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Acta sci. vet. (Impr.); 40(3): Pub. 1064, 2012. ilus

Artigo em Português | VETINDEX | ID: biblio-1373721

Resumo

Background: Congenital anomalies are structural and functional abnormalities that are present at birth, and they are frequently the result of environmental or genetic factors or both. Their etiology may also be related to infectious agents, such as viruses, hereditary factors, or the ingestion of toxic plants or chemical agents. Congenital anomalies usually occur sporadically, but they also can occur as outbreaks. The objective of this paper is to describe the multiple congenital malformations observed in an aborted bovine fetus. Case: A bovine fetus was sent to Laboratory Veterinary Pathology UFRGS for necropsy, histological analysis and complementary exams such as bacteriology, direct immunofluorescence for Leptospira sp. and immunohistochemistry for bovine viral diarrhea virus (BVDV). The fetus presented multiple congenital alterations, such as dextraposition of the aorta and absence of the pulmonary artery, tracheal stenosis, a hypoplastic lung, multiple heart defects, arthrogryposis, osteopetrosis, and the absence of the middle phalanx and accessory digits in the forelimbs. Furthermore, dystocia and enlargement of the liver were observed, the organ showed irregular surface, firm consistency and nodular formation. A histological exam verified the accentuated hepatic periportal fibrosis. All complementary exams were negative. Discussion: Congenital anomalies can affect only one organ or can be multisystemic due to a malformation of one part of the body leading to the loss of another. Arthrogryposis can delay delivery, and signs of dystocia may be present in the resulting fetus. The etiology of arthrogryposis is difficult to determine, and even studies that were previously performed in ruminants have failed to identify a specific agent. Osteopetrosis, which was also observed, is a congenital skeletal anomaly caused by the failed resorption of cartilage and endochondral bone, and it has been associated with intrauterine BVDV infections, can also be associated with autosomal recessive genes in the Angus bovine breed. Congenital heart defects are relatively rare in cattle. Ventricular sept defects and transposition of the great vessels are two of the most common cardiovascular anomalies in bovines, and they can occur individually or in association with other heart defects. Generally, these malformations are linked to genetic factors. In this study, the animal presented with several conformational heart defects that resulted in embryonic development alterations in its structure or that resulted in progressive heart failure. Blood flow changes caused by an anatomic defect can significantly influence the structural and functional development of the circulation, resulting in secondary alterations. In this case, the primary defect is hard to determine, but the observed bilateral pulmonary hypoplasia may be the consequence of a blood flow decrease to the lungs because the pulmonary artery was absent. Pulmonary hypoplasia is defined as the incomplete development of the lungs, reducing the number of divisions of the bronchial tree and the associated alveoli. Many causes of pulmonary hypoplasia have been described in human beings and animals, such as chest abnormalities, congenital diaphragmatic hernia, chromosome anomalies, musculoskeletal disorders and heart failure. The accentuated hepatic fibrosis observed in this study, which was predominantly periportal, correlated with congestive heart failure due to the cardiac and pulmonary malformation observed in the fetus, which would have altered the systemic blood flow. It is suggested that the studied case is a congenital malformation of sporadic origin, characterized by multiple deformities associated with unknown genetic factors.

Biblioteca responsável: BR68.1