Malaria vectors in South America: current and future scenarios.
BACKGROUND
Malaria remains a significant public health issue in South America. Future climate change may influence the distribution of the disease, which is dependent on the distribution of those Anopheles mosquitoes competent to transmit Plasmodium falciparum. Herein, predictive niche models of the habitat suitability for P. falciparum, the current primary vector Anopheles darlingi and nine other known and/or potential vector species of the Neotropical Albitarsis Complex, were used to document the current situation and project future scenarios under climate changes in South America in 2070.


METHODS
To build each ecological niche model, we employed topography, climate and biome, and the currently defined distribution of P. falciparum, An. darlingi and nine species comprising the Albitarsis Complex in South America. Current and future (i.e., 2070) distributions were forecast by projecting the fitted ecological niche model onto the current environmental situation and two scenarios of simulated climate change. Statistical analyses were performed between the parasite and each vector in both the present and future scenarios to address potential vector roles in the dynamics of malaria transmission.


RESULTS
Current distributions of malaria vector species were associated with that of P. falciparum, confirming their role in transmission, especially An. darlingi, An. marajoara and An. deaneorum. Projected climate changes included higher temperatures, lower water availability and biome modifications. Regardless of future scenarios considered, the geographic distribution of P. falciparum was exacerbated in 2070 South America, with the distribution of the pathogen covering 35-46% of the continent. As the current primary vector An. darlingi showed low tolerance for drier environments, the projected climate change would significantly reduce suitable habitat, impacting both its distribution and abundance. Conversely, climate generalist members of the Albitarsis Complex showed significant spatial and temporal expansion potential in 2070, and we conclude these species will become more important in the dynamics of malaria transmission in South America.


CONCLUSIONS
Our data suggest that climate and landscape effects will elevate the importance of members of the Albitarsis Complex in malaria transmission in South America in 2070, highlighting the need for further studies addressing the bionomics, ecology and behaviours of the species comprising the Albitarsis Complex.
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil. gabrielzorelo@usp.br.|Laboratório de Informática Médica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. gabrielzorelo@usp.br.|Setor de Pós-graduação, Pesquisa e Inovação, Faculdade de Medicina do ABC, Santo André, SP, Brazil. gabrielzorelo@usp.br.
Gabriel Zorello
GZ
Laporta
Division of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, USA. LintonY@si.edu.|Walter Reed Biosystematics Unit, Museum Support Center, Smithsonian Institution, Suitland, MD, USA. LintonY@si.edu.|Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. LintonY@si.edu.|Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA. LintonY@si.edu.
Yvonne-Marie
YM
Linton
Division of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, USA. Wilkersonr@si.edu.|Walter Reed Biosystematics Unit, Museum Support Center, Smithsonian Institution, Suitland, MD, USA. Wilkersonr@si.edu.|Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Wilkersonr@si.edu.
Richard C
RC
Wilkerson
Superintendência de Controle de Endemias (SUCEN), Secretaria de Estado da Saúde de São Paulo, Araraquara, SP, Brazil. edusteber@gmail.com.
Eduardo Sterlino
ES
Bergo
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil. sayuri20@usp.br.
Sandra Sayuri
SS
Nagaki
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil. denisecs@usp.br.
Denise Cristina
DC
Sant'Ana
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil. masallum@usp.br.
Maria Anice Mureb
MA
Sallum
D000818:Animals; D000852:Anopheles / Q000254:growth & development* / Q000469:parasitology; D057231:Climate Change; D004772:Entomology; D007303:Insect Vectors / Q000254:growth & development* / Q000469:parasitology; D016778:Malaria, Falciparum / Q000635:transmission; D015233:Models, Statistical; D058974:Phylogeography; D010963:Plasmodium falciparum / Q000302:isolation & purification; D013020:South America / Q000453:epidemiology