Cloacal Bursa Research Articles

Comparative Pathology of Chickens Experimentally Inoculated with Avian Influenza Viruses of Low and High Pathogenicity

Pathologic changes and distribution of viral antigen as determined by immunohistochemistry were compared among 4-wk-old specific-pathogen-free chickens inoculated intratracheally with avian influenza virus (AIV) isolates of either low or high pathogenicity. Viruses of low pathogenicity, previously characterized as mildly pathogenic (MP), included A/chicken/Pennsylvania/21525/83 (H5N2) (MP-Penn) and A/chicken/Alabama/7395/75 (H4N8) (MP-Alab). Viruses of high pathogenicity included A/chicken/Pennsylvania/1370/83 (H5N2), A/chicken/Victoria/A185/85 (H7N7), and A/turkey/Ontario/7732/66 (H5N9). Extremely variable clinical signs ranging from mild respiratory distress to high mortality were present among chickens inoculated with these viruses. Chickens inoculated with highly pathogenic (HP) virus had histologic lesions of necrosis and inflammation in cloacal bursa, thymus, spleen, heart, pancreas, kidney, brain, trachea, lung, and skeletal muscle, whereas chickens inoculated with MP virus had histologic lesions most frequently in lung and trachea or lacked histologic lesions. Immunospecific staining for avian influenza viral proteins was most common in cells within heart, lung, kidney, brain, and pancreas of chicken inoculated with HP viruses, but immunospecific staining was present only and infrequently in trachea and lung of chickens inoculated with MP-Penn AIV. MP-Alab did not produce lesions nor have viral antigen in inoculated chickens but did produce serologic evidence of infection. The pattern of organ involvement and viral antigen distribution in chickens intratracheally inoculated with HP AIV isolates indicates a common capability to spread beyond the respiratory tract and confirms the pantrophic replicative, pathobiologic, and lethal nature of the viruses. However, variability in severity and lesion distribution exists between different HP AIVs. By contrast, MP viruses had the ability to replicate in respiratory or enteric tracts or both and produce lesions within the respiratory tract. These MP viruses exhibited a restricted ability to replicate or produce lesions or both in nonrespiratory or nonenteric tissues; such effects were associated with only sporadic deaths.

Cloacal morphology of Nothura maculosa (Temminck, 1815), Aves tinamiformes

Cloacae of male Nothura maculosa (spotted tinamous) were dissected and studied with routine histological and histochemical techniques. In the cloaca of this species the following cranio-caudally oriented regions can be recognized: the coprodeum, the urodeum and the proctodeum, separated by the coprourodeal and the uroproctodeal folds respectively. The coprodeum is an abrupt dilatation of the rectum which receives the ureters, contrary to other birds in which they open into the urodeum. The urodeum is the smallest compartment of the cloaca. Its wall presents the paracloacal vascular bodies and the ductus deferens receptacles which open into the ejaculatory fossa through a pair of papillae. The ejaculatory fossa forms the ventral floor of the urodeum and is characterized by the presence of a secretory epithelium and a lamina propria showing rich vascularization. The proctodeum is connected to the exterior through the cloacal opening and ventrally it presents the phallic structures and the proctodeal lamella. Its dorsolateral wall forms the cloacal bursa, its mucosa shows morphological variations depending on the degree of regression. Enclosing the uroproctodeal wall are the cloacal sphincter muscle and the skin.

Comparative Pathology of Intravenously Inoculated Wild Duck- and Turkey-Origin Type A Influenza Viruses in Chickens

Five-week-old specific-pathogen-free chickens were inoculated intravenously with one of 16 low-pathogenicity type A influenza virus isolates; 14 were of wild duck origin, and two were of turkey origin. Tubulointerstitial nephritis was the most frequent specific histopathologic change. The frequency and severity of kidney lesions were independent of the virus hemagglutinin-neuraminidase subtype or titer of the challenge virus. Influenza nucleoprotein was most frequently demonstrated in the kidney and was consistently localized to necrotic proximal and/or distal renal tubule epithelium. Common nonspecific histopathologic changes were lymphoid hyperplasia of the spleen and cecal tonsils, as well as lymphocyte depletion in the cloacal bursa. Uncommon histopathologic changes, in decreasing order of frequency, were interstitial pneumonia, lymphoid follicular hyperplasia in the myocardium, and lymphocytic tracheitis. Histopathologic changes were rare or absent in the jejunum, duodenum, pancreas, and brain. The low-pathogenicity avian-origin type A influenza virus isolates were epitheliotropic in chickens, primarily nephrotropic. Such findings were dissimilar from findings with highly pathogenic avian-origin type A influenza virus isolates both in severity and in tissue distribution of histopathologic changes and influenza viral antigen.

The anatomy of the cloacal bursa (bursa of Fabricius) in the helmeted guinea fowl (Numida meleagris galeata).

The cloacal bursa (bursa of Fabricius) in the guinea fowls appeared either as an oval blind sac with a short thick stalk in one group or had a pointed cranial blind end with a slightly bulging middle part that was followed by a thick caudal stalk in the other group. Both groups of bursae originated from the proctodeal wall of the cloaca and were placed dorsal to the rectum. The average length of the bursa was 18 mm while the average width at the mid section was 15 mm. The internal surface showed about 12-14 primary folds. Histologically, the outline of the bursa was well established by day 18 of incubation. The primary folds had also been formed. Lymphocytes had already been encountered within the framework of the bursa at this day. The epithelium bordering the tunica propria was composed principally of two layers of cuboidal cells. Epithelial buds had also formed and some were already detached from the epithelial lining. The blood vessels present were positioned just beneath the outer covering. At day 19 of incubation, most of the epithelial buds had two layers of cells arranged in a circumscribed manner while a few had three layers of cells. Blood vessels had increased in number and were deeper placed inside the bursa than previously. At day 20, the cells of the upper layer of the epithelium were dorsoventrally flattened and stained paler than the cells of the lower layer. It was possible to distinguish the cortex from the medulla and the basement lining between both zones was distinct. Tiny vesicles within the cytoplasm of the epithelial cells at the mucosa and follicles were observed. Macrophages were also observed within the gland. At day 21, blood vessels were observed in the cortex of the follicles. The maximum number of primary folds (14) had been formed. At day 22, several follicles had severed connections with the mucosal epithelium. The mucosal lining had dropped to a single layer of cells in some areas. Goblet cells were observed amongst the mucosal cells. A plasma cell had first appeared. By day 25, dead cells had increased quite in number and there was also an increase in number of medium and small-sized lymphocytes within the gland. By day 26, the upper layer of the surface epithelium was composed primarily of tall columnar cells with numerous large vacuoles. Macrophages had suddenly increased within the thin interfollicular spaces and most of them were crowded internally with various sizes of debris.(ABSTRACT TRUNCATED AT 400 WORDS)

Increase of the bursal follicular medullary compartment in chicks intracloacally inoculated with Bordetella pertussis

The cloacal bursa is a primary lymphoid organ responsible for the maturation of B-lymphocytes. It has been suggested that the bursa may also play a peripheral role when antigens are inoculated by cloacal route. Qualitative and quantitative structural modifications in the bursa from chicks inoculated with Bordetella pertussis by the cloacal route were investigated. Observations indicated that the relative bursal growth as well as the volume fraction and the mitotic index of the follicular medulla from experimental bursae are significantly greater than those of the controls. Macrophages which have phagocytized bacteria, and a gradual relative increase of the RER of lymphoblasts, were other structural modifications found exclusively in the follicular medulla. The observations suggest that the bursal follicular cortex and medulla act as autonomous histophysiological compartments, the latter being responsible for an antigenic stimulation when Bordetella pertussis is intracloacally inoculated in chicks.

Three new species of the genusNeopolystoma (Monogenea) from river tortoises in Australia

Neopolystoma kreffti n.sp. from the mouth and pharyngeal cavity ofEmydura krefftii (Pleurodira, Chelidae) in southern Queensland,N. macleayi n.sp. from the cloacal bursa, andN. australis n.sp. from the mouth and pharyngeal cavity ofEmydura sp. in New South Wales are described. The new species differ from other species of the genus mainly in the number and shape of the genital hooks. New locality records ofN. chelodinae fromChelodina longicollis and ofPolystomoides australiensis fromE. krefftii are given. ac]19821026

Effects of dietary corticosterone on the growth and metabolism of immature Gallus domestlcus

Four-week-old chicks were fed on diets containing corticosterone (0, 5, 10, 20, and 40 mg/kg) for 9 days. Food intake, weight gain, plasma concentrations of corticosterone and other constituents, some organ weights, and adrenal cholesterol concentration were measured. Plasma corticosterone concentration was increased ( P < 0.05) by dietary corticosterone, particularly at the two highest rates of inclusion. The concentrations of glucose, cholesterol, triglyceride, protein, and uric acid in the plasma increased ( P < 0.05) with increasing concentrations of dietary corticosterone. Growth rate and relative weight of the cloacal bursa declined ( P < 0.05), while the relative weight of the liver increased ( P < 0.01), with increasing dietary corticosterone; relative weights of the spleen and adrenals were not significantly affected, nor was the adrenal concentration of cholesterol. Abdominal fat was increased sixfold by the two highest corticosterone concentrations.

Acute toxicity of citrinin in Turkeys and Ducklings

Citrinin, a naturally occurring mycotoxin, was dissolved in dimethyl-sulphoxide - 70% ethanol (3:1, v/v) and administered orally in two trials to 7-day-old male turkey poults and male white Pekin ducklings. The single dose LD50 value in 7-day-old male turkey poults was 56 mg/kg and in 7-day-old male white Pekin ducklings it was 57 mg/kg. The mycotoxin was nephrotoxic in both species, but the renal lesions were more severe in turkeys and were characterised by degeneration and necrosis of renal tubular epithelium. In turkeys, lesions were found in the liver and included hepatic cell necrosis and biliary hyperplasia. Lymphoid necrosis with depletion involved the thymus and cloacal bursa of turkeys and ducklings. These latter lesions were the most prominent histopathological alterations in citrinin-treated ducklings.

Immune Response of White Leghorn Chicks from Vaccination with Different Strains of Infectious Bursal Disease Virus and in the Presence of Maternal Antibodies

SUMMARY White Leghorn chicks 1 to 11 days old possessing maternal antibodies to infectious bursal disease (IBD) were vaccinated with the 2512-P48, 2512-P84, LKT, and BV strains of IBD virus by different routes. Their dams had been vaccinated against IBD at one day old and revaccinated at 14 weeks and every 90 days thereafter. The 2512-P48, 2512-P84, and LKT strains did not bestow satisfactory immunity on the progeny as measured by challenge and the agar-gel precipitin test. In contrast, the BV strain engendered good immunity when used as a vaccine at as early as 4 days old. Moderate lesions were found histologically in the cloacal bursa in the postvaccination period, although no clinical signs of IBD were noted. Significant immunosuppression did not occur when chicks were vaccinated with BV IBD virus at 4 days old, vaccinated against Newcastle disease 7 days later, and subsequently given Newcastle disease challenge virus. Primary vaccination of White Leghorn chicks to be placed in IBD-endemic areas in the field is discussed with reference to susceptibility to virus infection, vaccination status of the breeders, level of maternal antibodies (7), and the need for using IBD vaccine strains of differing degrees of virulence and immunogenicity to meet frequently varying field conditions.

Histochemical Localization of T-Cells in Tissue Sections

Utilizing the acid alpha-naphthyl acetate esterase histochemical staining technique, cells with established T-cell (thymus-derived) staining characteristics could be consistently demonstrated in the periarteriolar lymphatic sheaths of the spleen and the diffusely infiltrated area of the cloacal bursa. The same areas failed to stain positively in significant numbers following a preincubation period with a specific inhibitor for carboxyl esterase. Lymphoid cells in the thymus, the splenic follicles, and bursal follicles were mostly negative.