Annapolis • (410) 224-0121
Towson • (410) 828-0911
Columbia • (410) 441-3304


Mark E. Hitt, DVM, MS

Diplomate American College of Veterinary Internal Medicine - Specialty of Internal Medicine In 1992, Dr. Mark E. Hitt started Atlantic Veterinary Internal Medicine in Annapolis, Maryland. Dr.Hitt was born in Rockville, Maryland. He graduated from Iowa State University in 1979 with his Doctor of Veterinary Medicine degree. After working in general, small animal veterinary practices in Fort Lauderdale, FL and Richmond, VA, for 4 years he decided to continue his education and was accepted to a residency program in veterinary internal medicine at the University of Missouri College of Veterinary Medicine. This program was completed in 1986. Dr.Hitt was invited to apply for the first internal medicine position at a new veterinary college, the Atlantic Veterinary College at the University of Prince Edward Island in Canada. In this role, he participated in the development of the clinical facilities and curriculum from the ground up. This was a unique and rewarding experience. He then went on to serve terms as chief of the internal medicine section, head of the critical care unit, lecturer in several areas of internal medicine, and the leader of the small animal practice rotations for senior students. During his stay with the AVC, Dr. Hitt earned an MS degree in the Department of Pathology and Microbiology. Promotion to associate professor and tenure were granted in 1991. But after almost seven years, the Hitt family decided it was time to move back "south" to the United States. In 1992, Atlantic Veterinary Internal Medicine joined  with other specialty groups in Annapolis to form the umbrella organization of Chesapeake Veterinary Referral Center, LLC. The second center was opened in the Baltimore area in 1998, joining the Annapolis location.  Doctor Hitt has contributed as an author for  many  textbooks on topics of internal medicine and has published many articles in the veterinary literature over the past years. In past years, he also served as a reviewer for veterinary journals. He continues to be invited as a contributor to veterinary textbooks and frequently lectures on topics of Veterinary Internal Medicine at local, regional, and national veterinary meetings. Although practicing in all areas of internal medicine, his particular interests are in endoscopy, abdominal ultrasound, and diseases of the gastrointestinal tract and liver.

  • 1979-Doctor of Veterinary Medicine - Iowa State University
  • 1979-1983-general small animal veterinary practices in Ft. Lauderdale and Richmond
  • 1983-1986-Residency Certificate in Veterinary Internal Medicine - University of Missouri
  • 1986-1996-Diplomate of the American Board of Veterinary Practitioners
  • 1987-current-Diplomate of the American College of Veterinary Internal Medicine - Specialty of Internal Medicine
  • 1986-1992-Assistant Professor Atlantic Veterinary College, UPEI
  • 1991-Associate Professor with Tenure Atlantic Veterinary College, UPEI
  • 1992-Master of Science - Atlantic Vet College, Department of Pathology & Toxicology
  • 1992-current-Atlantic Veterinary Internal Medicine started in Annapolis
  • 1998-current-Atlantic Veterinary Internal Medicine expanded to Towson


John P. Paola, DVM   back to top ^

Dr. Paola is a native of Pittsburgh (Go Steelers!) and a graduate of the Michigan State University (Go Spartans!) College of Veterinary Medicine.  He worked as a general veterinary practitioner in Pittsburgh for two years after graduation, before moving on to an internship at the Ohio State University (Go Buckeyes!).  This served as a springboard to a residency in small animal internal medicine, also at Ohio State. He passed the certifying examination for the American College of Veterinary Internal Medicine upon the completion of his residency.  After three years as an internist in Pittsburgh, he moved to Annapolis and joined AVIM in 1997.


A project completed during his residency allowed him to develop a strong interest and ability in gastrointestinal endoscopy and disorders of the GI tract.  While other areas of special interest include hypercalcemia and hematologic disorders, Dr. Paola has maintained a broad interest in many aspects of small animal internal medicine.


Outside the clinic, his life is enriched by his wife and their two young daughters. The newest additions to the family are two guinea pigs, Snickers and Marshmallow.   Dr. Paola is a very proud third-generation Italian-American, and recent travel to Italy has advanced his interest in the Italian language and all things Italian


Janet L. Peterson, DVM, MS   back to top ^

Diplomate American College of Veterinary Internal Medicine, - Specialty of Oncology Dr. Peterson is a native of Texas. She completed a veterinary residency in oncology with "the" Ohio State University's College of Veterinary Medicine. She passed her specialist examinations in 1994. After that she has been recruited to practice in specialty veterinary cancer medicine in California, Texas, Kansas, and finally Maryland. She is now a  happy "Marylander". Dr. Peterson deals with all areas of veterinary oncology and works with the other specialists of the referral center as well as other specialists in the region to create an integrative multimodality approach to the treatment of cancer. She believes in providing and discussing with owners all options of treatment for cancer before a decision is made as to  which plan is appropriate for your pet.


Deb Klaser, DVM   back to top ^

Diplomate American College of Veterinary Internal Medicine - Specialty of Internal Medicine Dr. Klaser grew up in Southern California and attended veterinary school at the University of Georgia, graduating in 2000. She completed both her internship and residency in internal medicine at the Animal Medical Center in New York City. Dr. Klaser enjoys spending time with her two young children, husband, and loving yellow Labrador, Caribou. She also loves to cook and take advantage of the opportunities for family activities that the region provides.


Adam Gonzales, DVM   back to top ^

Diplomate American College of Veterinary Internal Medicine - Specialty of Internal Medicine Dr. Gonzales was a specialist in northern Virginia until relocating to be with Atlantic Veterinary Internal Medicine in 2005. He completed his residency training at the Veterinary College at Tufts University. He has strong interests in urinary diseases and diagnostic tests and procedures. He is  skilled at endoscopy and diagnostic laparoscopy. But, as with all of our internists, he maintains interests and skills  in all aspects of veterinary internal medicine. He is also an avid snow boarder and has not hurt himself much, yet.


AVIM of Towson Veterinarians:

Dan J. Petrus, DVM   back to top ^

Diplomate American College of Veterinary Internal Medicine - Specialty of Internal Medicine Dr. Petrus completed an internship at North Carolina State University and a three year residency with the veterinary college at the University of Wisconsin. He joined AVIM after a 3 year teaching fellowship with the Royal College of Veterinary Medicine in London, England. Dr. Petrus  has traveled extensively in the world, having lived and visited about every continent.  This continues to be a pursuit in his out of clinic time. He also bikes a lot in the Baltimore area.  Dr. Petrus has a strong interest in medical endocrinology (study of hormonal related diseases) and their interactions with other diseases and disorders of the body. But he likes all areas within internal medicine and sees a diversity of problem cases. _______________________________________________________

Nivia Martinez, DVM   back to top ^

Diplomate American College of Veterinary Internal Medicine - Specialty of Internal Medicine Dr. Martinez was born and raised in Puerto Rico. She graduated Magna Cum Laude from the University of Puerto Rico, Rio Peidras Campus, with a major in Biology in 1988. She received her D.V.M. degree in 1992 from The Ohio State University, in Columbus, Ohio. After graduation from veterinary school, she worked at a private practice in Michigan. After one year in private practice, she went to Purdue University, in West Lafayette, Indiana, to complete a one year rotating internship in Small Animal Medicine and Surgery. She then went back to Puerto Rico, where she gained invaluable experiences as a general practitioner that serve her well now as a specialist. In 1999, she returned to the United States for a Small Animal Internal Medicine Residency and graduate studies at the Virginia-Maryland Regional College of Veterinary Medicine, in Blacksburg, Virginia. She conducted research on the pathophysiology of hypertension in canine hyperadrenocorticism as part of her graduate studies. During her residency, she was awarded the Bente Flatland Memorial Award in recognition of her clinical abilities and compassion toward pets and owners. She completed her residency and was awarded a masters degree in Veterinary Clinical Sciences in 2002. She became board certified in Internal Medicine in 2002. Dr. Martinez stayed at the VMRCVM as a Clinical Instructor in the areas of Neurology and Internal Medicine for one year. She joined AVIM in August of 2003 and likes all areas of veterinary internal medicine and many of the wonderful activities that living in the Baltimore area allows



Dr. Anthony Calo, DVM, 

Practice Limited to Oncology 

Dr. Tony Calo, originally from New Jersey, joined Atlantic Veterinary Internal Medicine & Oncology in August of 2011. Dr. Calo attended Rutgers University and obtained a degree in animal science, then stayed on at Rutgers for 2 years after graduation doing nutrition research in the animal science department. Dr. Calo graduated from the Ross School of Veterinary Medicine. He did his clinical training at The University of Minnesota College of Veterinary Medicine, and then completed a rotating small animal internship there. Prior to his residency, he was in private practice in New York City at the West Chelsea Veterinary Hospital. Then Dr. Calo went to  Tufts University School of Veterinary Medicine to complete extensive training in feline mammary gland carcinoma, lymphoproliferative disorders, neuroendocrine tumors, and  medical oncology.

Dr. Calo has a special interest in the human-animal bond, and has worked for Pets Are Wonderful Support San Francisco (PAWS – SF). During his time there, he worked on the Healthy Pets, Healthy People project, as well as completed a client based survey study and was honored with the Jules and Lucy Silver Animal Bedside Manner Award. His approach to veterinary oncology deals with the medical aspects of chemotherapy, immunotherapy, and radiation therapy.



Dr. Mariah Frank, DVM, Internal Medicine 


Dr. Mariah Frank was born in Germany on a military base and has lived at bases all over the United States. Her family settled in Maryland in 1994 and she earned a bachelors in animal science from the University of Maryland College Park in 2001.She earned her veterinary degree from Ross University in 2007 after spending 3 years in St Kitts and finishing her year of clinical work at The Ohio State University. Following graduation she completed a 1 year rotating medicine and surgery internship at Metropolitan Veterinary Hospital in Akron, Ohio. She then completed a 1 year internal medicine internship and 3 year internal medicine residency with Northeast Ohio Internal Medicine in Akron, Ohio.

When she is not working, Dr. Frank enjoys spending time with her furry friends: Meisha, (shepherd mix), Piper (Jack Russell Terrier), and Luna (an island dog she picked up while going to school at St. Kits). She also enjoys horseback riding, hiking and rock climbing.



AVIM of Columbia Veterinarians: 


Frederic Jacob, DVM, PhD   back to top ^

Diplomate of the American College of Veterinary Internal Medicine - Frederic Jacob is a graduate of the University of Montreal and grew up in Quebec, Canada. After obtaining his veterinary medical degree in 1995, he pursued an internship in Small Animal Medicine and Surgery at Washington State University. In 1996, he was accepted in a combined Residency/PhD program in Veterinary Internal Medicine at the University of Minnesota. In 2000, Dr. Jacob was certified as a Diplomate of the American College of Veterinary Internal Medicine (small animal). During his PhD program, Dr. Jacob and colleagues published several significant studies that helped identify key factors (such as diet, high blood pressure and increased protein in the urine) that play an important role in the progression of kidney (renal) failure, survival time and quality of life for dogs with kidney  failure and other urological (kidney related) diseases. It is during his Residency/PhD program that Dr. Jacob developed his keen interest in studying hypertension and diseases of the kidneys with attention to the interactive treatment options in dogs with chronic renal diseases. In 2002, this genuine interest led him to pursue a post-doctoral fellowship to investigate the interactive role of specific areas of the brain and the kidneys in the long-term control of blood pressure. His training in internal medicine and special interest in urological diseases of dogs and cats is complemented by  the dedicated staff of the Atlantic Veterinary Internal Medicine group in Towson.

Dr. Jacob enjoys very active sports including many triathalons.  He lives in the central Maryland area with his wife and twin sons. 



Michelle Silver, DVM   back to top ^

Diplomate American College of Veterinary Internal Medicine, - Specialty of Oncology. 

Dr. Silver is a native of New Jersey. She graduated from Salisbury University in 2000 (when it was still Salisbury State University) and went to veterinary school at Iowa State University from 2000-2004. She went on to complete a rotating internship at Regional Veterinary Referral Hospital in Springfield, VA in 2005 and was accepted into their oncology internship from 2005-2006. Dr. Silver was fortunate to be accepted into Dr. Khanna’s program at Friendship Hospital for Animals in Washington, DC and worked for a year gaining knowledge in clinical trials and research until she was accepted for residency in 2007. She completed her 3 year residency program and board certification in 2010 at New England Veterinary Oncology Group in Massachusetts and stayed on as one of their medical oncologists until 2016 when she relocated with her husband, Jason, back to his home state of Maryland.  They are very happy to be back in Maryland with their 3 rescue dogs Flanders, Grace and Pipsqueak and their turtle Flash.

Dr. Silver has known she wanted to be a veterinarian since she was 8 years old and is so happy to be living out her dream of helping people and their pets. Her passion for oncology came when her own dog was diagnosed with cancer while she was in veterinary school.  “The bond you share with your clients is unlike most other specialties and it is one of the things I love most about this profession”. Dr. Silver is excited to meet and work with the veterinarians in the Columbia area to help provide the best care for every patient.  She believes in providing and discussing with owners all options of treatment for cancer before a decision is made as to which plan is appropriate for your pet.In her spare time, Dr. Silver enjoys any outdoor activity, especially if it is on the water. She and her husband are avid hikers. She also is a big sports fan and has been watching and cheering on the Nationals since they came back to DC in 2005.


Bookmark and Share

News & Events

Columbia Location NOW open!!

 Questions and Answers about Ebola and Pets – CDC guidelines

CVRC Sponsored Continuing Education Events

Laparoscopy at CVRC!  

Diagnostic Endoscopy, Endoscopic Interventional Procedures & Urethral Collagen Injections

Advanced Imaging for your pet - MRI or CT?

Talks and Travels

Advanced Medical Care at AVIM

Grief Counseling Discussion Group through AVIM

Publications Relating to AVIM&O's Doctors



Conveniently located in
Annapolis and Towson.
Map and Directions . . .
Atlantic Veterinary Internal Medicine & Oncology, LLC
808 Bestgate Road, Annapolis, MD 21401
(410) 224-0121
1209 Cromwell Bridge Road, Towson, MD 21286
(410) 828-0911
10000 Old Columbia Rd, Columbia, MD 21046 (410) 441-3304
© 2016 Atlantic Veterinary Internal Medicine, LLC
_______________________________________________________________ _________