J.F. García Marín

Differences in the immune responses in lambs and kids vaccinated against paratuberculosis, according to the age of vaccination

In order to evaluate and compare the peripheral immune responses induced by the vaccination against paratuberculosis in relation with the age of immunization, two groups of lambs and goat kids were vaccinated at 15 days and 5 months old, respectively. A heat-killed commercial vaccine was inoculated subcutaneously and humoral and cellular immune responses were measured by an ELISA and IFN-gamma assay, respectively, at 0, 30, 90, 180, 270 and 360 dpv in the lambs and 0, 30, 90 and 180 dpv in the caprine. IFN-gamma values did not show statistically significant differences between both groups, but when compared to the unvaccinated controls, this cytokine response tend to disappear earlier in animals vaccinated at 15 days old. The antibody response was always higher and more persistent in animals vaccinated at 5 months. The possibility of the incomplete degree of maturation of the immune system in 15 days old animals as the cause of the differences in the immune response to vaccination is suggested.

Histopathological Classification of Lesions Observed in Natural Cases of Paratuberculosis in Free-ranging Fallow Deer (Dama dama)

Ninety-five adult fallow deer, legally hunted in the Regional Hunting Reserve of El Sueve (Northern Spain), were subjected to a post-mortem examination for paratuberculosis, samples being taken from the proximal and distal jejunum, proximal and distal ileum, ileocaecal valve and associated lymph nodes. The lesions were divided into four categories. Focal lesions (n=19 cases) consisted of small granulomas, mainly in the jejunal and ileal lymph nodes. Multifocal lesions (n=4) consisted of well-demarcated granulomas in the intestinal lymphoid tissue and also in the intestinal lamina propria. Diffuse multibacillary lesions (n=2) were characterized by a severe granulomatous enteritis and lymphadenitis. Macrophages and numerous Langhans giant cells containing many mycobacteria were present, resulting in macroscopical changes in the normal gut morphology. These changes were found from the proximal jejunum to the ileocaecal valve, but lesions were always particularly severe in the distal jejunum. In diffuse intermediate (multibacillary-lymphocytic) lesions (n=3) the infiltrate consisted of lymphocytes, macrophages and Langhans giant cells, with small numbers of mycobacteria. Mycobacterium avium subspecies paratuberculosis was identified by a polymerase chain reaction technique. The widespread occurrence of paratuberculosis in fallow deer in this Reserve represents a potential source of infection for other susceptible species.

Tuberculosis in roe deer from Spain and Italy

TUBERCULOSIS (TB) is a chronic infectious disease caused by bacteria of the genus Mycobacterium ([Grange and others 1990][1]). The detection of wildlife reservoirs of disease is important, particularly in areas where there is a relatively low incidence of the disease in domestic animals.

Control of paratuberculosis (Johne's disease) in goats by vaccination of adult animals

Correspondence to Dr Perez PARATUBERCULOSIS is a chronic wasting disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis. In Spain, the disease is present in all domestic ruminant species (Juste 1990). The infection in goats was first diagnosed in this country in 1979 (Garrido and Le6n 1979) and has been responsible for causing annual losses of greater than 10 per cent of a flock in several regions (Garcia Marin and others 1994). Conventional procedures to control paratuberculosis, based on the identification and culling of infected animals, have been very difficult in small ruminant species due to the lack of sensitivity of the majority of diagnostic tests for identifying infected animals (Kreeger 1991). However, vaccination has offered good results in controlling the disease in several countries (Sigurdsson 1960, Crowther and others 1976, Saxegaard and Fodstad 1985, Cranwell 1993, Perez and others 1995). Since paratuberculous infection is usually initiated very soon after birth, it has been recommended that vaccination should take place during the first few weeks of life (Larsen and others 1964, Saxegaard and Fodstad 1985). However, in ovine species, very good results have been achieved after vaccinating six-month-old sheep which are already likely to be infected (Sigurdsson 1960), or even adult animals (Crowther and others 1976, Perez and others 1995) in areas with a high prevalence of the disease. In all of these cases, a rapid and dramatic decrease in the presentation of new clinical cases was observed among the vaccinated animals. However, there are only a few reports dealing with vaccination of young goats, using either live (Saxegaard and Fodstad 1985, Marly and others 1988) or killed (Leslie and others 1988) vaccines. In all of the cases, a slow and progressive decrease in the prevalence of the infection and the number of clinical cases was observed over some years of follow-up. This study describes the results achieved after the vaccination of adult animals in a flock of goats with a high percentage of losses due to paratuberculosis, confirmed at least four years before the study. During the year before this study, the deaths of more than 15 per cent of animals in a flock of 189 adult, pure Guadarrama goats was recorded by a clinician, presumably due to paratuberculosis. The flock was managed in an extensive system and located in a dry and mountainous area of Madrid Community. Subsequently, paratuberculosis was diagnosed on the basis of clinical signs and by pathological methods in three culled goats, confirming the importance of the disease. A vaccination trial was established and approximately 50 per cent of the flock was vaccinated by the subcutaneous inoculation of 1 ml inactivated commercial vaccine (Gudair; cz Veterinaria) in the flank. In the remaining goats that were kept as non-vaccinated controls, 1 ml phosphatebuffered saline (PBS) was inoculated at the same site. During the following two years, a clinical follow-up was carried out and all the goats culled during this period, for any reason, were examined by pathological methods at the veterinary faculty of Leon. The animals were culled by an intravenous injecgm a S.S 7

Distribution of Lymphocyte Subsets in the Small Intestine Lymphoid Tissue of 1-Month-Old Lambs

Distribution of lymphocyte subpopulations along the small intestine lymphoid tissue has been examined in 1‐month‐old lambs using flow cytometric and immunohistochemical techniques. Monoclonal antibodies against CD4, CD8, γδ, CD45R and B receptors have been employed in samples from continuous ileal Peyer’s patch (IPP), discrete jejunal Peyer’s patches (JPP), ileocaecal valve lymphoid tissue (ICVPP), mesenteric lymph node (MLN) and intra‐epithelial (IEL) and lamina propria (LPL) lymphocytes. Histological studies were also done. Differences in the lymphocyte distribution have been observed between some of the regions examined, especially between IPP and JPP for most of the markers. A remarkable feature was the existence of morphological and lymphocyte distribution differences between ICVPP and IPP, locations that had been traditionally considered as similar. The antibody against CD45R receptor used in this study, that was supposed to mark B cells and some T cells, detected cell populations located in the dome of the follicles in all the samples, whereas the centre was negative. Lymphocytes positive to the B marker employed were located mainly in the centre, suggesting that both antibodies would mark B cells in different maturation status.

Seroprevalence of maedi-visna infection in sheep in the north-east of Spain

Abstract A study was undertaken on the seroprevalence of maedi-visna infection, and its related pathology, in the North-East of Spain. The study included the provinces of Zaragoza (Saragossa), Huesca, Teruel, La Rioja and the south of Navarra (Navarre), and dealt mainly with Rasa, the main local breed of sheep. Two hundred and thirty-three randomly selected flocks, proportionally distributed in accordance with the total sheep population of each province, were studied. Each flock was visited and 20 randomly selected serum samples were taken. Pathological examinations were carried out on 43 live animals with obvious respiratory signs and/or cachexia. Two hundred and twenty-six (97%) flocks showed at least one seropositive animal, and 40.7% of the animals sampled were seropositive. There was little variation between provinces. Among the 43 animals subjected to pathological examination, 31 (72.1%) were seropositive, and typical lesions in the lungs and/or the mammary glands were detected in 24 of these animals. Lesions of sheep pulmonary adenomatosis (SPA) were observed in four sheep, all of them seropositive to maedi-visna virus.

First Confirmation of Schmallenberg Virus in Cattle in Spain: Tissue Distribution and Pathology

Between January and June 2013, nine stillborn bovine foetuses with congenital malformations from nine cattle herds located in Salamanca (central Spain) were detected. Necropsy was performed on two calves. Pathological lesions together with molecular genetics and serological results allowed a definitive diagnosis: first confirmation of Schmallenberg virus (SBV) infection in cattle in Spain. SBV was detected in different tissues and organic fluids in both animals including blood, suggesting a possible viraemia. The umbilical cord was also positive for the presence of SBV in both animals. The former tissue provides an easy to obtain sample and might be a sample of choice when necropsy is carried out in the field.

Immunological detection of sheep experimentally infected with strains of Mycobacterium avium subspecies containing insertion sequence IS901/IS902 and a 40 kDa protein

A monoclonal antibody raised against a 40 kDa protein present in certain M. avium strains (IS901/IS902 positive) was used for developing a blocking ELISA. Sera from experimentally infected sheep were evaluated by indirect ELISA, AGID and blocking ELISA. The blocking assay proved to be highly specific for differentiation of sheep infected with different subspecies of M. avium.

Lambs are Susceptible to Experimental Challenge with Spanish Goat Encephalitis Virus

Spanish goat encephalitis virus (SGEV) is a member of the genus Flavivirus, family Flaviviridae, and causes encephalomyelitis in goats. The aim of this study was to determine whether sheep are susceptible to experimental challenge with SGEV by two different routes. The results show that SGEV can infect sheep by both the subcutaneous and intravenous routes, resulting in neurological clinical disease with extensive and severe histological lesions in the central nervous system. Lambs challenged subcutaneously developed more severe lesions on the ipsilateral side of the brain, but the lesion morphology was similar irrespective of the route of challenge. The clinical presentation, pathogenesis, lesion morphology and distribution shows that SGEV is very similar to louping ill virus (LIV) and therefore any disease control plan must take into account any host species and SGEV vectors as potential reservoirs. Furthermore, discriminatory diagnostics need to be applied to any sheep or goat suspected of disease due to any flavivirus in areas where SGEV and LIV co-exist.

Adenocarcinoma of the small intestine in a goat

A case of intestinal adenocarcinoma is described in a 4-year-old dairy goat with progressive emaciation. At necropsy, a tumour was found in the middle part of the jejunum as an annular, firm white mass which resulted in stenosis and dilation of the intestine proximal to the lesion. Spread of the tumour, with thickening of the contiguous mesentery, and metastasis to the mesenteric lymph nodes were observed. Microscopically, the tumour was characterized by nests or sheets of mucin-rich cuboid or columnar epithelial cells, which formed irregular acinar structures that infiltrated all layers of the intestinal wall. In the mesentery, neoplastic cells were surrounded by an intense fibrous reaction. A diffuse inflammatory infiltrate of lymphocytes was observed both in the mesentery and in the intestinal layers. These findings are compared with those observed in sheep, in which this type of tumour occurs more frequently.