Page 1971 - Cote clinical veterinary advisor dogs and cats 4th

Toxoplasmosis/Neosporosis 985

may rupture, resulting in clinical relapses ○ Abdominal radiographs may show gondii and are not completely effective at killing
during immunosuppression. hepatomegaly, ascites, intestinal masses, the organism. There is limited information on
VetBooks.ir infectious stages: tachyzoites, tissue cysts • Other tests Acute and Chronic Treatment Diseases and Disorders
• The life cycle of N. caninum involves three
effectiveness of treatment of neosporosis.
or mesenteric lymphadenopathy.
found primarily in the CNS, and oocysts.
○ Oocysts may be detected in the feces of
○ Tissue cysts and tachyzoites are found in
of choice in dogs and cats.
with clinical neosporosis, but shedding has
intermediate hosts. cats with clinical toxoplasmosis or dogs • Toxoplasmosis: clindamycin is the treatment
○ Transmission is suspected to occur through often already stopped by the time clinical • Neosporosis should be treated early in the
ingestion of sporulated oocysts, ingestion illness is noted, leading to false-negative disease with the same drugs used for treating
of infected tissues, or transplacentally. results. toxoplasmosis. Treatment should continue
○ Transplacental transmission may be the ○ Cytologic exam of ascitic fluid, tracheal at least 2 weeks after resolution of clinical
predominant route in dogs. washes, and pleural fluid may reveal signs.
○ The organism may be found in macro- tachyzoites of either organism. • Clindamycin (dogs) 10-20 mg/kg PO q 12h
phages, polymorphonuclear cells, spinal for at least 2 weeks
fluid, and neural cells (brain, spinal cord, Advanced or Confirmatory Testing • Clindamycin (cats) 12-25 mg/kg PO q 12h
peripheral nerves, retina), as well as other Toxoplasmosis: for a minimum of 2-4 weeks
cells, causing focal necrosis. • A presumptive diagnosis is usually based on • Azithromycin (cats) 10 mg/kg PO q 24h
the combination of appropriate clinical signs, for 4 weeks is also a good choice.
DIAGNOSIS positive results of serologic tests, exclusion of • Alternatively, trimethoprim-sulfonamide
other causes for clinical signs, and positive 15-30 mg/kg PO q 12h for 2-4 weeks
Diagnostic Overview response to treatment. may be used if the patient cannot tolerate
The diagnosis of toxoplasmosis or neosporosis ○ Serologic testing: ELISA tests designed clindamycin.
is based on the combination of clinical findings specifically for dogs or cats should be used. • Ponazuril 20 mg/kg PO q 24h for 28 days
and results of specific diagnostic tests. A fourfold rise in immunoglobulin (Ig) was used successfully in one dog with toxo-
G over a 2-3 week period or a high IgM plasmosis and has been used to lessen tissue
Differential Diagnosis titer suggests active infection. cysts in rodent models. This drug can be
• Uveitis: infectious (FeLV, FIV, FIP [corona- ○ Positive IgM titers can have a short dura- considered in dogs or cats with toxoplasmosis
virus]), immune-mediated, trauma tion, but 80% of cats with clinical disease that are intolerant to other drugs.
• Respiratory signs: feline asthma, pneumonia associated with toxoplasmosis have positive • Barring corneal ulceration or conjunctivitis,
(bacterial, Mycoplasma, parasitic, fungal), IgM titers. uveitis should be treated with 1% predniso-
pulmonary edema, neoplasia, heartworm ○ IgG reflects only past exposure, but a posi- lone acetate ophthalmic drops.
disease, trauma tive titer along with appropriate clinical
• Hepatic: hepatic lipidosis (cats), cholangitis/ signs may suggest toxoplasmosis. Possible Complications
cholangiohepatitis (cats), infectious hepatitis, • Cytologic detection of tachyzoites in body • Clindamycin may cause anorexia, vomiting,
neoplasia, toxic hepatopathy fluids or histologic detection of bradyzoites and diarrhea with higher doses.
• GI: infectious (bacterial, viral, parasitic), associated with inflammation in tissues • Trimethoprim-sulfonamides are associated
dietary, endocrine (hypoadrenocorticism), suggests toxoplasmosis, and the agent can with bone marrow suppression (anemia,
obstructive, pancreatitis be confirmed by polymerase chain reaction leukopenia, thrombocytopenia), keratocon-
• Neurologic signs: meningoencephalitis (FeLV, (PCR) assays. junctivitis sicca (KCS), depression, immune-
FIV, FIP, canine distemper, ehrlichiosis, • T. gondii DNA can be amplified from blood, mediated disease, cutaneous drug eruptions,
Rocky Mountain spotted fever, rabies, fungal aqueous humor, CSF, and tissues and is kidney injury, GI signs, and hepatotoxicosis
disease, parasitic disease, thiamine deficiency positive in clinically ill cats. (especially in Doberman pinschers). Reduce
[cats], immune-mediated disease) Neosporosis: dose of trimethoprim-sulfadiazine in kidney
• Neuromuscular: hepatozoonosis, Lyme • A presumptive diagnosis is usually based on disease, and avoid use in hepatic disease,
borreliosis, immune-mediated disease (poly- the combination of appropriate clinical signs, anemia, leukopenia, and congenital bleeding
radiculoneuritis, polymyositis) positive results in serologic tests, exclusion of disorders. Cats dislike the taste of sulfa drugs
other causes for clinical signs, and positive (hypersalivation).
Initial Database response to treatment. • In cases of fulminant infection, some patients
• CBC, serum biochemistry profile, urinalysis ○ Serologic testing with IFA, ELISA, and worsen after antimicrobials are started.
○ Nonregenerative anemia, neutrophilic direct agglutination tests.
leukocytosis, lymphocytosis, monocytosis, • Cytologic detection of tachyzoites in body Recommended Monitoring
and eosinophilia are possible with either fluids or histologic detection of bradyzoites Clinical findings and routine laboratory
infection. associated with inflammation in tissues abnormalities can be rechecked at appropriate
○ Leukopenia (lymphopenia, neutropenia, suggests neosporosis, and the agent can be intervals for the individual patient. There is
degenerative left shift) is possible in cats confirmed by PCR assays. no evidence indicating that T. gondii– or N.
severely affected with toxoplasmosis. Both organisms: caninum–specific tests are of clinical utility,
• Serum biochemistry profile may show elevated • Can be grown in cell culture and in and treatment decisions should be based on
activities of alanine aminotransferase (ALT), mice clinical responses.
aspartate aminotransferase (AST), alkaline • CSF analysis and aqueous humor may have
phosphatase (ALP), amylase, lipase, and elevated protein levels and leukocytes in PROGNOSIS & OUTCOME
creatine kinase (CK) in dogs or cats with either toxoplasmosis and neosporosis.
infection. Hyperbilirubinemia, hyperglobu- • Most affected kittens or puppies or immune-
linemia, hypoalbuminemia, hypoproteinemia, TREATMENT suppressed animals with fulminant disease
proteinuria, and bilirubinuria may also occur. will die or require euthanasia.
• Radiographs Treatment Overview • Animals may survive acute disease if treated
○ Thoracic radiographs may show a diffuse Treatment is predominantly supportive, with intensively and rapidly.
interstitial to alveolar pattern and mild antimicrobials used as appropriate for the ○ Guarded for complete resolution of
pleural effusion. organism. Drugs suppress replication of T. neuromuscular signs

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