Diezma-Díaz C, Jiménez-Meléndez A, Fernández M, Gutiérrez-Expósito D, García-Lunar P, Ortega-Mora L M, Pérez-Salas J A, Blanco-Murcia J, Ferre I, Álvarez-García G
SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
Instituto de Ganadería de Montaña (CSIC-ULE), 24346, León, Spain.
Vet Parasitol. 2017 Nov 30;247:10-18. doi: 10.1016/j.vetpar.2017.09.017. Epub 2017 Sep 23.
Bovine besnoitiosis, caused by the apicomplexan Besnoitia besnoiti, is a chronic and debilitating disease characterized by cutaneous and systemic manifestations that primarily affects adult beef cattle. Previous studies have reported that clinical besnoitiosisis is rare in calves. However, we isolated B. besnoiti from a chronically infected calf for the first time. The identity of the Besnoitia species was determined after parasite isolation and molecular genotyping. According to the results obtained in vitro the new isolate, named as Bb-Spain3, was characterized in a reproducible in vitro model and was categorized as a low invader and low prolific isolate with a slower lytic cycle compared to Bb-Spain 1 isolate. Specific traits that differentiate isolates obtained from adult animals from those infecting calves were not found. Next, we described the first case report of chronic besnoitiosis in a female calf less than 6 months-old with a low body condition. The disease was confirmed by the presence of specific anti-B. besnoiti antibodies and parasite detection in the skin. At post-mortem examination, tissue samples were collected for histological, immunohistochemical and molecular analyses. DNA-parasite was detected in 31 different calf's tissues, being the most highly parasitized tissues the skin and the respiratory and reproductive tracts. In addition, the parasite was also present in heart, eyes, lymph nodes and brain. The high parasite load, a wide intra-organic parasite distribution and the presence of both viable and degenerated cysts, were indicative of a rapid progression of the disease. This case report underlines the need to include the inspection of young animals in besnoitiosis control.
牛贝诺孢子虫病由顶复门的贝诺孢子虫引起，是一种慢性衰弱性疾病，其特征为皮肤和全身症状，主要影响成年肉牛。先前的研究报道，临床牛贝诺孢子虫病在犊牛中罕见。然而，我们首次从一头慢性感染的犊牛中分离出贝诺孢子虫。在寄生虫分离和分子基因分型后确定了贝诺孢子虫的种类。根据体外获得的结果，新分离株命名为Bb-Spain3，在可重复的体外模型中进行了特征描述，与Bb-Spain 1分离株相比，被归类为低侵袭性和低繁殖力分离株，其裂解周期较慢。未发现区分成年动物分离株与感染犊牛分离株的特定特征。接下来，我们描述了第一例小于6月龄、体况较差的雌性犊牛慢性贝诺孢子虫病病例报告。通过检测皮肤中特异性抗贝诺孢子虫抗体和寄生虫确诊该病。尸检时，采集组织样本进行组织学、免疫组织化学和分子分析。在31种不同的犊牛组织中检测到DNA寄生虫，皮肤以及呼吸道和生殖道是寄生虫感染最严重的组织。此外，寄生虫还存在于心脏、眼睛、淋巴结和大脑中。高寄生虫载量、广泛的器官内寄生虫分布以及活囊肿和退化囊肿的存在，表明疾病进展迅速。该病例报告强调了在牛贝诺孢子虫病防控中对幼龄动物进行检查的必要性。
