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. 2025 Aug 6;124(8):87.
doi: 10.1007/s00436-025-08540-x.

Seasonality, control, and risk factors for Gasterophilus intestinalis egg intensity in horses from Romania under field conditions

Ș O Rabei  1 , D Pivariu  2 , A I Cocian  3 , D Vaccaro  3 , P Costache-Bobescu  4 , A D Mihalca  5   6
Affiliations

Seasonality, control, and risk factors for Gasterophilus intestinalis egg intensity in horses from Romania under field conditions

Ș O Rabei et al. Parasitol Res. .

Abstract

This study aimed to assess the efficacy of pyrethroid-based insecticides against Gasterophilus spp. egg-laying activity and to establish the seasonality patterns in the specific climatic area of Transylvania, Romania. To fulfil the aims of the study, a total of 40 horses were treated every 4 weeks and inspected every 2 weeks between 11 May and 6 November (Pilo et al. Parasitol Res 114:1693-1702, 2024). Through this period, eggs were found between 24 June and 2 November. The eggs were found on 34 out of 40 horses (prevalence = 85%, CI 95% = 73.43-96.56%). Overall, a total of 50,029 Gasterophilus spp. eggs were counted during this study, and all were morphologically identified as G. intestinalis. Statistical analysis revealed no significant difference in prevalence and intensity between treated and control horses (p > 0.05). The number of laid eggs varied significantly across body regions (p < 0.05). The risk factors associated with increased egg-laying activity were significantly (p < 0.05) associated with dark-color coats, outside husbandry regime, and the month of exposure. No significant differences in egg numbers and prevalence were found across gender or age groups (p > 0.05). The applied statistical tests were as follows: the non-parametric Mann-Whitney U test, the Friedman test, Wilcoxon test corrected by the Bonferroni method, the Kruskal-Wallis test, and the Bonferroni correction for multiple comparisons. These results highlight gasterophilosis as an important parasite in horses. In conclusion, we recommend that, in order maintain a low prevalence of Gasterophilus spp., treatment should include the use of larvicidal drugs and the mechanical removal of the eggs.

Keywords: Gasterophilus intestinalis; Color; Eggs; Husbandry; Repellent; Seasonality.

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Conflict of interest statement

Declarations. Ethics approval: All horse owners allowed the enrollment of their animals in this study by signing an agreement for participation. Consent of publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
G. intestinalis egg morphology
Fig. 2
Fig. 2
G. intestinalis eggs prevalence across control dates
Fig. 3
Fig. 3
G. intestinalis eggs mean intensity and mean abundance across control dates
Fig. 4
Fig. 4
G. intestinalis eggs mean abundance across husbandry groups. a Indoor-outdoor. b Outdoor only
Fig. 5
Fig. 5
G. intestinalis eggs mean intensity across color groups. a Light colored. b Dark colored
Fig. 6
Fig. 6
G. intestinalis eggs mean intensity across anatomical regions (all X axes show the date of examination)
See this image and copyright information in PMC

References

    1. AbdElKader NA, Sheta E, AbuBakr HO, El-Shamy OAA, Oryan A, Attia MM (2021) Effects of chitosan nanoparticles, ivermectin and their combination in the treatment of Gasterophilus intestinalis (Diptera: Gasterophilidae) larvae in donkeys (Equus asinus). Int J Trop Insect Sci 41:43–54. 10.1007/s42690-020-00171-2
    1. Anderson JR (2006) Oestrid myiasis of humans. In: Colwell DD, Hall MJR, Scholl PJ (eds) The oestrid flies: biology, host-parasite relationships, impact and management. CABI, Wallingford, pp 201–209
    1. Attia MM, Abou-Okada M, Shamseldean MSM, El-Gameel SM (2022) Insecticidal effects of curcumin (Curcuma longa) against the horse stomach bot fly, Gasterophilus intestinalis (diptera: oestridae). Int J Trop Insect Sci 42:917–926. 10.1007/s42690-021-00618-0
    1. Blahó M, Egri Á, Száz D, Kriska G, Åkesson S, Horváth G (2013) Stripes disrupt odour attractiveness to biting horseflies: battle between ammonia, CO₂, and colour pattern for dominance in the sensory systems of host-seeking tabanids. Physiol Behav 119:168–174. 10.1016/j.physbeh.2013.06.013 - PubMed
    1. Brocard P, Pfister K (1991) The epidemiology of gasterophilosis of horses in Switzerland. Schweiz Arch Tierheilkd 133:409–416 - PubMed

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