Imperial College London
Alternate

DrMartinWalker

Faculty of Medicine, School of Public Health

Honorary Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 3229m.walker06 CV

 
 
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Location

 

G2716 South Wharf RoadSt Mary's Campus

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Summary

 

Publications

Citation

BibTex format

@article{Neves:2021:10.1371/journal.pntd.0009396,
author = {Neves, MI and Gower, CM and Webster, JP and Walker, M},
doi = {10.1371/journal.pntd.0009396},
journal = {PLoS Neglected Tropical Diseases},
pages = {1--16},
title = {Revisiting density-dependent fecundity in schistosomes using sibship reconstruction.},
url = {http://dx.doi.org/10.1371/journal.pntd.0009396},
volume = {15},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The stability of parasite populations is regulated by density-dependent processes occurring at different stages of their life cycle. In dioecious helminth infections, density-dependent fecundity is one such regulatory process that describes the reduction in egg production by female worms in high worm burden within-host environments. In human schistosomiasis, the operation of density-dependent fecundity is equivocal and investigation is hampered by the inaccessibility of adult worms that are located intravascularly. Current understanding is almost exclusively limited to data collected from two human autopsy studies conducted over 40 years ago, with subsequent analyses having reached conflicting conclusions. Whether egg production is regulated in a density-dependent manner is key to predicting the effectiveness of interventions targeting the elimination of schistosomiasis and to the interpretation of parasitological data collected during monitoring and evaluation activities. Here, we revisit density-dependent fecundity in the two most globally important human Schistosoma spp. using a statistical modelling approach that combines molecular inference on the number of parents/adult worms in individual human hosts with parasitological egg count data from mainland Tanzania and Zanzibar. We find a non-proportional relationship between S. haematobium egg counts and inferred numbers of female worms, providing the first clear evidence of density-dependent fecundity in this schistosome species. We do not find robust evidence for density-dependent fecundity in S. mansoni because of high sensitivity to some modelling assumptions and the lower statistical power of the available data. We discuss the strengths and limitations of our model-based analytical approach and its potential for improving our understanding of density dependence in schistosomiasis and other human helminthiases earmarked for elimination.
AU  - Neves,MI
AU  - Gower,CM
AU  - Webster,JP
AU  - Walker,M
DO  - 10.1371/journal.pntd.0009396
EP  - 16
PY  - 2021///
SN  - 1935-2727
SP  - 1
TI  - Revisiting density-dependent fecundity in schistosomes using sibship reconstruction.
T2  - PLoS Neglected Tropical Diseases
UR  - http://dx.doi.org/10.1371/journal.pntd.0009396
UR  - https://www.ncbi.nlm.nih.gov/pubmed/33983965
UR  - https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0009396
UR  - http://hdl.handle.net/10044/1/89373
VL  - 15
ER  -
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