Guadalupe Family Health, PA is the name chosen for the combined Family Medicine practices of Dr. Arlynn Hartfiel (retired), Dr. David Rider, Dr. James Rider, DO, Dr. Joseph Schuerger, Dr. Mark Mangiapane and Cassandra Fossler, PA. Dr. David Rider founded the practice in 2009 when he took over Dr. Jim Lee’s thriving practice of over 30 years at Dr. Lee’s retirement.  Dr. David Rider welcomed his younger brother Dr. James Rider into the practice in 2012. Dr. Arlynn Hartfiel joined the Drs. Rider after completion of our new building, Guadalupe Medical Park, in June 2014 after serving the community in private practice for over 30 years.  Dr. Joseph Schuerger migrated back to Texas in February 2016 and Dr. Mark Mangiapane joined our practice in August 2016.  Cassandra Fossler joined the practice as a Physician Assistant in August 2015.

For obvious reasons, staff and patients refer to “Dr. David” and “Dr. James” when referring to one of the Dr. Rider brothers.  Feel free to refer to our other providers by Dr. Joey, Dr. Mark and PA Cassie.

Our clinical support staff include Linda Leibovitz, LVN, Carolyn Whitener, LVN, Amanda Urquiza, LVN, Samantha Talamantez, MA, and Gaby Pence, MA.  Our Practice Administrator is Lisa Schulze.  Our administrative support team include Julie Lind, Ruby Serna, Emily Holz, and Yady Leal.

Meet Our Staff

David Rider, M.D.


Dr. Rider comes to Seguin from Waco, where he held the title of Chief Resident and completed a three year residency in Family Medicine.  Prior to residency, Dr. Rider attended medical school at the University of Texas Medical Branch at Galveston, and was one of his class’ most decorated graduates.  In addition to being one of two students awarded the school’s most prestigious scholarship as a second year medical student (the Osler Student Scholarship), Dr. Rider received a Pisacano Scholarship as a third year student by the American Board of Family Medicine.  This award is given to a handful of Family Medicine students in the country each year and is meant to promote future leaders of the Family Medicine specialty.

Prior to medical school, Dr. Rider engaged in a wide-ranging career in public health which led him to live in four different Latin American Countries directing a variety of public health and health education oriented projects.  As a consequence, Dr. Rider is bilingual in Spanish, speaks Portuguese conversantly, and knows more about building latrines than young man from Central Texas by any rights should.  He was born in Houston, raised in Austin, and graduated with dual majors in Political Science and Healthcare Policy Analysis from Rice University.

James Rider, D.O.

Physician, Osteopath

James Rider was born in Houston, Texas, grew up in Austin, and on the Texas coast. He finished college in Sherman, Texas, at Austin College. He then attended Kirksville College of Osteopathic Medicine, in Missouri, where he met his wife, Amber. After a three year residency in Family Medicine and Osteopathic Manipulative Treatment, he moved back to Texas with his wife and son, Liam, in 2012. Here, he joined Guadalupe Family Health and Guadalupe Regional Medical Center. Dr. James enjoys spending time at home with his family, including a second son, Aedan, and getting down to the coast whenever possible.

Joseph Schuerger, M.D.


Dr. Schuerger was born and raised in Southeast Missouri. He joined the United States Air Force in February 2000 and spent most of his military career in San Antonio. He served as a medical laboratory technician graduating with honors in both phase I and phase II of his technical training and earned an Associate of Applied Science Degree in Medical Laboratory Science in 2003. In 2006, Dr. Schuerger received his Bachelor of Science degree graduating Summa Cum Laude from Park University. He was honorably discharged from the Air Force in 2007 so he could attend medical school at the University of Missouri-Columbia School of Medicine (Mizzou). He graduated medical school in 2011 after being elected to the Alpha Omega Alpha Honor Medical Society. Dr. Schuerger completed his Family Medicine Residency in Muncie, Indiana at Indiana University Health Ball Memorial Hospital in 2014. There he received the American Academy of Family Physicians/Bristol Myers Squibb Award for Excellence in Graduate Medical Education, a national award given to only 12 family medicine residents each year. Dr. Schuerger practiced medicine in his home town of Poplar Bluff, Missouri after graduating residency for almost two years before heading back down to Texas to join the staff at Guadalupe Family Health. He is board certified in Family Medicine and is an active member of the American Academy of Family Physicians.

In his spare time, Dr. Schuerger enjoys martial arts and holds a 3rd degree black belt in the style of Bak Yong Kong Soo Do. He also enjoys grilling, basketball (GO SPURS GO) and crossfit. Dr. Schuerger and his wife, Jancee, live in Seguin and have one daughter, Karastyn, and one step-son, Trevor.

Mark Mangiapane, D.O.

Physician, Osteopath

Dr. Mark Mangiapane attended The University of Arizona, where he majored in Physiology and minored in Chemistry. He then attended Nova Southeastern University and earned his Doctor of Osteopathic Medicine degree in 2011. After graduating, he completed his Family Medicine residency in 2014 at Genesys Regional Medical Center in Grand Blanc, Michigan. He was awarded the 2014 Society of Teachers of Family Medicine Resident Teacher Award upon graduation. He then joined the teaching faculty at the same residency.

Prior to joining Guadalupe Family Health in 2016, Dr. Mangiapane was a Clinical Associate Professor at Michigan State University College of Osteopathic Medicine. He is Board Certified to practice Family Medicine and Osteopathic Manipulation. He holds membership in the American Osteopathic Association, the American Academy of Family Physicians, and the American College of Osteopathic Family Physicians.

Dr. Mangiapane met his wife, Dr. Maansi Doshi, in medical school and her specialty is Otolaryngology and Facial Plastic Surgery. His hobbies include basketball, golf, running, and playing guitar.

Cassandra Fossler, PA-C, MPAS

Physician Assistant

Cassandra Fossler, PA-C, MPAS, was raised in the small town of Kenedy, TX. Cassandra began her education at Our Lady of the Lake University where she graduated with a Bachelor of Science in Biology and was a member of the Sigma Zeta National Honor Society. She subsequently was accepted into The University of Texas Health Science Center at San Antonio where she received a Master of Physician Assistant Studies.

Cassandra Fossler is a fellow member of the Bexar County Physician Assistant Society, American Academy of Physician Assistants, and an associate member of the Texas Academy of Physician Assistants.

In her spare time, she enjoys exercising, music, traveling, camping, and spending time with her two daughters, Iris and Kara, her son, Kagen, and husband Jared.

Cassandra is thrilled to provide quality healthcare to the City of Seguin and surrounding communities.

“I believe that the greatest gift you can give your family and the world is a healthy you.” ~ Joyce Meyer