Our Doctors

Frank Kostolitz

Dr. Frank Kostolitz (Hospital Owner)

Dr. Frank Kostolitz attended the University of Parma in Italy where he received his  DVM. He started practicing veterinary medicine in Middletown in 1984, providing  care to both small and large animal medicine and surgery, and in 1990 he  established Yalesville Veterinary Hospital in Wallingford, CT.

Dr. Kostolitz's main goal is to provide a stress and fear free environment to our  patients big and small and to their owners.  The hospital was designed so as to  provide separate exam rooms and treatment areas for different species which is at the core of Dr. Kostolitz's holistic approach to veterinary medicine.  His belief in maintaining the human/animal bond is evident in both the way he practices as well as communicating this belief to all the staff here at Yalesville. 

Dr. Kostolitz is also committed to keeping his hospital current, both in medical technology and staff training.  His interest in cutting edge medicine enables the doctors, staff and our clients access to some of the latest technologies available.  Keeping current with advancing medical technology affords the veterinarians at Yalesville the opportunity to provide optimum care not often found at privately owned hospitals.

Dr. Kostolitz lives in Cheshire with his wife, 3 children, Stella their greyhound, and 2 cats.  His outside interests include, travel, theater, food, and motorcycles. 

Dr. Lisa Saravis (Medical Director)

Lisa Saravis

Dr. Lisa Saravis is a Connecticut native. She obtained her Bachelor’s Degree in Biochemistry graduating cum laude from Connecticut College.

She was inducted into the Society of Phi Zeta, the Honor Society of Veterinary Medicine while attending veterinary school and graduated cum laude from the University of Pennsylvania School of Veterinary Medicine in 1994.

Dr. Saravis went on to practice small animal medicine in North Haven for the next eleven years before joining Yalesville Veterinary Hospital. She is the past president of the New Haven County Veterinary Medical Association and enjoys spending her free time with her family, horses and her cat Brownie.

ocallaghanDr. Jill O’Callaghan

Dr. Jill O’Callaghan is a Connecticut native. She grew up in New Canaan, CT and graduated from Wake Forest University in North Carolina with a degree in Biology in 1997.

She then attended Kansas State University where she received her D.V.M. degree in 2002. Upon graduation she worked at a small animal hospital in New London for seven years before joining the Yalesville staff in August 2009.

Her clinical interests include internal medicine, surgery and acupuncture. She is a certified veterinary acupuncturist through the International Veterinary Acupuncture Society.

Dr. O’Callaghan is also an adjunct faculty member at Middlesex Community College, where she teaches part-time in the veterinary technology program. She lives in Guilford with her husband, children and a dog named Maggie.


Dr. Robert Hallock

Dr. Robert Hallock is a 1969 graduate of the University of Pennsylvania School of Veterinary Medicine. He was the owner of Meriden-Wallingford Veterinary Associates from 1971 until 2014 when both hospitals merged. We are thrilled to have him on our staff!

Dr. Hallock has served on the board of directors for the Fidelco Guide Dog Federation as well as serving as their staff veterinarian. He has also been very active in Retriever Field Trials – having bred, trained and competed with his own Labrador, Flat Coated and Curly Coated Retrievers.

Dr. Hallock was also on the executive board of the Connecticut Veterinary Medical Association for 8 years. Currently he is a member of the Connecticut Veterinary Medical Association, the New Haven County Veterinary Medical Association, the American Association of Feline Practitioners and the executive board of the Connecticut Boxer Club.

His current interest is in the breeding of Boxers and competing in Obedience and Conformation events. Over the years, he and his wife have had 13 Champions, two of which were nationally ranked in the top 20.


Dr. Dana Muir-Preston

Dr. Dana Muir-Preston is originally from upstate New York. She received her BS in Animal Science from Cornell University’s College of Agriculture and Life Sciences in 2007 and her MPS in Animal Science with a focus on Canine Hip Dysplasia from Cornell University’s College of Agriculture and Life Sciences in 2009. She graduated with her DVM from Cornell University’s College of Veterinary Medicine in 2012. She practiced small animal medicine in upstate NY for 3 years before moving to Connecticut and joining the team at Yalesville Veterinary Hospital.

Dr. Muir likes to build relationships with her clients and patients, and enjoys doing house calls as well as regular office calls. She is enthusiastic about continuing education courses to stay up-to-date on the latest recommendations in veterinary medicine. She also enjoys community outreach and general public education about pet care and common issues that can arise during a cat or dog’s lifetime - you may see her from time to time at the Wallingford community center, or notice her name in the byline of some of our blog entries. In her off time, she enjoys cooking, exploring fun and beautiful places in Connecticut (and beyond!), and spending time with both her human and her canine family members.

Catherine Donewald

Dr. Catherine Donewald

Dr. Catherine Donewald grew up in Wallingford, CT and is very excited to be back "home" at Yalesville Vet. Prior to and during college she worked at Yalesville Veterinary Hospital, starting in 2006, in a variety of positions including Veterinary Technician. Her love for working with and helping animals directed her to UCONN where she received her bachelor's degree in Animal Science, Dr. Donewald then went on to Kansas State University and graduated from their College of Veterinary Medicine. Her special interests include animal dermatology and internal medicine. 

While Dr. Donewald is very passionate about veterinary medicine and providing the best care to her patients, she seeks to always make every visit to Yalesville positive for her clients as well. Dr. Donewald is a member of the American Veterinary Medical Association.

When she is not caring for patients at Yalesville, Dr. Donewald enjoys spending time with her family and friends, watching movies, and going to the beach. She lives in Wallingford with her husband and cat, Motzi, where they recently purchased a house and are enjoying working at making it their home.

Dr. Resa McLellan

Dr. Resa McLellan

Dr. Resa McLellan is a native of the Naugatuck Valley and is fulfilling her lifelong dream of serving as a veterinarian. She received a Bachelor of Arts degree in Biological Sciences with a cell and molecular concentration from Connecticut College. She then attended the University of Pennsylvania School of Veterinary Medicine, where she obtained her VMD degree.

During the course of her education, Dr. Resa was passionate about cancer research and participated in several programs, including fellowships at Yale Medical School and Penn Medical School. She also engaged in a wide variety of animal experiences, including rehabilitation of seals and beluga whales at the Mystic Aquarium, veterinary care at the Beardsley Zoo, and performing pregnancy ultrasounds on alpacas and llamas in the Andes Mountains of Peru. 

Dr. Resa’s clinical interests include soft tissue surgery, oncology, and exotics medicine. She would be more than happy to meet your guinea pig, rabbit, ferret, or hamster! Apart from the hospital, she enjoys art, singing, and playing various musical instruments. She also participates in running road races in the community, alongside members of the Yalesville Veterinary Hospital staff.

Dr. Sarah Dale

Sarah Dale

Dr. Sarah Dale was born and raised in the suburbs of Boston, Massachusetts. She graduated from Bowdoin College with a degree in Biochemistry in 2011 and went on to attend the Cummings School of Veterinary Medicine at Tufts University . Upon graduation in 2015 Dr. Dale also earned her Masters in Public Health. 

She is very excited to be working with the Yalesville Veterinary Hospital team. Dr. Dale has a strong interest in preventative health including nutrition and weight management. She also has a special interest in dermatology.  

In her free time Dr. Dale enjoys reading in her hammock, working in her garden, going skiing or rowing when possible, and playing with her family's Tibetan Spaniel named Stella

Dr. Molly Chirunomula

Molly Chirunomula

Coming soon!