Meet Our Team!

Meet the veterinarians & team of All Pet Animal Hospital! We’re pleased to provide exceptional vet care for your pets!

Get to Know Our Team!

We are solely dedicated to your pet’s care! We look forward to getting to know you and hope you’ll take the time to scroll down and get to know us.


Dr. Samantha Burkhart
Dr. Stephen Treese

Medical Director

Dr. Treese grew up outside of New Orleans and earned his Bachelor’s and Master’s degrees at Louisiana State University. He continued his education at the University of Missouri, earning his Doctor of Veterinary Medicine degree in 2015. Dr. Treese has special interests in orthopedic surgery and ultrasound. Also, he enjoys working closely with wildlife rehabilitators and animal rescue groups.  Dr. Treese has an amusing pet family at home. He has a St. Bernard, Cypress, a blind husky, Blizzard, and two chinchillas. Also, while he never planned to have cats, he now has three: Mama Jame, Orca, and Fluffy Xena.  When Dr. Treese is not caring for animals, he enjoys spending time in his garden. He grows an assortment of roses, pumpkins, and melons. Dr. Treese also tends to three saltwater fish tanks!

Dr. Carolee W. Switalski
Dr. Carolee W. Switalski


Dr. Switalski is a graduate of the University of Georgia, College of Veterinary Medicine. She has over 17 years of experience working with zoos and exotic animals, and for the past ten years, she has been working as a relief veterinarian in the local area. Currently, she spends two days per week at APAH, focusing on canine and feline medicine.

Dr. Switalski is married with three adult children and four cats and loves cooking, traveling, boating, bicycling, and spoiling her grandson.

Veterinary Office Staff

Linda Marlin

Practice Manager

Passionate about pets, people and creating positive work environments, Jen loves the diverse and rewarding encounters that come with her role at All Pet Animal Hospital after 7 years of veterinary practice management experience. Beyond her love for animals, Jennifer finds relaxation in capturing moments through photography, exploring the great outdoors, and cherishing quality time with her two amazing teenagers.

Linda Marlin

Lead Customer Service Representative

Kerri has been in the veterinary industry for over 15 years with experience including: emergency medicine, dermatology, cardiology and dentistry. She is also a proud Veteran of the United States Air Force. When she is not delivering amazing customer service at All Pet Animal Hospital she enjoys camping, traveling and spending quality time with her family; which consists of her husband, 2 boys and a set of spoiled Pitbulls.

Diane Johnstone

Customer Service Representative

After a wide variety of previous occupations, Diane decided the veterinary field was the place for her, and she has been with APAH since 2002. She performs a variety of duties around the hospital and has developed a great client relationship with many of APAH’s regular clientele. Diane is a mother of one and grandmother of two and takes care of one African Grey and one Chi-Weiner dog.

Diane Johnstone

Customer Service Representative

Morgan has been with us since she graduated from Slippery Rock University in 2021 with a degree in Healthcare Administration.  She is currently only with us on Saturdays as a receptionist and works at Dicks Sporting Goods Corporate during the week!  In her free time, Morgan enjoys riding horses.  She has two pets of her own, a Golden Retriever, Maddie who is 14 years young, and a French Bulldog, Stone who is 3 months old, as well as a leased horse named Mocha.

Linda Marlin

Customer Service Representative/Vet Assistant

Bio coming soon!

Veterinary Nursing Staff

Lynne Schiller


Lynne had spent a number of years as an Information Technology Project Manager when she decided to go back to school for a career change. Lynne volunteered at APAH while attending the Vet Tech Institute of Pittsburgh and completed externships with PVS-EC (a 24-hour emergency veterinary hospital) and the Pittsburgh Zoo. She has been a Veterinary Technician with APAH since Oct 2016 and passed her certification exam in Dec 2016.

Lynne is the proud owner of one very talkative cat.

Nina Collavo


Nina graduated from the Vet Tech Institute in February of 2021 and recently passed her state board exam in December. She completed her externship with us, and her interest in exotics has led her to a full-time position. She has always dreamt of a career with animals and is very happy to be a part of the All Pet team.

Nina has two pets of her own; “Baxter,” a Beagle she adopted through West Deer Dog Shelter, and “Puff,” the noisy and retired office kitty.

Linda Marlin
Vet Assistant

A veterinary assistant at All Pet Animal Hospital who is dedicated to the well-being of our furry friends. A proud pitbull advocate and fur-parent to a lively crew of 12 dogs, 3 cats, and 10 rabbits. When not at work, you can find her relaxing in the great outdoors with her loving husband and three great kids.

Linda Marlin
Vet Assistant

Pittsburgh native with a Montana spirit, Mikayla enjoys working with the diverse animals that frequent All Pet Animal Hospital. Her two dogs keep her on her toes while she pursues a bachelor’s degree. When she’s not caring for horses or studying, you can find her traveling to new places, camping or exploring nature.

Linda Marlin

Vet Assistant

Claire came to work with us in the summer of 2023. She graduated the Vet tech institute in January 2021 and is currently working on becoming a certified technician. Claire is fascinated by exotics and loves cuddles from her feline and canine patients as well. When she is not at All Pet, Claire can be found with a coffee and sketch pad while relaxing with her 2 dogs, Millie and Huckleberry.