The lamb disease alveld: Search for fungi and bacteria on Narthecium ossifragum foliage and roots

•The causality of the serious hepatogen sheep (Ovis aries) photosensitization disease alveld is not explained.•Three species of bacteria and 16 species/genera of microfungi, several of which were new to this plant, were identified.•The ecology of some of the identified species of microfungi and bacteria and their possible relevance to the alveld pathosystem is discussed.

The causality of the serious hepatogen sheep (Ovis aries) photosensitization disease alveld is not explained. In this study the bog asphodel (Narthecium ossifragum) foliage and roots were sampled for associated species of microfungi and bacteria in Møre og Romsdal, Western Norway 2001. Three species of bacteria and 16 species/genera of microfungi, several of which were new to this plant, were identified. Metabolites of saponins produced by N. ossifragum have long been suggested as the sole cause of the disease, here two additional hypotheses are discussed. Several findings have indicated that an unknown “cofactor” is required to explain causality. The cofactor hypothesis is that bacterial or fungal populations consumed with feed might either affect biological membranes and influence physiological processes through production of toxic metabolites or directly interfere with present rumen microbial populations. The second hypothesis is that secondary production of phytoalexins in Narthecium due to impact from swarms of microfungi spores is another valid possibility. The ecology of some of the identified species of microfungi and bacteria and their possible relevance to the alveld pathosystem is discussed.