Immunopathogenesis of bovine neosporosis throughout gestation

Despite Neospora caninum being recognised as a major cause of bovine abortion, its pathogenesis is only partially understood. Evidence of immune mediated placental pathology has been reported as being responsible for compromising pregnancy probably due to an exacerbated Th1 immune response at the maternal-foetal interface. Different clinical outcomes are known to follow experimental infections at different stages of gestation, with foetal death being the most common finding during early gestation infections, and the birth of live congenitally infected calves following infection in mid or late gestation. The aim of the current study was to characterise the placental cellular immune responses and cytokine expression following experimental Neospora infection during pregnancy. Placentomes were collected from cattle experimentally inoculated with the tachyzoites of the Nc-1 strain during early, mid and late gestation. Inflammation in early gestation was generally moderate to severe. Differently in mid gestation, inflammation was mild to moderate and minimal to mild in late gestation. Generally cellular infiltrates were mainly characterised by the presence of CD3+, CD4+ and γδ T-cells; whereas CD8+ and NK cells were less numerous. Macrophages were detected in larger numbers during later time-points after infection. A moderate to severe infiltration of IL-12, IFN-γ and TNF-α expressing cells was observed in the placentas collected in early gestation. This infiltration was more pronounced in the samples of placentome collected from dams carrying a dead foetus or in those that had aborted, compared with mothers carrying live foetuses at the time of sampling. The distribution of the cellular subsets observed in the three studies was similar. However, cellular infiltrates were more severe following infection during the first trimester in comparison to the second and third trimester. Similarly, the infiltration of Th1 cytokine expressing-cells was more severe in early gestation compared with the milder and more minimal infiltrations observed following N. caninum infection in mid and late gestation, respectively. These results may explain the milder clinical outcome observed when animals are infected in later stages of pregnancy

Editorial: Infectious Diseases Affecting Reproduction and the Neonatal Period in Cattle

Editorial on the Research TopicEven with the global scenario after the SARS CoV-2 pandemic, human population keeps growing, and therefore food safety and quality demand is increasing. So, it is required to improve the efficiency in most livestock production systems including the cattle industry. Because the efficiency of cattle industry is far away from optimum (1?3), the intensification of the production systems emerges as a challenge. Currently, over 1 billion heads are raised in our planet. Countries like Argentina, Australia, Brazil, China, and United States extensively raise their cattle on pastures, which represents over 50% of the productive cattle stock worldwide. The main objective of cow-calf systems is to produce the largest quantity of calves per bred cow. Nevertheless, top beef producing countries in some cases achieve only above 50% of weaning rate. Common causes of this low weaning rate usually occur during the breeding season. In this period, cows are usually under suboptimal body condition, exposed to environmental stress and/or infectious diseases, and therefore low pregnancy rates are recorded. The diagnosis of the cause of this early reproductive failure is challenging, unless they are related with infectious diseases. Many research articles reports abortion and perinatal mortality varying from 5 to 12% and 2 to 5%, respectively (4?8) representing a huge loss of calves. During the period from pregnancy diagnosis to calf delivery, the efficiency of detecting the aetiological agents or diseases is still below 50% even though several studies and experimental models on this topic have been developed.Fil: Moore, Dadin Prando. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Innovación Para la Producción Agropecuaria y El Desarrollo Sostenible. - Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Instituto de Innovación Para la Producción Agropecuaria y El Desarrollo Sostenible.; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Cantón, Germán J.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Departamento de Producción Animal; ArgentinaFil: Louge Uriarte, Enrique Leopoldo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Departamento de Producción Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Lesiones patológicas inusuales en una vaquillona afectada por Trueperella pyogenes

Four Hereford heifers of approximately 18 months of age presented nodular formations in the uterus detected by transrectal palpation. This pathology had been previously diagnosed in the herd, which led to the early discarding of 1-2% of heifers per year. Post mortem examination in a severely affected heifer revealed multiple abscesses in the pelvic and abdominal cavity associated with the uterus, serosa of the forelimbs, and liver. Microscopically, the abscesses were characterized by a necrotic center with viable and degenerated neutrophils and necrotic debris, surrounded by a well-defined wall of connective tissue. In addition, multifocal neutrophilic ruminitis associated with acidosis was observed. Intralesional gram-positive bacilli were detected in the abscesses. Trueperella pyogenes was isolated from the purulent content. It is assumed that rumen acidosis was the origin of the dissemination and abscess formation of T. pyogenes in various tissues, including the uterus.Cuatro vaquillonas Hereford de aproximadamente 18 meses de edad presentaron formaciones nodulares en el útero detectadas por palpación transrectal. Esta patología había sido previamente diagnosticada en el rodeo, lo que llevó al descarte temprano de 1-2% de vaquillonas por año. El examen post mortem en una vaquillona gravemente afectada reveló múltiples abscesos en la cavidad pélvica y abdominal asociados al útero, serosa de los preestómagos y el hígado. Microscópicamente, los abscesos se caracterizaron por un centro necrótico con neutrófilos viables y degenerados y restos necróticos, rodeados por una pared bien definida de tejido conectivo. Además, se observó ruminitis neutrofílica multifocal asociada a acidosis. Se detectaron bacilos grampositivos intralesionales en los abscesos. Del contenido purulento se aisló Trueperella pyogenes. Se asume que la acidosis ruminal fue el origen de la diseminación y formación de abscesos de T. pyogenes en varios tejidos, incluido el útero

Seroprevalencia de Chlamydia abortus en majadas ovinas de la provincia de Buenos Aires

Chlamydia abortus es la bacteria causante del aborto enzoótico ovino (AEO), que se caracteriza por provocar importantes pérdidas económicas en muchas áreas del mundo debido a las fallas reproductivas que ocasiona. Existen evidencias de que esta bacteria circula en el país, pero hasta el momento se desconoce la seroprevalencia en algunas regiones.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

Evaluation of species-specific polyclonal antibodies to detect and differentiate between Neospora caninum and Toxoplasma gondii

Neosporosis and toxoplasmosis are major causes of abortion in livestock worldwide, leading to substantial economic losses. Detection tools are fundamental to the diagnosis and management of those diseases. Current immunohistochemistry (IHC) tests, using sera raised against whole parasite lysates, have not been able to distinguish between Toxoplasma gondii and Neospora caninum. We used T. gondii and N. caninum recombinant proteins, expressed in Escherichia coli and purified using insoluble conditions, to produce specific polyclonal rabbit antisera. We aimed to develop species-specific sera that could be used in IHC on formalin-fixed, paraffin-embedded (FFPE) tissue sections to improve the diagnosis of ruminant abortions caused by protozoa. Two polyclonal rabbit sera, raised against recombinant proteins, anti–Neospora-rNcSRS2 and anti–Toxoplasma-rTgSRS2, had specificity for the parasite they were raised against. We tested the specificity for each polyclonal serum using FFPE tissue sections known to be infected with T. gondii and N. caninum. The anti–Neospora-rNcSRS2 serum labeled specifically only N. caninum–infected tissue blocks, and the anti–Toxoplasma-rTgSRS2 serum was specific to only T. gondii–infected tissues. Moreover, tissues from 52 cattle and 19 sheep previously diagnosed by lesion profiles were tested using IHC with our polyclonal sera and PCR. The overall agreement between IHC and PCR was 90.1% for both polyclonal anti-rNcSRS2 and anti-rTgSRS2 sera. The polyclonal antisera were specific and allowed visual confirmation of protozoan parasites by IHC, but they were not as sensitive as PCR testing.</p

Phenotypic characterisation of the cellular immune infiltrate in placentas of cattle following experimental inoculation with Neospora caninum in late gestation

Abstract Despite Neospora caninum being a major cause of bovine abortion worldwide, its pathogenesis is not completely understood. Neospora infection stimulates host cell-mediated immune responses, which may be responsible for the placental damage leading to abortion. The aim of the current study was to characterize the placental immune response following an experimental inoculation of pregnant cattle with N. caninum tachyzoites at day 210 of gestation. Cows were culled at 14, 28, 42 and 56 days post inoculation (dpi). Placentomes were examined by immunohistochemistry using antibodies against macrophages, T-cell subsets (CD4, CD8 and γδ), NK cells and B cells. Macrophages were detected mainly at 14 days post inoculation. Inflammation was generally mild and mainly characterized by CD3+, CD4+ and γδ T-cells; whereas CD8+ and NK cells were less numerous. The immune cell repertoire observed in this study was similar to those seen in pregnant cattle challenged with N. caninum at early gestation. However, cellular infiltrates were less severe than those seen during first trimester Neospora infections. This may explain the milder clinical outcome observed when animals are infected late in gestation.The authors acknowledge the Scottish Government’s Rural and Environment Science and Analytical Services Division (RESAS), UK, and Instituto Nacional de Tecnología Agropecuaria (INTA), Argentina, for funding this study and Dr Alex Schock from Animal Health and Veterinary Laboratories Agency and Prof. Gary Entrican from Moredun Research Institute for useful and constructive discussion.Peer Reviewe

Characterization of the immune cell response in the placentas from cattle following experimental inoculation with Neospora caninum throughout pregnancy

Trabajo presentado al 2nd International Meeting on Apicomplexan Parasites in Farm Animals (Kusadasi, Turquía, 31 octubre al 2 noviembre, 2013).Despite Neospora caninum (NC) being a major cause of bovine abortion worldwide, its pathogenesis is not completely understood. Evidence of immune mediated placental pathology has been reported as being responsible for compromising pregnancy probably due to the adverse effect of an exacerbated Th1 response at the maternal-foetal interface. Different clinical outcomes are known to follow experimental infections at different stages of gestation, with foetal death being the most common finding during early gestation infections, and the birth of live congenitally infected calves upon infection at mid or late gestation. The aim of our studies was to characterise placental immune responses following experimental infection during pregnancy. Cows were infected with NC tachyzoites at day 70, 140 and 210 of pregnancy and culled at 14, 28, 42 and 56 days post inoculation. Placentomes were examined by immunohistochemistry using antibodies against macrophages, T-cells (CD3, CD4, CD8, ¿¿TCR), NK and B cells and by in situ hybridization to characterize cytokine expression (IL-12, IFN-¿, TNF-¿ and IL-4). Inflammation was mainly characterised by the presence of CD3+, CD4+ and ¿¿ T-cells during the three time points. In early gestation inflammation was generally moderate to severe and mainly characterized by infiltration of IL-12, IFN-¿ and TNF-¿ expressing cells. This infiltration was more pronounced in the samples of placentome collected from dams carrying a dead foetus or one that had aborted, compared with the mothers carrying live foetuses at the time of sampling. In contrast, the infiltration of CD3+, CD4+, CD8+ and ¿¿ T-cells and Th1 cytokine expressing-cells was less evident following NC infection at mid gestation and scarce during infection at late gestation. These findings may partially explain the milder clinical outcome observed when animals are infected with NC at mid or late gestation.Peer Reviewe

Dictyocaulosis in beef cows in Buenos Aires province, Argentina: description of two outbreaks

La dictiocaulosis o bronquitis verminosa es ocasionada por Dictyocaulus viviparus, un nematode de ciclo de vida directo, y está asociada, mayormente, a brotes de enfermedad clínica en bovinos jóvenes en su primera temporada de pastoreo. El presente trabajo describe dos brotes de bronquitis verminosa que provocó la mortandad de entre el 13,6 % y el 15,7 % de dos rodeos de vacas de cría de establecimientos de la provincia de Buenos Aires, Argentina. En ambos brotes, los hallazgos clínicopatológicos en los animales afectados y la presencia de nematodes pulmonares, en algunos casos solo observados en el estudio histopatológico, permitieron confirmar este diagnóstico.Dictyocaulosis or parasitic bronchitis is caused by Dictyocaulus viviparus, a direct life cycle nematode, and is most frequently associated with clinical disease in young cattle during their first grazing season. This work describes two outbreaks of dictyocaulosis, in two cowcalf farms in Buenos Aires province, Argentina that caused the death of 13.6 % and 15.7 % of animals, respectively. In both outbreaks, clinical and pathological findings, and the presence of nematodes in respiratory tract, in some cases only observed in the histopathological analysis, allowed diagnosis confirmation.Facultad de Ciencias Veterinaria

Brote de abortos ovinos por Campylobacter fetus fetus en Argentina

Campylobacter infection is one of the major causes of ovine abortionsworldwide. However there are no previous reports of Campylobacter fetussubspecies fetus associated to outbreak ovine abortion in Argentina. Thisstudy constitutes the first report of C. fetus fetus outbreak ovine abortion innaturally infected ewes in Argentina. The problem was presented in a dairyflock of 205 pampinta ewes. In one week 7 abortions were recorded. Some ofthe aborted sheep also retained placentas and showed vaginal discharges.Twins and three placentas were sampled to determine the cause of theabortions. C. fetus fetus was isolated in lung, liver and abomasal fluids fromboth fetuses and in 2 out of 3 placentas. C. fetus fetus DNA was detected in2/3 placentas tested and in lungs of both fetuses. Additionally, N. caninumDNA was amplified in a ewe placenta. No N. caninum or T. gondii serologicaltests were carried out in the ewes, therefore these protozoa infection couldnot be ruled out in the flock. Toxoplasma and Neospora infection are relativelycommon in Argentinean flocks. However, protozoan abortion in smallruminants has not been extensively reported, therefore it is important to ruleout the presence of these pathogens when ovine abortions are registered.Further work is needed in order to quantify the impact of C. fetus fetusinfection in sheep production systems of the region.Fil: Fiorentino, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Stazionati, Micaela Fiorela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Hecker, Yanina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Morsella, Claudia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Germán Cantón. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Romero Harry, Hernán. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Velilla, Alejandra Vanesa. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Gallo Vaulet, Maria Lucia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Rodríguez Fermepin, Marcelo. Instituto de Fisiopatología y Bioquímica Clinica; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Bedotti, Daniel Osvaldo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentin

Controlling Endemic Neospora caninum-Related Abortions in a Dairy Herd From Argentina

After diagnosis of endemic abortions due to neosporosis in a commercial dairy farm, routes of Neospora caninum-transmission were evaluated in order to choose the best strategy for reducing its seroprevalence and related abortions. Fifty two dam-calf pairs were bled at parturition. Additionally, 22 female calves were also sampled at regular 3 month intervals until 18–22 months. N. caninum specific antibodies were assayed by IFAT. Serum samples were tested at a dilution 1:25 for calves before colostrum intake and heifers before mating and 1:100 for multiparous cows. Only serum samples from IFAT seropositive cattle involved in the evaluation of the routes of transmission were assessed by a commercial IgG avidity ELISA. Seropositive cows or heifers were artificially inseminated with semen from Hereford bulls. The progenies from these female animals were sent to a feed lot to produce meat. Different generalized linear models (GLM) were used to study the relationship between abortion, age category, and serostatus. Seropositive heifers were more likely to have a record of abortion (OR 2.7; 95% CI 1.6–4.7). Vertical transmission frequency was 55.5% (5 seropositive calves/9 seropositive cows). Horizontal transmission was 22.7% (5 female calves seroconverted at least one time/22 females calves sampled during 24 months) and these 5 female calves had low avidity. In heifers, both seroprevalence and abortion rates decreased from 22.1 and 8.4% of 475 in 2009 to 6.1 and 4.3% of 578 in 2015, respectively (p < 0.01). Over 5 years, N. caninum-seroprevalence and the related abortions in heifers decreased after the control strategy was assessed.Fil: Lagomarsino, H.. No especifíca;Fil: Scioli, Agustín. No especifíca;Fil: Rodríguez, Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Armendano, Joaquín Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Fiorani, Franco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Bence, Ángel. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: García, Joaquín. No especifíca;Fil: Hecker, Yanina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gual, Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Cantón, Germán. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Odeón, Anselmo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Campero, Carlos Manuel. No especifíca;Fil: Moore, Dadin Prando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin