Dog skin parasite load, TLR-2, IL-10 and TNF-α expression and infectiousness

Area of Science:

• Veterinary Immunology
• Parasitology
• Molecular Biology

Background:

• Visceral leishmaniosis is a zoonotic disease transmitted by Lutzomyia longipalpis sandflies.
• Dogs are the primary reservoir, with disease progression linked to immune response type (Type 1 vs. Type 2).
• The roles of toll-like receptor 2 (TLR-2) and inducible nitric oxide synthase (iNOS) in immune response determination are unclear.

Purpose of the Study:

• To investigate parasite load and the expression of TLR-2, iNOS, IL-10, and TNF-α in the skin of infected dogs.
• To determine the association between parasite burden and specific immune gene expression in canine leishmaniosis.
• To assess the relationship between parasitism and infectiousness to sandflies via xenodiagnosis.

Main Methods:

• Analysis of parasite load and gene expression (TLR-2, iNOS, IL-10, TNF-α) in skin samples from 29 infected and 8 control dogs.
• Quantitative assessment of parasite burden in the canine dermis.
• Xenodiagnosis to evaluate sandfly infectivity from infected dogs.

Main Results:

• Increased parasite load in dog skin correlated with the upregulation of TLR-2, IL-10, and TNF-α.
• Abundance of these transcripts (TLR-2, IL-10, TNF-α) was significantly associated with Leishmania infection.
• Xenodiagnosis confirmed that higher parasitism levels in dogs increase their risk of transmitting the disease to sandflies.

Conclusions:

• Parasite load is a key factor influencing the expression of specific immune-related genes in canine leishmaniosis.
• TLR-2, IL-10, and TNF-α expression levels are indicative of infection status and parasite burden in dog skin.
• Elevated parasitism in dogs poses a significant risk for visceral leishmaniosis transmission, underscoring the importance of reservoir control.