NAVLE（北美执业兽医考题）Day 786

You note the abnormality seen on the blood smear below of a dog presenting to you for weakness and fever. What is the likely route that the dog was infected?
你在由于虚弱和发烧前来就诊的犬的血涂片中看到了如下图出现的异常。该犬最可能由于什么问题导致的这种感染？