Parasite field study in central Kentucky on thoroughbred foals (born in 2004) treated with pyrantel tartrate daily and other parasiticides periodically

Abstract

Foals (79), born in 2004 on three thoroughbred horse farms (C, M, and S) in central Kentucky, were fed pyrantel tartrate daily, beginning at about 3 months of age. In addition, other parasiticides [fenbendazole (FBZ), ivermectin (IVM) alone or with praziquantel (PRAZ), oxibendazole (OBZ), pyrantel pamoate (PRT), and moxidectin (MOX)] were given periodically. All treatments were administered by farm personnel. Over a 14-month period, from May 2004 to July 2005, collections (n=989) of feces were made from the foals for determination of presence of internal parasite eggs/oocysts by qualitative and/or quantitative methods. Conclusions on drug activity are based necessarily on considering the combined effect of pyrantel tartrate and the other compounds. For small strongyles, this was related to which specific additional compound was given. Based on the percentage of foals with strongyle-egg-positive feces and/or the level of eggs per gram of feces (EPG) counts for the foals after treatment, drug activity on small strongyles was highest to lowest for MOX, IVM and IVM/PRAZ, FBZ, OBZ, PRT, and FBZ (2x for 5 days). The macrocyclic lactones (MOX and IVM) were highly superior to the other compounds. Some of the strongyle counts were high (over 2,000), especially on one farm (S), during periods when foals received only pyrantel tartrate, but a few days after administration of therapeutic dose rates of the drugs IVM or MOX, they were negative or very low. Ascarid eggs were present in feces of three foals after treatment with a combination of IVM and PRAZ. The qualitative method was more efficient than the quantitative method in detection of ascarid and strongyle eggs in the feces. Prevalence of eggs of ascarids (Parascaris equorum) was low (0, 4, and 31%), of strongyles high (80, 100, and 100%), of Strongyloides westeri very low (only one infected foal), and oocysts of Eimeria leuckarti medium to high (36, 41, and 85%) for the three farms, C, M, and S, respectively. It is uncertain whether the low ascarid prevalence was from activity of pyrantel tartrate and/or the other drugs or to a limited source of infective eggs.

Screening for anthelmintic resistance in equid strongyles (Nematoda) in Romania

“…Despite the fact that between 2005-2009, the use of BZs in horses was significantly reduced, being reinstated only in the last three or four years, the resistant strongyle species have not disappeared, a phenomenon that has been mentioned in other studies as well (Osterman Lind et al 2007, Lyons et al 2007). It has not yet been demonstrated that it is possible to re-establish the efficacy of a drug category to which a certain level of resistance had previously existed, even if these drugs were not used for a given period of time (Slocombe et al 2008, von Samson-Himmelstjerna 2012.…”

Morphological features of development of Strongyloides westeri (Nematoda, Rhabditida) in vitro

“…According to the literature, levels of equine infection depend on the animals' age, living conditions, prophylactics, climatic conditions. Prevalence can reach 90% (Lyons et al, 2007;Araujo et al, 2012;Ricardo et al, 2012;Tolliver, 2014, 2015;Miller et al, 2017).…”

Content of Glutathione and Vitamin C in the Liver of Rats Exposed to Dimethoate and Pyrantel Tartrate

“…Pyrantel tartrate (trans-1, 4, 5, 6-tetrahydro-1-methyl-2-[2-(thienyl)-vinyl] pyrimidine) is a commonly used, effective agent against intestinal nematodes in horses and pigs (Valdez et al 1995;Lyons et al 2007). It exhibits a strong agonistic effect on nicotine receptors (AChRs) and capacity for blocking open ion channels linked with AChRs (Rayes et al 2001).…”