Listeria monocytogenes is a zoonotic bacterium widely distributed in the environment and capable of infecting a broad range of animal species, including humans, usually as a food-borne disease. Although listeriosis is well recognized across multiple hosts, information in small mammals such as rodents and lagomorphs remains comparatively limited, with most reports describing sporadic systemic disease. This study describes two cases of septicemic listeriosis with reproductive involvement in pregnant long-tailed chinchillas (Chinchilla laniger) from a breeding facility in Argentina. Both animals developed depression, anorexia, prolonged gestation, and died. Grossly, both animals had mucosanguineous vaginal discharge and fetal maceration; one also showed multifocal random hepatic necrosis. Histopathology revealed severe multifocal necrosuppurative hepatitis, enteritis, endometritis and placentitis, and pulmonary thromboembolism. Immunohistochemistry demonstrated abundant intralesional Listeria spp. antigen in the liver and uterus. L. monocytogenes DNA was detected in the liver by real-time PCR. The present work expands the knowledge of listeriosis in chinchillas by providing detailed documentation of systemic infection with reproductive involvement. Given the zoonotic nature of L. monocytogenes, early recognition of infection in captive animal populations is relevant for both animal and public health.

Endometrial receptivity failure and recurrent implantation failure (RIF) are clinically heterogeneous outcomes shaped by embryo competence, uterine anatomy, endocrine support, immune adaptation, and the timing of embryo-endometrial synchrony. This Review focuses on how immune-cellular niches, cell-specific and spatiotemporal mechanisms, disease-modified receptivity states, and evidence-to-translation boundaries should be interpreted in assisted reproduction. Single-cell, spatial, and multi-omics studies increasingly resolve abnormalities in stromal, sepithelial, vascular, perivascular, and immune compartments, including altered decidualization, epithelial competence, inflammatory tone, metabolic signaling, and microbiota-immune communication. However, most of these signals remain mechanistic, preclinical, associative, or candidate-biomarker evidence rather than proof of clinical utility. Therefore, biological plausibility should not be conflated with routine care: transcriptome-based receptivity timing tests, empirical immune profiling or treatment, microbiota-directed interventions, endometrial scratching, and regenerative add-ons require cautious interpretation unless they improve clinically meaningful outcomes. Future progress depends on standardized RIF phenotyping, cycle-phase and sampling control, euploid embryo transfer where relevant, external validation of cell-specific markers, prospective trials, live-birth endpoints, safety follow-up, and transparent separation of discovery evidence from clinically actionable strategies.

The study by Yang et al. (https://doi.org/10.1038/s41467-026-76937-y) redefines chronic endometritis as an immunopathological mess driven not only by endometrial stromal plasmacytes and B cells but also by the 'bad company' of co-infiltrating follicular helper T-like cell subsets. These three aberrant local immunocompetent cell types in chronic endometritis might work hand in glove, potentially deteriorating the mucosal immunity and integrity required for successful pregnancy.

Endometrial immune homeostasis is essential for uterine recovery and fertility in postpartum dairy cows, whereas dysregulated inflammation can lead to cytological endometritis (CE) and impaired reproductive performance. Although microRNAs (miRNAs) regulate inflammatory responses, how inflammatory intensity and origin shape miRNA programs in the bovine endometrium remains unclear. In this study, bovine endometrial epithelial cells (BEECs) were exposed to graded inflammatory stimuli, including low- and high-dose lipopolysaccharide (LPS; 10 and 100 μg/mL) and interleukin-1β (IL-1β; 100 ng/mL), followed by small RNA sequencing. A total of 407 miRNAs were retained, among which 16 showed dose-dependent patterns and were classified as early-responsive, threshold-induced, or high-intensity-associated repression groups. Nine miRNAs were early-responsive, whereas six were activated only under high-intensity stimulation. Notably, bta-miR-12053 showed repression under high-dose LPS. In total, 24 inflammation-responsive miRNAs were identified, including 13 with consistent regulation between LPS and IL-1β, and 5 and 6 showing LPS- and IL-1β-biased responses. Integration with in vivo datasets showed selective and time-dependent recapitulation of inflammation-responsive miRNAs, with bta-miR-155 elevated at both day 7 and day 21 and bta-miR-146a elevated at day 21. Predicted targets of miRNAs upregulated under stronger inflammatory stimulation showed enrichment toward downregulated transcripts in CE and were associated with pathways including regulation of the actin cytoskeleton, MAPK signaling, cell adhesion, chemokine signaling, NF-κB signaling, and mTOR signaling. High-intensity-associated miRNAs were enriched toward the disease-associated end of in vivo profiles. Collectively, inflammatory intensity drives shifts in miRNA programs, while stimulus origin shapes specificity. These miRNAs may link excessive inflammation to impaired endometrial immune homeostasis and help identify cows at risk of CE.

Efficient reproductive management in commercial swine production requires minimising non-productive days and ensuring rapid return to oestrus after weaning. The present study evaluated the effect of pre-weaning administration of cloprostenol, a PGF2α analogue, on early reproductive indicators in sows under commercial farm conditions. A total of 734 clinically healthy multiparous sows (parity 2-9) from a commercial farm were randomly allocated to two groups before weaning. Control sows (n = 367) received no treatment, whereas treated sows (n = 367) received an intramuscular injection of cloprostenol sodium 12 h before piglet removal. Reproductive parameters evaluated included the weaning-to-first-service interval (WFSI), proportion of sows in oestrus within 7 days after weaning, pregnancy rate, early endometritis and abortion rate within the first 42 days of gestation. Sows treated with cloprostenol showed a significantly shorter WFSI compared with control sows (treated: 4.94 ± 0.18 days vs. control: 6.41 ± 0.27 days; p = 0.001) and a higher proportion of oestrus within 7 days after weaning (93.19% vs. 84.2%; p = 0.008). Pregnancy rate and early endometritis incidence were not affected by treatment. However, cloprostenol significantly reduced abortion rate during early gestation (0.55% vs. 3.27%; p = 0.006). Under the conditions of this field study, pre-weaning administration of cloprostenol was associated with a shorter WFSI, a higher proportion of sows showing oestrus within 7 days after weaning, and a lower early abortion rate. These findings suggest that cloprostenol may influence early reproductive indicators in multiparous sows under commercial farm conditions, although further studies including endocrine, ovarian and farrowing outcomes are required.