Gasterophilus intestinalis (Diptera: Oestridae) in the diaphragmatic muscle: An unusual finding.

This research article reveals an unusual discovery of the larvae of the bot-fly species Gasterophilus intestinalis embedded in the diaphragmatic muscle of a horse, instead of the usual site in the gastrointestinal tract. The article discusses the need for a combination of morphological and molecular tools to identify the species due to its atypical location and absence of regular clinical signs.

Identification of Gasterophilus intestinalis In An Uncommon Location

• The research was provoked by an unusual discovery of the larva from the Gasterophilus intestinalis bot-fly species embedded deeply in the diaphragmatic muscle of a horse. This was an unexpected observation since the typical habitat for these larvae is the gastrointestinal tract of equids. Their presence in the equid’s system usually results in a condition known as intestinal myiasis.
• In Italy, five species of the Gasterophilus genus, including G. intestinalis, G. nasalis, G. inermis, G. pecorum, and G. haemorrhoidalis, have been reported. These species have mostly been observed during necropsies, lodged within different regions of the equid’s gastrointestinal tract.

Methods of Species Identification

• Due to the unusual location of the larvae and the absence of noticeable clinical signs associated with intestinal myiasis, the researchers had doubts about the species identity of the larvae.
  Thus, they combined morphological and molecular methods to identify the species.
• The correlation of the morphological characteristics of the larvae with the accurate molecular tools provided a confirmatory approach to the identification of the insect species.

Insights on Migration Patterns of G. intestinalis

• The unusual finding has provided vital information regarding the erratic migration patterns of the larval forms of G. intestinalis.
• The researchers believe that understanding these patterns is critical because gasterophiliasis, the disease caused by the larvae, is one of the less researched types of intestinal myiasis in horses.