Decoding Leishmania in equines: A comparative analysis of molecular targets.

Area of Science:

• Veterinary Parasitology
• Molecular Epidemiology
• Equine Health

Background:

• Leishmania spp. cause significant health and economic issues in animals, particularly equines.
• Equine leishmaniasis presents complex clinical signs affecting weight, skin, liver, and spleen.
• There is a critical lack of data on Leishmania occurrence in equines in Southern Punjab, Pakistan.

Purpose of the Study:

• To determine the prevalence of Leishmania in equines in District Rahim Yar Khan, Southern Punjab, Pakistan.
• To compare the diagnostic sensitivity of mitochondrial (Cytochrome b) and nuclear (18S rRNA) genes for Leishmania detection in equines.
• To identify potential risk factors associated with Leishmania infection in the equine population.

Main Methods:

• Blood samples from 384 equines (horses, mules, donkeys) were collected.
• Microscopy (Microhematocrit method) and molecular techniques (PCR amplification of 18S rRNA and Cytochrome b genes) were employed for parasite detection.
• DNA extraction using commercial kits and phylogenetic/sequence analyses were performed.
• Data on risk factors were collected via a structured questionnaire.

Main Results:

• Overall Leishmania prevalence was 2.1% (microscopy), 7.3% (18S rRNA), and 8.8% (Cytochrome b).
• Higher infection rates were observed in female, older, and underweight equines.
• Infection was more prevalent in gestating, non-dewormed, symptomatic, and poor body condition animals.
• Phylogenetic analysis identified Leishmania (Leishmania) infantum.

Conclusions:

• The study highlights the presence of Leishmania in equines in Southern Punjab, Pakistan.
• The nuclear 18S rRNA gene is a more sensitive molecular marker for equine leishmaniasis diagnosis than the mitochondrial Cytochrome b gene.
• Risk factors such as sex, age, body condition, and management practices influence Leishmania infection prevalence in equines.