Susceptibility of helminth species from horses against different chemical compounds in Brazil.
By means of parasitological necropsies, the present study aimed to evaluate, in six experiments, the degree of susceptibility or resistance of different helminth species which naturally infect horses to ivermectin 0.2 mg/kg, abamectin 0.2 mg/kg, moxidectin 0.4 mg/kg, trichlorfon 35 mg/kg, ivermectin 0.2 mg/kg+praziquantel 2.5 mg/kg, abamectin 0.2 mg/kg+praziquantel 2.5 mg/kg and ivermectin 0.2 mg/kg+6.6 mg/kg pyrantel. At experimental day zero, the horses were allocated to treatment groups based on average counts of strongylid eggs per gram of feces (EPG) obtained on days -3, -2 and -1. Oxyuris sp. infections were confirmed as positive or negative. All the animals in the six experiments were naturally infected by this helminth species. Each group (control or treated) consisted of six animals. All the assessed Habronema muscae populations analyzed were susceptible to ivermectin, abamectin and moxidectin. Of the six Trichostrongylus axei populations, four were susceptible to ivermectin, abamectin, moxidectin, trichlorfon and ivermectin+praziquantel, and two were resistant to abamectin+praziquantel and ivermectin+pyrantel. Both Strongyloides westeri populations analyzed were susceptible to ivermectin, abamectin, moxidectin and abamectin+praziquantel. For O. equi, resistance was found in four different populations treated with ivermectin, abamectin, moxidectin, trichlorfon and ivermectin+praziquantel. Only combinations of abamectin+praziquantel and ivermectin+pyrantel were effective against this parasite species. All the large strongyles diagnosed in the present study (Strongyus edentatus, Strongyus vulgaris and Triodontophorus serratus) were susceptible to all the chemicals tested, with the exception of trichlorfon. Of the Cyathostominae populations, one was diagnosed as resistant to ivermectin and another to trichlorfon. The remaining populations from this nematode group were considered to be sensitive to ivermectin, abamectin, moxidectin, ivermectin+praziquantel, abamectin+praziquantel and ivermectin+pyrantel. New studies should be performed in different regions to evaluate the efficacy of trichlorfon in others field populations of helminthes.
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Gustavo
G
Felippelli
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Breno Cayeiro
BC
Cruz
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Lucas Vinicius Costa
LV
Gomes
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil; Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO 74605-050, Brazil.. Electronic address: wdzlopes@hotmail.com.
Welber Daniel Zanetti
WD
Lopes
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Weslen Fabrício Pires
WF
Teixeira
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Willian Giquelin
WG
Maciel
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Carolina
C
Buzzulini
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Murilo Abud
MA
Bichuette
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Gabriel Pimentel
GP
Campos
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Vando Edésio
VE
Soares
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Paula Luzia Formigoni
PL
Bergamasco
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Gilson Pereira
GP
de Oliveira
CPPAR - Animal Health Research Center, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, Via de acesso Prof. Paulo Donatto Castellane, s/n°. CEP: 14884-900, Jaboticabal, São Paulo, Brazil.
Alvimar José
AJ
da Costa
D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology*; D001938:Brazil / Q000453:epidemiology; D004351:Drug Resistance; D006374:Helminthiasis, Animal / Q000453:epidemiology / Q000469:parasitology*; D006376:Helminths / Q000187:drug effects*; D006734:Horse Diseases / Q000469:parasitology*; D006736:Horses
D000871:Anthelmintics
Anthelmintic resistance; Drugs; Efficacy; Horses