Evaluation of parasiticidal activity of fenbendazole, ivermectin, oxibendazole, and pyrantel pamoate in horse foals with emphasis on ascarids (Parascaris equorum) in field studies on five farms in Central Kentucky in 2007

Abstract

Horse foals on five farms in Central Kentucky were used in field studies in 2007 evaluating activity of paste formulations of four compounds (fenbendazole-FBZ, ivermectin-IVM, oxibendazole-OBZ, and pyrantel pamoate-PRT) against internal parasites with emphasis on ascarids (Parascaris equorum). It has been well established the last few years that there is widespread resistance of P. equorum to ivermectin. The main purpose of the present research was to obtain current data on ascaridicidal activity of FBZ, OBZ, and PRT; also, to acquire further information on ascarid resistance to ivermectin. Additionally, data were documented on drug activity on small strongyles. Detection of ascarid and strongyle eggs in feces of foals was by a qualitative method (presence or absence) or a quantitative method (eggs per gram of feces). Strongyle eggs all were assumed to be from small strongyles. This is based on fecal cultures from horses on one farm and historic records from horses in this area on excellent deworming programs. A girth tape was used to estimate the body weight of each foal so that the appropriate dose rate of each drug could be given. Many of the foals were used in more than one cycle of treatments. Efficacy of the drugs, administered intraorally, was determined by calculating the average percentage reduction (% red.) of the number of foals passing eggs after vs. before treatment: (1) FBZ at 10 mg/kg was tested on four farms; 76 foals were examined, 50 with ascarid eggs (84% red.) and 62 with strongyle eggs (0% red.); (2) IVM at 200 microg/kg was tested on three farms; 58 foals were examined, 18 with ascarid eggs (0% red.) and 48 with strongyle eggs (100% red.); (3) OBZ at 10 mg/kg was tested on three farms; 181 foals were examined, 78 with ascarid eggs (94% red.) and 79 with strongyle eggs (0% red.); (4) PRT was tested on two farms, one farm at 1x (6.6 mg base/kg); 42 were foals examined, 16 with ascarid eggs (0% red.) and 33 with strongyle eggs (12% red.) and one farm at 2x (13.2 mg base/kg); 18 foals were examined, 13 with ascarid eggs (23% red.) and 15 with strongyle eggs (27% red.).

A field study on the anthelmintic resistance of Parascaris spp. in Arab foals in the Riyadh region, Saudi Arabia

“…infection in foals in Saudi Arabia (53%). The recorded prevalence is within the range (31%-61%) reported in previous studies from North America (Austin et al 1990;Lyons et al 2008), Europe (Lind & Cristensson 2009;Laugier et al 2012) and Australia (Armstrong et al 2014) which confirm the common incidence of Parascaris spp. in foals.…”

Recommendations for a sustainable control of gastro-intestinal worm infections in horses in Germany

“…Erste Berichte stammen aus den Niederlanden (Boersma et al 2002) und Kanada (Hearn und Peregrine 2003). Inzwischen liegen weitere Veröffentlichungen aus den Vereinigten Staaten (Craig et al 2007, Lyons et al 2008a, Dänemark (Schougaard und Nielsen 2007), Deutschland (Samson-Himmelstjerna et al 2007), Schweden (Lindgren et al 2008, Lind und Christensson 2009, Brasilien (Molento et al 2008), England (Stoneham und Coles 2006), Italien (Veronesi et al 2009) und der Türkei (Cirak et al 2010) vor. Infolge des in den letzten Jahren beobachteten verstärkten Einsatzes von IVM-Präparaten erscheint die Sorge einer Ausbreitung der bisher nur punktuell festgestellten IVM-AR durchaus berechtigt.…”

“…Infolge des in den letzten Jahren beobachteten verstärkten Einsatzes von IVM-Präparaten erscheint die Sorge einer Ausbreitung der bisher nur punktuell festgestellten IVM-AR durchaus berechtigt. Zudem deuten Studien aus den USA bei einzelnen Pferdebeständen auf multiple Resistenzen gegen mehrere Wirkstoffklassen (PYR und BZ) hin und darüber hinaus waren auf einzelnen Farmen neben P. equorum gleichzeitig auch Cyathostominen betroffen (Craig et al 2007, Lyons et al 2008a). …”

The Effectiveness of Cinnamomum zeylanicum, Punica granatum Flower and Capsicum annuum Extracts Against Parascaris equorum Infective Larvae

“…Resistance against macrocyclic lactones (ivermectin and/or moxidectin), pyrantel salts and occasional resistance to piperazine has been reported in the Netherlands (Van Doorn et al, 2007), United States (Craig et al, 2007;Lyons et al, 2008), Denmark (Schougaard and Nielsen, 2007) and Italy (Veronesi et al, 2009). Resistance clearly involves the entire macrocyclic lactone class because sequential dosing of individual foals with ivermectin and moxidectin failed to reduce egg counts after either treatment (Reinemeyer et al, 2010).…”

“…Although Pyrantel pamoate, Fenbendazole, and Oxibendazole have been used successfully to treat macrocyclic lactone-resistant populations of ascarids (Lyons et al, 2008;Schougaard and Nielsen, 2007;Slocombe et al, 2007), anthelmintic resistance issues and residues and toxicity problems (Gasbarre et al, 2001) have led to revival of interest in the validation of traditional veterinary practices (Ketzis et al, 2002;van Veen, 1997). Hence, there are numerous in vivo and in vitro surveys and scientific studies on validation of plants used as anthelmintics in the world (Alawa et al, 2003;Bizimenyera et al, 2006;Hussain et al, 2008;Iqbal et al, 2006a;Iqbal et al, 2006b;Jabbar et al, 2007).…”