Help with motivation letter for masters in epidemiology

Hello all,
here is what they want: In approximately 400-500 words, describe the reasons for wanting to be enrolled in the above-mentioned programs of your choice (one statement per major). In addition, state your current career objectives and how you expect the programs to enhance your career options.

I need someone to review my letter. I think I need to shorten it (521 words currently) but not sure how to do it. Please comment- I'm open to criticism

Thank you.

My desire of serving needy people in the Middle East and Africa as a physician took me to the United States to study Biological Sciences. I first started Biotechnology program in XX Community College, then I transferred to University xx to finish my undergraduate degree in Biological Sciences. I developed a strong background in science through my studies. I was absolutely fascinated by the complex mechanisms behind diseases and the relationship between humans and causes of the health problems in the courses Microbiology, Immunology, Parasitic Diseases and Humans, and Ion Channels and Diseases. I also took Calculus and Statistics classes because I enjoyed them and wanted to increase my analytical skills, even though they were not program requirements. My undergraduate research required demanding laboratory work, data analysis, reading articles and writing papers; time management was a bonus skill I gained through it.

When I heard about Epidemiology and Public Health during my undergraduate years, I realized that medical school may not be the only way to reach my goal of working in the health field. To get some hands-on experience and to make a final decision about the path I will take, I took a break from my studies. I had the opportunity to do attachment at the xx in Libya. I feel exceptionally fortunate to be involved in a center that focuses on HIV/AIDS in a MENA region country. I witnessed doctors, Public Health experts, social workers, and other professionals working together to protect the population from this horrible disease as well as treating the affected. The symposiums, conferences, and workshops I attended shifted my future educational plans toward Public Health field. I came to believe that it was much more efficient to work on preventive measures for the population rather than trying to treat a limited number of sick individuals. I set my mind upon Epidemiology as I got a deeper understanding of its role in Public Health. The data entry experience for a survey done by xx University for HIV/AIDS National Strategic Framework taught me that to establish a good Public Health policy, the level and concentration of the health problem should be assessed first. It also drew my attention to the interdisciplinary nature of Epidemiology. I find it both challenging and exciting to combine biology, statistics, and social science to address a health problem. To finalize my decision, I consulted with many doctors and NGO workers; and I was happy by their approval and encouragement.

In the future, I want to work as an epidemiologist for NGOs in the Middle East and Africa. The MS program in Epidemiology in XX Uni is the perfect place for me. The university is known for its long-established excellence in education. Being located in the Middle East, it will allow me to focus on the epidemiology in the region. I certainly have the required education, experience, and motivation to successfully complete the program. I also have the advantage of belonging to the region; my familiarity with the culture, practices, and sensitive issues will help me with approaching problems.

Thank you for your consideration and hope to hear your positive response.
Sincerely,