Canine Toxoplasmosis

This disease is a zoonotic protozoal disease distributed worldwide and is widely present in domestic and wild animals. The disease has been reported across the country.

The causative agent of canine toxoplasmosis and its life history

The causative agent of toxoplasmosis is Toxoplasma gondii, referred to as Toxoplasma gondii. Its entire development process requires two hosts. Cats are the ultimate host of Toxoplasma gondii. In the epithelial cells of the cat's small intestine, schizophrenia and gametogenesis similar to the development of coccidia are carried out. Finally, oocysts are formed and excreted with cat feces. The oocysts undergo multiplication and development in the external environment. An infective oocyst containing two sporangia.
Toxoplasma gondii is not strict in its selection of intermediate hosts. It is known that more than 200 species of animals, including mammals, birds, fish, reptiles and humans, can serve as its intermediate hosts. Cats can also serve as intermediate hosts for Toxoplasma gondii. In the intermediate host, Toxoplasma gondii can reproduce asexually in nucleated cells in tissues and organs throughout the body. Animals become infected by eating infectious oocysts in cat feces or the meat, viscera, exudates, excretions and milk of intermediate hosts containing Toxoplasma gondii or cysts. Tachyzoites can also infect the fetus through the skin and mucous membranes, and through the placenta.

Key points for diagnosis of canine toxoplasmosis

(1) Clinical symptoms: Most are asymptomatic latent infections. Infections are more common and the symptoms are more severe in puppies and young dogs, and fatal cases have also been reported in adult dogs. Symptoms are similar to canine distemper and canine infectious hepatitis. The main symptoms are fever, cough, anorexia, lethargy, weakness, secretions from the eyes and nose, pale mucous membranes, difficulty breathing, and even severe bloody diarrhea. A few sick dogs have severe vomiting, followed by paralysis and other neurological symptoms. When a pregnant female dog suffers a miscarriage or premature birth, the puppies often have symptoms such as loose stools, difficulty breathing, and movement disorders. Blood tests showed that in the acute phase, red and white blood cells decreased and neutrophils increased. Neutropenia and monocytosis are less common. The total number of white blood cells in chronic cases increases, mainly neutrophils, and thrombocytopenia, but there is no bleeding tendency.
(2) Laboratory examination: It is easy to be confused with canine distemper, especially neurological canine distemper, relying solely on clinical symptoms. Therefore, after comprehensive judgment such as epidemiological analysis and clinical symptoms, the diagnosis must be confirmed by detecting the pathogen or confirming an increase in antibody titers in the serum.

Treatment of canine toxoplasmosis

For acute infection cases, sulfadiazine (SD), 70 mg per kilogram of body weight, or trimethoprim (TMP) can be used. Take 14 mg per kilogram of body weight orally twice a day for 3-4 days. Due to the low solubility of sulfadiazine, it is easier to precipitate crystals in urine. When taking it orally, it should be mixed with an equal amount of sodium bicarbonate and drink more water. In addition, sulfonamide-6-methoprim (sulfamethoxazine, sulfamethoxine, SMM, DS-36) or sulfonyl dapsone (SDDS) can be applied.

Toxoplasma canisDisease prevention

Do not feed raw meat, prevent dogs from predating rodents, and prevent cat feces from contaminating feed and drinking water.