Plasmodium vivax, one of the causative agents of human malaria, causes untold morbidity and mortality in the developing world [1]. Despite the importance of P. vivax for human health and the importance of vector control as part of any malaria control program, there has been little research on the interactions between mosquitoes and the parasite. This lack of knowledge is largely due to our inability to grow P. vivax in culture, meaning we depend on human samples for any work with this parasite [2]. In this project, we will partner with the Armed Forces Research Institute of Medical Sciences in Bangkok, Thailand to give us access to P. vivax infected blood. We will use this blood to infect both transgenic mosquitoes with an increased immune response and wild-type mosquitoes. The transgenic mosquitoes we will take are highly resistant to P. falciparum infection [3], and this study will allow us to determine whether the same immune responses are responsible for resistance to P. vivax as P. falciparum, thereby covering the two main pathogens that cause human malaria. We will also gather samples of infected wild-type mosquitoes on which we will perform transcriptomic analysis using microarrays to identify the global transcriptomic changes following infection with P. vivax. This information will allow us to determine the major mosquito immune-pathways responsible for P. vivax resistance and provide us some much needed knowledge about the interactions between this important parasite and its mosquito vector.