Helminthenmanagement beim adulten Pferd: Notwendigkeit einer Neuorientierung

Abstract

The epidemiological situation of strongyle infections in adult horses in Switzerland is characterized by a strong dominance of small strongyles (Cyathostominae) and an overall low level of egg shedding in the faeces. The prevailing attitude towards anthelmintic therapy considers neither husbandry conditions nor pasture hygiene measures. Instead, calendar-based routine medication, comprising usually 3 to 4 annual treatments, is the typical strategy. Such an approach, however, often results in an excessive administration of anthelmintics. With respect to the continuous spread of drug resistant cyathostomins a change of strategy seems inevitable. A consensus has been agreed on between equine parasitologists and clinicians of the Vetsuisse Faculty in Zurich and Berne to focus on the concept of a selective control approach, based on individual faecal egg counts as the central element. It is now recommended that clinically healthy horses (> 4 y) are treated only when their strongyle egg count is equal to or higher than 200 eggs per gram of faeces. A regular analysis of the strongyle population based on larval cultures, the control of drug efficacy, and quarantine measures for incoming horses are mandatory components of the concept. Recent experiences in several pilot farms have indicated that only 4 % of the McMaster analyses resulted in a deworming treatment. For horses that did not receive any nematicidal anthelmintic during the current season, a "safety" treatment is recommended at the end of the grazing period.

Detection of Strongylus vulgaris in equine faecal samples by real-time PCR and larval culture – method comparison and occurrence assessment

“…This low occurrence of S. vulgaris is in line with previously conducted studies investigating faecal samples from German horses obtained by larval culture with a prevalence ranging from 0.2 to 1.3% [10, 19–21]. A comparable prevalence has also been reported in Switzerland [3]. …”

“…The intensive anthelmintic treatment regime of the last decades as well as the long prepatent period of six to 7 months might be responsible for the current low occurrence of S. vulgaris in Germany [3, 46, 47]. Based on these arguments, a low occurrence for S. vulgaris under 5% was reported by Hertzberg et al [3] for horses living in Switzerland.…”

“…Assuming a German horse population of 1.1 million [38] with a prevalence for an infection with S. vulgaris of 1% [3, 10, 19–21], a minimum of 459 horses had to be investigated since in this case the probability to detect at least one infected horse was above 99% [39]. Thus, samples of 501 of 1455 horses (horse level, 34.4%) were investigated by real-time PCR for an infection with S. vulgaris (Fig.…”

“…Due to the emerging resistance of Cyathostominae to available anthelmintic drugs, an alternative approach based on selective anthelmintic therapy (SAT) has been implemented in some horse farms [13, 14]. The principle of SAT comprises a major change in the frequency of applying anthelmintics with an anti-strongyle spectrum based on the treatment of horses with a faecal egg count (FEC) of strongyle eggs above a certain threshold, determined with a quantitative faecal egg count method, such as the McMaster [3, 15–18]. Nevertheless, for reliable detection of infections with other important equine parasite species like Anoplocephala perfoliata , O. equi, and Strongylus spp.…”

Evaluation of Baermann apparatus sedimentation time on recovery of Strongylus vulgaris and S. edentatus third stage larvae from equine coprocultures

“…Recent research has illustrated that strict reliance on fecal egg counts and a subsequent inability to diagnose Strongylinae infections has the potential to lead to the reemergence of S. vulgaris, and other Strongylinae, within evidence based programs (Nielsen et al, 2012). Consequently, routine monitoring of S. vulgaris infections is recommended in such programs, and performance of coprocultures is now an established practice for a large proportion of Danish, equine practitioners and are likely to be more frequently implemented in other countries now adopting similar programs (Hertzberg et al, 2014;Nielsen et al, 2014).…”