Molecular characterization of Thelazia lacrymalis (Nematoda, Spirurida) affecting equids: a tool for vector identification.

The research focuses on detailing a procedure developed to identify the intermediate host of the parasite Thelazia lacrymalis, a nematode responsible for a parasitic disease in equines, using Polymerase Chain Reaction – Restriction Fragment Length Polymorphism (PCR-RFLP) analysis.

Objectives and Background

• The study aims to address the lack of information about the epidemiology and presence of intermediate hosts of Thelazia lacrymalis, a nematode causing equine thelaziosis – a parasitic disease that affects equids and is transmitted by muscid flies.
• The authors outlined the challenge posed by the unknown intermediate hosts of T. lacrymalis, restricting the understanding of its ecology and epidemiology.

Methodology

• The research makes use of a PCR-RFLP based assay. PCR-RFLP stands for Polymerase Chain Reaction – Restriction Fragment Length Polymorphism, which is a technique utilised for DNA analysis.
• This analysis is conducted on the DNA from the first and second internal transcribed spacer (ITS1 and ITS2) of the ribosomal DNA from T. lacrymalis.

Findings

• The outcome of the assay differentiates T. lacrymalis from four species of Musca (Diptera, Muscidae) – Musca autumnalis, Musca domestica, Musca larvipara, and Musca osiris – which are potential vectors of equine eyeworms.
• The high sensitivity of the assay allows for efficient detection of T. lacrymalis DNA, making it an effective approach for identifying its intermediate host(s).

Contributions and Implications

• The newly developed technique provides a significant tool for investigating the natural conditions, ecology, and epidemiology of T. lacrymalis by facilitating the identification of its intermediate hosts.
• This assay can further contribute to research on controlling equine eyeworm, a global health issue for horses, by enhancing the understanding of its transmission cycle.