Hepatogenous photosensitization by Brachiaria spp. in sheep: first report in Mexico

Ruminants are highly susceptible to photosensitization caused by the ingestion of hepatotoxic plants. In two adjacent farms in Colima, Mexico, several sheep exhibited signs of depression and crusting dermatitis involving the ears, periorbital skin, eyelids, nostrils, and axillary regions. Results of serum biochemistry were indicative of liver injury. Post mortem examination revealed jaundice, craniofacial edema as well as an enlarged liver having an orange-brown discoloration; on the cut surface, the hepatic parenchyma had a subtle zonal pattern. Histopathological findings were those of severe necrotizing dermatitis, lymphoplasmacytic cholangiohepatitis, and renal tubular necrosis. Acicular crystals were microscopically and ultrastructurally evident in hepatocytes, Kupffer cells, biliary ducts, renal tubules and interstitium. The clinical, gross and microscopic findings were consistent with hepatogenous photosensitization. A field investigation revealed that affected sheep had been grazing Brachiaria spp., a potentially toxic grass originated from Africa and commonly cultivated in Australia and South America. This grass contains hepatotoxic saponins that cause liver injury and secondary hepatogenous photosensitization. Although frequently reported in South America, to our knowledge, this is the first report of Brachiaria spp. toxicity in Mexico.(AU)

Hepatogenous photosensitization by Brachiaria spp. in sheep: first report in Mexico

Ruminants are highly susceptible to photosensitization caused by the ingestion of hepatotoxic plants. In two adjacent farms in Colima, Mexico, several sheep exhibited signs of depression and crusting dermatitis involving the ears, periorbital skin, eyelids, nostrils, and axillary regions. Results of serum biochemistry were indicative of liver injury. Post mortem examination revealed jaundice, craniofacial edema as well as an enlarged liver having an orange-brown discoloration; on the cut surface, the hepatic parenchyma had a subtle zonal pattern. Histopathological findings were those of severe necrotizing dermatitis, lymphoplasmacytic cholangiohepatitis, and renal tubular necrosis. Acicular crystals were microscopically and ultrastructurally evident in hepatocytes, Kupffer cells, biliary ducts, renal tubules and interstitium. The clinical, gross and microscopic findings were consistent with hepatogenous photosensitization. A field investigation revealed that affected sheep had been grazing Brachiaria spp., a potentially toxic grass originated from Africa and commonly cultivated in Australia and South America. This grass contains hepatotoxic saponins that cause liver injury and secondary hepatogenous photosensitization. Although frequently reported in South America, to our knowledge, this is the first report of Brachiaria spp. toxicity in Mexico.

Congenital biliary atresia in a Beefmaster calf

Biliary atresia is a congenital cholangiopathy characterized by a progressive fibrosis of the bile ducts leading to impaired biliary flow, hepatic failure, icterus and early death. This paper describes the gross and microscopic findings in a 4-week-old Beefmaster calf that unexpectedly died with severe jaundice. On postmortem examination, the liver was firm in texture and exhibited an orange-yellow discoloration. Microscopically, there were cholestasis, hyperplasia, fibrosis and obliteration of the bile ducts, and mural fibrosis of the gall-bladder. Massons trichrome and Gomoris stain revealed excessive collagen deposition in the portal areas and biliary ducts, and occasionally around central veins. Immunohistochemistry confirmed biliary epithelial cells, not only lining the bile ducts but also were forming tubular-like structures devoid of a lumen. Blood test was negative for babesiosis and anaplasmosis. Based on these findings, the final diagnosis was congenital biliary atresia.(AU)

Congenital biliary atresia in a Beefmaster calf

Biliary atresia is a congenital cholangiopathy characterized by a progressive fibrosis of the bile ducts leading to impaired biliary flow, hepatic failure, icterus and early death. This paper describes the gross and microscopic findings in a 4-week-old Beefmaster calf that unexpectedly died with severe jaundice. On postmortem examination, the liver was firm in texture and exhibited an orange-yellow discoloration. Microscopically, there were cholestasis, hyperplasia, fibrosis and obliteration of the bile ducts, and mural fibrosis of the gall-bladder. Massons trichrome and Gomoris stain revealed excessive collagen deposition in the portal areas and biliary ducts, and occasionally around central veins. Immunohistochemistry confirmed biliary epithelial cells, not only lining the bile ducts but also were forming tubular-like structures devoid of a lumen. Blood test was negative for babesiosis and anaplasmosis. Based on these findings, the final diagnosis was congenital biliary atresia.