Sidney C. Ontai, M.D., MBA

Sidney C. Ontai, M.D., MBA

Assistant Professor, Texas A&M College of Medicine

Dr. Ontai is a full time Texas A&M clinical faculty and a director of DeTar Healthcare System's family medicine residency program. He has been in practice for 30 years, in private rural practice for a community clinic and as faculty in three previous family practice residencies at the University of California - Irvine, University of Southern California and Texas Tech University.

A graduate of Harvard University, Dr. Ontai received his medical degree from the University of Hawaii Medical School, and obtained an MBA from the University of California –Los Angeles. He is certified by the American Board of Family Medicine.

Dr. Ontai has a special interest in reversing and preventing diabetes, coronary artery disease and other chronic illnesses with whole plant based diets and water only fasting. He also uses telemedicine to see patients in rural West Texas communities and to expose residents to this important clinical tool.


Mark L. Stevens, M.D.

Mark L. Stevens, M.D.

Assistant Professor, Texas A&M College of Medicine

Dr. Stevens brings 25 years of family medicine experience, including time spent in private practice, to the residency clinic.

Dr. Stevens received his medical degree from the University of Texas Medical School in San Antonio, and completed his residency at San Jacinto Methodist Hospital in Baytown. He worked as Clinical Preceptor for the University of Texas Medical Branch School of Medicine where he was named UTMB’s Preceptor of the Year. He is certified by the American Board of Family Medicine.

Dr. Stevens is a Victoria native, having been born at DeTar Hospital, and he is dedicated to the health and well-being of the people of this area. He is particularly interested in diabetes prevention and management.


Manju Sachdev M.D.

Manju Sachdev, M.D.

Clinical Assistant Professor at Texas A&M

Dr. Manju Sachdev is a Board Certified Pediatrician who was born and raised in Newfoundland, Canada. She began her career in Victoria, Texas as a private practitioner. Her aspiration to learn more about the administrative aspects of medicine led her to join Driscoll Children’s Hospital Quick Care Clinic Victoria as their Medical Director, while continuing to balance a private practice. After being approached about developing the pediatric facet of Detar Hospital’s Family Medicine Residency program, Dr. Sachdev immediately took a proactive role by volunteering to teach the residents about common pediatric illnesses. She subsequently transitioned into joining as a faculty member; her enduring enthusiasm has since led to the tremendous growth and development of the program’s pediatric component, thus etching the realm of pediatrics as a key and integral part of the curriculum.

In addition to her dedication to medicine, Dr. Sachdev has a vast array of interests which she has incorporated into her existence as a wife, mother and a physician. One of her most telling moments was as a participant in the 2004 Mrs. Texas-America Pageant when she was asked by one of the judges how a woman of her ethnicity could fit into the traditional norm to become a pageant title holder in the state of Texas. She creatively replied, “The fundamental beauty of Texas lies in its acceptance and diversity, and that is what has brought me this far.” That statement earned her a ‘top ten’ title, making her one of the first Indo-American women to place in a state-wide national pageant. This renewed sense of self-confidence instilled a yearning to pursue her other interests, including a passion for public speaking, thus lending a national television health series to her name as host, writer and producer.

Indian Classical and Bollywood-style dancing has been engrained “in her blood” from a very young age, and to showcase that, she choreographed and performed in an unprecedented medical parody video in 2019 titled One Sikh with the celebrity physician ZDoggMD alongside the Detar Family Medicine residents.

Dr. Sachdev is a strong proponent of the beliefs of Mahatma Gandhi who beautifully stated that, “The best way to find yourself is to lose yourself in the service of others.” This attitude is reflected in her multitude of philanthropic projects, including helping to raise funds for the victims of Hurricane Harvey, being a strong supporter of the American Veteran’s Association, and supporting numerous animal rights and rescue groups.


Mtarajan Venkatayan, M.D.

Natarajan Venkatayan, M.D.

Clinical Assistant Professor at Texas A&M

Dr. Venkatayan is a full time Texas A&M clinical faculty, who works at DeTar Family Medicine residency program. He has been in medical practice for 15 years, in various capacities. He is very compassionate, respectful and listens to his patients giving them at most attention with dedication, aiming to bring a change in their health.


Shae Castaneda M.D.

Shae Castaneda, M.D.

Julia Shae Krause-Castaneda, M.D., is a native of Karnes City, Texas and attended Texas A&M University at Galveston receiving her undergraduate degree in Marine Biology and minor in Chemistry. She obtained her medical degree at Texas Tech University Health Science Center in Lubbock, Texas. Dr. Krause-Castaneda completed her training at Texas A&M Family Medicine Residency Program in Bryan/College Station, Texas, where she was chief resident.

She is a full scope, board certified, family medicine physician with special interest in gynecology and obstetrics including prenatal and postnatal care. Medicine is ever changing as we have witnessed through the current pandemic. She feels that it is important to have soundly educated physicians with a passion for lifelong learning that can be practiced in a compassionate, empathetic, evidence-based manner.

Dr. Krause-Castaneda currently is a member of the Texas Medical Association Rural Health Committee. She is also involved in numerous committees throughout the community including the Area Go Texan Committee. She feels that it is important to be involved in the community of which you live and practice medicine in order to bring measurable positive change.

Dr. Krause-Castaneda and her husband Eliezer Castaneda, MD, who is also a family medicine physician, are excited to be here in Victoria and are happy to be raising their two young children here.


Deke Eberhard M.D.

Deke Eberhard, M.D.

Dr. Eberhard is a native Texan, originally from New Braunfels, where he grew up. He is the first physician in his family, and developed an interest in medicine after overcoming childhood leukemia at a young age. In a way, Dr. Eberhard feels that medicine found him. He graduated from New Braunfels High School in 2004, and went on to attend Texas A&M University in College Station, where he graduated with a Bachelor of Science (B.S.) in Biology and a Bachelor of Science (B.S.) in Kinesiology. He then completed a Master of Science (M.S.) in the Medical Sciences from the University of North Texas Health Science Center, Graduate School of Biomedical Science in Forth Worth. He completed his Doctorate of Medicine (M.D.) from the University of Medicine and Health Sciences, St. Kitts and earned a Master of Business Administration (M.B.A.) in Healthcare Management from Davenport University in Grand Rapids, Michigan. He completed his residency training here in Victoria with DeTar Family Medicine Program. Toward the end of his training he was offered a position as core faculty, which he felt would be a great opportunity to help further the success the Detar Family Medicine Program and continue to serve the community here in Victoria. His hobbies include fishing, hunting and rooting on his favorite team, the Fightin’ Texas Aggies. He believes in a well-rounded approach to patient care and enjoys educating, not only future physicians, but his patients as well, as knowledge is often the key to a healthy lifestyle.