Coccidiosis as a Cause of Transmural Lymphocytic Enteritis and Mortality in Captive Nashville Warblers (Vermivora Ruficapilla)

Abstract

Transmural lymphocytic enteritis was diagnosed in thirteen Nashville warblers (Vermivora ruficapilla) during an epornitic with high mortality. In the intestinal lesions, asexual stages of coccidia were present within lymphocytes and asexual and sexual stages of coccidia were present within intestinal villar epithelium. Ultrastructurally, the infiltrating lymphocytes resembled granular ("intraepithelial") lymphocytes, a cell known to be important in the life cycle of some avian coccidia. Gross and histopathologic features of this enteritis resemble intestinal changes described for Isospora/Atoxoplasma spp. in other passeriformes and lymphoproliferative disease in gold-finches.

Proliferative visceral Isospora (atoxoplasmosis) with morbid impact on the Israeli sparrow Passer domesticus biblicus Hartert, 1904

“…Division of the first generation of the proliferative (extraintestinal) meronts proceeded similarly to that seen in the intestinal phase. The connection between the waitingstages and IEL has been suggested in previous ultrastructural studies (Milde 1979;Swayne 1991). Many waiting merozoites occurred in pairs, which could suggest endodyogenic division.…”

“…Affected birds have heavy extraintestinal merogonic infection, usually accompanied by gut Isospora infection (Partington 1989;Swayne et al 1991;McNamee et al 1995). Cooper et al (1989) termed the condition of weight loss and severe diarrhea in the succumbing birds, "going light" syndrome.…”

“…The cell hosting the proliferative stages was rich in mitochondria and endoplasmic reticulum and cisternae, seemingly a mononuclear or another reticuloendothelial cell type. The cell hosting the waiting merozoites was characterized by a paucity of cellular organelles and was identifiable with granular lymphocyte (Milde 1979;Swayne 1991) or intra-epithelial lymphocytes (IEL; Lawn et al 1988). The waiting merozoite with its PV was positioned within a notch in the host-cell nucleus, lined with a dense granular substance.…”

Differential effects of endoparasitism on the expression of carotenoid- and melanin-based ornamental coloration

“…Thus, we speci¢cally tested the e¡ect of endoparasitism on the expression of ornamental coloration in male gold¢nches. We felt that intestinal coccidians from the genus Isospora would be appropriate parasites for testing this assumption because coccidia commonly infect a number of songbird species (zebra ¢nch (Taeniopygia guttata, Helman et al 1984), Nashville warbler (Vermivora ru¢capilla, Swayne et al 1991), northern cardinal (Cardinalis cardinalis, Baker et al 1996) and black siskin (Carduelis atrata, Giacomo et al 1997)) and because there are clear physiological mechanisms by which they compromise the condition of moulting males. These endoparasites directly inhibit the uptake of essential dietary components, including carotenoids, in the gastrointestinal tracts of chickens (Ru¡ et al 1974;Augustine & Ru¡ 1983;Allen 1987Allen , 1988Allen , 1992 and consequently depress bright carotenoid-based pigmentation in poultry (`pale bird syndrome'; Tyczkowski et al 1991) and male house ¢nches (Carpodacus mexicanus, Brawner et al 2000).…”

Eimeria

“…Wild birds that are kept in zoological parks or other captive facilities are more likely to develop coccidiosis than their free-ranging counterparts (Panigrahy et al 1981;Barker et al 1984;Swayne et al 1991;Giacomo et al 1997;Novilla and Carpenter 2004). This problem can be compounded in facilities where large numbers of very closely related host species are housed together because closely related hosts may be susceptible to the same coccidian species.…”