Marcelo Nascimento Burattini,
Francisco Antonio Bezerra Coutinho, and
First author: School of Veterinary Medicine, University of São Paulo, São Paulo, SP, Brazil; second, third, and fourth authors: School of Medicine, University of São Paulo and LIM 01-HCFMUSP, São Paulo, SP, Brazil; and fourth author: London School of Hygiene and Tropical Medicine, UK.
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Accepted for publication 4 June 2010.
In this article, we propose a mathematical model that describes the competition between two plant virus strains (MAV and PAV) for both the host plant (oat) and their aphid vectors. We found that although PAV is transmitted by two aphids and MAV by only one, this fact, by itself, does not explain the complete replacement of MAV by PAV in New York State during the period from 1961 through 1976; an interpretation that is in agreement with the theories of A. G. Power. Also, although MAV wins the competition within aphids, we assumed that, in 1961, PAV mutated into a new variant such that this new variant was able to overcome MAV within the plants during a latent period. As shown below, this is sufficient to explain the swap of strains; that is, the dominant MAV was replaced by PAV, also in agreement with Power's expectations.
© 2010 The American Phytopathological Society