Ehrlichia canis is a type of bacteria that primarily infects dogs, causing a disease known as canine ehrlichiosis. This bacterium is transmitted through the bite of infected ticks, particularly the Rhipicephalus sanguineus or brown dog tick. Symptoms of the infection can include fever, lethargy, loss of appetite, and weight loss. The disease can progress through different stages, leading to more severe health issues if left untreated. Diagnosis typically involves blood tests to detect the presence of the bacteria or antibodies. Treatment usually includes antibiotics, and early intervention is crucial for a better prognosis.