NAVLE（北美执业兽医考题）Day 681

Q1:A 3-year-old male neutered Labrador retriever from the Ohio river valley basin is presented with chronic large bowel diarrhea and signs of respiratory disease (cough, fever).A lymph node smear shows round to ovoid (1-4 micrometers) encapsulated structures inside macrophages and giant cells. The organisms have thin cell walls, with thin clear zone between cell wall and cytoplasm. What is the diagnosis？一只来自俄亥俄河流区域的3岁雄性已去势的拉布拉多猎犬患有慢性大肠性腹泻和呼吸道疾病（咳嗽，发烧）的迹象。淋巴结涂片显示巨噬细胞内有圆形到卵圆形（1-4微米）的包囊结构。 这个生物体具有一层薄的细胞壁，细胞壁和细胞质之间还有一部分薄的透明区域。 诊断是什么？[图片]