Symptoms and Signs of Leptospirosis in Dogs: A Comprehe

Patients typically develop symptoms within 1 to 2 weeks after infection, and the clinical course is divided into three distinct phases:

1. Early Stage

This phase lasts for about 2 to 4 days and is characterized by a range of symptoms, including fever, generalized weakness, headache, pain in the calf muscles, conjunctival congestion, and superficial lymph node swelling, all indicative of systemic toxicity.

2. Intermediate Stage (The Acute End of Lymephagia)

During the 4th to 10th day postinfection, patients may exhibit symptoms of meningitis, such as severe headache, frequent vomiting, and cervical spine prominence. In some cases, the brain or brainstem may be involved, and the cerebrospinal fluid may contain Leptospira bacteria.

3. Late Stage (PostIncidence or Recovery Phase)

Most patients recover fully, but some may experience two types of neurological complications:

(1) PostInfectious Meningitis

This type often presents with symptoms of acute meningeal irritation, including increased lymphocytes and proteins in the cerebrospinal fluid. Leptospira antibodies can be detected in the body.

(2) Leptospiral Arteritis

This condition develops after the acute fever subsides and can last from half a year to five months. It primarily manifests as common neurological complications, evolving into a more prevalent form of cerebral arteritis. Due to intimal thickening and vascular occlusion, it can lead to cerebral infarction. Dogs may exhibit central facial and tongue paralysis, and some may suffer from hemiparesis or monoparesis, losing the ability to move. In cases of pseudobulbar palsy and pathological signs, seizures may occur, either generalized or localized, and may be persistent. After the occlusion of the main arteries, the formation of collateral circulation can gradually lead to an abnormal network of brain base vessels, resembling the condition known as烟雾 disease.

Pet Doctor's Tip: For more information on canine leptospirosis, click on "What is Canine Leptospirosis" to read an informative article.