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, Dr. Joseph Schuerger, Cassandra Fossler, PA-C, Madelyn Woods, PA-C and Megan Wenzel, APRN, NP-C.

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, retiring from private practice in February 2016.  Dr. Joseph Schuerger migrated back to Texas in February 2016 and Cassandra Fossler joined the practice as a Physician Assistant in August 2015.  In July 2018, we expanded our practice by opening an office in New Braunfels.  Nurse Practitioner, Megan Wenzel, joined Guadalupe Family Health’s Seguin office in August 2019.  Beginning September 1st, 2019, Dr. David Rider is available in Seguin on Mondays and in New Braunfels Tuesday through Friday where he shares the office with Madelyn Woods, PA-C, who sees patients in our New Braunfels location, Monday through Friday.  Dr. Sullivan sees patients in New Braunfels every Monday, and Seguin Tuesday through Thursday.

Our clinical support staff includes medical assistants Shannon Kohl (Dr. David), Samantha Talamantez (PA Cassie), Angel Flores (Dr. Schuerger), Magalie Garcia (PA Mady), Jennifer Lagunas (NP Megan) and Stephanie Scott (Dr. James).  Dr. Sullivan’s nurse is Katrina Harper.  Our administrative support team includes Julie Lind, Ruby Juarez, Emily Holz, Lyndsey Ormond, Stacey Pfeil and Julia Herrera.  Our Practice Administrator, Lisa Schulze, has been with Guadalupe Family Health since March 2014.

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.

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

Madelyn Woods, MPAS, PA-C

Physician Assistant

Madelyn Woods, MPAS, PA-C was raised in a small West Texas town called Monahans. Madelyn received her Bachelor of Science in Biology from the University of Texas Permian Basin, where she graduated Summa Cum Laude and was a member of the National Society for Leadership and Success. She was then admitted into the physician assistant program at The University of Texas Rio Grande Valley in Edinburg, TX where she received a Master of Physician Assistant Studies. She is board certified through the National Commission on Certification of Physician Assistants.

Mady is a member of the Texas Academy of Physician Assistants and the American Academy of Physician Assistants.

In her spare time, Mady enjoys spending time with her dogs Mory and Mila. She likes to run, hike, take hot yoga classes, and play her Nintendo Switch.  She ended up settling here in this area to spend time with her retired grandparents who live in Seguin, TX. She also loves to spend time at the beach in Rockport, TX with her parents and brother.

Megan Wenzel, APRN, FNP-C

Nurse Practitioner

Megan Wenzel, APRN, FNP-C was born in Muleshoe, Texas. Raised in the West Texas area, Megan relocated to New Braunfels with her family and graduated from New Braunfels High School. Megan started her medical career as a Pharmacy Technician just out of High School. She went on to receive an Associate of Applied Science in Nursing from Del Mar College in Corpus Christi, TX and started her Nursing career. Megan then graduated with a Bachelor of Science in Nursing from UT Arlington before completing her Masters in Science in Nursing – Family Nurse Practitioner at UT Arlington.

While working on her Nursing career, Megan also became a Mommy, her most coveted role. She spends her days with two beautiful daughters Haley and Lillian plus her loving husband Michael. All are busy in many extracurricular activities including youth sports, swimming, exercising and traveling extensively.

Megan has lived and worked in the New Braunfels/Seguin areas as a Nurse since 2012. She is an accredited member of the American Association of Nurse Practitioners.

Linda Sullivan, D.O.


Our GFH family continues to blossom with the addition of Dr. Linda Sullivan July 1st! Dr. Sullivan has practiced in Seguin for 11 years and will be serving patients in both of our locations.  Originally from Oklahoma, Dr. Sullivan is a graduate of The University of North Texas Health Science Center, where she completed their Rural Track Program for Family Medicine. She completed a three-year residency in Family Medicine at the Waco Family Medicine Residency Program in Waco, Texas, where she served as Chief Resident in her final year of training. Dr. Sullivan also holds a Master’s Degree in Music (cello performance) and performed frequently with the Mid-Texas Symphony Orchestra in Seguin before starting her medical training. She lives in Seguin with her husband and their daughters and is excited to join our amazing team at Guadalupe Family Health.