Previous History Of Malaria Research Articles

Application of artificial intelligence in the Prediction of Complications in patients with Malaria

Introduction: This study aims to develop a neural network (NN) that can serve as a useful tool for early diagnosis of complicated malaria. Materials and methods: In this study, a feedforward NN was developed, incorporating 10 clinical variables in the input nodes, hidden layer, and output node. The data were included in the input layer. Various validation techniques such as V cross, Random V cross, Modified Holdout, and Proportional Percentage Sample were applied to train and validate the network using data from 412 patients. Results: The variables included in the analysis were mean arterial pressure, hemoglobin, leukocyte count, platelet count, total bilirubin, presence of dyspnea, vomiting, previous history of malaria, prior use of malaria medication, and persistent fever. The V cross technique, Random V cross Validation, Modified Holdout Validation, and Proportional Percentage Sample Validation were utilized to evaluate the performance of a NN in diagnosing malaria. Sensitivity values varied from 13% to 47%, with positive predictive value values ranging from 37% to 88%. Specificity remained consistently high, ranging from 79% to 90%. Discussion: Sensitivity, specificity, and positive predictive values varied across techniques: V cross and random V cross validation showed narrower sensitivity ranges with strong specificities, while modified holdout validation exhibited wider sensitivity variability.

Knowledge of Malaria and Preventive Behaviour Amongst Allied Healthcare Workers at the Central African Republic

Objective: to determine the knowledge of malaria and preventive behaviour among Allied Healthcare Workers at the Central African Republic. Study Design: Cross-sectional study. Place and Duration of Study: Central African Republic from Dec 2021 to May 2022. Methodology: Allied Healthcare Workers deployed at the Central African Republic as part of the International Organization for Peacekeeping were included in the study. A questionnaire was designed to determine the study participants’ knowledge and preventive behaviour. Association was made between the previous history of malaria and preventive behaviour using the chi-square test. Results: A total of two hundred and twenty-one (n=221) study participants were included in the study with a mean age of 35.73±4.89 years (Range: 22 to 47 years). 49(22.17%) Allied Healthcare Workers had a previous history of malaria. 212(95.9%) of the study participants had adequate knowledge about the mode of transmission and prevention practices. There was a significant association between the previous history of malaria and Allied Healthcare Workers’ preventive behaviour p<0.001). Conclusion: Most study participants had an adequate understanding of malaria, and those with prior malaria exhibited better preventive behaviour. In malaria-stricken regions, it is essential to take preventative measures.

Correlation between parasitemia and different complications of malaria – The clinical outlook

Background: Malaria is one of the most severe public health problems worldwide. India contributes a substantial burden of malaria. It can cause several complications. Aims and Objectives: This study was conducted to determine the association of parasitemia of current malaria with age of patients, hemoglobin level, liver function test (LFT), platelet count, previous history of malaria, and relapse/recrudescence of malaria up to 1 year. Materials and Methods: An observational study conducted in hospital settings included thin and thick smear preparation with Leishman’s staining to determine the parasitemia as per the WHO guidelines from the blood samples of 280 malaria parasite dual antigen (MPDA) kit positive patients and their details were taken during study period of 2 years. Hemoglobin, LFT, and platelet count were tested and they were correlated with parasitemia. The previous history of malaria was taken and follow-up was done up to 1 year for relapse/recrudescence and their association with parasitemia in current disease was evaluated. Statistical tool R was used for data analysis. Results: Age group 20–40 years was most commonly affected with maximum mean percentage parasitemia. Higher parasitemia was associated with higher grade of anemia, LFT derangement, and thrombocytopenia. Disease severity was maximum for mixed infection followed by falciparum and vivax malaria. About 9.28% of patients with the previous history of malaria developed lower parasitemia in current infection. Relapse rate in vivax malaria –2.325% and recrudescence rate in falciparum malaria–12.5%. Conclusion: Malaria parasitemia should be reported routinely as it carries prognostic importance.

Antigenic sites in SARS-CoV-2 spike RBD show molecular similarity with pathogenic antigenic determinants and harbors peptides for vaccine development

The spike protein of coronavirus is key target for drug development and other pharmacological interventions. In current study, we performed an integrative approach to predict antigenic sites in SARS-CoV-2 spike receptor binding domain and found nine potential antigenic sites. The predicted antigenic sites were then assessed for possible molecular similarity with other known antigens in different organisms. Out of nine sites, seven sites showed molecular similarity with 54 antigenic determinants found in twelve pathogenic bacterial species (Mycobacterium tuberculosis, Mycobacterium leprae, Bacillus anthracis, Borrelia burgdorferi, Clostridium perfringens, Clostridium tetani, Helicobacter Pylori, Listeria monocytogenes, Staphylococcus aureus, Streptococcus pyogenes, Vibrio cholera and Yersinia pestis), two malarial parasites (Plasmodium falciparum and Plasmodium knowlesi) and influenza virus A. Most of the bacterial antigens that displayed molecular similarity with antigenic sites in SARS-CoV-2 RBD (receptor binding domain) were toxins and virulent factors. Antigens from Mycobacterium that showed similarity were mainly involved in modulating host cell immune response and ensuring persistence and survival of pathogen in host cells. Presence of a large number of antigenic determinants, similar to those in highly pathogenic microorganisms, not merely accounts for complex etiology of the disease but also provides an explanation for observed pathophysiological complications, such as deregulated immune response, unleashed or dysregulated cytokine secretion (cytokine storm), multiple organ failure etc., that are more evident in aged and immune-compromised patients. Over-representation of antigenic determinants from Plasmodium and Mycobacterium in all antigenic sites suggests that anti-malarial and anti-TB drugs can prove to be clinical beneficial for COVID-19 treatment. Besides this, anti-leprosy, anti-lyme, anti-plague, anti-anthrax drugs/vaccine etc. are also expected to be beneficial in COVID-19 treatment. Moreover, individuals previously immunized/vaccinated or had previous history of malaria, tuberculosis or other disease caused by fifteen microorganisms are expected to display a considerable degree of resistance against SARS-CoV-2 infection. Out of the seven antigenic sites predicted in SARS-CoV-2, a part of two antigenic sites were also predicted as potent T-cell epitopes (KVGGNYNYL444-452 and SVLYNSASF366-374) against MHC class I and three (KRISNCVADYSVLYN356-370, DLCFTNVYADSFVI389-402, and YRVVVLSFELLHA508-520) against MHC class II. All epitopes possessed significantly lower predicted IC50 value which is a prerequisite for a preferred vaccine candidate for COVID-19.

Malaria among migrants in a university hospital in Colombia during 2018: A case series.

Imported malaria has increased in Colombia since 2015 and has been attributed to migrants coming from Venezuela. We present a series of malaria cases, nested in a retrospective cross-sectional study between 2017 and 2018, aimed at calculating the prevalence of medical diseases among immigrants in a University Hospital in Colombia. Among 154 immigrants admitted for medical causes between 2017 and 2018, 8 were diagnosed with malaria, all due to Plasmodium vivax. Of these, seven had uncomplicated malaria, five had a previous history of malaria, one was critically ill, but none died. We highlight that, similar to other case series of imported malaria, Latin American migrants were young, with similar clinical profiles, having a low proportion of severe cases, and P. vivax was the most frequent cause.

Prevalence and Risk Factors of Asymptomatic Plasmodium Infection in Gondar Zuria District, Northwest Ethiopia.

BackgroundMalaria is one of the major public health problems worldwide. In Ethiopia, an increase in malaria incidence may be attributed to the presence of community-wide asymptomatic Plasmodium infection. This study aims to assess asymptomatic Plasmodium infection and associated factors in Gondar Zuria district, Northwest Ethiopia.MethodsA community-based cross-sectional study was conducted in Gondar Zuria district from May to June 2019. Angacha and Hamsafeg villages were randomly selected from Tachtseda and Hamsafeg kebeles, respectively. Fifty-three (53) households were selected using systematic random sampling to recruit a total of 251 study participants. Sociodemographic data were collected using structured questionnaires. Thin and thick blood films were prepared and examined for evidence of parasites. Data were entered and analyzed using SPSS version 23. The association between dependent (asymptomatic Plasmodium infection) and independent (sex, age group, family size and previous history of malaria) variables was explored using bivariate and multivariate logistic regression. Statistically significant association was declared at a P-value of <0.05.ResultsA total of 251 individuals were tested, of whom 53.4% were females and 33.5% were above the age of 30 years. The prevalence of asymptomatic Plasmodium infection was 12%. The highest prevalence of malaria was observed in females (6.4%) and among the age group 15–29 years (4.4%). The majority (70%) of study participants had <500 parasites/μL of blood. A high parasitemia level (ie ≥1000 parasites/μL of blood) was observed in the age group 15–29 years. Age group, bed net usage and previous history of malaria were significantly associated with asymptomatic Plasmodium infection (P<0.05).ConclusionAsymptomatic Plasmodium infection remains an important public health problem in the study area. Further studies using more sensitive diagnostic methods are required to scale up the eradication and control program of malaria.

A First Plasmodium vivax Natural Infection Induces Increased Activity of the Interferon Gamma-Driven Tryptophan Catabolism Pathway.

The human immune response that controls Plasmodium infection in the liver and blood stages of the parasite life cycle is composed by both pro- and anti-inflammatory programs. Pro-inflammatory responses primarily mediated by IFN-γ controls the infection, but also induce tolerogenic mechanisms to limit host damage, including the tryptophan (TRP) catabolism pathway mediated by the enzyme Indoleamine 2,3-Dioxygenase (IDO1), an enzyme that catalyzes the degradation of TRP to kynurenines (KYN). Here we assessed total serum kynurenines and cytokine dynamics in a cohort of natural Plasmodium vivax human infection and compared them to those of endemic healthy controls and other febrile diseases. In acute malaria, the absolute free kynurenine (KYN) serum levels and the KYN to TRP (KYN/TRP) ratio were significantly elevated in patients compared to healthy controls. Individuals with a diagnosis of a first malaria episode had higher serum KYN levels than individuals with a previous malaria episode. We observed an inverse relationship between the serum levels of IFN-γ and IL-10 in patients with a first malaria episode compared to those of subjects with previous history of malaria. Kynurenine elevation was positively correlated with serum IFN-γ levels in acute infection, whereas, it was negatively correlated with parasite load and P. vivax LDH levels. Overall, the differences observed between infected individuals depended on the number of Plasmodium infections. The decrease in the KYN/TRP ratio in malaria-experienced subjects coincided with the onset of anti-P. vivax IgG. These results suggest that P. vivax infection induces a strong anti-inflammatory program in individuals with first time malaria, which fades with ensuing protective immunity after subsequent episodes. Understanding the tolerance mechanisms involved in the initial exposure would help in defining the balance between protective and pathogenic immune responses necessary to control infection and to improve vaccination strategies.

Prevention strategies of transfusion-transmitted parasitic infections (TTPIs): Strengths and challenges of current approaches, and evaluation of the strategies implemented in Iran

BackgroundSeveral strategies are being implemented in blood transfusion centers of the world to prevent the transfusion-transmitted parasitic infections (TTPIs). The objective of this study was to determine and describe the strategies to minimize the transmission risk of parasitic agents via blood transfusion in Iran. MethodsThis study was conducted in the Iranian blood transfusion organization (IBTO). The data were extracted from the latest version of the “medical interview” standard operating procedure (SOP). ResultsThe donor selection is the first and only step to reduce the risk of TTPIs in endemic and non-endemic areas of Iran. In all blood transfusion centers of the IBTO, the blood donation volunteers with a previous history of malaria, Chagas disease, visceral leishmaniasis (VL), muco-cutaneous leishmaniasis and babesiosis, as well as those with clinical toxoplasmosis, cutaneous leishmaniasis (CL) and with a history of residence in, or travel to, malaria-endemic areas are permanently or temporarily deferred from the blood donation. ConclusionsSince malaria, toxoplasmosis and VL are endemic in parts of Iran, as well as the increasing travels to endemic areas and immigrations from endemic to non-endemic areas of parasitic infections, the extensive use of blood and blood components and the asymptomatic occurrence of most parasitic infections in blood donors, the donor selection strategy is not sufficient to prevent the TTPIs. Therefore, the changing of donor selection process and the use of other common preventive strategies are recommended to reduce the risk of TTPIs, especially for high-risk groups of toxoplasmosis and VL.

Prevention strategies of transfusion‐transmitted parasitic infections (TTPIs) in Iran, an endemic area for malaria, toxoplasmosis and leishmaniasis

AbstractBackground and ObjectivesParasitic infections are one of the most important adverse reactions of blood transfusion. Several strategies are being implemented in blood transfusion centers of the world to prevent the transfusion‐transmitted parasitic infections (TTPIs). The objective of this work was to clarify and describe the strategies to minimize the transmission risk of endemic parasitic agents in Iran via blood transfusion.Materials and MethodsThis study was conducted in the Iranian blood transfusion organization (IBTO). The data were extracted from the latest version of the “medical interview” standard operating procedure (SOP) and then recorded in the prepared sheets.ResultsThe donor selection is the first and only step to reduce the risk of TTPIs in endemic and non‐endemic areas of Iran. In all blood transfusion centers of the IBTO, the blood donation volunteers with a previous history of malaria, Chagas disease, visceral leishmaniasis (VL), muco‐cutaneous leishmaniasis and babesiosis, as well as those with toxoplasmosis, cutaneous leishmaniasis (CL) and with a history of residence in, or travel to, malaria‐endemic areas are permanently or temporarily deferred from the blood donation.ConclusionFor some reasons, including the prevalence of malaria, toxoplasmosis and VL in parts of Iran, the donor selection strategy is not sufficient to prevent the TTPIs. Therefore, the changing of donor selection process and the use of other common preventive strategies are recommended to reduce the risk of TTPIs, especially for high‐risk groups of toxoplasmosis and VL.

Early treatment-seeking behaviour for malaria in febrile patients in northwest Ethiopia

BackgroundAs malaria is among the leading public health problems globally, early diagnosis and treatment of cases is one of the key interventions for its control and elimination. Nevertheless, little is known about early treatment-seeking behaviour for malaria of people in Ethiopia. This study was conducted to investigate early treatment-seeking behaviour and associated factors among febrile patients in Dera district, one of the malaria hotspot districts in Ethiopia.MethodsAn institution-based, cross-sectional study was conducted among malaria-suspected febrile patients in Dera district, Amhara Regional State, Ethiopia from September to December 2017. The study used the lottery method to select sample health facilities, and participant allocation to facilities was done in proportion to client flow to the respective health facilities. Data were collected by interview. Thus, binary logistic regression model was fitted to the data. Crude and adjusted odds ratios with the respective confidence intervals and p-values were computed. An explanatory variable with a p-value ≤ 0.05 was considered statistically significant. SPSS version 20 was used for the analysis.ResultsA total of 680 respondents completed the study with a response rate of 96.6%. The study revealed that 356 (52.4%) participants sought treatment within 24 h of fever onset, and patients who: knew the advantage of sleeping under nets [AOR 95% CI 2.8 (1.70–4.60)]; knew mosquito breeding sites [AOR 95% CI 1.9 (1.10–3.30)]; had good, overall knowledge about malaria [AOR 95% CI 2.7 (1.56–4.76)]; had previous history of malaria [AOR 95% CI 3.26 (1.64–6.49)]; were at a distance of < 6 km from a health centre [AOR 95% CI 2.5 (1.72–3.60)]; and, had family size < 5 [AOR 95% CI 2.1 (1.43–3.20)], were more likely to seek treatment within 24 hof fever onset.ConclusionA low proportion of malaria-suspected patients sought treatment within 24 h of fever onset compared to the national target. Awareness about the advantage of sleeping under nets, knowledge about mosquito breeding sites and malaria itself, previous history of malaria, distance from the health centres, and family size were found to be predictors of early treatment-seeking behaviour for malaria. Strengthening strategies tailored to increasing awareness for communities about malaria prevention methods and early treatment-seeking behaviour is essential.

Comparison of microscopy and PCR for the detection of human Plasmodium species and Plasmodium knowlesi in southern Myanmar

ObjectivesTo determine the distribution of Plasmodium (P) species including Plasmodium knowlesi and to compare the specificity and sensitivity of microscopy with nested PCR in malaria diagnosis. MethodsThe study was conducted in Kawthaung, southern Myanmar. Ninety clinically suspected malaria patients were screened for malaria by Giemsa stained microscopy and confirmed by nested PCR. ResultsAmong the participants, 57 (63.3%) were positive and 33 (36.7%) were negative by microscopy. Of positive samples, 39 (68.4%) were Plasmodium falciparum, 17 (29.8%) Plasmodium vivax and 1 (1.8%) Plasmodium malariae, whereas 59-amplified by PCR were 40 (67.8%), 18 (30.5%) and 1 (1.7%) respectively. PCR amplified 2 microscopy negative samples. Two samples of P. falciparum detected by microscopy were amplified as P. vivax and vice versa. All samples were negative for Plasmodium ovale, P. knowlesi and mixed infections. Microscopy had a very good measure of agreement (κ = 0.95) compared to nested PCR. Sensitivity and specificity of microscopy for diagnosis of P. falciparum were 92.5% (95% CI: 79.6–98.4) and 96.0% (95% CI: 86.3–99.5) respectively, whereas for P. vivax were 83.3% (95% CI: 58.6–96.4) and 97.2% (95% CI: 90.3–99.7). ConclusionsP. knowlesi was not detected by both microscopy and PCR. Giemsa stained microscopy can still be applied as primary method for malaria diagnosis and is considered as gold standard. As to the lower sensitivity of microscopy for vivax malaria, those with previous history of malaria and relapse cases should be diagnosed by RDT or PCR combined with microscopy. Inaccuracy of species diagnosis highlighted the requirement of training and refresher courses for microscopists.

TOLLIP gene variant is associated with Plasmodium vivax malaria in the Brazilian Amazon

BackgroundToll-interacting protein is a negative regulator in the TLR signaling cascade, particularly by impeding the TLR2 and, TLR4 pathway. Recently, TOLLIP was shown to regulate human TLR signaling pathways. Two common TOLLIP polymorphisms (rs5743899 and rs3750920) were reported to be influencing IL-6, TNF and IL-10 expression. In this study, TOLLIP variants were investigated to their relation to Plasmodium vivax malaria in the Brazilian Amazon.MethodsThis cohort study was performed in the municipalities of Careiro and, Manaus, in Western Brazilian Amazon. A total of 319 patients with P. vivax malaria and, 263 healthy controls with no previous history of malaria were included in the study. Genomic DNA was extracted from blood collected on filter paper, using the QIAamp® DNA Mini Kit, according to the manufacturer’s suggested protocol. The rs5743899 and rs3750920 polymorphisms of the TOLLIP gene were typed by PCR–RFLP.ResultsHomozygous individuals for the rs3750920 T allele gene had twice the risk of developing malaria when compared to individuals homozygous for the C allele (OR 2.0 [95% CI 1.23–3.07]; p = 0.004). In the dominant model, carriers the C allele indicates protection to malaria, carriers of the C allele were compared to individuals with the T allele, and the difference is highly significant (OR 0.52 [95% CI 0.37–0.76]; p = 0.0006). The linkage disequilibrium between the two polymorphisms was weak (r2 = 0.037; D′ = 0.27).ConclusionsThese findings suggest that genes involved in the TLRs-pathway may be involved in malaria susceptibility. The association of the TOLLIP rs3750920 T allele with susceptibility to malaria further provides evidence that genetic variations in immune response genes may predispose individuals to malaria.

Magnitude of Anemia and Associated Factors among Pregnant Women Attending Antenatal Care in Nekemte Health Center, Nekemte, Ethiopia

Background: Anemia is defined as a condition in which there is less than the normal hemoglobin (HB) level in the body, which decreases oxygen-carrying capacity of red blood cells to tissues. Anemia in pregnancy also leads to premature births, low birth weight, fetal impairment and infant deaths. The aim of this study was to determine the magnitude of anemia and associated factors among Pregnant Women Attending Antenatal Care in Nekemte Health Center, Nekemte, Ethiopia. Methods: A cross-sectional study was conducted among Pregnant Women Attending Antenatal Care in Nekemte Health Center (NHC) between May 20, 2011 and June 25, 2011. A total of 150 pregnant women were selected continently. Blood specimen was collected and processed based on standard operating procedures where hemoglobin level was determined by Cell-Dyn1800. A structured questionnaire was used to collect data on Sociodemographic and associated risk factors. Data were entered and analyzed using SPSS version 20 software. Logistic regressions were applied to assess any association between explanatory factors and outcome variables. P values <0.05 were taken as statistically significant. Results: The total prevalence of anemia was 52%. Mild, moderate and severe anemia account for 50(64%), 17(21.8%) and 11(14.2%), respectively. Fifty three (68%) of the anemic pregnant women had normocytic normochromic RBCs. Anemia was significantly higher in pregnant women with diarrhea [AOR, 95% CI (5.6(1.7, 17.3), P<0.05] and in those with previous history of malaria [AOR, 95% CI (2.7(1.4, 9.33), P<0.05]. Conclusion: The prevalence of anemia in the study area is significantly high. Regular antenatal care follow up, adjustment of dietary and screening of parasitic infections are recommended to prevent impacts of anemia in

First case of a naturally acquired human infection with Plasmodium cynomolgi

Since 1960, a total of seven species of monkey malaria have been reported as transmissible to man by mosquito bite: Plasmodium cynomolgi, Plasmodium brasilianum, Plasmodium eylesi, Plasmodium knowlesi, Plasmodium inui, Plasmodium schwetzi and Plasmodium simium. With the exception of P. knowlesi, none of the other species has been found to infect humans in nature. In this report, it is described the first known case of a naturally acquired P. cynomolgi malaria in humans.The patient was a 39-year-old woman from a malaria-free area with no previous history of malaria or travel to endemic areas. Initially, malaria was diagnosed and identified as Plasmodium malariae/P. knowlesi by microscopy in the Terengganu State Health Department. Thick and thin blood films stained with 10% Giemsa were performed for microscopy examination. Molecular species identification was performed at the Institute for Medical Research (IMR, Malaysia) and in the Malaria & Emerging Parasitic Diseases Laboratory (MAPELAB, Spain) using different nested PCR methods.Microscopic re-examination in the IMR showed characteristics of Plasmodium vivax and was confirmed by a nested PCR assay developed by Snounou et al. Instead, a different PCR assay plus sequencing performed at the MAPELAB confirmed that the patient was infected with P. cynomolgi and not with P. vivax.This is the first report of human P. cynomolgi infection acquired in a natural way, but there might be more undiagnosed or misdiagnosed cases, since P. cynomolgi is morphologically indistinguishable from P. vivax, and one of the most used PCR methods for malaria infection detection may identify a P. cynomolgi infection as P. vivax.Simian Plasmodium species may routinely infect humans in Southeast Asia. New diagnostic methods are necessary to distinguish between the human and monkey malaria species. Further epidemiological studies, incriminating also the mosquito vector(s), must be performed to know the relevance of cynomolgi malaria and its implication on human public health and in the control of human malaria.The zoonotic malaria cannot be ignored in view of increasing interactions between man and wild animals in the process of urbanization.

Ultrasonic measurement of the liver in search of Plasmodium vivax cases that relapse

ObjectiveTo find out whether relapse can be differentiated in vivax patients. MethodsSixty three people suffering from vivax were taken and ultrasonography was done. ResultsAmong 63 persons, previous history of vivax was obtained in 51. Out of remaining 12, previous history of falciparum was found in 5, four had previous history of uncertain malaria and in three, no previous history of malaria was recorded. The liver was within normal size (≤140 mm) in 36 persons, and increased in size in 27 persons, of which enlarged (141–150 mm) in 14 and highly enlarged (beyond 150 mm) in 13 persons. Out of these 27 persons with enlarged livers 22 suffered from vivax previously. Altogether 18 out of 63 cases considered to be suffering from relapsed vivax cases in this study, which is alarming. ConclusionsThis simple, noninvasive procedure might provide a clue as to how relapse vivax cases can be determined.

Plasmodium falciparum infection in pregnant women attending antenatal care in Luanda, Angola

Malaria during pregnancy remains a serious public health problem. The aim of this study was to establish the prevalence and possible risk factors for malaria in pregnant women attending antenatal care at Augusto Ngangula Specialized General Hospital in Luanda, Angola. Pregnant women (679 total) who attended antenatal care from April to September 2008 were included in the study after signing informed consent. For each participant, the social-demographic profile and malaria and obstetric histories were investigated via a questionnaire. Diagnosis was made by optic microscopy, and hemoglobin concentration measured. The associations between age, parity, gestational age, residence, schooling, malaria during gravity, anemia and treatment with incidence of Plasmodium falciparum infection were analyzed through logistic regression. During the period of study, 74 (10.9%) out of 679 women were infected by P. falciparum. The average concentration of hemoglobin was 11.1 ± 0.07 g/dL, and there were significant associations between the history of malaria during pregnancy, P. falciparum infection (p<0.01) and anemia at the time of observation (p<0.001). Previous history of malaria during pregnancy represents a risk factor for current infection and anemia was an important complication associated with malaria, even in women who were treated with sulfadoxine-pyrimethamine during pregnancy.

Factors Influencing the Usage of Insecticide Treated Mosquito Nets among Pregnant Women

Purpose: Malaria in Sudan is a leading cause of morbidity and mortality. Incidence remains very high especially among pregnant women and children under five. study was conducted to determine the factors influencing the usage of insecticide treated mosquito nets (ITNs) for prevention of malaria among pregnant women. Methods: A cross-sectional study design with convenience nts, prevalence of malaria was 71.2%. The coverage of ITNs was 58.7% but only 11.5% used ITNs regularly. Ninety six (92.3%) showed good knowledge on malaria causes, 103 (99%) had good knowledge on malaria complications and 62 (59.6%) showed good knowledge on the aim of ITNs usage. Only 23 (22.1%) knew the proper usage of ITNs. Maternal age, income, gravidity, parity, abortion, number of family members, usage of ITNs during last pregnancy, previous history of malaria, usage of ITNs by other family members and accessibility to ITNs were significantly associated with current usage of ITNs. Conclusion: Although there was good knowledge of ITNs among women in Sudan, proper usage of ITNs is poor. Factors influencing usage of ITNs among the pregnant women include maternal age, income, gravidity, parity, abortion, number of family members, usage of ITNs during last pregnancy, previous history of malaria, usage of ITNs by other family members and accessibility to ITNs. Keywords: ITN, malaria, pregnancy, Sudan.

Cytotoxicity of human natural killer (NK) cell subsets for Plasmodium falciparum erythrocytic schizonts: stimulation by cytokines and inhibition by neomycin

Quantification of human peripheral blood NK subsets has been made in a group of Kenyan adults and children with acute P. falciparum malaria. Results were compared with data obtained from three age- and sex-matched control cohorts: parasitaemic but asymptomatic children; aparasitaemic children and adults; and adult Caucasians with no previous history of malaria. Separated NK subsets were tested in vitro for cytotoxicity to erythrocytic schizonts of P. falciparum in the presence and absence of cytokines. There was a statistically significant quantitative and qualitative depression of the CD3-CD56+ subset in patients with acute malaria and this was accompanied by an expansion of the 'non-functional' CD3-CD57+CD16-CD56- subset. Both CD3-CD16+ and CD3-CD56+ NK cells from all patients and donors lysed schizonts, and this cytotoxicity was enhanced by the addition of recombinant interferon-alpha and/or IL-2, notably with the CD3-CD56+ subset. Interestingly, asymptomatic donors had the highest levels of CD3-CD56+ NK cells, which also demonstrated an enhanced response to cytokine stimulation. Cytotoxicity to schizonts was accompanied by the release of soluble NK cell lytic factors. Neomycin suppressed cytotoxicity in a dose-dependent manner, indicating that the lysis of schizonts by NK cells involves phospholipase C-mediated phosphoinositide metabolism. Our findings define a role for NK cells in immunity to malaria through the lysis of infected erythrocytes as a first-line defence against the parasite.

Leptospirosis in febrile men ingestingAgouti pacain South America

To explore the relationship between the ingestion of Agouti paca (AP) and human leptospirosis in Guyana, 19 febrile men who said they had hunted and eaten A. paca were screened for malaria, using bloodsmears, and for leptospirosis, using an enzyme immuno-assay that detects Leptospira -specific IgM. Those found positive for anti-Leptospira IgM were then evaluated further, with a microscopical agglutination test based on a limited panel of serovars from three pathogenic species of Leptospira. Although six of the 18 patients who provided suitable samples for the serology were found seropositive for acute leptospirosis, only three of the 19 patients were found smear-positive for malaria. A clinical-decision model, based on medical histories, the results of physical examinations, and the use of routine urine dipsticks, and enabling prediction of the serological results, was developed. This model, which had 83% sensitivity and 100% specificity for leptospirosis, indicated that, in the absence of serology, most febrile patients reporting AP ingestion could be correctly treated if each was checked for malaria using traditional bloodsmears. The smear-positives should be treated with antimalarial drugs whereas the smear-negatives should be treated for leptospirosis if they had any of the following: a skin rash; lymphadenopathy; abnormal urine sediment (proteinuria or haematuria); and/or no previous history of malaria. In the present study, the relative risk of leptospirosis among the patients who were smear-negative for malaria and fulfilled at least one of these four criteria was 13 (P = 0.0007). In Guyana at least, leptospirosis appears to be common among men who hunt, prepare and ingest AP. Vaccines may be the best, practical form of protection among such men.

IgG antibody response against Plasmodium vivax in children exposed to malaria, before and after specific treatment

OBJECTIVE: To assess the IgG antibody response against P. vivax (IgG anti-PV), and cytophilic (IgG1 and IgG3) and noncytophilic (IgG2) IgG subclasses in 34 children aged 0 to 15 years old infected with P. vivax malaria. METHODS: IgG levels were determined by indirect fluorescent antibody technique during the acute and therapeutic control phase. Patients were distributed into 2 groups according to the presence or absence of a previous malaria episode. IgG anti-PV levels were measured on the first and last day of treatment, and compared by Studentacute;s t test. Antibody levels were correlated with asexual parasitemia (Spearmańs correlation test). RESULTS AND CONCLUSIONS: Increased IgG levels were observed on the first and on the last day of treatment. The geometric means for IgG subclass titers found in patients with previous history of malaria were: IgG1 (806.35) > IgG3 (28.28) > IgG2 (20). In patients infected for the first time, the responses obtained were: IgG1 (709.21) > IgG3 (39.3) > IgG2 (10.7). There was no association between asexual parasitemia and antibody levels on the first day of treatment. Cytophilic antibodies (IgG1, IgG3) predominated over noncytophilic antibodies (IgG2).