Dataset Information

The age patterns of severe malaria syndromes in sub-Saharan Africa across a range of transmission intensities and seasonality settings.

ABSTRACT:

Background

A greater understanding of the relationship between transmission intensity, seasonality and the age-pattern of malaria is needed to guide appropriate targeting of malaria interventions in different epidemiological settings.

Methods

A systematic literature review identified studies which reported the age of paediatric hospital admissions with cerebral malaria (CM), severe malarial anaemia (SMA), or respiratory distress (RD). Study sites were categorized into a 3 × 2 matrix of Plasmodium falciparum transmission intensity and seasonality. Probability distributions were fitted by maximum likelihood methods, and best fitting models were used to estimate median ages and to represent graphically the age-pattern of each outcome for each transmission category in the matrix.

Results

A shift in the burden of CM towards younger age groups was seen with increasing intensity of transmission, but this was not the case for SMA or RD. Sites with 'no marked seasonality' showed more evidence of skewed age-patterns compared to areas of 'marked seasonality' for all three severe malaria syndromes.

Conclusions

Although the peak age of CM will increase as transmission intensity decreases in Africa, more than 75% of all paediatric hospital admissions of severe malaria are likely to remain in under five year olds in most epidemiological settings.

SUBMITTER: Roca-Feltrer A

PROVIDER: S-EPMC2992028 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature

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Publications

The age patterns of severe malaria syndromes in sub-Saharan Africa across a range of transmission intensities and seasonality settings.

Roca-Feltrer Arantxa A Carneiro Ilona I Smith Lucy L Schellenberg Joanna Rm Armstrong JR Greenwood Brian B Schellenberg David D

Malaria journal 20101013

<h4>Background</h4>A greater understanding of the relationship between transmission intensity, seasonality and the age-pattern of malaria is needed to guide appropriate targeting of malaria interventions in different epidemiological settings.<h4>Methods</h4>A systematic literature review identified studies which reported the age of paediatric hospital admissions with cerebral malaria (CM), severe malarial anaemia (SMA), or respiratory distress (RD). Study sites were categorized into a 3 × 2 matr ...[more]

PMID: 20939931

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Project description:BACKGROUND: There is evidence that the age-pattern of Plasmodium falciparum malaria varies with transmission intensity. A better understanding of how this varies with the severity of outcome and across a range of transmission settings could enable locally appropriate targeting of interventions to those most at risk. We have, therefore, undertaken a pooled analysis of existing data from multiple sites to enable a comprehensive overview of the age-patterns of malaria outcomes under different epidemiological conditions in sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS: A systematic review using PubMed and CAB Abstracts (1980-2005), contacts with experts and searching bibliographies identified epidemiological studies with data on the age distribution of children with P. falciparum clinical malaria, hospital admissions with malaria and malaria-diagnosed mortality. Studies were allocated to a 3x2 matrix of intensity and seasonality of malaria transmission. Maximum likelihood methods were used to fit five continuous probability distributions to the percentage of each outcome by age for each of the six transmission scenarios. The best-fitting distributions are presented graphically, together with the estimated median age for each outcome. Clinical malaria incidence was relatively evenly distributed across the first 10 years of life for all transmission scenarios. Hospital admissions with malaria were more concentrated in younger children, with this effect being even more pronounced for malaria-diagnosed deaths. For all outcomes, the burden of malaria shifted towards younger ages with increasing transmission intensity, although marked seasonality moderated this effect. CONCLUSIONS: The most severe consequences of P. falciparum malaria were concentrated in the youngest age groups across all settings. Despite recently observed declines in malaria transmission in several countries, which will shift the burden of malaria cases towards older children, it is still appropriate to target strategies for preventing malaria mortality and severe morbidity at very young children who will continue to bear the brunt of malaria deaths in sub-Saharan Africa.

Project description:BackgroundSub-Saharan Africa harbors the majority of the global burden of malaria and schistosomiasis infections. The co-endemicity of these two tropical diseases has prompted investigation into the mechanisms of coinfection, particularly the competing immunological responses associated with each disease. Epidemiological studies have shown that infection with Schistosoma mansoni is associated with a greater malaria incidence among school-age children.MethodologyWe developed a co-epidemic model of malaria and S. mansoni transmission dynamics which takes into account key epidemiological interaction between the two diseases in terms of elevated malaria incidence among individuals with S. mansoni high egg output. The model was parameterized for S. mansoni high-risk endemic communities, using epidemiological and clinical data of the interaction between S. mansoni and malaria among children in sub-Saharan Africa. We evaluated the potential impact of the S. mansoni-malaria interaction and mass treatment of schistosomiasis on malaria prevalence in co-endemic communities.Principal findingsOur results suggest that in the absence of mass drug administration of praziquantel, the interaction between S. mansoni and malaria may reduce the effectiveness of malaria treatment for curtailing malaria transmission, in S. mansoni high-risk endemic communities. However, when malaria treatment is used in combination with praziquantel, mass praziquantel administration may increase the effectiveness of malaria control intervention strategy for reducing malaria prevalence in malaria- S. mansoni co-endemic communities.Conclusions/significanceSchistosomiasis treatment and control programmes in regions where S. mansoni and malaria are highly prevalent may have indirect benefits on reducing malaria transmission as a result of disease interactions. In particular, mass praziquantel administration may not only have the direct benefit of reducing schistosomiasis infection, it may also reduce malaria transmission and disease burden.

Project description:In 2013, 78% of malaria deaths occurred in children aged 5 years and below, in sub-Saharan Africa. Treatment of severe malaria requires a health facility with inpatient care. However, in most sub-Sahara African countries, access to health facilities is a major problem. Pre-referral antimalarial treatments aim to delay the progress of severe malaria as patients seek to access health facilities. Rectal artesunate can be administered in the community as a pre-referral treatment in rural hard-to-reach areas. In Kenya, though pre-referral rectal artesunate has been included in the National Guidelines for pre-referral treatment, it is yet to be implemented in the public healthcare system. It is important, therefore, to establish its cost-utility compared to current parenteral treatments. This study evaluated the cost-utility of provision of pre-referral treatments by community health workers compared to similar services at a primary health facility.This was a decision model-based cost-utility analysis, comparing pre-referral antimalarial treatments provided by: community health workers (CHWs), primary health facility, direct access to a tertiary health facility and no access to treatment. A theoretical cohort, of 1000 children, who were below 5 years old; residing in rural hard-to-reach areas, was taken as the reference population. Data was collected through key informant interviews, to assess the costs, while key measures of effectiveness, were obtained from existing studies. The key measure of outcomes was Disability Adjusted Life Years (DALYS) averted. Probabilistic sensitivity analysis was carried out to assess the robustness of the model.Provision of rectal pre-referral treatment by community health workers was estimated to avert 13,276 DALYs, at a cost of $68,428 for a cohort of 1000 children. Provision of rectal pre-referral treatment at a primary health facility was estimated to avert 9993 DALYs, at a cost of $73,826 for a cohort of 1000 children, while going directly to a tertiary health facility was estimated to avert 15,801 DALYs, at a cost of $114,903 for a cohort of 1000 children. The incremental cost effectiveness ratios for provision of pre-referral treatment by community health care and primary health workers were $5.11 and $7.30 per DALYs averted respectively.Use of CHWs was more cost effective than provision of pre-referral treatments at a primary health facility especially, with high referral compliance. Rectal artesunate can easily be administered by community health workers, unlike parenteral pre-referral interventions.

Dataset Information

The age patterns of severe malaria syndromes in sub-Saharan Africa across a range of transmission intensities and seasonality settings.

Background

Methods

Results

Conclusions

Publications

The age patterns of severe malaria syndromes in sub-Saharan Africa across a range of transmission intensities and seasonality settings.

Similar Datasets

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