Rubber Jaw Syndrome in a Juvenile Labrador Retriever: A Rare Sequela of Babesia Gibsoni-induced Renal Secondary Hyperparathyroidism

A seven-month-old male Labrador Retriever was presented to the Veterinary Clinical Complex, College of Veterinary Science, Assam Agricultural University, with complaints of progressive facial swelling, anorexia, intermittent vomiting and generalized weakness. Clinical examination revealed mandibular and maxillary enlargement, pliable jaw bones and loose teeth-suggestive of fibrous osteodystrophy. Hematological evaluation revealed macrocytic hypochromic anemia, while Giemsa-stained peripheral blood smears confirmed intraerythrocytic Babesia gibsoni. Serum biochemistry demonstrated marked elevations in blood urea nitrogen (BUN), creatinine, phosphorus and parathyroid hormone (PTH), alongside mild hepatic enzyme elevation and hypocalcemia, consistent with renal dysfunction and secondary hyperparathyroidism. Cranial radiographic imaging of the skull showed osteolytic changes in the facial bones, while abdominal ultrasonography revealed splenomegaly and renal cortical thickening with loss of cortico- medullary junction. Clinical findings such as mandibular pliability ("rubbery jaw”), hematobiochemical abnormalities (anemia, azotemia, hyperphosphatemia, hyperparathyroidism) and diagnostic imaging supported the diagnosis of fibrous osteodystrophy secondary to chronic kidney disease (CKD), complicated by canine babesiosis-induced renal insufficiency. This case highlights a rare presentation of metabolic bone disease associated with vector-borne hemoprotozoan infection in a juvenile dog. It underscores the need for integrated diagnostic approaches when systemic signs coincide with bone pathology, especially in endemic regions where babesiosis and renal disorders coexist.