Improved surveillance of amphistome parasites and their intermediate hosts is crucial for comprehending their epidemiology and developing effective prevention and control measures, since amphistomosis is among the neglected parasitic diseases of ruminants, alongside schistosomiasis and fasciolosis. This study characterized the diversity of freshwater gastropods collected from six South African provinces and assessed their potential in the transmission of amphistomes infecting livestock. A total of 472 freshwater gastropods were collected from 6 provinces of South Africa between 2021 and 2023, and 11 snail species were identified based on shell morphology and confirmed using the mitochondrial cytochrome c oxidase I (COI) gene. Snails were screened for amphistome infection by cercarial shedding, followed by polymerase chain reaction (PCR) using the internal transcribed spacer 2 (ITS-2) region. Of these, 43 snails comprising Radix (R.) natalensis (n = 15), Physella (P.) acuta (n = 20), and Melanoides (M.) tuberculata (n = 8) shed cercariae. DNA was extracted from the shed cercariae and successfully amplified for amphistome DNA. However, only seven sequences obtained from cercariae shed by P. acuta (n = 5) and M. tuberculata (n = 2) were identified as amphistome spp. Cercariae from P. acuta were identified as Calicophoron microbothrium (n = 2) and Paramphistomidea spp. (n = 3), while the two cercarial samples from M. tuberculata were also identified as C. microbothrium. Whole tissue from the remaining 429 snails that did not shed cercariae was harvested and screened for amphistome DNA. Of these, 59 snails yielded an amplicon of the expected band size (380 bp) for amphistomes; however, the majority failed downstream quality control, while some amplified gastropod DNA. To the best of our knowledge, these findings provide the first confirmation of M. tuberculata as an intermediate host in the natural transmission of C. microbothrium in South Africa, as well as the first report of natural infection with C. microbothrium in P. acuta in sub-Saharan Africa. This study therefore represents a significant addition of this invasive snail species to the list of known intermediate hosts of amphistomes in Africa.
Joaquín Mozo, Julieta María Decundo, Guadalupe Martínez, Susana Nelly Dieguez, Alejandro Luis Soraci, Denisa Soledad Pérez Gaudio
The environmental dissemination of veterinary antibiotics through livestock feces represents a relevant concern within the One Health framework due to its potential effects on ecosystem functioning and antimicrobial resistance (AMR) selection. Oxytetracycline (OTC), widely used in swine production systems, is excreted largely as parent compound and may reach surrounding environments through rainfall-driven runoff. This study evaluated the seasonal persistence and runoff-mediated transport of OTC from swine feces under natural field conditions. Experimental fecal deposits fortified with OTC were exposed outdoors for 30 days across four seasons, and runoff water generated after natural precipitation events was collected and analyzed by HPLC-UV. In parallel, culturable aerobic mesophilic bacteria were quantified in exposed soils to assess potential microbiological responses. Meteorological variables were integrated to evaluate their influence on OTC mobilization and environmental behavior. OTC residues were detected in runoff water in all seasons and persisted until late-stage rainfall events, indicating sustained environmental availability and continuous hydrological transport. Higher concentrations were generally associated with increased precipitation intensity and erosivity, whereas cumulative precipitation and temperature emerged as key explanatory variables in regression models. Sediment production followed similar seasonal patterns, highlighting the potential relevance of particle-associated transport pathways that warrant further quantitative investigation. OTC-exposed soils showed significantly higher culturable bacterial counts than controls, indicating shifts in microbial abundance under antibiotic exposure, which potentially reflects the selection of tolerant bacterial populations. Importantly, all detected concentrations exceeded the predicted no-effect concentration for resistance selection (PNEC MIC), resulting in consistently high risk quotients across all seasons, and indicating a high potential risk for resistance selection. These findings demonstrate that runoff represents a relevant pathway for the environmental dissemination of OTC from swine feces under realistic field conditions. The persistence of residues and the consistently high AMR selection risk highlight the need to integrate environmental monitoring and resistance risk assessment into livestock waste management strategies.
Lipopolysaccharide (LPS) is a key virulence factor that induces intestinal oxidative damage in livestock and poultry, and cellular ferroptosis is one of the triggers of oxidative stress. Ferulic acid (FA) is a natural phenolic acid with antioxidant, anti-inflammatory and anti-ferroptosis properties. This study aimed to investigate the protective effects of FA against LPS-induced ferroptosis in the porcine small intestinal epithelial cell line (IPEC-J2) and to elucidate the underlying mechanisms. The experiment included four treatment groups: control group (CON), 50 μg/mL FA group (FA), 10 μg/mL LPS group (LPS), and 50 μg/mL FA combined with 10 μg/mL LPS group (FA and LPS), with all treatments lasting 24 h. The results showed that FA inhibited ferroptosis in IPEC-J2 cells. LPS successfully induced ferroptosis, as evidenced by decreased cell viability, increased levels of ROS, MDA, and Fe 2+, downregulation of GPX4 and SLC7A11, and upregulation of TFRC and ACSL4. FA effectively alleviated LPS-induced ferroptosis in IPEC-J2 cells, with an efficacy comparable to that of the ferroptosis inhibitor Fer-1. Transcriptomic analysis revealed that FA significantly reversed the gene expression changes induced by LPS, with differentially expressed genes enriched in pathways related to ferroptosis, TNF signaling, NF-κB signaling, arachidonic acid metabolism, and PI3K-Akt signaling. Protein–protein interaction (PPI) network analysis indicated that genes such as HMGCS1, CXCL8, and IL-18 may serve as key nodes mediating the protective effects of FA. In conclusion, FA alleviates LPS-induced ferroptosis in IPEC-J2 cells by regulating glutathione metabolism, maintaining iron homeostasis, and inhibiting lipid peroxidation. This effect is closely associated with the coordinated regulation of inflammatory responses, lipid metabolism, and ferroptosis-related signaling pathways.
Lilian Rayanne de Castro Eloy, Markyson Tavares Linhares, Hodias Sousa de Oliveira Filho, João Victor Ferreira Campos, Rodrigo Otávio Silveira Silva, Carlos Augusto de Oliveira Junior, Lucas Rannier Ribeiro Antonino Carvalho, Ricardo Barbosa Lucena
Clostridial gangrenous dermatitis is an acute, often fatal, necrotising soft-tissue disease well recognised in commercial poultry, but it is rarely documented in non-poultry avian species and has not been reported as a peer-reviewed case in greater rheas (Rhea americana). This report describes a fatal case of gangrenous dermatitis with severe necrotising cellulitis, fasciitis and secondary myonecrosis associated with clostridial organisms in an adult captive female greater rhea. The bird developed acute anorexia, depression, inability to stand, loose stools and a focally extensive, irregular, moderately demarcated lesion in the dorsal pelvic region, characterised by dark-red to black discolouration, multifocal bluish-green areas and feather loss shortly after transport with two other adult rheas, and was submitted for post-mortem examination less than 1 h after death. Grossly, the dorsal pelvic, pericloacal, tail-base and proximal hindlimb regions had extensive necrotising dermatitis, emphysematous cellulitis and fasciitis, and haemorrhagic myonecrosis of the affected skeletal muscle. Histologically, there was severe acute necrotising dermatitis, cellulitis, fasciitis, panniculitis and myonecrosis, with oedema, fibrin, haemorrhage, gas spaces, heterophilic inflammation and numerous bacilli within necrotic subcutaneous and fascial tissues. Impression smears contained numerous rod-shaped bacilli compatible with spore-forming bacteria. Anaerobic culture of affected deep subcutaneous/fascial tissue yielded Clostridium perfringens type A, C. septicum and C. chauvoei, with PCR confirmation performed on bacterial growth/isolates. Histological Gram staining demonstrated Gram-positive rod-shaped bacilli within the necrotic tissue matrix. Aerobic culture and Gram staining of cytological smears were not performed. The findings support a fatal gangrenous dermatitis with necrotising cellulitis, fasciitis and secondary myonecrosis associated with clostridial organisms, although the involvement of aerobic or facultative co-pathogens cannot be completely excluded. This case expands the pathological spectrum of gangrenous soft-tissue disease in ratites and indicates that gangrenous dermatitis with deep cellulitis, fasciitis and secondary myonecrosis should be considered in captive greater rheas with acute emphysematous and necrohaemorrhagic soft-tissue lesions.
Jiho Choi, Seongmo Yang, Yelim Lee, Yunjin Sung, Yeon Chae, Taesik Yun, Byeong-Teck Kang, Soochong Kim, Sungin Lee, Hakhyun Kim
Two cats presented with acute progressive vomiting. One cat (Case 1) received prednisolone for suspected chronic inflammatory enteropathy for 14 months. The cat showed hypoalbuminemia, hypocobalaminemia, small intestinal thickening, and focal jejunal stricture with severe proximal dilation on ultrasonography. Exploratory laparotomy confirmed the stricture, and histopathology revealed submucosal fibroplasia with mild lymphoplasmacytic enteritis. The cat died on postoperative day 12. Another cat (Case 2) showed proximal small intestinal obstruction on ultrasonography. A wide-margin resection of the obstructed lesion was performed. Histopathology revealed mild intestinal wall fibrosis with mesenteric inflammation. Masson’s trichrome staining showed submucosal collagen bundles. Immunohistochemistry and clonality analysis by PCR for antigen receptor rearrangement supported the diagnosis of low-grade intestinal T-cell lymphoma. The cat recovered uneventfully and remained restenosis-free during prednisolone treatment for 12 months after surgery. Intestinal stenoses were identified during long-term medical management of chronic enteropathy. This suggests that the extent of the lesion and the surgical resection strategy could be relevant factors for management and prognosis.
