Symptoms of Canine Leptospirosis in Shih Tzu Dogs

Pathogen

Lyme spirochetes can survive in the bloodstream for about 10 days, in urine for a day, and in diluted urine for several months. Their survival time in water depends on factors like temperature and pH levels, generally lasting several months. These bacteria are highly sensitive to dry conditions, and they can die within minutes in a dry environment. They are also extremely sensitive to acids and strong alkalis, and can be killed by most disinfectants. They are easily inactivated by substances like dilute hydrochloric acid, 70% ethanol, bleach, phenol, soap water, and Lysol. Lyme spirochetes have a weak resistance to physical and chemical factors, such as ultraviolet light, temperatures between 50 to 55 degrees Celsius, and 30 minutes of exposure, which can all kill them. They are also sensitive to antibiotics like tetracycline, streptomycin, and chlortetracycline.

Epidemiology

Lyme spirochetes are widely distributed globally. In China, most climate conditions are suitable for their growth and reproduction, with the southern regions being particularly conducive. The disease has a wide range of hosts, and with frequent flooding in China, there is a potential for large outbreaks. China is one of the countries most severely affected by this disease, with over 2.5 million people affected since 1958, and a relatively high mortality rate.

The disease is primarily transmitted through direct contact, as well as through intact mucous membranes and skin wounds, and the digestive tract. It presents as either endemic or sporadic outbreaks, with dogs being particularly susceptible to infection.

Symptoms

The incubation period for the disease is between 5 to 15 days, and it primarily manifests as acute hemorrhagic jaundice and subacute or chronic nephritis.

Acute hemorrhagic jaundice: Initially, dogs may exhibit fever, depression, vomiting, and loss of appetite, along with bleeding under the skin or blood spots. They may also experience widespread muscle tenderness and weakness. Many dogs will then develop jaundice, with cloudy urine that may appear as soybean oil or red. Some may vomit, have nosebleeds, or pass bloody stools. In severe cases, liver failure may occur, leading to ascites or hepatic encephalopathy symptoms. Affected dogs may have an enlarged abdomen, with punctures revealing bloody ascites.

Subacute or chronic nephritis: Dogs may initially show systemic symptoms like fever, but as the disease progresses, kidney dysfunction becomes the main issue. Dogs may have oliguria or anuria, and some may develop uremia due to extensive kidney damage. Symptoms include vomiting, dehydration, and a foul odor in the mouth, leading to coma and death in the later stages.

Since different types of Lyme spirochetes can cause different clinical symptoms, some dogs may exhibit more pronounced symptoms, such as high fever, bleeding mucous membranes, jaundice, ulcers, or necrosis, and hemoglobinuria. Others may show no symptoms at all.

Diagnosis

The diagnosis is based on clinical signs such as fever, jaundice, bleeding spots on the skin and mucous membranes, reduced urine output, and sticky, cloudy urine that may be soybean oil or red. Other indicators include a decrease in protein cells, an increase in white blood cells, and a decrease in platelets in the blood. Elevated levels of serum urea nitrogen and creatinine, as well as necrosis of the liver and kidneys, can also suggest the disease. For dogs with less apparent clinical signs, laboratory tests are necessary. Urine samples are centrifuged at 1500 rpm for 5 minutes, and the sediment is observed under a lowpower microscope in darkfield. The presence of疑似“？”Lyme spirochetes confirms the diagnosis.

Prevention

Prevention is the key to managing this disease. Measures include eliminating carriers and sources of excretion, disinfecting and cleaning contaminated water, areas, and equipment to prevent the spread of the disease, and vaccination. Vaccines against Lyme spirochetes are highly effective in preventing infection and protecting dogs from contaminating the environment with the pathogen. It is recommended that dogs be vaccinated for the first time at 8 weeks of age, with a second vaccination 2 to 4 weeks later, and then an annual booster.

In areas with outbreaks, rodent control and proper management of domestic animals are essential. Strengthening animal quarantine measures, especially for pet dogs, is crucial to prevent infection. Vaccination is the best way to protect dogs from infection.

Treatment

In the early stages of the disease, dogs should rest and receive a diet rich in nutrients and easy to digest, maintaining fluid and electrolyte balance. Dogs with the disease should receive symptomatic treatment promptly. In cases of severe bleeding, immediate blood transfusions and hemostatic agents should be administered. For dogs with significant pulmonary hemorrhage, sedation should be maintained, and sedatives may be used as needed. Dogs with liver damage should receive liverprotective treatment and avoid hepatotoxic medications.

Lyme spirochetes are sensitive to a variety of antibiotics. Effective use of antibiotics early in the disease is crucial to eliminate and suppress the pathogen. Delayed treatment can lead to liver damage, reducing the effectiveness of treatment.