Necrotising enteritis in a lamb associated with adenoviral infection

Enteric viral infections in lambs or kids

Diarrhoea in lambs and kids is often a complex, multi-factorial syndrome. Common infectious causes of diarrhoea in lambs and kids during the first month of life are of bacterial or parasite nature. However, despite appreciable improvements in management practices and prevention and treatment strategies over the last decades, diarrhoea is still a common and costly syndrome affecting newborn small ruminants. Recent advances in the diagnostics and metagenomic investigations of the enteric environment have allowed discovering a number of novel viruses, although their pathobiological properties remain largely unknown. Assessing more in depth the impact of these viruses on the health and productions of these livestock animals is necessary and requires the development of accurate diagnostic tools and updating of the diagnostic algorithms of enteric pathological conditions.

DNA sequencing and phylogenetic analysis of the protease gene of ovine adenovirus 3 suggest that adenoviruses of sheep belong to two different genera

Until now, the only published ovine adenovirus DNA sequence was the complete genome of ovine adenovirus isolate 287 (OAV287) which, compared to other mammalian adenoviruses, possesses strikingly unique genomic organisation and should properly be classified into a new adenovirus genus. The protease gene sequence of ovine adenovirus type 3 (OAdV-3) was determined and analysed. The results of phylogenetic analysis of the 205 residue long protein demonstrated that OAdV-3 belongs to the genus Mastadenovirus, and is surprisingly closely related to bovine adenovirus type 2. In spite of the common host origin, the evolutionary distance between OAdV-3 and OAV287 proved to be great suggesting that sheep, similarly to cattle and fowl, might be infected by distantly related adenoviruses belonging to different genera.

Bovine adenovirus type 10 identified in fatal cases of adenovirus-associated enteric disease in cattle by in situ hybridization

A severe, naturally occurring enteric disease of cattle in which adenovirus inclusions are present in the intestinal vascular endothelium has been recognized in several countries; three different adenovirus serotypes have been isolated from affected animals. An in situ hybridization technique for the detection of bovine adenoviral DNA was developed and applied to tissue from 13 cattle in Northern Ireland diagnosed to have the disease. Bovine adenovirus serotype 10 (BAV-10) was identified in the vascular inclusions of all cattle, providing strong evidence that adenoviral enteric vascular disease in cattle is associated with this serotype. The existence of BAV-10 has only recently been recognized. The first molecular biology-based technique for the diagnosis of BAV-10 infection is described. The animals in the present study are the first in which BAV-10 has had a confirmed role in a pathologic process.