Noel Teola, Suepaul Rod, Adesiyun Abiodun A
School of Veterinary Medicine, Faculty of Medical Sciences, University of the West Indies, St. Augustine 999183, Trinidad and Tobago.
Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria 0110, South Africa.
Pathogens. 2025 Jun 20;14(7):611. doi: 10.3390/pathogens14070611.
A killed, whole-cell vaccine was produced to induce immunity in dogs against leptospirosis. The vaccine, containing serovar Copenhageni, was produced and administered to 12 beagle dogs at both 8 and 12 weeks of age. Ten unvaccinated dogs of the same age group served as the control group. A live, virulent inoculum of (1.52 × 10-4.40 × 10 leptospires per dog) was used to challenge the dogs at 2 weeks (Study 1) and 14 months (Study 2) post-booster vaccination. At regular intervals, pre- and post-challenge (PC), the microscopic agglutination test (MAT) was performed to measure antibody titers. Leptospiremia and leptospiruria were determined via culture, and the cytokine, biochemical, and pathological profiles of vaccinates and controls were also assessed. A high antibody response was measurable after booster administration. In Study 1 (onset of immunity), acute leptospirosis was observed in five (100%) out of five unvaccinated dogs. In contrast, no acute clinical leptospirosis developed in vaccinated dogs, except in one (20%) dog with mild clinical signs. In Study 2 (duration of immunity), mild clinical signs were observed in two (40%) of the control dogs, while all vaccinated dogs remained clinically normal. The incidence of leptospiruria and leptospiremia PC was lower in the vaccinated dogs compared to the unvaccinated group. Severe thrombocytopenia occurred in 100% (5/5) of the unvaccinated dogs in Study 1 that exhibited acute severe leptospirosis, whereas 80% (4/5) of the unvaccinated dogs in Study 2 showed mild to moderate thrombocytopenia 3 days after challenge. Four out of five unvaccinated dogs (80%) in Study 1 exhibited icteric tissues and hemorrhages in the lungs and mucosal surfaces of the stomach and intestines. A high IL-10 to TNF-α ratio, observed in the control group of both studies, and severe thrombocytopenia observed in the control group of Study 1, indicative of acute leptospiral disease, were detected. The vaccine prevented acute clinical leptospirosis and reduced the renal carrier state in beagle dogs, and further investigation is required using a larger sample size.
一种灭活全细胞疫苗被生产出来，用于诱导犬类对钩端螺旋体病产生免疫力。该疫苗含有哥本哈根血清型，在8周龄和12周龄时分别生产并接种给12只比格犬。10只同年龄组未接种疫苗的犬作为对照组。在加强免疫后2周（研究1）和14个月（研究2），使用活的强毒株接种物（每只犬1.52×10 - 4.40×10个钩端螺旋体）对犬进行攻毒。在攻毒前后定期进行显微镜凝集试验（MAT）以测量抗体滴度。通过培养确定钩端螺旋体血症和钩端螺旋体尿症，并评估接种疫苗和未接种疫苗犬的细胞因子、生化和病理特征。加强免疫后可检测到高抗体反应。在研究1（免疫开始）中，5只未接种疫苗的犬中有5只（100%）出现急性钩端螺旋体病。相比之下，接种疫苗的犬中除1只（20%）出现轻微临床症状外，未发生急性临床钩端螺旋体病。在研究2（免疫持续时间）中，2只（40%）对照犬出现轻微临床症状，而所有接种疫苗的犬临床均正常。与未接种疫苗组相比接种疫苗的犬攻毒后钩端螺旋体尿症和钩端螺旋体血症的发生率较低。在研究1中，出现急性严重钩端螺旋体病的未接种疫苗犬中有100%（5/5）发生严重血小板减少，而在研究2中，80%（4/5）的未接种疫苗犬在攻毒后3天出现轻度至中度血小板减少。在研究1中，5只未接种疫苗的犬中有4只（80%）出现黄疸组织以及肺和胃肠道黏膜表面出血。在两项研究的对照组中均观察到高IL - 10与TNF - α比值，在研究1的对照组中观察到严重血小板减少，提示急性钩端螺旋体病。该疫苗预防了比格犬的急性临床钩端螺旋体病并降低了肾脏携带状态，需要使用更大样本量进行进一步研究。
