Parasitic Encephalitis in a Bitch
Authors: Galeno Lygia Silva , Do Nascimento Medeiros Brenda Lurian , De Carvalho Sávio Matheus Reis , Pinheiro Rodrigues Vanessa Brígida , Veloso de Sousa Pablo Martins , Sousa Albuquerque Joanna Jéssica , Araújo Bruno Martins , Silva Francisco Lima 
Published: March 2020

ABSTRACTBackground: Encephalitis is common in most inflammatory and infectious diseases of the central nervous system, and bacterial and viral pathogens, protozoa, fungi, and erythematous parasites are recognized as etiological agents. Clinical signs vary according to the anatomical location and severity of the inflammation. Some parasites may undergo aberrant migration into the brain of dogs and cats, which is are considered a rare clinical phenomenon. This case report describes the occurrence of parasitic encephalitis in a mixed breed bitch about 4 year-old.Case: A mixed breed bitch, about 4 year-old, rescued from the street with weakness of the pelvic limbs, was treated at the Veterinary Hospital of the Federal University of Piauí - UFPI. After A clinical and neurological examination, the patient was hospitalized for diagnosis, treatment, confirmation and follow-up of her clinical evolution. Complementary tests were performed to evaluate her general condition, given her unknown history because she was a rescue dog. Complete blood count (CBC), hemoparasite screening, biochemical function (urea, creatinine, ALT, alkaline phosphatase, total protein, albumin and globulin), abdominal and pelvic ultrasound, serological and parasitological tests for leishmaniasis, distemper antigen and ehrlichiosis antibody detection tests were performed, and cerebrospinal fluid (CSF) was collected for analysis. The CBC revealed normocytic hypochromic anemia and thrombocytopenia. Biochemical functions were within normal limits, except for alanine aminotransferase (ALT), which was slightly low. The ultrasound examination showed splenomegaly. The canine distemper, ehrlichiosis and leishmaniasis tests were negative. The results of the CSF analysis revealed the presence of spherical structures compatible with parasitic cysts, suggestive of Echinococcus granulosus. After the laboratory diagnosis of parasitic encephalitis, the animal was treated with prednisolone, albendazole, praziquantel and doxycycline. Three days after starting treatment for parasitic encephalitis, the patient presented significant clinical improvement, began to feed again and to move around.Discussion: The presence of parasitic cysts in cerebrospinal fluid is uncommon; however, encephalitis due to aberrant parasite migration has been described in dogs and cats. The migration and growth of the parasite causes extensive damage to the neural parenchyma. The clinical signs of worm encephalitis tend to show acute to super-acute onset, and the definitive diagnosis depends on the identification of the parasitic agent in the patient’s brain. This type of diagnosis has so far been performed only during necropsy. In the case reported here, parasitic cysts were identified in CSF, thus confirming and formulating a definitive diagnosis. It is rare to find microorganisms and tumor cells in samples of cerebrospinal fluid; however, if this occurs, a definitive diagnosis can be formulated. The use of cerebrospinal fluid is therefore an important diagnostic tool when other imaging tests such as tomography and magnetic resonance provide limited access. Praziquantel and Albendazole are recommended for the treatment of Echinococcus, prednisolone is recommended for cases of encephalitis, and prophylactic antibiotic therapy is used to prevent secondary bacterial meningoencephalitis. The recommended treatment was efficient for this patient, and could be adopted to treat other dogs with parasitic encephalitis. The main forms of prevention in dogs are periodic worming, and the ingestion of only processed or cooked foods and treated water.