[The epidemiology of gasterophilosis of horses in Switzerland].

The researchers examined the presence and frequency of Gasterophilus spp, a type of horsefly, in horses in various areas of Switzerland. They discovered a prevalence rate of 64.6%, with the occurrence showing seasonal distribution and a distinct regional bias towards the Western part of Switzerland.

Study Overview

• The researchers conducted a two-year study running from March 1988 to December 1989. They analyzed 198 gastrointestinal tracts from slaughtered horses across different regions of Switzerland.
• They monitored the presence of Gasterophilus spp at various life stages (eggs and subsequent developmental stages) in these animals.
• Additionally, 200 live horses from selected areas in Western Switzerland were checked between July and November of each year for further understanding of how the infection affected horses.

Key Findings

• The prevalence of Gasterophilus spp. in Swiss horses was approximately 64.6%, indicating a high level of infection.
• A noticeable seasonal pattern was found. The exact nature of this pattern was not specified, but it suggests that certain times of the year may be more conducive to horsefly activity or the survival of their larvae.
• Only one species of horsefly—Gasterophilus intestinalis—was identified in the study, suggesting it is the most common or perhaps the only species present in Switzerland.
• Horses in the Western part of Switzerland were found to be considerably more contaminated than those from other regions. The specific reasons for this were not identified, but the researchers suggested that intensive horse-traffic at the border might be a contributing factor.
• Horses with darker coats were found to be more frequently parasitized, although no distinct differences were observed in relation to the horses’ age or sex.

Conclusion

• The high prevalence of Gasterophilus spp. in Swiss horses confirmed that gasterophilosis (the medical term for the infection caused by these horseflies) is a serious concern that warrants significant attention in Switzerland.
• The report implies that prophylactic measures—such as horsefly repellents, hygiene practices and vaccination—could be beneficial to reduce the rate of infection.