Imperial College London

DrJoelHellewell

Faculty of MedicineSchool of Public Health

Research Associate
 
 
 
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Contact

 

j.hellewell14

 
 
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Location

 

Sir Alexander Fleming BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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3 results found

Hellewell J, Walker P, Ghani A, Rao BV, Churcher Tet al., 2018, Using ante-natal clinic prevalence data to monitor temporal changes in malaria incidence in a humanitarian setting in the Democratic Republic of Congo, Malaria Journal, Vol: 17, ISSN: 1475-2875

BackgroundThe number of clinical cases of malaria is often recorded in resource constrained or conflict settings as a proxy for disease burden. Interpreting case count data in areas of humanitarian need is challenging due to uncertainties in population size caused by security concerns, resource constraints and population movement. Malaria prevalence in women visiting ante-natal care (ANC) clinics has the potential to be an easier and more accurate metric for malaria surveillance that is unbiased by population size if malaria testing is routinely conducted irrespective of symptoms. MethodsA suite of distributed lag non-linear models was fitted to clinical incidence time-series data in children under 5 years and ANC prevalence data from health centres run by Médecins Sans Frontières in the Democratic Republic of Congo, which implement routine intermittent screening and treatment (IST) alongside intermittent preventative treatment in pregnancy (IPTp). These statistical models enable the temporal relationship between the two metrics to be disentangled. ResultsThere was a strong relationship between the ANC prevalence and clinical incidence suggesting that both can be used to describe current malaria endemicity. There was no evidence that ANC prevalence could predict future clinical incidence, though a change in clinical incidence was shown to influence ANC prevalence up to 3 months into the future. ConclusionsThe results indicate that ANC prevalence may be a suitable metric for retrospective evaluations of the impact of malaria interventions and is a useful method for evaluating long-term malaria trends in resource constrained settings.

Journal article

Guelbeogo WM, Goncalves BP, Grignard L, Bradley J, Serme SS, Hellewell J, Lanke K, Zongo S, Sepulveda N, Soulama I, Wangrawa DW, Yakob L, Sagnon N, Bousema T, Drakeley Cet al., 2018, Variation in natural exposure to anopheles mosquitoes and its effects on malaria transmission, ELIFE, Vol: 7, ISSN: 2050-084X

Journal article

Gonçalves BP, Kapulu MC, Sawa P, Guelbéogo WM, Tiono AB, Grignard L, Stone W, Hellewell J, Lanke K, Bastiaens GJH, Bradley J, Nébié I, Ngoi JM, Oriango R, Mkabili D, Nyaurah M, Midega J, Wirth DF, Marsh K, Churcher TS, Bejon P, Sirima SB, Drakeley C, Bousema Tet al., 2017, Examining the human infectious reservoir for Plasmodium falciparum malaria in areas of differing transmission intensity., Nature Communications, Vol: 8, ISSN: 2041-1723

A detailed understanding of the human infectious reservoir is essential for improving malaria transmission-reducing interventions. Here we report a multi-regional assessment of population-wide malaria transmission potential based on 1209 mosquito feeding assays in endemic areas of Burkina Faso and Kenya. Across both sites, we identified 39 infectious individuals. In high endemicity settings, infectious individuals were identifiable by research-grade microscopy (92.6%; 25/27), whilst one of three infectious individuals in the lowest endemicity setting was detected by molecular techniques alone. The percentages of infected mosquitoes in the different surveys ranged from 0.05 (4/7716) to 1.6% (121/7749), and correlate positively with transmission intensity. We also estimated exposure to malaria vectors through genetic matching of blood from 1094 wild-caught bloodfed mosquitoes with that of humans resident in the same houses. Although adults transmitted fewer parasites to mosquitoes than children, they received more mosquito bites, thus balancing their contribution to the infectious reservoir.

Journal article

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