Multi-organ involvement of Heterobilharzia americana infection in a dog presented for systemic mineralization.

Canine schistosomiasis due to Heterobilharzia americana is a clinically underdiagnosed disease in dogs, which is found primarily in the Gulf Coast and south Atlantic region of the United States. A 3-year-old dog from Texas with a clinical diagnosis of systemic mineralization of unknown origin in the absence of evidence of hypercalcemia was found at necropsy to have severe disseminated H. americana infection involving the liver, pancreas, small and large intestine, lungs, and kidneys. Calcification of many of the large number of H. americana eggs gave the false impression of soft-tissue mineralization on radiographic and ultrasonographic images. Polymerase chain reaction amplification and sequencing of DNA derived from formalin-fixed sections of small intestine and liver, using primers specific for a 487-base pair segment of the H. americana small subunit ribosomal RNA gene, confirmed the presence of H. americana.