Biodiversity Can Help Prevent Malaria Outbreaks in Tropical Forests

Author(s)

Laporta, Gabriel Zorello ^[1] ; Knegt Lopez de Prado, Paulo Inacio ^[2] ; Kraenkel, Roberto Andre ^[3] ; Coutinho, Renato Mendes ^[3] ; Mureb Sallum, Maria Anice ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Saude Publ, Dept Epidemiol, BR-01255 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Ecol, Sao Paulo - Brazil

^[3] Univ Estadual Paulista, Inst Fis Teor, Sao Paulo - Brazil

• Document type: Journal article
• Source: PLoS Neglected Tropical Diseases; v. 7, n. 3 MAR 2013.
• Web of Science Citations: 26

Abstract

Background: Plasmodium vivax is a widely distributed, neglected parasite that can cause malaria and death in tropical areas. It is associated with an estimated 80-300 million cases of malaria worldwide. Brazilian tropical rain forests encompass host- and vector-rich communities, in which two hypothetical mechanisms could play a role in the dynamics of malaria transmission. The first mechanism is the dilution effect caused by presence of wild warm-blooded animals, which can act as dead-end hosts to Plasmodium parasites. The second is diffuse mosquito vector competition, in which vector and nonvector mosquito species compete for blood feeding upon a defensive host. Considering that the World Health Organization Malaria Eradication Research Agenda calls for novel strategies to eliminate malaria transmission locally, we used mathematical modeling to assess those two mechanisms in a pristine tropical rain forest, where the primary vector is present but malaria is absent. Methodology/Principal Findings: The Ross-Macdonald model and a biodiversity-oriented model were parameterized using newly collected data and data from the literature. The basic reproduction number (R-0) estimated employing Ross-Macdonald model indicated that malaria cases occur in the study location. However, no malaria cases have been reported since 1980. In contrast, the biodiversity-oriented model corroborated the absence of malaria transmission. In addition, the diffuse competition mechanism was negatively correlated with the risk of malaria transmission, which suggests a protective effect provided by the forest ecosystem. There is a non-linear, unimodal correlation between the mechanism of dead-end transmission of parasites and the risk of malaria transmission, suggesting a protective effect only under certain circumstances (e. g., a high abundance of wild warm-blooded animals). Conclusions/Significance: To achieve biological conservation and to eliminate Plasmodium parasites in human populations, the World Health Organization Malaria Eradication Research Agenda should take biodiversity issues into consideration. (AU)

• FAPESP's process: 05/53973-0 - Systematics of the Anopheles (Nyssorhynchus) (Diptera: Culicidae)
• Grantee: Maria Anice Mureb Sallum
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 10/09464-1 - Structured populations dynamics
• Grantee: Renato Mendes Coutinho
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/09939-5 - Understanding the effects of landscape and biodiversity on dynamics of malaria transmission
• Grantee: Gabriel Zorello Laporta
• Support Opportunities: Scholarships in Brazil - Post-Doctoral