Our Team

Andrea J. Alejo, MD
Andrea J. Alejo, MDDr. Alejo received her medical degree from Pontificia Universidad Catolica Madre y Maestra in the Dominican Republic before spending a year serving a rural clinic there. She then moved to the U.S. to complete an internal medicine residency at Lincoln Medical and Mental Health Center in the Bronx, New York. Dr. Alejo is board certified by the American Board of Internal Medicine.

With a passion for underserved populations, geriatrics and post-acute care, Dr. Alejo takes an individualized, interdisciplinary approach to internal medicine for all ages. This means her treatment decisions are informed by a larger understanding of her patients, their environments and their lives. Dr. Alejo's bilingual skills are also valuable in her mission to reach out to those who may be afraid of going to the doctor.

Shortly after she was born in the Dominican Republic, Dr. Alejo's family moved to New York City, where they stayed for 12 years before returning to the island. Although familiar with New York, Dr. Alejo was more attracted to living and practicing in Virginia, especially the coastal location of Gloucester, where she and her husband now enjoy residing. Her interests include reading, music and dancing.


David Alpert, M.D.
David Alpert, M.D.After receiving a B.A. in biology from the University of Virginia, Dr. Alpert earned his medical degree from the Tufts University School of Medicine in Boston. He completed an internship and residency in internal medicine at the Medical College of Virginia Hospital. He is board certified by the American Board of Internal Medicine, with additional board certification in emergency medicine.

With 30 years of experience in emergency and general internal medicine, Dr. Alpert passionately shares Riverside's mission "to care for others as we would care for those we love." His own cancer diagnosis as a young resident enabled him to personally identify with how it feels to be a patient, shaping his medical philosophy accordingly.

Kassem Khreis, M.D.
Kassem Khreis, MD Dr. Khreis received his initial training in the Ukraine, earning a medical degree from Zaporozhye State Medical University before completing an internal medicine/cardiology residency as well as an interventional cardiology fellowship. After moving to the U.S., he completed an internal medicine residency at the Jamaica Hospital Medical Center in New York as well as a geriatric medicine fellowship at the University of Texas Medical Branch at Galveston. Dr. Khreis is board certified by the American Board of Internal Medicine with certification in geriatric medicine.

Dr. Khreis' devotion to internal medicine and working with older adults stems from his father's struggle with heart problems, diabetes and blindness that led to depression and a fall that ultimately killed him at age 76. This motivates Dr. Khreis to get to know each of his patients, treating more than diseases but the whole person, including their safety and health at home.

A native of Lebanon, Dr. Khreis now resides in Gloucester with his wife. The couple enjoys exploring the outdoors--fishing, hiking Beaverdam Park near the Gloucester Village, traveling throughout Virginia and getting to know the Middle Peninsula.


Francisco X. Valls, MD
Dr. VallsDr. Valls graduated from Francisco Marroquin University and completed his residency at Berkshire Medical Center. He is board-certified by the American Board of Internal Medicine.




Peter Zullo, MD
Dr. ZulloDr. Zullo graduated from Georgetown University School of Medicine and completed his residency at Albany Medical Center. He is board-certified by the American Board of Internal Medicine. Dr. Zullo chose internal medicine as his specialty because it allows him to provide for all the health needs of his patients. He enjoys working in Gloucester because he can take the time to get to know each patient on a personal level.