Molecular characterization of Fasciola hepatica obtained from cattle and horse in Central Chile.

Molecular analysis of Fasciola hepatica from cattle and horses in Central Chile reveals significant genetic diversity and highlights the importance of comprehensive sequencing for accurate characterization of this parasite.

Background and Significance

• Fasciola hepatica is a liver fluke causing fascioliasis, a zoonotic parasitic disease affecting mammals, including humans.
• The disease poses challenges for public health, animal health, and ecosystem stability due to its wide host range and impact.
• Molecular characterization of the parasite helps understand its genetic diversity, which is critical for developing effective control and treatment strategies.
• Prior to this study, there was no genetic data on F. hepatica from Chile.

Study Objectives and Methods

• The main aim was to perform the first genetic characterization of F. hepatica from Chile, focusing on samples from two host species: cattle and horses.
• The mitochondrial gene cox1 was used as the genetic marker; this gene is commonly employed for parasite genetic studies due to its variability and maternal inheritance.
• Samples were obtained from Central Chile, allowing an investigation of the parasite’s genetic diversity across different hosts and geographic origins.
• Both full-length and shorter traditionally used sequences of the cox1 gene were analyzed to compare their effectiveness in detecting haplotype diversity.

Key Findings

• Out of all haplotypes detected, 70% were host-specific, meaning they were found either in cattle or in horses, corresponding well with the geographical locations from which the samples originated.
• Using full-length cox1 gene sequences, 80% of the sequences were unique, showing a high level of genetic diversity.
• When only the shorter, traditionally used cox1 sequences were analyzed, unique sequences dropped to 45%, indicating that shorter sequences underestimate genetic diversity.
• This difference underscores the added resolution gained by sequencing the entire gene, which can reveal more diversity within the parasite population.

Implications of the Study

• Comprehensive sequencing of full-length mitochondrial genes provides a better understanding of the genetic variation present in F. hepatica.
• Increased knowledge of genetic variability can inform more targeted and effective disease control measures, as genetic differences may relate to drug resistance, pathogenicity, or transmission dynamics.
• Understanding population structure and host-specific haplotypes can assist in epidemiological surveillance and reduce zoonotic transmission risk.
• This study highlights the necessity for broader genetic sampling and sequencing efforts globally to avoid underestimations of parasite diversity.
• Ultimately, such genetic insights help optimize intervention strategies in both livestock management and public health sectors in Chile and other affected regions.