Halicephalobus gingivalis (Nematoda) infection in a Grevy's zebra (Equus grevyi).

A 6-yr-old female Grevy's zebra (Equus grevyi) with a disseminated rhabditiform nematode infection is described. Antemortem clinical signs were limited to blindness and abnormal behavior believed to be caused by a recurrent nematode-induced uveitis. Histologic examination of the kidneys, heart, eyes, uterus, and lymph nodes revealed granulomas containing multiple sections of rhabditiform nematodes. Most of the recovered nematodes were larval stages with only a few adult females noted. The adults measured 243-297 microm x 11-16 microm (x = 269 x 14 microm). The distinctive rhabditiform esophagi had corpus:isthmus:bulb proportions of 19:11:5. On the basis of adult morphology, the nematode was identified as Halicephalobus gingivalis. This is the first report of this parasite in a zebra and indicates that this parasitic granulomatous disease should be considered in zebras with neurologic disease.

Ocular Onchocerca infections in two dogs in western United States.

Two dogs, one from California and one from Arizona, were found to have aberrant infections caused by filarial nematodes of the genus Onchocerca. In both cases, the parasites are localized in or near the eye. In one case the worm was located in the cornea and was surgically removed. In the second case, a very marked granulomatous reaction was induced in the retrobulbar space, mimicking an abscess. This eye was enucleated. The worms in both instances were female, and were gravid, i.e. contained microfilariae in utero, indicating that a male worm(s) had been present and mating had occurred. The exact identity of the species of Onchocerca responsible cannot be determined, although the features observed are most like Onchocerca lienalis of cattle. These cases represent the fourth and fifth such cases reported from the US, and are especially interesting because of the unusual location of the worms, the small number of recognized cases, and the similarity to a recent zoonotic human infection.

Clinical and morphologic findings of familial goiter in bongo antelope (Tragelaphus eurycerus).

Inherited defects of thyroglobulin synthesis resulting in congenital goiter are well described in certain breeds of domestic ungulates and in human beings. Goiter associated with synthesis of an abnormal thyroglobulin and the presence of thyroidal albumin was identified in five closely related bongo antelopes (Tragelaphus eurycerus). The goiter had an adult onset, and the affected bongos appeared to remain euthyroid with normal serum T3 and T4 values, normal serum cholesterol concentrations, and nonelevated concentrations of circulating thyroid stimulating hormone (TSH). Goitrous bongos had significant reproductive difficulties, including reduced cyclic activity and prolonged gestations, but were otherwise normal. Over the course of the disease, the thyroid glands greatly enlarged (up to 10 x 20 cm) and became polycystic. Microscopically, there was an admixture of giant colloid-filled follicles and follicles of normal size lined with variable follicular epithelium ranging from squamoid to mildly to moderately hyperplastic. The pathogenesis of goiter in the bongo may reflect a mixture of genetic predisposition coupled with environmental factors, including a period of exposure to a goitrogen.

A study of manatee leukocytes using peroxidase stain.

Leukocytes of the manatee, dog, cat, horse, rabbit, bird, and human were stained with modified Wright-Giemsa stain and myeloperoxidase stain. The predominant segmented leukocyte of the manatee stained positive for myeloperoxidase in a manner similar to the human, dog, cat, and horse neutrophil. Rabbit and bird heterophils stained unlike the manatee predominant leukocyte with myeloperoxidase stain. Eosinophils of all species examined also stained differently from the predominant manatee leukocyte. We conclude that the predominant segmented cell type of the manatee is not biochemically similar to the heterophil of the bird and rabbit or to the eosinophil of the human, dog, cat, horse, bird, and rabbit.

Rheumatoid-like arthritis in a lion tailed macaque.

Very few satisfactory models of rheumatoid arthritis (RA) exist in nonhuman species. It is particularly striking that nonhuman primates have only rarely been described to have disease processes resembling classic RA seen in humans. We describe the case of a lion tailed macaque (Macaca silenus), housed at the National Zoological Park in Washington DC, that had a polyarticular inflammatory arthropathy resembling RA. Gross and histopathologic examination of necropsy tissues and radiographic findings strongly suggest a rheumatoid-like disease, never before described in this species.

The effectiveness of chemical carcinogens to induce atherosclerosis in the white Carneau pigeon.

The frequency of atherosclerotic lesions of the abdominal aorta has been reported to increase significantly in chickens exposed to benzo[a]pyrene and 7,12-dimethylbenz[a,h]anthracene. The present studies were performed to determine in another experimental model frequently used in atherosclerotic studies (i.e. White Carneau Pigeons) whether these and other chemical carcinogens enhance atherosclerosis. The induction and enhancement of atherosclerotic lesions were observed in pigeons treated with 7,12-dimethylbenz[a,h]anthracene, benzo[a]pyrene and 3-methylcholanthrene. The number and size of plaques in the aorta were frequently greater in pigeons treated with the higher concentration (i.e. 100 mg/kg) of these 3 polycyclic aromatic hydrocarbons. Benzo[e]pyrene and 2,4,6-trichlorophenol were ineffective in the induction or enhancement of atherosclerosis in the pigeons. The results of the present and previous studies suggest that the polycyclic aromatic hydrocarbons (excluding benzo[e]pyrene) may be the only potential atherogens in avian atherosclerosis. This relationship may be associated with how these hydrocarbons are transported in the plasma (i.e. by lipoproteins) as demonstrated by the present distribution studies.