Canine leishmaniasis: the key points for qPCR result interpretation

Area of Science:

• Veterinary Parasitology
• Molecular Diagnostics
• Canine Infectious Diseases

Background:

• Canine leishmaniasis (CanL) diagnosis and follow-up are challenging due to varied clinical signs and high seroprevalence in endemic areas.
• Accurate diagnostics are crucial for effective disease management and control.

Purpose of the Study:

• To demonstrate the advantages of Leishmania quantitative PCR (qPCR) for diagnosing and controlling CanL.
• To highlight the prognostic value of qPCR in CanL.
• To propose guidelines for tissue selection and infection monitoring in CanL.

Main Methods:

• A study involving 710 dogs in a leishmaniasis-endemic area.
• Comparison of qPCR and ELISA for detecting Leishmania infection.
• Analysis of clinical signs, serological status, and parasite load.

Main Results:

• 36.3% of dogs were infected; qPCR detected 4.5% (solely qPCR positive), ELISA 16.2%, and both 15.6%.
• Symptomatic dogs with high ELISA titers were qPCR-positive; dogs with inconclusive ELISA and high qPCR parasitemia developed disease.
• Asymptomatic ELISA-positive dogs with qPCR-confirmed parasitemia (medium to high) developed CanL; bone marrow/lymph node aspirates are recommended for asymptomatic cases.

Conclusions:

• qPCR is effective for confirming CanL diagnoses with inconclusive ELISA results.
• qPCR is valuable when dogs have not yet seroconverted.
• qPCR facilitates accurate treatment monitoring through parasite quantification.