Hepatozoonosis

Transmission

Unlike many other tick-borne diseases, hepatozoonosis is not transmitted by tick bites, but by ingestion of infected ticks. Dogs become infected when, while licking or biting to remove ticks, they accidentally ingest a tick carrying Hepatozoon sporozoites.

Life cycle of the parasite

The life cycle of Hepatozoon involves the tick as an intermediate host and the dog as the definitive host. After ingestion by the dog, the parasite penetrates the intestinal wall and travels through the bloodstream to various tissues, including the liver, muscles and white blood cells (leukocytes).

• Hepatozoon canis: This parasite tends to cause a milder infection, which is often asymptomatic or produces mild symptoms. It is mainly found in Africa, Asia, South America and southern Europe.
• Hepatozoon americanum: Causes a more severe form of the disease, known as American hepatozoonosis, which is endemic in the southern United States. This parasite induces a significant inflammatory response in skeletal muscles, resulting in more severe symptoms.

Symptoms

Symptoms of hepatozoonosis may vary depending on the Hepatozoon species and parasite load. Dogs affected by Hepatozoon americanum usually have more severe symptoms than those infected with Hepatozoon canis.

• Mild hepatozoonosis (Hepatozoon canis):
  • Intermittent fever.
  • Weight loss.
  • Mild anaemia.
  • lymphadenopathy (swollen lymph nodes).
  • In some cases, the infection may be subclinical, i.e. without obvious symptoms.
• Severe hepatozoonosis (Hepatozoon americanum):
  • Persistent fever.
  • Severe muscle pain, especially in the hind limbs, which may lead to lameness.
  • Muscle stiffness and weakness.
  • Anorexia and significant weight loss.
  • Depression and lethargy.
  • Occasional ocular and nasal discharge.
  • In severe cases, the infection can be fatal if untreated.

Diagnosis

Diagnosis of hepatozoonosis is based on a combination of clinical symptoms, history of tick exposure and laboratory tests. Diagnostic techniques include:

• Blood examination: The presence of the parasites within white blood cells can be seen in a blood smear under a microscope.
• Muscle biopsy: In cases of Hepatozoon americanum, parasite cysts can be identified in muscle tissue samples.
• Serological and molecular tests: These tests can detect antibodies to Hepatozoon or parasite DNA in the dog's blood.

Treatment

Treatment of hepatozoonosis varies according to the species of parasite and the severity of infection:

• For Hepatozoon canis:
  • Antibiotic treatment such as doxycycline is generally used to control the infection.
  • Treatment may also include the use of antiprotozoals, such as imidocarb dipropionate.
• For Hepatozoon americanum:
  • Due to the more severe nature of this infection, treatment is more complex and includes combinations of drugs such as trimethoprim-sulfadiazine, clindamycin and pyrimethamine.
  • Treatment is often prolonged and may require long-term maintenance drugs to prevent relapse.
• Symptom management:
  • Analgesics and anti-inflammatory drugs may be needed to relieve pain and muscle inflammation.
  • Nutritional support and general care to help the dog recover from weakness and weight loss.

Prevention

Prevention of hepatozoonosis relies on tick control and prevention of tick ingestion by dogs. Preventive measures include:

• Regular tick control: Use deworming collars, topical or systemic treatments to prevent tick infestation.
• Tick inspection and removal: Check and remove ticks from dogs immediately after being in areas with high tick infestation.
• Prevent dogs from eating ticks: Watch dogs so that they do not lick or bite ticks attached to their bodies.

Importance of hepatozoonosis

Hepatozoonosis is an important disease in endemic areas, especially in regions with high tick prevalence. Although it is most common in dogs, it can also affect other animals and, rarely, humans. Prevention is key to controlling this disease, as infections can be difficult to treat and can have serious health consequences for affected animals.

In summary, hepatozoonosis is a parasitic disease transmitted through the ingestion of infected ticks. It can cause mild to severe disease in dogs, and prevention through tick control is essential to protect pets.

Arriba Volver Atrás