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Mark Anthony A. Diaz

Mark Anthony A. Diaz, MD

Infectious Disease and Internal Medicine

"Have faith in humanity."

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Office Information

About Me

Infections can affect anyone, from any background, age and walk of life. When you need help, know that Mark Anthony A. Diaz, MD, at Avera Medical Group Infectious Disease Specialists in Sioux Falls, SD, is here to address your infectious condition. Growing up watching his mother who was a pulmonologist and active in various medical missions, Dr. Diaz has been around medicine, clinics and patients since being a young child.

Expert Care for Infections

With a strong love of detective work, Dr. Diaz found that infectious diseases fit his curious personality. He grew up in a third-world country with exposure to preventable and communicable diseases, influencing his choice to pursue medicine. His background in economics contributes to his practice—finding the most effective, efficient treatments for patients. Dr. Diaz treats adults, and helps diagnose and treat infections throughout the entire body.

His specialties include:

  • Infectious diseases
  • Bacterial, mycobacterial, fungal and viral infections, including pneumonia, influenza, STD, HIV/AIDS and prosthetic joint infections
  • Antibiotic stewardship
  • Infection control
  • Vaccination
  • Public health
  • Travel medicine

“Always wash your hands and stay healthy,” Dr. Diaz says to his patients. He enjoys learning about new diseases, giving a holistic aspect of care and making sure that he addresses patients’ primary concerns for their visit. His goal is to prevent and cure communicable diseases.

Active Lifestyle

In his free time, Dr. Diaz enjoys listening to music, playing basketball and watching movies. He also loves spending time with his Siberian husky. He is originally from Manila and speaks Tagalog.



University of Santo Tomas, Manila, Philippines, Medical School


Monmouth Medical Center, Long Branch, NJ, Internal Medicine


Mayo Clinic School of Graduate Medical Education, Jacksonville, FL, Infectious Disease

Professional Memberships

  • Infectious Disease Society of American
  • HIV Medicine Association
  • Society of Hospital Medicine
  • American College of Physicians
  • American Medical Association
  • American Transplant Society

Honors, Awards, etc.

  • Humanism in Medicine Award, Internal Medicine Residency Program - 2017


  • American Board of Internal Medicine
  • American Board of Internal Medicine-Infectious Disease

This directory contains information about the provider members of Independent Health Care Associates, Avera Health and all Avera entities, members of the Avera Medical Group, and employed select providers with Avera McKennan, Sioux Falls, SD and Avera Marshall, Marshall, MN and physicians with hospital privileges at Avera St. Luke's, Aberdeen, SD; Avera Sacred Heart, Yankton, SD; Avera Queen of Peace, Mitchell, SD; Avera St. Mary's, Pierre, SD.

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Moving Health Forward

Avera is a health ministry rooted in the Gospel. Our mission is to make a positive impact in the lives and health of persons and communities by providing quality services guided by Christian values.

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