Irish Veterinary Journal最新文献

Background: Streptococcus agalactiae, a Gram-positive bacterium, has emerged as an important pathogen for the aquaculture industry worldwide, due to its increased induced mortality rates in cultured fish. Developing interventions to cure or prevent infections based on natural alternatives to antibiotics has become a priority, however, given the absence of scientific evidence regarding their mode of action progress has been slow.

Methods: In this study we aimed to investigate the effect of a mixture of organic acids (natural antimicrobials), AuraAqua (Aq), on the virulence of S. agalactiae using Tilapia gut primary epithelial cells and an in vitro Tilapia gut culture model. Our results show that Aq was able to reduce significantly, in vitro, the S. agalactiae levels of infection in Tilapia gut primary epithelial cells (TGP) when the MIC concentration of 0.125% was tested.

Results and discussion: At bacterial level, Aq was able to downregulate bacterial capsule polysaccharide (CPS) gene expression, capC, resulting in a significant decrease in bacterial surface capsule production. The decrease in CPS production was also associated with a reduction in the pro-inflammatory IFNγ, IL1β, TNFα, SOD and CAT gene expression and H₂O₂ production in the presence of 0.125% Aq (P < 0.0001). The antimicrobial mixture also reduced the levels of S. agalactiae infection in an in vitro gut culture model and significantly reduced the IFNγ, IL1β, TNFα, SOD, CAT gene expression and H₂O₂ production in infected tissue. Moreover, genes involved in Tilapia resistance to S. agalactiae induced disease, MCP-8 and Duo-1, were also downregulated by Aq, as a consequence of reduced bacterial levels of infection.

Conclusion: Conclusively, our study shows that mixtures of organic acids can be considered as potential alternative treatments to antibiotics and prevent S. agalactiae infection and inflammation in the Tilapia fish digestive tract.

Background: Contagious bovine pleuropneumonia (CBPP) is an economically important infectious disease that is characterized by a variable course and insidious nature. A cross-sectional study was conducted in El Jazeera State, Central Sudan, to determine the seroprevalence and risk factors of CBPP in cattle from seven localities. A total of 218 serum samples were randomly collected from apparently healthy cattle aged older than 6 months between April and May 2021 and were tested serologically using a commercial ELISA kit.

Results: The overall seroprevalence of CBPP was 50.5% (110/218). Univariate analysis showed a significant difference (p < 0.05) between sex, locality and water source and seropositivity to CBPP. Multivariate analysis revealed that the independent risk factors (sex, locality and water source) were also statistically significant (p < 0.05). At herd level, out of 20 herds 16 (80%) proved to be positive for CBPP antibodies. It is apparent from the present study that CBPP infection is prevalent among cattle in El Jazeera State, Central Sudan.

Conclusions: To the best of our knowledge, this is the first seroepidemiological study on CBPP infection in Central Sudan. The authors recommend major awareness both in the production area and quarantine centers, as CBPP may result in restrictions on the international trade of animals and animal products.

Background: This cross-sectional study describes a survey designed to fill knowledge gaps regarding farm management practices, parlour management practices and implemented technologies, milking management practices, somatic cell count (SCC) control strategies, farmer demographics and attitudes around SCC management on a sample of Irish dairy farms.

Results: We categorized 376 complete responses by herd size quartile and calving pattern. The average respondent herd was 131 cows with most (82.2%) operating a seasonal calving system. The median monthly bulk tank somatic cell count for seasonal calving systems was 137,000 cells/ml (range 20,000 - 1,269,000 cells/ml), 170,000 cells/ml for split-calving systems (range 46,000 - 644,000 cells/ml) and 186,000 cells/ml for 'other' herds (range 20,000 - 664,000 cells/ml). The most common parlour types were swing-over herringbones (59.1%) and herringbones with recording jars (22.2%). The average number of units across herringbone parlours was 15, 49 in rotary parlours and two boxes on automatic milking system (AMS) farms. The most common parlour technologies were in-parlour feeding systems (84.5%), automatic washers on the bulk tank (72.8%), automatic cluster removers (57.9%), and entrance or exit gates controlled from the parlour pit (52.2%). Veterinary professionals, farming colleagues and processor milk quality advisors were the most commonly utilised sources of advice for SCC management (by 76.9%, 50.0% and 39.2% of respondents respectively).

Conclusions: In this study, we successfully utilised a national survey to quantify farm management practices, parlour management practices and technology adoption levels, milking management practices, SCC control strategies and farmer demographics on 376 dairy farms in the Republic of Ireland. Rotary and AMS parlours had the most parlour technologies of any parlour type. Technology add-ons were generally less prevalent on farms with smaller herds. Despite finding areas for improvement with regard to frequency of liner changes, glove-wearing practices and engagement with bacteriology of milk samples, we also found evidence of high levels of documentation of mastitis treatments and high use of post-milking teat disinfection. We discovered that Irish dairy farmers are relatively content in their careers but face pressures regarding changes to the legislation around prudent antimicrobial use in their herds.

Background: Ovine gammaherpesvirus 2 (OvHV-2) is the causative agent of sheep associated malignant catarrhal fever (MCF). As sheep are the adapted host for OvHV-2, it is generally presumed that infection is not associated with disease in this species. However, a recent case review combined in-situ hybridisation, PCR and histopathology and correlated the viral distribution with systemic necrotizing vasculitis and concluded OvHV-2 was the likely agent responsible for sporadic, MCF-like vascular disease in sheep.

Case presentation: Using similar methods this case study reports on the findings of the first reported cases in an Irish Flock of MCF- like systemic necrotizing vasculitis in sheep associated with OvHV-2. Sheep A, a 16-month-old Texel-cross hogget displayed signs of ill- thrift, Sheep B, a nine-month-old Belclare-cross lamb, was found dead having displayed no obvious symptoms. Both cases occurred on the same farm, however the animals were not related. Lymphohistiocytic vasculitis of various tissues was the predominant histopathological finding in both animals.

Conclusion: By combining histopathology, PCR and in-situ hybridisation results, MCF- like systemic necrotizing vasculitis associated with OvHV-2 has been diagnosed for the first time in an Irish flock.

Background: Penile fibropapilloma is a condition caused by bovine papilloma virus and is frequently encountered in young bulls. Penile fibropapillomatosis is thought to be spread through homosexual mounting behaviour. Fibropapillomas of the penis are painful, often bleed and can impede normal intromission. Treatment may range from allowing time for slow, spontaneous regression to surgical resection but recurrence following surgery is reported by some authors.

Case presentation: Thirty one bulls that were presented to University College Dublin Veterinary Hospital from March 2017 to March 2023 for surgical resection of penile fibropapillomas were included in this retrospective case series. Twenty-seven of the 31 bulls (87%) were under two years of age. The majority (42%) of bulls presented were Hereford, but Angus, Charolais, Holstein-Friesian and Limousin breeds were also seen. Following examination and diagnosis of penile fibropapilloma, regional anaesthesia (xylazine-procaine epidural and internal pudendal nerve block) and standing surgical intervention (resection and cautery) was performed in each case. Phone call follow-up was performed by one author (EET) in all 31 cases and 2 cases out of the 28 that were contactable showed post-surgical recurrence of penile fibropapillomatosis (i.e., 7.1% recurrence rate).

Conclusion: This case series summarises the history and presenting findings of 31 bovine penile fibropapilloma cases and describes a regional anaesthetic and standing surgical approach for successful case management.

Globally, Mastitis is a disease commonly affecting dairy cattle which leads to the use of antimicrobials. The majority of mastitis etiological agents are bacterial pathogens and Staphylococcus aureus is the predominant causative agent. Antimicrobial treatment is administered mainly via intramammary and intramuscular routes. Due to increasing antimicrobial resistance (AMR) often associated with antimicrobial misuse, the treatment of mastitis is becoming challenging with less alternative treatment options. Besides, biofilms formation and ability of mastitis-causing bacteria to enter and adhere within the cells of the mammary epithelium complicate the treatment of bovine mastitis. In this review article, we address the challenges in treating mastitis through conventional antibiotic treatment because of the rising AMR, biofilms formation, and the intracellular survival of bacteria. This review article describes different alternative treatments including phytochemical compounds, antimicrobial peptides (AMPs), phage therapy, and Graphene Nanomaterial-Based Therapy that can potentially be further developed to complement existing antimicrobial therapy and overcome the growing threat of AMR in etiologies of mastitis.

Background: Starting primarily as an inflammation of the mammary gland, mastitis is frequently driven by infectious agents such as Staphylococcus aureus. Mastitis has a large economic impact globally, which includes diagnostic, treatment, and the production costs not to mention the potential milk contamination with antimicrobial residues. Currently, mastitis prevention and cure depends on intramammary infusion of antimicrobials, yet, their overuse risks engendering resistant pathogens, posing further threats to livestock.

Methods: In our study we aimed to investigate, in vitro, using bovine mammary epithelial cells (MAC-T), the efficacy of the AuraShield an antimicrobial mixture (As) in preventing S. aureus attachment, internalisation, and inflammation. The antimicrobial mixture (As) included: 5% maltodextrin, 1% sodium chloride, 42% citric acid, 18% sodium citrate, 10% silica, 12% malic acid, 9% citrus extract and 3% olive extract (w/w).

Results and discussion: Herein we show that As can significantly reduce both adherence and invasion of MAC-T cells by S. aureus, with no impact on cell viability at all concentrations tested (0.1, 0.2, 0.5, 1%) compared with untreated controls. The anti-apoptotic effect of As was achieved by significantly reducing cellular caspase 1, 3 and 8 activities in the infected MAC-T cells. All As concentrations were proven to be subinhibitory, suggesting that Ac can reduce S. aureus virulence without bacterial killing and that the effect could be dual including a host modulation effect. In this context, we show that As can reduce the expression of S. aureus clumping factor (ClfB) and block its interaction with the host Annexin A2 (AnxA2), resulting in decreased bacterial adherence in infection of MAC-T cells. Moreover, the ability of As to block AnxA2 had a significant decreasing effect on the levels of pro inflammatory cytokine released upon S. aureus interaction with MAC-T cells.

Conclusion: The results presented in this study indicate that mixtures of natural antimicrobials could potentially be considered an efficient alternative to antibiotics in treating S. aureus induced mastitis.

Background: This is the first report of Besnoitia bennetti in donkeys in Ireland. B. bennetti, an apicomplexan protozoan parasite specific to equids, is an emerging pathogen in Europe. This parasite forms chronic intracytoplasmic cysts in cells of the mesenchymal lineage, mainly fibroblasts, in the skin, sclera and mucosa. Clinical signs in affected equine hosts vary from mild to severe debilitating disease. Little is known of the phylogeny, epidemiology or transmission of B. bennetti infection in donkeys, mules or horses.

Case presentation: Two cases of besnoitiosis in donkeys are presented. Both donkeys were born and raised in theSouthwest of Ireland. The first case was a 2.5-year-old donkey that had a suspect sarcoid removed, while the second case,a 2-year-old donkey, had a biopsy of nodular dermatitis of the muzzle. Diagnosis was made by histopathology and the parasite species, B. bennetti, was confirmed by PCR followed by sequencing and microsatellite analysis. Both donkeys had high antibody titres against Besnoitia spp. Small (0.5 mm) scleral, conjunctival and dermal cysts over the muzzle were subsequently observed in both animals. Treatment with trimethoprim sulfadiazine for 30 days did not lead to clinical resolution. The findings are compared to the cases of besnoitiosis in donkeys reported in the past 10 years throughout Europe.

Conclusions: Besnoitiosis should be considered as a differential diagnosis for chronic skin disease particularly in cases of cutaneous masses, non-pruritic dermatitis, and dermatitis that is not responsive to treatment in donkeys and other equids. Future studies are needed to investigate the prevalence of the disease in Irish donkeys, the spread of the disease and the potential impact on the health and welfare of the donkeys.

Background: Virulent systemic feline calicivirus (VS-FCV) infection is an emerging disease. It is distinct from classic oronasal calicivirus infection as it manifests with unique systemic signs including severe cutaneous ulcerations, limb oedema, and high mortality, even in adequately vaccinated cats. Devastating epizootic outbreaks with hospital-acquired infections have been described in the United States, the United Kingdom, continental Europe and Australia with up to 54 cats affected in one outbreak and a mortality rate of up to 86%. This highly contagious and potentially fatal disease has not yet been reported in Ireland.

Case presentation: An 11-month-old male neutered vaccinated domestic shorthair cat was presented with a 10-day history of lethargy, decreased appetite and progressively worsening pitting oedema in all four limbs. The signs were first noted after another kitten from a high-density cat shelter was introduced in to the household. Additional physical examination findings included marked pyrexia, and lingual and cutaneous ulcers. Virulent systemic feline calicivirus was diagnosed based on compatible history and clinical signs, exclusion of other causes, and calicivirus isolation by RT-PCR both in blood and oropharyngeal samples. Negative calicivirus RT-PCR in blood following resolution of the clinical signs further supported the diagnosis.

Conclusion: This case represents the first known case of VS-FCV infection in Ireland. Given the severity of the clinical signs, and the high risk for epizootic outbreaks, Irish veterinarians should be aware of the disease to ensure prompt diagnosis and implementation of adequate preventive measures, in order to limit the threat that this disease represents for the wider cat population and particularly given the risk of hospital-acquired VS-FCV infection. Virulent systemic calicivirus should be suspected in cats with pyrexia of unknown origin, oedema or ulceration affecting the limbs or the face, and exposure to rescue cats from high-density households.