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. 2024 Sep 14;12(9):1898.
doi: 10.3390/microorganisms12091898.

The Alligator and the Mosquito: North American Crocodilians as Amplifiers of West Nile Virus in Changing Climates

Desiree Kirsten Andersen  1 , Gracie Ann Fischer  1 , Leigh Combrink  1
Affiliations

The Alligator and the Mosquito: North American Crocodilians as Amplifiers of West Nile Virus in Changing Climates

Desiree Kirsten Andersen et al. Microorganisms. .

Abstract

In an age of emerging zoonoses, it is important to understand the intricate system of vectors and reservoirs, or hosts, and their relation to humans. West Nile Virus (WNV) has been detected in a myriad of nonhuman hosts. Transmission of the virus to humans is reliant on amplified seroprevalence within the host, which occurs primarily in birds. However, recent studies have found that other animal groups, including crocodilians, can obtain seroprevalence amplification to levels that make them competent hosts able to transmit WNV to mosquitoes, which can then transmit to humans. Climate change could exacerbate this transmission risk by shifting the distributions of mosquito vectors towards novel geographic ranges. Here, we use maximum entropy models to map the current and future distributions of three mosquito vector species and four crocodilian species in North America to determine the emerging risk of WNV outbreaks associated with changing climates and WNV associated with crocodilians in North America. From our models, we determined that one mosquito species in particular, Culex quinquefasciatus, will increase its distribution across the ranges of all crocodilian species in all tested climate change scenarios. This poses a potential risk to public health for people visiting and living near crocodilian farms and high-density natural crocodilian populations.

Keywords: North America; One Health; West Nile Virus; crocodilian; mosquito; transmission.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Crocodilian distributions in North America. Alligator mississippiensis is represented by teal, Caiman crocodilus by dark blue, Crocodylus acutus by cross-hatching, and Crocodylus moreletii by orange. Image credits: Desiree Andersen (Alligator mississippiensis, Crocodylus acutus), Gautier Poupeau (Crocodylus moreletii; Creative Commons Attribution-Share Alike 3.0 Unported license; https://commons.wikimedia.org/wiki/File:Crocodile_de_Morelet.jpeg, accessed on 4 August 2024), and Gail Hampshire (Caiman crocodylus; Creative Commons Attribution 2.0 Generic license; https://commons.wikimedia.org/wiki/File:Caiman_crocodilus._Spectacled_Caiman_%2842253684125%29.jpg, accessed on 4 August 2024).
Figure 2
Figure 2
Modeling flow and components of this study.
Figure 3
Figure 3
Crocodilian distribution (dark gray) overlaid with three West Nile Virus vector Culex mosquito species’ distributions, representing the greatest overlap for all climate change projections.
Figure 4
Figure 4
Percent of Alligator mississippiensis distribution overlapped with Culex quiquefasciatus through 2100 for four Shared Socioeconomic Pathways (climate change scenarios) and two climate models.
Figure 5
Figure 5
Estimated mosquito richness across North America overlaid with locations of crocodilian farms. Crocodilian farms are categorized as entertainment (or tourism), commercial (hide/meat/hunt), both (entertainment and commercial), or other. Crocodilian farms are listed in Table S9.
See this image and copyright information in PMC

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