SUBEPIDERMAL VESICULOBULLOUS FILARIAL DERMATITIS IN FREE-RANGING AMERICAN BADGERS (TAXIDEA-TAXUS)

Skin and superficial lymph nodes from the 65 juvenile (< 1 year old) a nd adult free-ranging American badgers (Taxidea taxus) of both sexes t hat were killed from late July to late October 1991 as part of the rec overy program for the endangered black-footed ferret (Mustela nigripes ) were examined for evidence of Filaria taxideae. Fifty-one badgers (5 1/64, 80%) were infected. Both adult badgers (30/32, 94%) and juvenile badgers (21/32, 67%) were infected by adult filarial worms, which occ urred most commonly in subcutaneous tissues of the inguinal area, prox imal thigh, and ventral abdomen. Sections of formalin-fixed skin and, from many badgers, subcutaneous lymph nodes were stained with hematoxy lin and eosin, Jones' methenamine silver (for basement membrane), and an avidin biotin peroxidase complex method (for factor VIII-related an tigen). Superficial dermatitis attributable to embryonated filarial ov a and larvae was present in 26/64 badgers (41%), all of them adult (> 1 year old). Acute lesions consisted of multifocal vesiculobullous der moepidermal separation and superficial perivascular dermatitis. Ultras tructural examination and Jones' silver-stained sections revealed sepa ration between basal keratinocytes and the basal lamina (subepidermal vesiculation). Older lesions consisted of ulcerative superficial granu lomatous dermatitis associated with ova and larvae. Multifocal granulo matous endolymphangitis, which involved afferent lymphatics of subcuta neous lymph nodes, was associated with viable as well as degenerative ova and larvae. Adult filarial worms were found in the subcutis alone and did not provoke an inflammatory reaction.