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Center for Gastroenterology & Metabolic Diseases
Seneca Hill Health Services Center
105 Co. Rt 45A
Suite 400
Oswego, NY
Phone: 315.312.0089
Map and driving directions

Our specialists at the Center for Gastroenterology & Metabolic Diseases offer the highest quality of care for a wide spectrum of diseases and disorders affecting the gastrointestinal (GI) tract, which includes the esophagus, stomach, liver, gallbladder, bile ducts, pancreas, intestines, colon and rectum.

Common conditions treated:

  • Cancers of the digestive system
  • Gastroesophageal reflux disease (GERD) (Barrett's esophagus)
  • Heartburn/reflux
  • Swallowing and esophageal disorders (achalasia)
  • Abdominal pain
  • Gallstones
  • Biliary stones, stricture and leaks
  • Pancreatitis
  • Peptic ulcer disease
  • Inflammatory bowel disease (IBD)
  • Celiac disease
  • Diverticular disease
  • Tumors and growths of the digestive system
  • Intestinal obstruction
  • Cirrhosis of the liver
  • Hepatitis (A, B, C)
  • Screening for colon cancer
  • NASH—nonalcoholic steatohepatitis
  • Anorectal disease (hemorrhoids, anal fissure, anorectal abscess and fistula)


Mohammad Fahad Ali, MD

Dr. Mohammad Fahad Ali has experience treating a variety of gastroenterology diseases and has a special interest in GI motility and inflammatory bowel disease (IBD). Prior to joining Oswego Health, he has worked at the Guthrie Cortland Medical Center, where he served as the Chair of the Department of Medicine and the Chief of Endoscopy since 2021.

Earning his medical degree at SUNY Stony Brook University of Medicine in 2012, Dr. Ali completed his post-graduate training along with Chief Residency and Fellowship at the New York University Langone Hospital in Long Island. He served as a Trainee in the GI Motility Laboratory of Temple University Lewis Katz School of Medicine in Philadelphia. He earned his Bachelors in Biological Sciences from Columbia University in 2006.

Dr. Ali is board certified in Gastroenterology and Internal Medicine. He is a member of the American College of Gastroenterology and President of the Cortland County Medical Society. He is a member of the American College of Gastroenterology’s Research Committee, and in 2021 he was recognized by the ACG as a Young Physician Leadership Scholar.

Since 2013 he has published several research and scholarly articles and maintains his own Medical Blog, Musings on Medicine.

Suri Karthikeyan, MD

Dr. Suri Karthikeyan has nearly 30 years of experience treating a variety of gastroenterology diseases in addition to performing advanced endoscopy procedures.

Earning his medical degree at Madras Medical College, located in Chennai, India, Dr. Karthikeyan has quite an extensive clinical background including Resident in Internal Medicine at various NHS hospitals in the UK and obtained specialist certification in Internal Medicine, MRCP(UK) by the Royal College of Physicians of the United Kingdom, followed by Residency in Gastroenterology in Leicester.

Subsequently he pursued an Internal Medicine Residency and Gastroenterology Fellowship at McMaster University in Ontario, Canada, and obtained specialist certifications in Internal Medicine and Gastroenterology, FRCP(C) by the Royal College of Physicians and Surgeons of Canada followed by board certifications in Internal Medicine and Gastroenterology by the American board of Internal Medicine.

For the past 26 years, he has been in private practice in both New London, Connecticut, and Rochester, NY from 2001-2020. In addition to clinical work, Dr. Karthikeyan has been very involved in teaching medical students and medical residents at the University of Rochester and Unity Hospital of Rochester. Dr. Karthikeyan is board certified in Gastroenterology and is a member of American College of Gastroenterology.

Ajoy Roy, MD

Dr. Ajoy Roy has been practicing gastroenterology care for the more than 30 years in Oswego County. He earned his medical degree from Patna Medical University in India. He completed his fellowship at Yall University Medical School and is board-certified.

Johna Halko, PA-C

Johna Halko, PA-C earned her Physician Assistant Master of Science in 2022 and her Bachelor of Science in Medical Studies in 2021 from DeSales University.

Throughout her training, Halko had clinical rotations in family medicine, general surgery, emergency medicine, psychiatry, pediatrics, OB/GYN, and internal medicine, however, her passion has always been in gastroenterology. In particular, during her gastroenterology elective, Halko focused on coordinating patient care between the gastroenterology and primary care teams and assisted in the development of targeted patient education materials on preventative measures for patients impacted by complex gastroenterology issues.

Rewati Bhattarai, MSN, NP-C

Rewati Bhattarai, MSN, NP-C earned her Bachelor of Science in Biology in 2015 at Syracuse University. In 2017 she attended Utica College for their Accelerated Nursing Program to earn her BSN before completing her MSN in 2020 at SUNY Upstate.

With a well-rounded clinical background, Bhattarai has previously held positions as a Nurse Practitioner at Sodus Rehabilitation & Nursing Center, and as a Registered Nurse in the Transitional Care Unit at SUNY Upstate.

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