Fungi Associated with Bovine Abortion in the Northern Plains States (USA)

Abstract

Mycotic infection was diagnosed in 6.8% of 6,858 cases of bovine abortion and stillbirth examined during a 9-year period. Aspergilli were associated with approximately 5% of all abortion cases and 71% of 446 cases that were cultured for fungi and diagnosed as mycotic abortion. Aspergillusfumigatus was the most frequent isolate (62%), followed by A. terreus (6.7%), Emericella (Aspergillus) nidulans (3.0%), A. flaws (2.9%), and E. rugulosus (< 1.0%). Zygomycetes ( Absidia, Mortierella, Rhizomucor, Rhizopus) accounted for 21% of the cases. Pseudallescheria boydii and yeasts ( Candida, Torulopsis) were each identified in 2% of the cases. Fungi that uncommonly cause infection accounted for 2% of the cases and included CurvuZaria geniculata, Exophilia jeanselmei, Hendersonula toruloidea, Lecythosphora hoffmannii, Talaromyces jlavus var. flavus (Penicillium vermiculatus), T. (Penicillium) thermophilus, and WangieZZa dermatitidis. About 10% of the mycotic cases were mixed fungal infections involving A. fumigatus (87%), A. flavus (12.5%), or E. nidulans (12.5%) coexisting with Absidia corymbifera (72%), Rhizomucor pusillus (4.3%), or Rhizopus arrhizus (4.3%). In each mixed infection, both septate and nonseptate hyphae were observed in placental tissues. Twelve percent of the mycotic abortion cases were diagnosed by histologic examination alone because isolation attempts were negative or only formalinpreserved tissues were available.