What Is Toxoplasma gondii?
Toxoplasma gondii is an obligate intracellular coccidian parasite with a worldwide distribution. It is capable of infecting virtually all warm-blooded vertebrates, including dogs, cats, humans, livestock, and wild animals. Felids — especially domestic cats — are the definitive hosts in which the sexual stage of the parasite occurs and oocysts are shed in faeces.
Dogs, humans and other mammals serve as intermediate hosts. Infection occurs through three principal routes:
- Ingestion of sporulated oocysts shed by infected cats (environmental contamination)
- Consumption of tissue cysts in raw or undercooked meat containing bradyzoites
- Vertical (transplacental) transmission from dam to offspring during acute infection
Toxoplasmosis is one of the most prevalent zoonoses globally. Serological surveys indicate that 30–50% of the human population carries latent T. gondii infection. Immunocompromised patients and pregnant women face the greatest risk of severe clinical disease. Accurate diagnosis in companion animals therefore also carries a direct public health dimension.
Life Cycle and Transmission Pathways
The life cycle of T. gondii alternates between definitive and intermediate hosts. In cats, the enteroepithelial cycle produces oocysts that are excreted unsporulated and become infectious after 1–5 days of environmental sporulation. A single infected cat can shed millions of oocysts per day during primary infection.
In intermediate hosts — including dogs — tachyzoites disseminate widely during acute infection before converting to bradyzoites within tissue cysts, predominantly in neural and muscular tissue. This cyst stage may persist for the life of the host and represents the source of reactivation in immunosuppression.
Toxoplasmosis in Dogs — Clinical Presentation
Most immunocompetent dogs mount effective immune responses and remain subclinically infected. Clinical disease is more likely in puppies, immunosuppressed dogs, or those co-infected with Canine Distemper Virus (CDV), which profoundly impairs cell-mediated immunity and can reactivate latent toxoplasmosis.
Systemic Signs
- Fever, lethargy, anorexia and weight loss
- Pneumonia with dyspnoea, tachypnoea (pulmonary toxoplasmosis)
- Hepatitis — jaundice, elevated liver enzymes
- Myocarditis, cardiac arrhythmias
- Lymphadenopathy
Neurological & Neuromuscular Signs
CNS involvement is a hallmark of severe toxoplasmosis and may present as:
- Ataxia, paresis, or ascending paralysis
- Seizures, behavioural changes, dementia
- Myositis — muscle pain, stiffness, gait abnormalities
- Polymyositis resembling immune-mediated disease
Ocular Signs
- Anterior uveitis, chorioretinitis
- Retinal detachment in severe cases
Dogs with concurrent Canine Distemper Virus infection are at markedly elevated risk of clinical toxoplasmosis. CDV suppresses T-cell immunity, allowing rapid tachyzoite proliferation. Always consider T. gondii serology when CDV is suspected, particularly in dogs with concurrent neurological and respiratory signs.
Toxoplasmosis in Cats — Clinical Presentation
Cats are the definitive host and typically remain healthy despite infection. Clinical toxoplasmosis in cats occurs most commonly following primary infection in immunologically naïve animals or in FIV/FeLV-positive cats with compromised immunity.
Key Clinical Features in Cats
- Ocular disease: Anterior uveitis, chorioretinitis — among the most common presentations; may be the only presenting sign
- Respiratory: Interstitial pneumonia, dyspnoea
- Gastrointestinal: Anorexia, vomiting, diarrhoea, weight loss
- Neurological: Ataxia, paresis, cranial nerve deficits
- Hepatic: Icterus, elevated liver enzymes (AST, ALT, ALP)
Cats positive for Feline Immunodeficiency Virus (FIV) or Feline Leukaemia Virus (FeLV) are at significantly elevated risk of fatal toxoplasmosis due to impaired cell-mediated immunity. Serological screening is strongly advised in all FIV/FeLV-positive cats presenting with uveitis, neurological or respiratory signs.
Diagnosis of Toxoplasmosis — How to Test
Definitive diagnosis of toxoplasmosis combines serology, clinical signs, haematological and biochemical findings, and response to treatment. Serology — the detection of anti-T. gondii antibodies — remains the cornerstone of ante-mortem diagnosis in companion animals.
Serological Interpretation
| IgM | IgG | Interpretation | Recommendation |
|---|---|---|---|
| Negative | Negative | No prior exposure; seronegative | Repeat if clinical suspicion remains; consider other differentials |
| Positive | Negative | Recent / acute infection | Confirm with repeat titre at 2–4 weeks; initiate treatment if clinical signs present |
| Negative | Positive | Past / chronic infection; likely immune | Generally not clinically significant in immunocompetent animals |
| Positive | Positive | Active / reactivated infection | Treat immediately; investigate for immunosuppression (FIV, FeLV, CDV) |
Comparison of Diagnostic Methods
| Method | Time to Result | Detects IgG+IgM | Point-of-care | Cost |
|---|---|---|---|---|
| Sabervet TOXO Ab Rapid Test | 10 min | Yes | Yes | Low |
| ELISA (laboratory) | 4–8 hours | Yes | No | Medium |
| IFA (reference laboratory) | 1–3 days | Yes | No | High |
| PCR | Hours–days | No (DNA only) | No | High |
| Histopathology / cytology | Days | No | No | High |
Sabervet TOXO Ab Rapid Test — Product Overview
Sabervet Toxoplasma Antibody Rapid Test
Lateral flow immunochromatographic assay for rapid detection of anti-Toxoplasma gondii IgG and IgM antibodies in canine and feline whole blood, serum or plasma.
- Result in 10 minutes
- Detects IgG (chronic) and IgM (acute) antibodies
- 10 µL whole blood, serum or plasma
- No instrument required
- CE-marked · ISO 13485 manufacturing
- Sensitivity ≥93% · Specificity ≥97%
- Storage 2–30 °C · 24-month shelf life
How to Perform the TOXO Ab Rapid Test
The test procedure is simple and requires no specialised training or equipment. Each test kit contains: test cassette, dropper, buffer solution, and package insert.
Prepare the Sample
Collect 10 µL of whole blood (EDTA or heparin anticoagulant), serum, or plasma. Allow refrigerated samples to reach room temperature before testing. Do not use haemolysed or grossly lipaemic samples.
Add Sample to Cassette
Remove the test cassette from its sealed foil pouch. Place it on a flat, dry surface. Using the dropper provided, add 1 drop (~10 µL) of sample to the sample well (S) on the cassette.
Add Buffer Solution
Immediately add 2 drops of buffer solution to the sample well. The chromatographic migration will begin within seconds.
Read the Result at 10 Minutes
Positive: Two coloured lines appear (control line C and test line T).
Negative: Only the control line C appears.
Invalid: No control line — repeat with a new cassette.
Do not read results after 15 minutes.
A faint T line should always be interpreted as positive regardless of colour intensity. The control line must appear for the test to be valid. If the C line is absent, the result is invalid and the test must be repeated.
Treatment of Toxoplasmosis in Dogs and Cats
Clindamycin is the treatment of choice for clinical toxoplasmosis in both dogs and cats. Alternative or combination protocols include trimethoprim-sulphonamide (TMP-SMZ) and pyrimethamine plus sulphonamide, the latter being the most efficacious combination but requiring monitoring for bone marrow suppression.
| Drug | Dose (Dog) | Dose (Cat) | Duration | Notes |
|---|---|---|---|---|
| Clindamycin | 10–20 mg/kg PO q12h | 25–50 mg/cat PO q12h | 4 weeks minimum | Drug of choice; monitor for GI side effects |
| TMP-SMZ | 15 mg/kg PO q12h | 15 mg/kg PO q12h | 4 weeks | Avoid in animals with folate deficiency |
| Pyrimethamine + Sulphonamide | 0.25–0.5 mg/kg q24h (pyrimeth.) | 0.25–0.5 mg/kg q24h | 4 weeks | Most efficacious; monitor CBC for myelosuppression; supplement folinic acid |
Clinical improvement is typically seen within 24–48 hours of initiating appropriate therapy. Neurological signs may take longer to resolve or may persist if CNS damage is established.
Frequently Asked Questions
How accurate is the Sabervet Toxoplasma Antibody Rapid Test?
The Sabervet TOXO Ab test demonstrates sensitivity ≥93% and specificity ≥97% when validated against reference ELISA and IFA methods. These performance characteristics meet the requirements for CE certification and provide reliable results for clinical decision-making in veterinary practice.
What sample types can be used?
The test accepts whole blood (EDTA or heparin anticoagulated), serum, and plasma. Only 10 µL of sample is required. Ensure samples are at room temperature before testing. Do not use haemolysed, lipaemic or grossly icteric samples as these may affect result accuracy.
Can the test distinguish between acute and chronic infection?
Yes. The test detects both IgM antibodies (indicating recent or active infection, typically peaking at 2–4 weeks post-infection) and IgG antibodies (indicating past or chronic exposure). An IgM-positive result in a clinically ill animal strongly supports active toxoplasmosis and warrants prompt treatment. An IgG-only positive in an otherwise healthy animal indicates prior exposure with likely immunity.
Is the test valid for both dogs and cats?
Yes. The Sabervet TOXO Ab Rapid Test is validated for use in both canine and feline patients using whole blood, serum or plasma. Cats as definitive hosts have a high natural seroprevalence; clinical context is essential when interpreting a positive IgG result in an otherwise asymptomatic cat.
What does a positive result mean clinically?
A positive IgM result in a symptomatic animal is highly suggestive of active toxoplasmosis. Initiate clindamycin therapy and investigate for underlying immunosuppression (FIV, FeLV, CDV). A positive IgG-only result in an asymptomatic animal indicates past exposure; clinical treatment is generally not required. Always interpret serology in conjunction with clinical signs, history, and other diagnostic findings.
What certifications does the test carry?
The Sabervet TOXO Ab Rapid Test is CE-marked and manufactured under an ISO 13485 quality management system. It is produced by Hangzhou Antigenne Technology Co., Ltd, a specialist veterinary diagnostics manufacturer with global distribution.
How should the test be stored?
Store at 2–30 °C in the original sealed foil pouch. Do not freeze. Keep away from direct sunlight and moisture. Shelf life is 24 months from manufacture date. Once removed from the foil pouch, the cassette must be used within 30 minutes.
Why Choose Sabervet Rapid Tests?
Sabervet is a veterinary diagnostic brand developed by Hangzhou Antigenne Technology Co., Ltd — a specialist manufacturer of rapid immunochromatographic assays for companion animal and livestock medicine. Sabervet tests are used by veterinary practices, diagnostic laboratories, and distributors in over 40 countries.
- Point-of-care design: No laboratory equipment, no training required — results in 10 minutes
- Dual-species validation: All canine tests validated for feline use where applicable
- CE-marked & ISO 13485: International quality certification for professional use
- Complete diagnostic portfolio: CHW, CPV, CDV, FPV, FeLV, FIV, FIPV, EHR, ANA, Brucella, Bovine Pregnancy and more
- Global distribution: Competitive MOQ, reliable supply chain, export to 40+ countries
