Evidence map›Paper›PMID 30728063›Full record

ArticleParasites & vectors2019

Environmental factors associated with the distribution of Loa loa vectors Chrysops spp. in Central and West Africa: seeing the forest for the trees.

Xavier Badia-Rius, Hannah Betts, David H Molyneux, Louise A Kelly-Hope

Open access · goldAbstract read
In one paragraph

Article in Parasites & vectors, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
0.3field-weighted citation impact, top 44% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed, 6 citations in OpenAlex.

  1. Geospatial analysis ofJournal of parasitic diseases : official organ of the Indian Society for Parasitology · 2025
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors at 1 institution in 1 country.

Xavier Badia-RiusDepartment of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
Hannah BettsDepartment of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
David H MolyneuxDepartment of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
Louise A Kelly-HopeDepartment of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK. Louise.Kelly-Hope@lstmed.ac.uk.ORCID http://orcid.org/0000-0002-3330-7629
Liverpool School of Tropical Medicine · GB

Funding

Department for International Development, UK Government NilErasmus+ Nil
6 · The paper itself

Abstract

backgroundLoiasis is caused by the filarial parasite Loa loa, which is widespread through Central and West Africa and largely confined the tropical equatorial rainforests. The tabanid flies Chrysops silacea and Chrysops dimidiata are the main vectors driving transmission. This study aimed to better define the spatial distribution and ecological niche of the two vectors to help define spatial-temporal risk and target appropriate, timely intervention strategies for filariasis control and elimination programmes.

methodsChrysops spp. distributions were determined by collating information from the published literature into a database, detailing the year, country, locality, latitude/longitude and species collected. Environmental factors including climate, elevation and tree canopy characteristics were summarised for each vector from data obtained from satellite modelled data or imagery, which were also used to identify areas with overt landcover changes. The presence of each Chrysops vector was predicted using a maximum entropy species distribution modelling (MaxEnt) method.

resultsA total of 313 location-specific data points from 59 published articles were identified across seven loiasis endemic countries. Of these, 186 sites were included in the climate and elevation analysis, and due to overt landcover changes, 83 sites included in tree canopy analysis and MaxEnt model. Overall, C. silacea and C. dimidiata were found to have similar ranges; annual mean temperature (24.6 °C and 24.1 °C, respectively), annual precipitation (1848.6 mm and 1868.8 mm), elevation (368.8 m and 400.6 m), tree canopy cover (61.4% and 66.9%) and tree canopy height (22.4 m and 25.1 m). MaxEnt models found tree canopy coverage was a significant environmental variable for both vectors.

conclusionsThe Chrysops spp. database and large-scale environmental analysis provides insights into the spatial and ecological parameters of the L. loa vectors driving transmission. These may be used to further delineate loiasis risk, which will be important for implementing filariasis control and elimination programmes in the equatorial rainforest region of Central and West Africa.

Indexed as

EnvironmentAfrica, CentralAfrica, WesternAnimalsDipteraInsect ControlInsect VectorsLoaLoiasisRainforestTreesAfricaChrysops dimidiataChrysops silaceaClimateEcologyEnvironmentLoa loaLoiasisMaxEntRainforest

Identifiers

PMID30728063
PMCPMC6366063
OpenAlexW2913772306

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.