The mathematical model proposed here applies to the Brazilian Amazon region, where the seasonal fluctuation of the mosquito density is clearly observed. The main vector of this region is the Anopheles darlingi, and its latent period is directly linked to the environment temperature. The mathematical model also considers different treatment levels accessible to the infected people. We believe that as the malaria treatment already exists it should be important to concentrate efforts on this theme in order to provide guidelines for the success of malaria control. The numerical simulations show the seasonal fluctuation effects and the relationship between the increase in temperature and treatment efficiency. Particularly it is shown that an increase in temperature strongly affects the latent period, reducing drastically the health care efficiency. (c) 2007 Elsevier B.V. All rights reserved.