Lyndsay G. Phillips

Biochemical Genetic Variation in Eight Endangered or Threatened Felid Species

Electrophoretic variation at 25 biochemical loci was detected in one or more of eight non-domesticated cat species, including representative small cats ( Felis, Leptailurus, Caracal ), the great cats ( Panthera ), and felids of intermediate size ( Leopardus, Neofelis ). In all, 50 distinct polymorphisms are described and each was tested for conformity to Mendelian expectation (in pedigree analysis) and for genetic equilibrium of allelic frequencies. Although most of the variation was detected by alterations in electrophoretic mobility, two isozyme loci showed the presence of “null” alleles (NAD-diaphorase and inorganic pyrophosphatase) in the sampled species. Two subspecies of tigers, Bengal Panthera tigris tigris and Siberian P. tigris altaica , had a different pattern at two loci (glutamate pyruvate transaminase and inorganic pyrophosphatase), which were both polymorphic in Bengal tigers but monomorphic in Siberian tigers. The description of these polymorphisms provides a genetic baseline of potential use in the management and captive breeding of felid populations.

Renal medullary amyloidosis in Dorcas gazelles

Between January 1976 and September 1987 renal medullary amyloidosis (RMA) was diagnosed in 17 Dorcas gazelles; the necropsy prevalence rate was 17/32 (53%). The most severe amyloid deposits were in the renal medulla; glomeruli were spared. Renal cortical lesions of interstitial fibrosis and tubular atrophy and dilatation significantly correlated with RMA (P < 0.01) and were considered to be secondary changes. There were varying degrees of lymphoplasmacytic inflammation and tubular cast formation which did not significantly correlate with RMA. Amyloid was confirmed histochemically and by electron microscopy and was identified as AA type by the permanganate method. Progressive renal failure was the cause of death or necessitated euthanasia in 7/17 (41%) gazelles. RMA in Dorcas gazelles does not appear to be familial. A high prevalence of chronic or recurring Actinomyces (Corynebacterium) pyogenes infections may be an important factor.

Mortality of captive tortoises due to viviparous nematodes of the genus Proatractis (Family Atractidae).

Between September 1982 and January 1984, verminous colitis was diagnosed post mortem in eight red-footed tortoises (Geochelone carbonaria) and three leopard tortoises (Geochelone pardalis) from the reptile collection of the National Zoological Park. This represented 69% of 16 tortoise necropsy accessions for that period. Etiology was determined to be a viviparous pinworm-like nematode of the genus Proatractis (Family Atractidae). Clinical signs were either nonspecific, consisting of anorexia, lethargy, and depression, or were absent. Limited trials with piperazine citrate and fenbendazole appeared to be ineffectual against the parasite and supportive therapy was unsuccessful. Post mortem examination revealed roughening and thickening of the mucosa of the cecum and colon, and in severe cases myriads of tiny (0.5–1.0 cm) nematodes were evident on the mucosal surface. In six tortoises, worms were found also in the small intestine. Histopathologic features in severe cases included mucosal necrosis with parasites and mixed inflammatory cells extending into the tunica muscularis. Focal to diffuse lymphoplasmacytic infiltrates were present consistently in the submucosa of the cecum and colon, and similar but milder lesions occasionally occurred in the small intestine.