[Contribution to the parasitic fauna of the GDR (German Democratic Republic). 7. Occurrence of Gasterophilus larvae (Diptera: Gasterophilidae) in horses].

This study investigates the prevalence and seasonal dynamics of Gasterophilus spp. larvae in horses in the German Democratic Republic from 1977 to 1980. It found that nearly all larvae from horses sent for butchering were Gasterophilus intestinalis, with the number of larvae ranging from 2 to 576 per horse.

Research Methodology and Scope

• The research was conducted over a span of three years from May 1977 to May 1980.
• It involved an examination of 2,539 horses that were destined for butchering, sourced from different districts of the German Democratic Republic.
• The study also included 79 horses that were subjected to control measures against gasterophilosis, a parasitic disease caused by Gasterophilus spp. larvae.

Findings

• The researchers discovered that 99.98% of the 13,742 second and third instar larvae found in horses for butchering were identified as Gasterophilus intestinalis, with only a meagre 0.02% being Gasterophilus nasalis.
• Among the 7,765 larvae studied post-control measures, Gasterophilus intestinalis dominated with a count of over 96%.
• Interestingly, Gasterophilus nasalis was only found in four districts of the country.

Prevalence and Intensity of Infestation

• The study noted that the mean extensive invasion from 1977 to 1980 was 8.7%, while the mean intensive invasion was 33.4 +/- 3.16 larvae per infected horse.
• The number of larvae found varied significantly, anywhere between 2 and 576 per horse.
• The intensity of invasion increased from 25.8 +/- 2.74 to 58.6 +/- 3.49 larvae per infected horse over the three-year period.

Seasonal and Geographical Patterns

• The study also observed seasonal patterns, with peaks in extensive invasion seen in the months of April, May, and October.
• Both second and third instar larvae of Gasterophilus spp. were found in horses from October to February.
• The instances of gasterophilosis were geographically concentrated in the northern parts of the German Democratic Republic.