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New Insights into Immunopathological Forms of Bovine Paratuberculosis
52
ESVP/ECVP Proceedings 2012
IMMUNE PHENOTYPING OF PLACENTAS FOLLOWING EXPERIMENTAL INOCULATION WITH NEOSPORA CANINUM DURING PREGNANCY G. Cant on *,y, J. Benavides *,z, S. Maley *, F. Katzer *, J. Palarea-Albaladejo x, P. Bartley *, M. Rocchi *, E. Innes * and F. Chianini* *Moredun Research Institute, Scotland, yINTA, Argentina, zInstituto de Ganaderıa de Monta~na, Spain and xBioSS, Scotland Introduction: Despite Neospora caninum (NC) being a major cause of bovine abortion worldwide, its pathogenesis is not completely understood. NC stimulates host cell-mediated immune responses, which may be responsible for placental damage leading to abortion. The aim of our studies was to characterize placental immune responses following experimental infection during pregnancy. Materials and Methods: Cows were infected with NC at days 70, 140 and 210 of pregnancy and were culled at 14, 28, 42 and 56 days post inoculation. Placentomes were examined by immunohistochemistry using antibodies against macrophages, T cells (CD3, CD4, CD8 and gdTCR), NK and B cells. Results: Inflammation in early gestation was generally moderate to severe. In mid-gestation inflammation was mild to moderate and it was slight to mild in late gestation. Cellular infiltrates were mainly characterized by the presence of CD3+, CD4+ and gd T cells, while CD8+ T cells and NK cells were less numerous. Macrophages were detected in increasing numbers during later time points after infection. Conclusions: The distribution of the cell subsets observed in the studies was similar. However, cellular infiltrates were more severe following infection during the first trimester in comparison with second and third trimester infections. This may explain the milder clinical outcome observed when animals are infected at mid or late gestation.
148:1, 2013
TOXOPLASMOSIS: DOES RECRUDESCENCE OCCUR IN A FLOCK IN BREEDING SEASONS AFTER AN OUTBREAK? J.F. Edwards * and J.P. Dubeyy *Texas A&M University, College Station, Texas and yUSDA, Agricultural Research Service, Animal and Natural Resources Institute, Beltsville, Maryland, USA Introduction: The question of whether toxoplasmosis will reoccur in a ewe in subsequent seasons or whether Toxoplasma abortion confers protective immunity is an unresolved, disputed question. Materials and Methods: A small closed flock of Suffolk sheep was studied for reoccurrence of toxoplasmosis after an outbreak where 28/41 ewes lost lambs due to the infection. The next breeding year, the precolostral sera from lambs were tested for Toxoplasma antibody and the aetiology of any newborn lamb losses was investigated for abortifacients including Toxoplasma. Ewe serum antibody titres were compared annually. The flock was monitored for 6 years. Results: In addition to new females reaching maturity in this closed flock, 23 of the original 41 animals were studied. Of ewes bled in the previous year, all were still Toxoplasma seropositive, but titres had declined. Only one ewe with a Toxoplasma titre of 3,200 and that had lost her lamb the previous year aborted a lamb from which virulent T. gondii was isolated. Other ewes lambed normally. Some lambs were lost due to non-Toxoplasma-related conditions. Except for normal lambs from three ewes that may have suckled, precolostral sera had no Toxoplasma antibodies. In subsequent years, abortions were not a problem in the flock and most of the original ewes had one to three normal lambs for 2e4 seasons after the abortion outbreak. Conclusions: The low incidence in view of the virulent isolate acting in this herd is significant. The results support the hypothesis that most sheep that have aborted due to T. gondii develop protection against future toxoplasmosis induced abortion.
Bacterial and Mycoplasma Diseases NEW INSIGHTS INTO IMMUNOPATHOLOGICAL FORMS OF BOVINE PARATUBERCULOSIS P. V azquez *, J.M. Garrido *, V. P erez y and R.A. Juste* *NEIKER-Tecnalia, Derio and yUniversity of Leon, Leon, Spain Introduction: Paratuberculosis is a complex disease. Here, we report a simplified classification of immunopathological forms of bovine paratuberculosis based on serological, microbiological and pathological findings and their implications on epidemiology and disease control. Materials and Methods: We examined 1,031 slaughtered adult Friesian cattle by ELISA for serum antibodies, by isolation and PCR for Mycobacterium avium subsp. paratuberculosis (MAP) detection in tissues, and by histopathological examination. Results: The five immunopathological forms were grouped into latent (delimited focal lesions), accounting for 38.9% of the animals, and patent (delimited multifocal and diffuse lesions), affecting 7.7%. Humoral responses were mostly related to patent forms (69.7%). MAP detection and viability rates increased with tissue damage extension. Age-pattern differed between forms. Latent form frequencies were relatively constant throughout adulthood, while patent forms sharply decreased beyond 4 years of age. No wasting or reduced lifespan was observed in latent forms. Carcass weights were markedly reduced in cows with high bacterial loads (22.2%) or diffuse enteritis (26.0%). Lifespan was nearly 1 year shorter in ELISA-positive or diffuse forms. Diffuse lymphocytic forms showed the shortest and least variable lifespan (37 4.5 months). Conclusions: Latent infections might represent forms of resistance because of reduced extension and low MAP viability rate. Patent forms had higher rates of bacterial viability, occupied larger sections of the intestine and were associated with shorter lifespan and smaller weight.
HISTOPATHOLOGICAL, IMMUNOHISTOCHEMICAL AND MOLECULAR STUDIES OF NATURALLY OCCURRING PARATUBERCULOSIS IN SHEEP G.C. Sonawane and B.N. Tripathi Animal Health Division, Central Sheep and Wool Research Institute, Avikanagar, Rajasthan 304501, India Introduction: Paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is an economically important disease of ruminants. In this study histopathological, immunohistochemical and molecular studies were carried out in MAP-infected sheep. Materials and Methods: Tissues of 56 sheep from an endemically infected organized flock were used for histopathological studies. Immunoperoxidase and conventional and quantitative polymerase chain reactions (qPCRs) were carried out for demonstration of MAP antigen or its genome. Results: All 56 sheep were classified as paucibacillary (PB 5 18) or multibacillary (MB 5 38) on the basis of histopathology and mycobacterial loads. In PB sheep, the small intestinal mucosa was infiltrated predominantly with large number of lymphocytes amidst which focal to multifocal granulomas with occasional acid-fast bacilli (AFB) and multinucleated giant cells were observed. Focal to multiple small granulomas were also observed in the mesenteric lymph nodes (MLN) of these sheep. In MB sheep, microscopical lesions were characterized by diffuse infiltration of epithelioid macrophages loaded with clusters of AFB in the intestinal mucosa. Positive immunolabelling for MAP was observed in 55.6% (10/18) and 77.8% (14/ 18) in PB and MB cases, respectively. The IS900 gene PCR detected 13.3% (2/15) of PB and 85.7% (24/28) of MB sheep. The qPCR detected 100% of PB (15/15) and MB (23/23) sheep tested. Conclusions: In the present study, characteristic histological changes of PB and MB sheep were described for post-mortem diagnosis of paratuberculosis. Immunohistochemical labelling and qPCR were sensitive methods in confirming PB cases with scarce or no bacilli.
ESVP/ECVP Proceedings 2012
IMMUNE PHENOTYPING OF PLACENTAS FOLLOWING EXPERIMENTAL INOCULATION WITH NEOSPORA CANINUM DURING PREGNANCY G. Cant on *,y, J. Benavides *,z, S. Maley *, F. Katzer *, J. Palarea-Albaladejo x, P. Bartley *, M. Rocchi *, E. Innes * and F. Chianini* *Moredun Research Institute, Scotland, yINTA, Argentina, zInstituto de Ganaderıa de Monta~na, Spain and xBioSS, Scotland Introduction: Despite Neospora caninum (NC) being a major cause of bovine abortion worldwide, its pathogenesis is not completely understood. NC stimulates host cell-mediated immune responses, which may be responsible for placental damage leading to abortion. The aim of our studies was to characterize placental immune responses following experimental infection during pregnancy. Materials and Methods: Cows were infected with NC at days 70, 140 and 210 of pregnancy and were culled at 14, 28, 42 and 56 days post inoculation. Placentomes were examined by immunohistochemistry using antibodies against macrophages, T cells (CD3, CD4, CD8 and gdTCR), NK and B cells. Results: Inflammation in early gestation was generally moderate to severe. In mid-gestation inflammation was mild to moderate and it was slight to mild in late gestation. Cellular infiltrates were mainly characterized by the presence of CD3+, CD4+ and gd T cells, while CD8+ T cells and NK cells were less numerous. Macrophages were detected in increasing numbers during later time points after infection. Conclusions: The distribution of the cell subsets observed in the studies was similar. However, cellular infiltrates were more severe following infection during the first trimester in comparison with second and third trimester infections. This may explain the milder clinical outcome observed when animals are infected at mid or late gestation.
148:1, 2013
TOXOPLASMOSIS: DOES RECRUDESCENCE OCCUR IN A FLOCK IN BREEDING SEASONS AFTER AN OUTBREAK? J.F. Edwards * and J.P. Dubeyy *Texas A&M University, College Station, Texas and yUSDA, Agricultural Research Service, Animal and Natural Resources Institute, Beltsville, Maryland, USA Introduction: The question of whether toxoplasmosis will reoccur in a ewe in subsequent seasons or whether Toxoplasma abortion confers protective immunity is an unresolved, disputed question. Materials and Methods: A small closed flock of Suffolk sheep was studied for reoccurrence of toxoplasmosis after an outbreak where 28/41 ewes lost lambs due to the infection. The next breeding year, the precolostral sera from lambs were tested for Toxoplasma antibody and the aetiology of any newborn lamb losses was investigated for abortifacients including Toxoplasma. Ewe serum antibody titres were compared annually. The flock was monitored for 6 years. Results: In addition to new females reaching maturity in this closed flock, 23 of the original 41 animals were studied. Of ewes bled in the previous year, all were still Toxoplasma seropositive, but titres had declined. Only one ewe with a Toxoplasma titre of 3,200 and that had lost her lamb the previous year aborted a lamb from which virulent T. gondii was isolated. Other ewes lambed normally. Some lambs were lost due to non-Toxoplasma-related conditions. Except for normal lambs from three ewes that may have suckled, precolostral sera had no Toxoplasma antibodies. In subsequent years, abortions were not a problem in the flock and most of the original ewes had one to three normal lambs for 2e4 seasons after the abortion outbreak. Conclusions: The low incidence in view of the virulent isolate acting in this herd is significant. The results support the hypothesis that most sheep that have aborted due to T. gondii develop protection against future toxoplasmosis induced abortion.
Bacterial and Mycoplasma Diseases NEW INSIGHTS INTO IMMUNOPATHOLOGICAL FORMS OF BOVINE PARATUBERCULOSIS P. V azquez *, J.M. Garrido *, V. P erez y and R.A. Juste* *NEIKER-Tecnalia, Derio and yUniversity of Leon, Leon, Spain Introduction: Paratuberculosis is a complex disease. Here, we report a simplified classification of immunopathological forms of bovine paratuberculosis based on serological, microbiological and pathological findings and their implications on epidemiology and disease control. Materials and Methods: We examined 1,031 slaughtered adult Friesian cattle by ELISA for serum antibodies, by isolation and PCR for Mycobacterium avium subsp. paratuberculosis (MAP) detection in tissues, and by histopathological examination. Results: The five immunopathological forms were grouped into latent (delimited focal lesions), accounting for 38.9% of the animals, and patent (delimited multifocal and diffuse lesions), affecting 7.7%. Humoral responses were mostly related to patent forms (69.7%). MAP detection and viability rates increased with tissue damage extension. Age-pattern differed between forms. Latent form frequencies were relatively constant throughout adulthood, while patent forms sharply decreased beyond 4 years of age. No wasting or reduced lifespan was observed in latent forms. Carcass weights were markedly reduced in cows with high bacterial loads (22.2%) or diffuse enteritis (26.0%). Lifespan was nearly 1 year shorter in ELISA-positive or diffuse forms. Diffuse lymphocytic forms showed the shortest and least variable lifespan (37 4.5 months). Conclusions: Latent infections might represent forms of resistance because of reduced extension and low MAP viability rate. Patent forms had higher rates of bacterial viability, occupied larger sections of the intestine and were associated with shorter lifespan and smaller weight.
HISTOPATHOLOGICAL, IMMUNOHISTOCHEMICAL AND MOLECULAR STUDIES OF NATURALLY OCCURRING PARATUBERCULOSIS IN SHEEP G.C. Sonawane and B.N. Tripathi Animal Health Division, Central Sheep and Wool Research Institute, Avikanagar, Rajasthan 304501, India Introduction: Paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is an economically important disease of ruminants. In this study histopathological, immunohistochemical and molecular studies were carried out in MAP-infected sheep. Materials and Methods: Tissues of 56 sheep from an endemically infected organized flock were used for histopathological studies. Immunoperoxidase and conventional and quantitative polymerase chain reactions (qPCRs) were carried out for demonstration of MAP antigen or its genome. Results: All 56 sheep were classified as paucibacillary (PB 5 18) or multibacillary (MB 5 38) on the basis of histopathology and mycobacterial loads. In PB sheep, the small intestinal mucosa was infiltrated predominantly with large number of lymphocytes amidst which focal to multifocal granulomas with occasional acid-fast bacilli (AFB) and multinucleated giant cells were observed. Focal to multiple small granulomas were also observed in the mesenteric lymph nodes (MLN) of these sheep. In MB sheep, microscopical lesions were characterized by diffuse infiltration of epithelioid macrophages loaded with clusters of AFB in the intestinal mucosa. Positive immunolabelling for MAP was observed in 55.6% (10/18) and 77.8% (14/ 18) in PB and MB cases, respectively. The IS900 gene PCR detected 13.3% (2/15) of PB and 85.7% (24/28) of MB sheep. The qPCR detected 100% of PB (15/15) and MB (23/23) sheep tested. Conclusions: In the present study, characteristic histological changes of PB and MB sheep were described for post-mortem diagnosis of paratuberculosis. Immunohistochemical labelling and qPCR were sensitive methods in confirming PB cases with scarce or no bacilli.