Quantitative Veterinary Epidemiology Group, Wageningen University and Research, Wageningen, The Netherlands.
Programa de Doctorado en Ciencias Veterinarias, Escuela de Graduados Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile.
Vet Res. 2023 Jul 31;54(1):64. doi: 10.1186/s13567-023-01190-w.
Pathogenic Leptospira spp. are zoonotic bacteria that infect wild and domestic animals. Humans contract leptospirosis directly through contact with infected animals or indirectly from contaminated water or soil. In mammalian reservoirs, the pathogen can colonize renal tubules for lengthy periods and persistently contaminate the environment through urine. Cattle have been reported to shed several serovars; with Hardjo the most common serovar found in cattle. Without clinical manifestations, the infection can spread within a herd, impairing productivity, and putting workers like farmers, abattoir operators and veterinarians at risk. The dynamics of pathogenic Leptospira shedding was studied in six dairy herds in southern Chile. Various intermittent urine shedding patterns were found, with elimination periods between 79 and 259 days and bacterial loads ranging from 3 × 10 to 4.4 × 10 bacteria/mL. The current study was the first to assess the various urine shedding patterns and loads of pathogenic leptospires shed through urine of naturally-infected dairy cows. In addition, the study suggests that vaccination does not prevent cattle infection, although it influences loads of pathogenic leptospires excreted in urine. Our study provides a great awareness of asymptomatic animal carriers in an endemic area and will contribute to improving disease control and designing better prevention strategies.
致病性钩端螺旋体是一种人畜共患的细菌，可感染野生动物和家畜。人类通过直接接触受感染的动物或间接接触受污染的水或土壤而感染钩端螺旋体病。在哺乳动物的蓄主中，病原体可以在肾小管中长期定植，并通过尿液持续污染环境。已经有报道称牛会排出多种血清型，其中哈久氏菌是在牛中最常见的血清型。在没有临床表现的情况下，感染可能在畜群中传播，从而降低生产力，并使农民、屠宰场工人和兽医等工人面临风险。本研究在智利南部的六个奶牛场研究了致病性钩端螺旋体的脱落动力学。发现了各种间歇性的尿液脱落模式，消除期在 79 至 259 天之间，细菌载量范围为 3×10 至 4.4×10 细菌/mL。本研究首次评估了自然感染奶牛通过尿液排出的致病性钩端螺旋体的各种尿液脱落模式和负荷。此外，该研究表明，疫苗接种不能预防牛的感染，尽管它会影响尿液中排出的致病性钩端螺旋体的负荷。我们的研究提供了对地方性地区无症状动物携带者的高度认识，并将有助于改善疾病控制和设计更好的预防策略。
