Identification of Ostertagia ostertagi specific cells in bovine abomasal lymph nodes

To investigate the contribution of different bovine cell subpopulations in the development of in vitro induced responses by Ostertagia ostertagi third larval antigen extract (L3), bovine abomasal lymph node cell suspensions were depleted of specific cell populations. The depleted cell suspensions were subsequently assayed for their proliferative responses to O. ostertagi L3 antigen extract. Proliferative responses to O. ostertagi L3 antigen extract were restricted to a CD2+ CD4- CD8- cell population and MHC II+ cells different from B-cells were of major importance. Depletion of CD4, CD8, CD4CD8, IgM or CD21 positive cells did not decrease proliferation to L3 antigen extract. Depletion of gammadelta T-cells, which also comprise a subpopulation of CD2+ CD4- CD8- cells, reduced proliferation to L3 antigen extract only in one animal. The results suggest that either gammadelta T-cells could be involved in the proliferation or that another as yet unidentified population is important for proliferation. The precise role of these populations during infection with O. ostertagi and the mechanism by which these cells may influence the host immune response are important issues that remain to be elucidated.     

Comparative histopathology of the lymph nodes, spleen, liver and kidney in experimental ovine trypanosomosis

The infection of Yankassa rams with three important trypanosome species affecting livestock, namely, Trypanosoma congolense, T. vivax and T. bruceiproduced both acute and chronic fatal conditions. Chronic infections were induced in the three infections by the application of subcurative doses of diaminazene aceturate (Berenil). Pathological changes in the infected animals included splenomegaly and hepatomegaly which were more pronounced in acute than in chronic T. congolense infection. However, these changes were more severe in chronic than in acute T. vivax infection. While splenomegaly was more pronounced in chronic T. bruceiinfection than in acute, hepatomegaly and lymphadenopathy were more severe in acute than in the chronic condition. The increases in size of the spleen, lymph nodes and liver were associated with congestion, increases in cell density related to increased immunological reactions in the spleen and lymph nodes as well as increase in numbers, size and activity of the phagocytic cells in these organs.     

Isolation of bovine syncytial virus from mesenteric lymph nodes of cattle

Bovine syncytial virus was isolated from mesenteric lymph nodes of young dairy calves, beef cattle, and mature dairy cattle. Isolations were made in cocultures of lymph node specimens and bovine embryonic lung cells or by subpassage of cocultures in which cytopathic effects were not initially detected. The bovine syncytial viral isolates after storage at -65 C for 3 months in either infected cell cultures of supernate fluids from suspensions or sonically treated infected cell monolayers were usually recovered. Bovine syncytial virus also was recovered from cell cultures after storage for 6 months at -25 C.     

Virulence-associated protein characterisation of Rhodococcus equi isolated from bovine lymph nodes

Rhodococcus equi has a low pathogenicity in cattle, but it occasionally causes lymph node granulomas, which are detected at abattoir post mortem inspection, and must be distinguished from tuberculous granulomas. Lymph node lesions were detected in 6719 cattle, from a total of 3,263,622 cattle examined post mortem in abattoirs, in the Republic of Ireland, during 1997 and 1998. Histological examination was performed on all lesions, principally for the purpose of identifying animals with tuberculosis. A total of 1122 of the lesions were cultured on blood agar and on Stonebrinks and Lowenstein-Jensen medium containing pyruvate, because the histological findings were difficult to interpret or were suggestive of R. equi infection. R. equi was isolated from 264 lesions. Almost all of the R. equi granulomas were confined to a single lymph node, and were present predominantly in the retropharyngeal, bronchial and mediastinal lymph nodes. R. equi granulomas were present in a significantly higher proportion of the lesions detected in steers and heifers compared to cows. The prevalence in the total population of 3.3 million cattle examined post mortem was 0.008%. The 15-17kDa antigens, associated with virulence in this organism, and the 20kDa antigen, associated with intermediate virulence, were not detected in isolates from 146 cattle, analysed by immunoblot assays. A PCR assay to detect the plasmid gene encoding the 15-17kDa antigens was also negative for isolates from these 146 animals. Plasmids were not detected in 30 isolates which were examined.     

Occurrence of salmonella in the ileum, ileocolic lymph nodes, tonsils, mandibular lymph nodes and carcasses of pigs slaughtered for consumption

This study evaluates the occurrence of Salmonella in pork carcasses and in some risk tissues (ileum, ileocolic and mandibular lymph nodes and tonsils), that can be involved in Salmonella contamination during slaughter. Salmonella was identified in 27 (26.7%) pigs and in 13 (12.9%) carcasses. From these positive carcasses, 69.2% presented the same serotype as that identified in the corresponding pig, which emphasize the pigs importance as a source of Salmonella during the slaughter, suggesting that measures should be taken at the level of pig production in order to reduce the slaughtering of Salmonella-positive animals. The highest value of Salmonella occurrence was reached in the ileocolic lymph nodes (18.8%) and in the ileum (13.9%), representing Salmonella potential faecal source during pork processing at the abattoir. In these samples, a high level of Salmonella was observed in the ileocolic lymph nodes in comparison with the ileum. The mandibular lymph nodes (12.9%) also presented a higher occurrence in comparison with the tonsils (9.9%). These results indicate that the lymph nodes analysis could be more sensitive in the detection of Salmonella than the closer drainage tissue. Otherwise, the presence of Salmonella in the lymph nodes indicates lymphatic spread of the organism, which reflects an increased risk of pork contamination. These results also indicate that, in order to achieve a better control of Salmonella contamination during the slaughter process, it is important to consider the improvement of the evisceration practices and the tonsils as well the extraction of mandibular lymph nodes after slaughter.     

Lymphocyte localization in lymph nodes of pubescent, prepartum, and postpartum sheep

It is generally accepted that lymphocytes associated with the mammary mucosal immune system of non-ruminants may be largely derived from gut-associated lymphoid tissue (GALT). The relationship between the mammary immune system and the GALT of ruminants has not been clearly defined. To address this question, we examined patterns of lymphocyte localization in sheep by 51Cr-labeled lymphocytes following infusion back into donor ewes. We found that lymphocytes taken from mammary lymph nodes of pubescent ewes returned preferentially to mammary nodes, while in prepartum and postpartum ewes, mammary node cells localized equally well in mammary and mesenteric lymph nodes. In contrast, ileal mesenteric lymph node cells from pubescent ewes localized equally well in mammary and mesenteric nodes, but in prepartum and postpartum ewes, localization in mammary nodes was markedly reduced. Comparison of the homing patterns of mammary, mesenteric, and peripheral lymph node cells indicated that mammary node cells behaved similarly to peripheral, rather than mesenteric node cells. This information may be relevant to the extent of communication between the gut and mammary gland in ruminants.     

Subpleural lymph nodes in goat lungs

Subpleural lymph nodes were found in more than 4% of 3245 goat lungs during a slaughterhouse survey of respiratory disease. Their frequency varied between flocks from 2% to as much as 27%. They were more common in feral goats than in crossbreds or Angoras. Their numbers were positively associated with carcass weight and the number of nodular muellerius lesions on the lung surface. Their distribution and architecture were different from the pulmonary lymphoid nodules described in cattle with dictyocaulus re-infection syndrome.     

Comparison of three culture techniques for the isolation of Brucella abortus from bovine supramammary lymph nodes

Three different culturing techniques were compared and evaluated to determine the most effective method for isolating Brucella abortus from bovine supramammary lymph nodes (SM's). In method I, the SM was sliced in half, and the inner surface was minced finely with a sterile scalpel. The minced surface was spread onto the agar surface of 4 selective media. In method II, the SM was cut into small pieces and placed in a bag with a volume of phosphate-buffered saline equal to the volume of the lymph node. The bag was placed in a laboratory blender and the SM was macerated for 5 min. The tissue suspension was spread with a sterile cotton swab onto the agar surface of 4 selective media. In method III, the SM was processed in the laboratory blender. One milliliter of the suspension was pipetted into a flask of biphasic medium, and 2 ml of the suspension was pipetted into another flask of biphasic medium. A total of 626 SM's from 285 cows were cultured. Brucella abortus was isolated from 149 (52.3%) cows by 1 or more methods. Brucella abortus was isolated from 136 cows by method I. 137 cows by method II, and 86 cows by method III. Nine (3.2%) cows were positive by method I only, 11 (3.9%) cows by method II only, and 2 (0.7%) cows by method III only. The isolation rate for method III was significantly lower than for method I or II. There was no significant difference between methods I and II.     

The sonographic evaluation of lymph nodes

Ultrasound can be used to detect and evaluate both normal and abnormal lymph nodes, as well as aid in biopsy sampling procedures, an important part of staging procedures in cancer patients. Several parameters can be evaluated using ultrasound; lymph node size, margins, echogenicity, echopattern (echotexture), acoustic transmission, presence and distribution of vascular flow, and vascular flow indices. The most diagnostically helpful include the short/long axis ratio of the lymph node, the pattern of distribution of the blood vessels within the lymph node, and to some extent the resistive and pulsatility indices. This review discusses the use of ultrasound for detecting, evaluating, and sampling peripheral, abdominal and thoracic lymph nodes in small animals.