Pathogenesis of Experimental Bovine Mycotic Placentitis Produced by Aspergillus fumigatus

Abstract

Eleven heifers were inoculated intravenously with a suspension of 1 x lo8 conidia of Aspergillus fumigatus at 169 or 170 days after artificial insemination. These principals were killed at 4, 7, or 14 days after inoculation or thereafter when abortion occurred. Four other heifers served as controls. Mycotic placentitis was not found at 4 days after inoculation. In principals killed at 7 and 14 days, 24% of placentomes had lesions of mycotic placentitis. Heifers that aborted had necrotizing lesions in approximately 90% of placentomes as well as extensive involvement of the interplacentomal area. A theory for the spread of the mycosis in the placenta is presented.

Placental Localisation of Aspergillus Fumigatus In Bovine Mycotic Abortion: Enhancement of Spore Germination In Vitro By Foetal Tissue Extracts

“…The placenta seems to be the only organ which provides a suitable environment for rapid vegetative growth of A . fumigatus (Hill et al, 1971) and we have demonstrated that placental extracts stimulate germination of A . fumigatus spores in vitro.…”

“…However, spores probably reach the placenta via the maternal blood since intravenous inoculation is the only successful method of experimental infection (Gilman and Birch, 1925;Bendixen and Plum, 1929;Hillman and McEntee, 1969;Hill et al, 1971). The placenta seems to be the only organ which provides a suitable environment for rapid vegetative growth of A .…”

“…Extra-placental lesions may develop after intravenous inoculation but these either remain small or rapidly disappear whereas infection persists and spreads throughout the placentae of both the cow (Hill et al, 1971) and sheep (Pier, Cysewski and Richard, 1972).…”

Porcine Abortions Associated with Fungi, Actinomycetes, and Rhodococcus sp

“…In cattle, fungi gain entrance through the digestive tract and the infection is carried to the placenta by the blood [3].…”

Alimentary Mycotic Lesions in Cattle: A Histological and Cultural Study

“…from the mesenteric lymph-nodes of healthy cattle is important in that these organisms have been shown to infect other organs, including the placenta. Experimental infection of cattle with organisms of either genus can result in the development of asteroid bodies in the placenta (Dawson, unpublished observations;Hill et al, 1971). The recent literature on mycotic abortion, reviewed by Campbell (1969), emphasises the gaps in our knowledge of pathogenesis, and there appears to be no direct evidence that the spores of fungi commonly implicated in systemic mycoses such as mycotic abortion pass directly from the gut into the circulation.…”