A review of the malaria situation in Zimbabwe with special reference to the period 1972–1981

Taylor, P. J.; Mutambu, Susan

doi:10.1016/0035-9203(86)90185-9

Cited by 82 publications

(78 citation statements)

References 3 publications

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“…We describe an analysis of the genetic variation of parasites in three areas of Zimbabwe using glurp, msp-1, msp-2 and neutral polymorphic microsatellite markers. These areas, Bindura, Chiredzi and Kariba, were described in a single study two decades ago to be of hypo-, meso-and hyperendemic transmission, respectively (Taylor and Mutambu, 1986). Transmission is seasonal in all these areas and the main mosquito vector is Anopheles arabiensis.…”

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confidence: 99%

Analysis of genetic polymorphism in select vaccine candidate antigens and microsatellite loci in Plasmodium falciparum from endemic areas at varying altitudes

Mlambo

Sullivan

Mutambu³

et al. 2007

Acta Tropica

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Plasmodium falciparum parasites obtained from symptomatic patients attending clinics in Bindura (altitude 1,100 m), Chiredzi (600 m) and Kariba (< 600 m), previously reported to differ in malaria endemicity were genotyped on the msp-1, msp-2 and glurp loci to examine the extent of parasite genetic diversity. While the parasites were monomorphic for msp-1 allele RO33 from the three locations, the K1 allele was overrepresented in Kariba (p=0.02) and Mad20 alleles occurred at a higher frequency in Bindura. A similar PCR analysis for glurp and the two main allelic families of msp-2, i.e IC/3D7 and FC-27 revealed minimal differences in the parasite population. A total of 8 msp-1 Block 2 and 11 msp-2 genotypes were identified from the three locations combined. On the glurp locus, thirteen different genotypes ranging in size from 660 to 1160 bp were detected in parasites obtained from Bindura and Kariba. To gain further insight into P. falciparum genetic diversity in the three different geographical locations, parasites were examined for neutral microsatellite markers (C4M8, C13M30 and TA81). The number of microsatellite alleles ranged from 8 to 17 and the average expected heterozygosity (HE) for the three areas combined was 0.83 suggesting that the parasite population of Zimbabwe is genetically heterogeneous. These findings have implications in understanding the impact of genetic variation on immunity and possibly emergence of drug resistance.Plasmodium falciparum parasites are highly genetically diverse and studies indicate that at any given time, humans or mosquitoes can harbor a number of different parasite clones (Babiker et al., 1991;Branch et al., 2001). The unique genetic characteristics of each parasite may determine clinical or parasitological outcomes and properties such as cytoadherence, immune evasion, resistance or susceptibility to drugs as well as infectivity to mosquitoes (Snounou et al., 1999). Understanding the distribution of genetically diverse P. falciparum parasites is important in malaria epidemiology as well as in designing vaccines as antigenic diversity continues to pose a big challenge to vaccine development. Additionally, the performance of Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. vaccine candidates employed will need to be monitored by assessing switching of allelic types resulting from either natural or vaccine induced immune selection. NIH Public AccessMsp-1 and msp-2 are highly polymorphic single copy genes and have been employed to investigate parasite genetic diversity (Anders and Smythe, 1989;Smythe et al., 1990). The examinatio...

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confidence: 99%

Analysis of genetic polymorphism in select vaccine candidate antigens and microsatellite loci in Plasmodium falciparum from endemic areas at varying altitudes

Mlambo

Sullivan

Mutambu³

et al. 2007

Acta Tropica

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“…In addition, elevation limited malaria transmission during the rainy season. Previous research in Zimbabwe suggested that malaria transmission does not typically occur at elevations exceeding 1,200 m. 1 Although the range of elevations for enumerated households was between 607 and 1,514 m, for sampled households, the range was limited to between 639 and 1,234 m. The limited range of elevation in the sampled households may be a result of logistical challenges reaching areas at higher elevations. Consequently, differences in malaria risk during the dry season related to elevation may have been masked by the underrepresentation of households at higher elevations.…”

Section: Discussionmentioning

confidence: 87%

“…Environmental factors previously identified as driving malaria transmission in the country include season, elevation, rainfall, temperature, and vapor pressure. 1,15,17,27 The model predicted higher risk of malaria among households sampled in the rainy season, located near the Mozambique border and further from health facilities. In addition, elevation limited malaria transmission during the rainy season.…”

Section: Discussionmentioning

confidence: 99%

“…1 Despite this, malaria has reemerged as a public health problem in the past decade and this resurgence has been attributed to limited funding for control, drug resistance by Plasmodium parasites, and insecticide resistance by major Anopheline vectors. [2][3][4][5] The reemergence of malaria in areas with previously successful control poses a challenge to the sustainability of gains made in reducing malaria and current efforts to reduce the burden of malaria to achieve elimination.…”

Section: Introductionmentioning

confidence: 99%

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High-Resolution Plasmodium falciparum Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control

Kanyangarara

Mamini

Mharakurwa

et al. 2016

The American Society of Tropical Medicine and Hygiene

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Abstract. In Zimbabwe, more than half of malaria cases are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. The objectives of this study were to develop a prediction model based on environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province. From October 2012 to September 2015, 483 households were surveyed, and 104 individuals residing within 69 households had positive rapid diagnostic test results. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates extracted from high-resolution remote sensing data sources. Model predictions and prediction standard errors were generated for the rainy and dry seasons. The resulting maps predicted elevated risk during the rainy season, particularly in low-lying areas bordering Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria risk scattered along the northern and western peripheries of the study area. These findings underscore the need for strong cross-border malaria control initiatives to complement country-specific interventions.

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“…The Burma Valley in Eastern Zimbabwe and Kariba are malaria endemic areas. [24][25][26] Written informed consent was sought from all the participants together with assent from their parents/guardians to partake in the study. Each study participants' demographic data was collected and recorded during the two year follow up period.…”

Section: Study Design and Populationmentioning

confidence: 99%

Evaluation of specific antibody responses to selected malaria vaccine candidates in Zimbabwean children

Marume

Nyandoro

Mutingwende

et al. 2015

Clinical Nursing Studies

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Introduction: There is high malaria related morbidity and mortality amongst infants and children in malaria endemic areas. An In-depth understanding of protective immunity correlates enables the long due necessary development of an effective malaria vaccine. This study aimed at evaluating antibody responses to apical membrane antigen 1 (AMA 1) that helps P falciparum entry into red blood cells, Glutamate rich protein (GLURP), an antigen expressed in the whole life cycle of the malaria causing pathogen, merozoite surface protein-1 (MSP 1) coding for a major antigen in the asexual stage of P falciparum and merozoite surface protein 3 (MSP 3), a polymorphic blood stage malaria antigen in Zimbabwean children living in malaria endemic areas. Methods: We characterized humoral immune responses to malaria vaccine candidates in a two year longitudinal survey among 136 children (6-16 years) from Burma and Kariba in Zimbabwe. Blood samples were collected and analyzed for malaria parasites, plasma and antibody titers against malaria vaccine candidates [MSP1, MSP3, GLURP, AMA] by ELISA technique. The blood samples were also checked for potential confounders like anemia, bilharzia and HIV sero-status using the ELISA technique. Results: Ig levels were significantly different (p < .0001) across the three time points, and against the different candidates (p < .0001). MSP3 had the highest (13,552.2) and GLURP the least (4,741.6) IgM titers. However, IgG, IgG1, IgG3 and IgG4 levels were highest against AMA compared to other vaccine candidates, 3) and anti-GLURP IgG4 (58.7)]. Anemia burden was about 44% at baseline with a threefold decrease (-16%) over the 12 month follow up. Conclusions: This study highlights the need for robust evaluation of several malaria vaccine candidates in combination to understand correlates of protective immunity as suggested by the significant antibody levels against the four vaccine candidates. Longer follow up periods are needed to assess the impact of continuous malaria exposure on host immune responses. Multivalent malaria vaccine development offer a better chance towards an efficacious malaria vaccine compared to monovalent vaccine. Antibody levels against the four vaccine candidates were significant suggesting that an ideal malaria vaccine should target more than one antigen.

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A review of the malaria situation in Zimbabwe with special reference to the period 1972–1981

Cited by 82 publications

References 3 publications

Analysis of genetic polymorphism in select vaccine candidate antigens and microsatellite loci in Plasmodium falciparum from endemic areas at varying altitudes

Analysis of genetic polymorphism in select vaccine candidate antigens and microsatellite loci in Plasmodium falciparum from endemic areas at varying altitudes

High-Resolution Plasmodium falciparum Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control

Evaluation of specific antibody responses to selected malaria vaccine candidates in Zimbabwean children

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