Diagnosis and treatment of toxoplasmosis in dogs

Canine toxoplasmosis is a human-animal commensal protozoan disease with a worldwide distribution and is widespread in domestic and wild animals. The presence of this disease has been reported throughout the country. The causative agent of toxoplasmosis and its life history is Toxoplasma gondii, or Toxoplasma gondii, which requires two hosts for its entire development. The cat is the final host of Toxoplasma gondii, which undergoes cleavage proliferation and gamete reproduction similar to coccidia development in the epithelial cells of the cat’s small intestine and finally forms an oocyst, which is excreted with cat feces. The oocyst develops into an infective oocyst containing two sporocysts after gown proliferation in the external environment. Toxoplasma gondii is not very selective about intermediate hosts, and more than 200 species of animals, including mammals, birds, fish, reptiles and humans, are known to 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 the nucleated cells of all tissues and organs of the body. Animals become infected by eating infective oocysts in cat feces or meat, viscera, exudates, excreta and milk of intermediate hosts containing Toxoplasma gondii or encysts. Toxoplasma gondii can also be infected through the skin, mucous membranes, and also through the placenta to the fetus. Diagnostic points of canine toxoplasmosis (1) Clinical signs: Most are asymptomatic recessive infections. Infection is more common and severe in puppies and young dogs, and there are fatal cases in adult dogs. Symptoms are similar to canine distemper and canine infectious hepatitis, mainly manifested as fever, cough, anorexia, depression, weakness, eye and nose discharge, pale mucous membrane, respiratory difficulties, and even violent hemorrhagic diarrhea. A few sick dogs have violent vomiting, followed by paralysis and other neurological signs. Pregnant bitches undergo miscarriage or premature delivery, and the resulting litters often show symptoms such as loose stools, respiratory distress and motor disorders. In the acute phase, blood tests show a decrease in red and white blood cells and an increase in neutrophils. Neutropenia and monocytosis are less common. In chronic cases, there is an increase in total leukocytes, mainly neutrophilic leukocytosis and thrombocytopenia, but there is no bleeding tendency. (2) Laboratory tests: Relying only on clinical signs it is easy to confuse with canine distemper, especially neurological distemper. Therefore, after comprehensive determination of epidemiological analysis and clinical symptoms, the diagnosis must also be confirmed by detection of the pathogen or confirmation of elevated antibody titers in the serum. Treatment of canine toxoplasmosis can be treated with sulfadiazine (SD), 70 mg per kg body weight, or methotrexate (TMP), 14 mg per kg body weight, administered orally twice daily for 3-4 days in acute cases. Since sulfadiazine has low solubility and is more likely to precipitate crystals in urine, it should be given internally with an equal amount of sodium bicarbonate and increased water intake. In addition, sulfadoxine-6-methylpyrimidine (sulfamethoxypyrimidine, bacteriophage, SMM, DS-36) or sulfonylsulfamethoxazole (SDDS) can be applied. Prevention of canine toxoplasmosis does not feed raw meat and prevents dogs from preying on rodents and prevents cat feces from contaminating feed and drinking water.