Report on Gasterophilus spp. (Diptera, Gasterophilidae) of Horses in Algeria: Prevalence, Intensity, and Monthly Variations.

This research paper studies the prevalence, variation, and intensity of Gasterophilus spp., a type of botfly, in horses in the Constantine region of East Algeria, over an 18-month period.

Research Objectives and Methodology

• The objective of the research was to understand the composition, prevalence, and seasonal dynamics of Gasterophilus spp. in the horses in Algeria. This would offer insights into controlling the infestation and improving the overall health of the horses.
• For the study, 128 horses were examined at the Constantine region’s slaughterhouse over 18 months. Researchers looked for the presence of the botflies and recorded their numbers, lifespan stages, and variations in different seasons.

Findings

• The research discovered that 124 out of the 128 horses (around 96.9%) were infested with Gasterophilus spp., with an average of 161 larvae found in each horse.
• Among the botfly species identified, Gasterophilus intestinalis and Gasterophilus nasalis were the most common, infesting 95.3% and 77.3% of the horses. Gasterophilus pecorum and Gasterophilus haemorrhoidalis were found in 14.0% and 10.1% of the horses, respectively.
• It was noted that the horses’ age, sex, and breed did not affect the spread of the infestation.

Seasonal Variation of Larvae Stages

• Second-stage larvae (L2) of Gasterophilus spp. were absent between April and July and present in significantly higher numbers between December and February.
• Third-stage larvae (L3) were found in fewer numbers mainly from September to November. This suggests that the adult botflies were most active in the fall. This evidence indicates that its activity period is two months longer and begins earlier than Gasterophilus haemorrhoidalis.
• The research found a correlation between the prevalence of the botfly infection and the rainiest months, suggesting external environmental factors play a role in the botfly lifecycle.

The findings of this study can serve as a foundation for implementing measures to control the spread of Gasterophilus spp. and improve horse health in the region. Further research may explore why these flies are more prevalent in specific months and the effects of weather patterns on their lifecycle and activity.