Immunohistochemical characterization of hepatic lesions associated with Elaeophora elaphi parasitism in red deer (Cervus elaphus).

This study was based on the immunohistochemical characterization of hepatic lesions caused by Elaeophora elaphi in 15 red deer. In eight animals filariae were found in branches of the portal vein. "Web-like" endophlebitis (15 cases), lymph nodule-like thrombi associated with filarial debris (12 cases) and fibrinous thrombi (three cases) were also observed in the portal vein. Multifocal granulomatous hepatitis (six cases) and lymph nodule-like tissue (three cases) were found in the liver parenchyma. The distribution of CD3 antigen, IgG-lambda light chains, and S-100 protein in lymphoid tissue in the portal vein thrombi and hepatic parenchyma was similar to that found in the cortex of the lymph nodes. In these lesions, lymphoid follicles with large germinal centres (mainly composed of IgG+ B lymphocytes, with occasional S-100+ follicular dendritic cells) predominated over interfollicular lymphoid tissue (mainly composed of CD3+ T lymphocytes and S-100+ interdigitating cells). This suggested that the local humoral immune response was more important than the cellular response in this parasitic disease. The presence of interdigitating and follicular dendritic cells confirmed the high degree of organization of the abnormal lymphoid tissue and suggested that antigen presentation to T and B lymphocytes and the subsequent proliferation of the latter was particularly efficient in such tissue. The latter may therefore be superior to diffuse granulomatous infiltrate in terms of the production of a local immune response.

Abnormal antler growth associated with testicular hypogonadism in red deer.

A wild 5-yr-old red deer (Cervus elaphus) was eulled from a privately owned herd because of deformed antlers, retained velvet and bilateral symmetrical testicular hypogonadism. The clinical and pathological changes seen in this deer were most consistent with congenital hypoplasia, but testicular atrophy was an alternative possibility for the etiology of their condition.

Elaeophorosis in red deer caused by Elaeophora elaphi: lesions of natural disease.

This is the first study of the lesions produced by Elaeophora elaphi, a filarial worm first reported in 1986. Only the morphologic characteristics of this species have been described previously. Samples for the study were taken from 74 red deer (Cervus elaphus), 1-10 years old, slaughtered in central Spain. Grossly, filariae were observed in the transverse, left, or right branches of the portal vein of 18 animals. In addition to filariae, whitish thrombi were found in the right and left branches of the portal vein in nine animals. Thrombi of similar characteristics were also observed in 12 deer in which no adult filariae were found. Microscopic changes were observed only in the right and left branches of the portal vein and consisted of thickening of the intima with surface formation of villi. Stroma of villi contained a moderate to intense infiltrate composed mainly of eosinophils and mononuclear cells. The tunica media of affected vessels was uniformly hypertrophic and in some cases presented a moderate inflammatory infiltrate similar to that observed in the stroma of villi. Thrombi consisted of a central area containing calcified filariae or cuticle debris, surrounded by giant cells and numerous lymphoid cells forming clearly defined nodules resembling lymphoid follicles. Thrombi were externally surrounded by a strip of connective tissue and beyond by endothelial cells that were occasionally continuous with the tunica intima. Other lesions probably associated with the infestation were multifocal granulomas in the periportal areas, lymphoid tissue formations in the hepatic parenchyma, and an interstitial nephritis.