Infectivity of Histomonas meleagridis in ducks.

The susceptibility of mule and muscovy ducks to "blackhead" disease caused by Histomonas meleagridis was studied, using an experimental intracloacal inoculation. Turkeys were used as controls. Morbidity, mortality and body weight gain were recorded regularly during the experiments. A direct examination of the caecal content was made to determine the absence or presence of the parasite. Gross and microscopic lesions were observed on days 7, 14, 21, 28 and 35 post infection to evaluate any clinical histomoniosis in ducks and to appraise the histomonad's carriage. A scoring system was developed both for gross and histological lesions of the caecum and liver. Infected mule and muscovy ducks (n = 83) never developed any clinical signs of histomoniasis. Weight gains of infected mule and muscovy ducks were similar to those of uninfected ducks. In 67% of the ducks (56/83), it was possible to demonstrate the parasite in the caecal content throughout the experiment. Typical macroscopic caecal lesions were observed in five of the ducks between days 7 and 21 post infection, with a caecal necropsy main lesion score (MLS = 1.6) less severe than that in turkeys (MLS = 2.9). Only caecal histological lesions occurred in six of the cases. Therefore, ducks do not seem to be a susceptible host for "blackhead" but may act as carrier animals for H. meleagridis. The virulence was apparently not changed, since 67% of turkeys (10/15) infected with the caecal content of positive ducks displayed classical signs of blackhead disease. Even if H. meleagridis alone does not represent a substantial danger in the duck production, its infectivity should to be taken into account in the transmission to more susceptible species.

Light and electron microscopic study of perineal gland in the grasscutter (Thryonomys swinderianus, Temminck 1827).

The thin and ultrathin structure of the perineal gland of the grasscutter was studied using routine histological, histochemical and electron microscopic techniques. The perineal glands were identified in the zona cutanea of the anal canal of males more than 4 months old. These glands are organized on a lobular model made up of sebaceous cells and isolated by connective parietal cells. The paler in colour the sebaceous cells, the more lipid vacuoles they contain. PAS-negative and Sudan III-positive secretions were demonstrated in these cells. Electron microscopy showed that the intracellular organelles were well-developed, which is a mark of high metabolic activity and storage by the glandular cells. Cystic vesicles were found in the lobules. The size and number of these cysts were variable. The position of the cyst cells and the variability of their size suggest that they are formed after lysis of some holocrine secretory cells. These observations suggest a progressive maturation of the gland towards its secretory site. No specific secretory duct for the purpose of draining secretions was observed, however, there were possible discharge pathways, although with no real walls, as is found for the biliary canaliculi.

Anatomical, histological and functional specificities of the digestive tract in the male grasscutter (Thryonomys swinderianus, Temminck 1827).

Using standard methods, the study of topographic and descriptive anatomy, and histology, has led to the specification of some special features and their relationship to the function of the grasscutter digestive tract. These details include the development of dorsal excrescence on the tongue, lack of a true pylorus, and advanced disappearance of Brünner glands in the last third of the duodenum submucosa. More interesting is the size of the caecum, which fills 60% of the abdominal cavity, and the presence of large anal glands, making this animal an unusual rodent.

[Comparative tomography of the lymph nodes of the Peulh Peulh sheep and the Sahel goat. II. Lymph nodes of the caudal vascular net. (Pelvic limbs, pelvis, abdomen and thorax)]. / Topographie comparée des noeuds lymphatiques du mouton Peulh Peulh et de la chèvre du Sahel II: Noeuds lymphatiques du réseau vasculaire caudal. (Membre pelvien, bassin, abdomen et thorax).

Peulh Peulh sheep and Sahel's goat are the most present small Ruminants in the slaughterhouses of Dakar. Former studies have been undertaken in order to facilitate differential diagnosis between the two carcasses. Here, the authors deliver complete topography of lymph nodes of Peulh Peulh sheep and Sahel's goat, for easier meat inspection in abattoirs. This second study is devoted to lymph nodes of caudal part of lymphatic system in the two species, and to the use of their topography in meat inspection.

[Comparative tomography of the lymph nodes of the Peulh Peulh sheep and the Sahel goat. I: Lymph nodes of the cranial vascular net (head, neck and thoracic limb)]. / Topographie comparée des noeuds lymphatiques du mouton Peulh Peulh et de la chèvre du Sahel. I: Noeuds lymphatiques du réseau vasculaire cranial (tête, encolure et membre thoracique).

Peulh Peulh sheep and Sahel's goat are the most present small Ruminants in the slaughterhouses of Dakar. Former studies have been undertaken in order to facilitate differential diagnosis between the two carcasses. Here, the authors deliver complete topography of lymph nodes of Peulh Peulh sheep and Sahel's goat, for easier meat inspection in abattoirs. This first study is devoted to lymph nodes of cranial part of lymphatic system in the two species.

[Experimental study of poisoning of goats with Pergularia tomentosa L]. / Etude expérimentale de l'intoxication des caprins par Pergularia tomentosa L.

A large number of ruminants are often lost in Niger due to poisoning caused by Pergularia tomentosa L. This plant traditionally used to tan skin was experienced in goats. The symptoms observed, the post-mortem findings and the search for toxic compounds suggest that P. tomentosa contains tannins. In addition, this plant most likely also includes substances with cardiac effects.

[Histological study of the lymph nodes of cattle, before and after antigenic stimulation. 2. Immunocytochemistry and electron microscopy]. / Etude histologique, du ganglion lymphatique du bovin, avant et après stimulation antigénique: 2. Immunocytochimie et Microscopie électronique.

A histological and cytological study of stimulated and non-stimulated bovine lymph nodes was performed using immunocytochemistry and electron-microscopic techniques. Immunohistochemical staining using polyclonal antibodies revealed cytoplasmic immunoglobulins producing lymphoid cells. A protein S100 specific serum evidenced antigen presenting cells, macrophages and endothelial cells. In order to identify T lymphocytes, two monoclonal antibodies (M1 and M12) were used. The electron-microscopic study confirmed the localization and identification of different lymphoid and non-lymphoid cells of the lymph node. The techniques used in the present work seem to be suitable for investigating bovine lymph nodes and those with pathologic alterations.

Preliminary report of familial thymic lymphosarcoma in Holstein calves.

Seventy-three cases of the thymic form of leukosis were found in Holstein calves in five departments of France over a period of five months. Most of the calves had been sired by the same bull. The calves were negative for specific antibodies to bovine leukaemia virus. Morphological studies including light and electron-microscopic cytology, and serological and virological studies of 14 of the cases suggest that the disease was transmitted genetically.

[Histologic study of a bovine lymph node before and after antigenic stimulation. 1. Histology, cytology and histometry]. / Etude histologique du ganglion lymphatique du bovin avant et après stimulation antigénique. 1. Histologie, cytologie, et histométrie.

The effect of antigenic stimulation on a bovine lymph node was studied using conventional histological and cytological techniques. The lesions observed in the bovine lymph node following immunological stimulation are similar to those described in other mammalian species. Histometrical studies showed an increase in the size of the nucleus of lymphoid cells in the stimulated lymph nodes. This probably reflects an activation of the lymphoid cell population. The number of the various cell types in the germinal centers appeared to be positively correlated with the stimulation intensity. The complete identification of the different sub-lines of lymphoid cells requires complementary immunocytochemical and electron-microscopic studies.