title: Biodiversity can help prevent malaria outbreaks in tropical forests.
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 non-vector 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.
  
  
  RESULTS
  The Ross-Macdonald model and a biodiversity-oriented model were parameterized using newly collected data and data from the literature. The basic reproduction number ([Formula: see text]) 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
  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.
authors.affiliation: Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, São Paulo, Brazil. gabrielzorelo@usp.br
authors.forename: Gabriel Zorello
authors.initials: GZ
authors.lastname: Laporta
authors.forename: Paulo Inácio Knegt
authors.initials: PI
authors.lastname: Lopez de Prado
authors.forename: Roberto André
authors.initials: RA
authors.lastname: Kraenkel
authors.forename: Renato Mendes
authors.initials: RM
authors.lastname: Coutinho
authors.forename: Maria Anice Mureb
authors.initials: MA
authors.lastname: Sallum
mesh_terms: D000818:Animals; D044822:Biodiversity; D001938:Brazil; D004196:Disease Outbreaks / Q000517:prevention & control*; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D005260:Female; D006801:Humans; D016780:Malaria, Vivax / Q000517:prevention & control* / Q000635:transmission*; D008962:Models, Theoretical; D014197:Trees; D014329:Tropical Climate
references.citation: Acta Trop. 2006 Nov;100(1-2):54-62
references.pmid: 17126279
references.citation: Nature. 2010 Dec 2;468(7324):647-52
references.pmid: 21124449
references.citation: Front Zool. 2010 Jan 21;7:3
references.pmid: 20205866
references.citation: Parasit Vectors. 2010 Dec 03;3:117
references.pmid: 21129198
references.citation: Parasitology. 2012 Jun;139(7):847-63
references.pmid: 22336330
references.citation: Acta Trop. 2008 Aug;107(2):179-85
references.pmid: 18620330
references.citation: Parasit Vectors. 2011 May 25;4:89
references.pmid: 21612587
references.citation: Parasit Vectors. 2010 Aug 16;3:72
references.pmid: 20712879
references.citation: PLoS One. 2008 Jun 25;3(6):e2488
references.pmid: 18575599
references.citation: Am J Trop Med Hyg. 1946 Jan;26:47-66
references.pmid: 21018584
references.citation: Proc Biol Sci. 2009 May 7;276(1662):1657-63
references.pmid: 19203926
references.citation: Rev Soc Bras Med Trop. 2010 Jan-Feb;43(1):52-8
references.pmid: 20305969
references.citation: Proc Natl Acad Sci U S A. 2006 Feb 14;103(7):2452-7
references.pmid: 16461902
references.citation: J Parasitol. 1974 Oct;60(5):874-83
references.pmid: 4430956
references.citation: Trends Parasitol. 2010 Mar;26(3):130-6
references.pmid: 20056485
references.citation: Malar J. 2003 Sep 19;2:32
references.pmid: 14565850
references.citation: Bull Math Biol. 2008 Jul;70(5):1272-96
references.pmid: 18293044
references.citation: Mem Inst Oswaldo Cruz. 2011 Aug;106 Suppl 1:239-45
references.pmid: 21881779
references.citation: PLoS Med. 2011 Jan 25;8(1):e1000406
references.pmid: 21311579
references.citation: Am J Trop Med Hyg. 2002 Jan;66(1):18-22
references.pmid: 12135261
references.citation: Rev Saude Publica. 1986 Feb;20(1):1-20
references.pmid: 3749771
references.citation: Nature. 2000 May 11;405(6783):228-33
references.pmid: 10821283
references.citation: Malar J. 2007 Mar 19;6:33
references.pmid: 17371598
references.citation: PLoS Med. 2011 Jan 25;8(1):e1000401
references.pmid: 21311587
references.citation: Proc Natl Acad Sci U S A. 2009 Oct 6;106(40):17067-70
references.pmid: 19805081
references.citation: PLoS One. 2009;4(5):e5461
references.pmid: 19421313
references.citation: PLoS Negl Trop Dis. 2011 Jun;5(6):e1160
references.pmid: 21738804
references.citation: Malar J. 2010 Apr 30;9:115
references.pmid: 20433744
references.citation: Lancet. 2012 Feb 4;379(9814):413-31
references.pmid: 22305225
references.citation: Proc Natl Acad Sci U S A. 1974 May;71(5):2141-5
references.pmid: 4525324
references.citation: Proc Biol Sci. 2009 Nov 22;276(1675):3911-9
references.pmid: 19692412
references.citation: Malar J. 2007 Sep 19;6:127
references.pmid: 17880709
references.citation: Trends Parasitol. 2001 Dec;17(12):578-81
references.pmid: 11756041
references.citation: Science. 2010 Jul 16;329(5989):276-7
references.pmid: 20647446
references.citation: PLoS Med. 2010 Aug 03;7(8):e1000303
references.pmid: 20689800
references.citation: PLoS Pathog. 2012;8(4):e1002588
references.pmid: 22496640