Intracellular pathogens such as Neospora caninum, Brucella abortus, and Bovine Viral Diarrhea Virus (BVDV) are major contributors to bovine abortions, yet many cases remain without a definitive etiological diagnosis despite inflammatory evidence. This study aimed to characterize the immune response in bovine fetuses aborted due to these intracellular agents, comparing them with fetuses showing inflammatory lesions of probable infectious origin and with negative controls. We analyzed cytokine expression (IFN-γ, TNFα, IL-4, IL-8, IL-12) and haptoglobin levels in mid- and late-gestation fetuses. Mid-gestation fetuses infected with intracellular agents exhibited elevated IFN-γ and IL-8 expressions, suggesting a Th1-type immune response, while late-gestation fetuses showed decreased of these cytokines, indicating a shift toward a Th2-type response. Probable infectious abortions at late gestation also showed downregulation of IFN-γ. No significant differences were observed in TNF-α and IL-12 expressions. Additionally, haptoglobin levels were lower in mid-gestation infected fetuses compared to controls. These findings highlight gestational age-dependent immune modulation in response to intracellular infections and suggest that other unidentified pathogens may contribute to abortions with inflammatory lesions but no confirmed etiology. This study enhances our understanding of fetal immune responses in bovine abortions and may support improved diagnostic approaches for reproductive losses in cattle.

Bovine viral diarrhea virus (BVDV) is an important pathogen in cattle and causes considerable economic losses worldwide. In Argentina, where there is no national control program, BVDV remains endemic. In this retrospective study, the epidemiological, clinical and pathological features of postnatal BVDV-associated diseases in 50 outbreaks in central Argentina (1995–2024) were analyzed. Data were obtained from field reports, necropsies, and virological results (virus isolation, RT-nPCR, immunochromatography). No seasonal pattern was found. Acute infections (AIs) and mucosal disease (MD) occurred with similar frequency. Clinical signs included salivation, weakness, emaciation and diarrhea. The lesions were widespread and involved the gastrointestinal tract, skin, lymphoid tissues and spleen. Although MD cases has more extensive tissue involvement, no significant differences in morbidity, mortality or distribution of lesions were observed between AIs and MD. BVDV-1b was the most frequently detected subtype. These results highlight the challenges of BVDV control in extensive production systems. Strengthening diagnostic surveillance, implementing targeted vaccination and eliminating persistently infected animals are essential to reduce BVDV impact in endemic regions such as Argentina.

Enzootic calcinosis (EC) is a chronic disease mainly affecting ruminants consuming calcinogenic plants. In Argentina, EC is associated by the consumption of Solanum glaucophyllum in beef grazing cattle and is one of the most frequent toxicities affecting livestock from low-flooded areas. In this paper, we describe 23 outbreaks of EC in beef cattle due to consumption of S. glaucophyllum in central Argentina between 1990 to 2024. Outbreaks occurred more frequently during the summer-autumn (February-May) and affected more frequently adult beef cattle. An average morbidity and mortality of 13.75% and 4.22% were registered, respectively. The main clinical signs were progressive emaciation, limbs stiffness, and lameness. Necropsies were performed, and gross findings included multifocal-coalescent mineralization of blood vessels, heart, and lung. Microscopically, severe diffuse mineralization was observed mainly in the endocardium and intima and media layers of the aorta. Intra-alveolar mineralization was observed lining the wall of the alveolar septa, confirming calcium salt deposits by von Kossa staining. Blood calcium and phosphorus values in affected cattle remained within the reference ranges. Consumption of S. glaucophyllum was confirmed in all outbreaks. Despite being an endemic problem in the beef industry in Argentina, there are no effective treatments or control strategies, therefore, further studies are necessary to prevent the occurrence of EC. Calcinose enzoótica (CE) é uma doença crônica que afeta principalmente ruminantes que consomem plantas calcinogênicas. Na Argentina, a CE está associada ao consumo de Solanum glaucophyllum em gado de corte e é uma das toxicidades mais frequentes que afetam o gado de áreas de baixa inundação. Neste artigo, descrevemos 23 surtos de CE em bovinos de corte devido ao consumo de S. glaucophyllum na Argentina central entre 1990 e 2024. Os surtos ocorreram com mais frequência durante o verão-outono (fevereiro-maio) e afetaram mais frequentemente o gado bovino adulto. Registou-se uma morbidade e mortalidade médias de 13,75% e 4,22%, respectivamente. Os principais sinais clínicos foram emagrecimento progressivo, rigidez dos membros e claudicação. Foram realizadas necropsias, e os achados macroscópicos incluíram mineralização multifocal a coalescente de vasos sanguíneos, coração e pulmão. Microscopicamente, observou-se mineralização difusa grave, principalmente no endocárdio e nas camadas íntima e média da aorta. Observou-se mineralização intra-alveolar revestindo a parede dos septos alveolares, confirmando depósitos de sais de cálcio pela coloração de von Kossa. Os valores de cálcio e fósforo no sangue dos bovinos afetados permaneceram dentro dos intervalos de referência. O consumo de S. glaucophyllum foi confirmado em todos os surtos. Apesar de ser um problema endêmico na indústria de carne bovina na Argentina, não existem tratamentos ou estratégias de controle eficazes, portanto, mais estudos são necessários para prevenir a ocorrência de CE.

Infectious abortion is a major cause of reproductive loss in cattle, yet the diagnosis remains challenging. In this study, we evaluated the gross and microscopic lesions of bovine fetuses aborted due to the main infectious agents in Argentina. Clear pathogen-specific patterns were identified. Neospora caninum was strongly associated with central nervous system (CNS) and cardiac inflammation, whereas Campylobacter fetus and Brucella abortus predominantly produced bronchointerstitial pneumonia. Leptospira spp. consistently affected hepatic and renal tissues and was associated with marked portal hepatitis and interstitial nephritis. Bovine viral diarrhea virus (BVDV) infections resulted in mild multisystemic and nonspecific lesions. Lesion severity also differed by fetal age. N. caninum produced more severe CNS and cardiac inflammation in mid-gestation fetuses, and C. fetus induced more severe hepatic lesions during mid-gestation. Statistical analyses confirmed distinct organ tropisms and lesion profiles among pathogens, supporting their diagnostic relevance. Based on these findings, targeted sampling of CNS and heart (for N. caninum ); lung (for C. fetus and B. abortus ); liver and kidney (for Leptospira spp. ); and heart, lung, and CNS (for BVDV) may improve diagnostic accuracy in abortion investigations. These findings provide robust criteria for differentiating major abortifacient agents in routine diagnostic practice.