Publications des scientifiques de l'IRD

Rossi J. P., Kadaoure I., Godefroid M., Dobigny Gauthier. (2018). Landscape epidemiology in urban environments : the example of rodent-borne Trypanosoma in Niamey, Niger. Infection Genetics and Evolution, 63, p. 307-315. ISSN 1567-1348.

Titre du document
Landscape epidemiology in urban environments : the example of rodent-borne Trypanosoma in Niamey, Niger
Année de publication
2018
Type de document
Article référencé dans le Web of Science WOS:000442167600040
Auteurs
Rossi J. P., Kadaoure I., Godefroid M., Dobigny Gauthier
Source
Infection Genetics and Evolution, 2018, 63, p. 307-315 ISSN 1567-1348
Trypanosomes are protozoan parasites found worldwide, infecting humans and animals. In the past decade, the number of reports on atypical human cases due to Trypanosoma lewisi or T. lewisi-like has increased urging to investigate the multiple factors driving the disease dynamics, particularly in cities where rodents and humans coexist at high densities. In the present survey, we used a species distribution model, Maxent, to assess the spatial pattern of Trypanosoma-positive rodents in the city of Niamey. The explanatory variables were landscape metrics describing urban landscape composition and physiognomy computed from 8 land-cover classes. We computed the metrics around each data location using a set of circular buffers of increasing radii (20 m, 40 m, 60 m, 80 m and 100 m). For each spatial resolution, we determined the optimal combination of feature class and regularization multipliers by fitting Maxent with the full dataset. Since our dataset was small (114 occurrences) we expected an important uncertainty associated to data partitioning into calibration and evaluation datasets. We thus performed 350 independent model runs with a training dataset representing a random subset of 80% of the occurrences and the optimal Maxent parameters. Each model yielded a map of habitat suitability over Niamey, which was transformed into a binary map implementing a threshold maximizing the sensitivity and the specificity. The resulting binary maps were combined to display the proportion of models that indicated a good environmental suitability for Trypanosoma-positive rodents. Maxent performed better with landscape metrics derived from buffers of 80 m. Habitat suitability for Trypanosoma-positive rodents exhibited large patches linked to urban features such as patch richness and the proportion of landscape covered by concrete or tarred areas. Such inferences could be helpful in assessing areas at risk, setting of monitoring programs, public and medical staff awareness or even vaccination campaigns.
Plan de classement
Santé : généralités [050] ; Entomologie médicale / Parasitologie / Virologie [052] ; Urbanisation et sociétés urbaines [102]
Description Géographique
NIGER ; NIAMEY
Localisation
Fonds IRD [F B010073793]
Identifiant IRD
fdi:010073793
Contact