Laboratory tests performed on Leishmania seroreactive dogs euthanized by the leishmaniasis control program.

Area of Science:

• Veterinary Medicine
• Infectious Diseases
• Parasitology

Background:

• Canine leishmaniasis is a significant public health concern, particularly in endemic areas like Rio de Janeiro.
• Existing control programs rely on diagnostic tests that may have limitations in accuracy.
• Accurate diagnosis is crucial for effective disease management and prevention of zoonotic transmission.

Purpose of the Study:

• To evaluate laboratory findings in dogs euthanized by the leishmaniasis control program in Rio de Janeiro.
• To assess the diagnostic performance of various tests used in canine leishmaniasis screening.
• To identify potential shortcomings in the current leishmaniasis control strategy for dogs.

Main Methods:

• Analysis of blood samples from 155 dogs with high Indirect ImmunoFluorescence (IIF) titers.
• Parasite isolation attempts (Leishmania chagasi, Leishmania braziliensis, Trypanosoma caninum) and Polymerase Chain Reaction (PCR) on skin fragments.
• Serological re-evaluation using IIF and enzyme immunoassay (EIA) on serum samples.

Main Results:

• Parasites were isolated from only 29 dogs, with mixed infections and other protozoa identified.
• PCR detected parasites in 17 dogs with intact skin.
• A significant proportion of dogs (59%) tested negative across all methods, suggesting potential false positives in initial screening.

Conclusions:

• The current visceral leishmaniasis control program in Rio de Janeiro requires adjustments to improve diagnostic specificity.
• There is a need to refine screening protocols to prevent the euthanasia of non-infected dogs.
• Improved diagnostic strategies are essential to accurately detect dogs infected with Leishmania chagasi in endemic regions.