Assessing the risk of West Nile Virus seasonal outbreaks and its vector control in an urbanizing bird community : an integrative R-0-modelling study in the city of Merida, Mexico

2023

Article référencé dans le Web of Science WOS:001000100400003

Flores-Ferrer A., Suzan G., Waleckx Etienne, Gourbiere S.

PLoS Neglected Tropical Diseases, 2023, 17 (5), p. e0011340 [21 p.] ISSN 1935-2735

Urbanization is a global trend associated with key socio-economic issues, one of them being to control the transmission of infectious diseases to a urban fraction of the world's population that shall reach 68% in 2050. While urban growth has been shown to favor mosquito species responsible for the transmission of the West Nile Virus (WNV), a major human arbovirosis, the effects of concomitant changes in the host bird communities remain hard to anticipate albeit essential to quantify disease risk and to plan control initiatives. We developed a R0 modelling of WNV transmission in a urban bird community to assess the risk of outbreak in Merida, one of the cities with the highest growth rate in Mexico. The model was parameterized using ecological and epidemiological data collected over the past 15-years on the local vector, Culex quinquefasciatus, and avian community. We identified a 3-weeks summer period during which the vector population strongly amplifies the WNV enzootic transmission and lead to a significant risk of outbreaks in humans. Extensive sensitivity analyses showed that urbanization induced changes in the bird community could lead to an up-to 6-fold increase in the duration of the risk period, while the daily risk could rise by 40%. Interestingly, the increase in Quiscalus mexicanus abundance had 4-5 times larger impact than any other change in the bird community. In such a context, annihilating the current and future risk of WNV outbreaks in Merida requires reducing the mosquito population by 13% and up to 56%, respectively. This study provides an integrative assessment of the current and future risks of WNV outbreak in the fast urbanizing city of Merida, and points toward the implementation of epidemiological monitoring combined with preemptive measures targeting both C. quinquefasciatus and Q. mexicanus populations, as they are expected to have synergistic effects. Author summaryUrbanization is a major trend in human evolution. By 2050, over 2/3 of the world population will live in urban areas. A key challenge associated with such a global trend is to protect urban residents against infectious diseases, while their environment may provide favourable conditions for parasites and other pathogens. The West Nile Virus (WNV) is a typical vector borne pathogen whose transmission to human is expected to be facilitated in urban environments, where mosquitoes transmitting the virus are favored. Here, we looked at the barely known effects of changes in the host bird community on the risk of WNV outbreak in humans. By designing empiricaly informed mathematical models of WNV transmission in the city of Merida, Mexico, we identified a 3-weeks summer period during which the virus circulation in urban birds lead to a risk of outbreaks in humans. Further analyses showed that changes in the bird community could increase the risk period up-to 6-fold and rise the daily risk by 40%. Such variations are primarily driven by the increase in a key reservoir species, Quiscalus mexicanus, whose effects are 4-5 times larger than those of other changes in the bird community. To control the current and future risks of WNV outbreaks in Merida requires reducing the mosquito population by 13% and up to 56%, respectively. These results strongly call for an epidemiological monitoring and preemptive measures targeting both C. quinquefasciatus and Q. mexicanus populations, as they are expected to have synergistic effects.

Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Entomologie médicale / Parasitologie / Virologie [052] ; Urbanisation et sociétés urbaines [102]

MEXIQUE ; MERIDA

Fonds IRD [F B010088175]

fdi:010088175