention of malaria. It has to be treated with insecticide and needs ongoing treatment with chemicals. Malaria infcetion during pregnancy is a amajor health problem in Ethiopia. Little is known about the utilization of ITN by pregnant women in the study area. This study was aimed to assess utilization and associated factors of insecticide-treated nets among pregnant women in Adis Zemen Hospital.

Methods: This hospital based cross-sectional study was conducted in Adis Zemen from May 1 to 30, 2018, among 226 pregnant mothers. After obtaining informed consent, data were collected using a pretested structured questionnaire via face to face interview. To reach the study unit, a systematic random sampling technique was used. The collected data were entered, cleaned, checked using Epi data version 3.1, and finally analyzed using SPSS version 20. Binary and multivariable logistic regressions were computed to identify significantly associated variables at 95% confidence interval.

Result: A total of 226 pregnant mothers attending antenatal clinics participated in making the response rate 100%. Among a total 226 subjects, 160(70.8%) of mothers had good utilization of insecticide bet net. Mothers who had an educational status of college and above were 2.8 times more likely to utilize insecticide-treated bed net than mothers who could not read and write (AOR; 2. 8: CI; 1.9, 6.5). Mothers whose age was >30 were 70% times less likely utilized insecticide-treated bed net than mothers whose age was 30 and less (AOR;.3: CI;.2,.6).

Conclusion and recommendation: Utilization of insecticide-treated bed net by pregnant women is low in the study area. The participants' age, educational status, household monthly income, and husband educational status were significantly associated with utilization of insecticide-treated bed net. Different stakeholders shall give a special attention to awareness creation on advantageous of insecticide bed net.

Background: The relationship between protein energy malnutrition (PEM) and malaria is controversial. While most studies demonstrate that PEM is associated with greater malaria morbidity, some indicate that PEM may in fact have a protective effect. PEM is differentiated into three subgroups: kwashiorkor (marked protein deficiency), marasmus (calorie deficiency), and kwashiorkor/marasmus. None of the studies concerning PEM and malaria seem to distinguish between these subgroups, and significant differences in susceptibility to malaria between these subgroups may have been overlooked. Plasmodium parasites and malaria infected erythrocytes are sensitive to oxidative stress. Since kwashiorkor patients seem to display an excess of prooxidants and as serum albumin is an important antioxidant, we hypothesized that patients with different forms of PEM might have different levels of malaria parasitaemia.

Methods: 72 PEM children older than 6 months admitted to Kwale Family Life Training Programme (Kenya) were included in the study.

Results: Mean parasitaemia was significantly lower in the kwashiorkor group than in the marasmus group (p < 0,001). There was no correlation between serum albumin and parasitaemia.

Conclusion: Our study suggests a protective effect of kwashiorkor against malaria, warranting further studies.

Background: In Republic of Congo, malaria diagnosis still widely relies on microscopy. We aimed to evaluate the performance of routine microscopy for malaria diagnosis at three different health centers in Brazzaville.

Methods: A total of 259, 416, and 131 patients with clinical signs of uncomplicated malaria were enrolled at the Hôpital de Mfilou, Centre de Santé Intégré "Maman Mboualé," and Laboratoire National de Santé Publique, respectively. Two thick blood smears were prepared for each patient, the first being examined by routine microscopists and the second by expert.

Results: At the Hôpital de Mfilou, sensitivity was 62.1% and specificity was 67.3%. Positive and negative predictive values were 55.6% and 72.9%, respectively. At the Centre de Santé Intégré "Maman Mboualé," sensitivity was 94.2% and specificity was 33.6%. Positive and negative predictive values were 50% and 89.1%, respectively. At the Laboratoire National de Santé Publique, sensitivity and specificity were high with 91.7% and 94.9%, respectively. Positive and negative predictive values were 64.7% and 99.1%, respectively.

Conclusion: The performance of routine malaria microscopy in Brazzaville remains inaccurate with large variations among different health centers. Therefore, repeated training including supervision and evaluation would improve routine malaria diagnosis for better management of malaria in Brazzaville, the Republic of Congo.

Background: Globally, 15 countries, mainly in Sub-Saharan Africa, account for 80% of malaria cases and 78% of malaria related deaths. In Uganda, malaria is endemic and the mortality and morbidity due to malaria cause significant negative impact on the economy. In Gulu district, malaria is the leading killer disease among children <5 years. In 2015, the high intensity of malaria infection in Northern Uganda revealed a possible link between malaria and rainfall. However, available information on the influence of climatic factors on malaria are scarce, conflicting, and highly contextualized and therefore one cannot reference such information to malaria control policy in Northern Uganda, thus the need for this study.

Methods and results: During the 10 year's retrospective study period a total of 2,304,537 people suffered from malaria in Gulu district. Malaria infection was generally stable with biannual peaks during the months of June-July and September-October but showed a declining trend after introduction of indoor residual spraying. Analysis of the departure of mean monthly malaria cases from the long-term mean monthly malaria cases revealed biannual seasonal outbreaks before and during the first year of introduction of indoor residual spraying. However, there were two major malaria epidemics in 2015 following discontinuation of indoor residual spraying in the late 2014. Children <5 years of age were disproportionally affected by malaria and accounted for 47.6% of the total malaria cases. Both rainfall (P=0.04) and relative humidity (P=0.003) had significant positive correlations with malaria. Meanwhile, maximum temperature had significant negative correlation with malaria (P=0.02) but minimum temperature had no correlation with malaria (P=0.29).

Conclusion: Malaria in Gulu disproportionately affects children under 5 years and shows seasonality with a generally stable trend influenced by rainfall and relative humidity. However, indoor residual spraying is a very promising method to achieve a sustained malaria control in this population.

Background: Utilization of long-lasting insecticide treated nets (LLINs) after free and mass distribution exercise has not been adequately studied. The objectives of this study were to assess ownership and utilization of LLINs following a mass distribution campaign in a Ugandan urban municipality.

Methods: We conducted a cross-sectional study in western Uganda among households with children under 5 years, at 6 months after a mass LLIN distribution exercise. We administered a questionnaire to measure LLIN ownership and utilization. We also measured parasitaemia among children under five years.

Results: Of the 346 households enrolled, 342 (98.8%) still owned all the LLINs. LLIN use was reported among 315 (91.1%) adult respondents and among 318 (91.9%) children under five. Parasitaemia was detected among 10 (2.9%) children under five. Males (OR=2.65, 95% CI 0.99-7.07), single respondents (OR=10.35, 95% CI 1.64-65.46), having a fitting bed net size (OR= 3.59, 95% CI 1.71-7.59), and no childhood malaria episode reported in the home in the last 12 months (OR=1.69, 95% CI 1.02-2.83) were all associated with LLIN use.

Conclusions: Ownership of LLIN is very high, and parasitaemia among the children was very low. Low parasitaemia may be attributed to high LLIN utilization. Long term follow-up should be done to determine durability of the ownership and utilization.

Background: The WHO currently advocates parasitological confirmation of malaria before treatment is commenced. However, many arguments have emerged both for and against this new position. To contribute to the debate, this secondary data analysis was conducted to determine the likelihood of malaria parasitaemia in a child presenting with fever, vomiting, or cough in the Kassena-Nankana District.

Methods: The dataset for this analysis was generated during a study to assess the incidence and risk factors for paediatric rotavirus diarrhoea in the Kassena-Nankana District. Over a two-year period, trained field staff recruited 2086 subjects with episodes of diarrhoea aged 24 months or below into the study. A standard case report form was used to collect data on histories of illness, symptoms, vaccination, and anthropometry. Blood smears were tested for malaria parasites. The data set generated was obtained, cleaned, and analysed using Epi Info version 7.1.1.14 statistical software.

Results: Of the 2086 subjects recruited, 2078 had blood smears done and 54.0% had malaria parasites. Fever and vomiting appeared to be associated with parasitaemia with odds ratios of 1.9 (95% CI: 1.5586-2.2370) and 1.2 (95% CI: 1.0352-1.4697), respectively. Cough however appeared protective with an odds ratio of 0.8 (95% CI: 0.6910-0.9765). The odds of parasitaemia appeared to increase where a child presented with more than one symptom.

Conclusion: Nearly half (46%) of the subjects in this study presented with symptoms but had no malaria. Presumptive treatment of malaria may therefore be useful in situations where diagnostic tests are not readily available, its routine practice should however not be encouraged.

Malaria is considered endemic in over hundred countries across the globe. Many cases of malaria and deaths due to malaria occur in Sub-Saharan Africa. The disease is of great public health concern since it affects people of all age groups more especially pregnant women and children because of their vulnerability. This study sought to use vector autoregression (VAR) models to model the impact of climatic variability on malaria. Monthly climatic data (rainfall, maximum temperature, and relative humidity) from 2010 to 2015 were obtained from the Ghana Meteorological Agency while data on malaria for the same period were obtained from the Ghana Health Service. Results of the Granger and instantaneous causality tests led to a conclusion that malaria is influenced by all three climatic variables. The impulse response analyses indicated that the highest positive effect of maximum temperature, relative humidity, and rainfall on malaria is observed in the months of September, March, and October, respectively. The decomposition of forecast variance indicates varying degree of malaria dependence on the climatic variables, with as high as 12.65% of the variability in the trend of malaria which has been explained by past innovations in maximum temperature alone. This is quite significant and therefore, policy-makers should not ignore temperature when formulating policies to address malaria.