Spontaneous arterial disease in exotic animals

Abstract

An account is given of the pathology and incidence of spontaneous arterial disease occurring in a series of about 2000 vertebrates, the majority of which died in captivity from natural causes. The personal observations are integrated with a fairly detailed review of the literature. Vascular lesions have been described in fish, amphibians, reptiles, birds and mammals. Particular attention is given in this paper to the comparative pathology of degenerative arterial disease and, more especially, atherosclerosis. Minor degrees of lipid infiltration of the arterial wall are seen commonly in many avian and mammalian orders, but more advanced atheromatous plaques occur frequently only in some avian orders and man. Atheroma has been observed occasionally in sub‐human primates and ungulates. Focal degeneration and calcification of the arterial media constitute the major arterial lesion in ungulates and marsupials; parasitic arteritides are seen principally in carnivores, equines and, possibly, reptiles. Arterial thrombosis in animals is usually secondary to local physical injury or infection; occlusive atherothrombosis is extremely rare in all animals. A hypothesis is presented on the histogenesis of atherosclerosis as it occurs in animals. It is concluded that the condition is a multifactorial disease. The role of dietary and other factors which may play a part in the pathogenesis of atherosclerosis is discussed. Age is the only factor shown to be fairly directly related to atherosclerosis, but the almost complete absence of lesions in some comparatively old animals emphasizes that atheroma is not an inevitable accompaniment of senescence. The morphological pattern of arterial disease would appear to be similar in free‐living and captive animals; and though increasing age and the conditions of captivity may potentiate lesions, it would seem likely that the primary causes of arterial disease are operative in natural, quasi‐natural or captive environments.

Arterial disease of reptiles

“…The present study supplements our previous observations (Finlayson, Symons & T-W-Fiennes, 1962;Finlayson, 1965) and those of others (Vastesaeger et al, 1965;Ardlie & Schwartz, 1965;Bohorquez, 1972) that intimal fatty streaking is both uncommon and usually of very limited extent in reptiles and that atherosclerosis is virtually unique. Reported cases of calcareous atheroma and arteriosclerosis are almost certainly examples of medial calcification, and the one acceptable case of atherosclerosis, which was limited to a few small plaques in the abdominal aorta of a Two-banded monitor (Varanus salvator) that had survived in captivity foI 20 years, is detailed by Vastesaeger et al (1965).…”

“…The literature on arterial disease of reptiles is sparse. Most of the reports are limited to isolated cases, such as those described by Yearsley (1904), Hamerton (1933Hamerton ( , 1935Hamerton ( & 1937, Reichenbach-Klinke & Elkan (1965), Wallach (1966) and Schuchman & Taylor (1970), or to small series that have been examined with particular reference to the prevalence of intimal fatty streaking and atherosclerosis (Finlayson, Symons & T-W-Fiennes, 1962;Ardlie & Schwartz, 1965;Finlayson, 1965;Vastesaeger, Delcourt & Gillot, 1965;Bohorquez, 1972). The one major survey was made by Cowan (1968), who carried out a retrospective analysis of the pathological disorders occurring in 1249 reptiles that died in the Philadelphia Zoological Garden over a period of 66 years.…”

Changes in aortic medial elastic structure at different sites in the primates Erythrocebus patas, Macaca irus and Callithrix jacchus

“…The occurrence of spontaneous atherosclerosis in primates is well documented (Finlayson, 1965;Gresham, Howard, McQueen & Bowyer, 1965;Stout & Groover, 1969;Kritchevsky, 1969), and the genesis of the disease may follow a similar pattern to that in man.…”

Lipoidal corneal degeneration in aged falcons

“…In our study, a single bird was necropsied and had postmortem evidence of systemic atherosclerosis. Atherosclerosis has been reported in many avian species, with reported risk factors including increasing age, female sex due to reproductive hormone differences compared to males, hypercholesterolemia, systemic hypertension, and sedentary/captive lifestyles . Kites are suggested to have increased susceptibility; however, reports of atherosclerosis in raptors are infrequent.…”