First report of multiple drug resistance in trichostrongyles affecting sheep under field conditions in Italy.
Drug resistance in sheep gastrointestinal trichostrongyles is a cosmopolitan major constraint to small ruminant production. Despite reports that anthelmintic drug resistance has become common, there are limited information on the presence of drug resistance in Italy. The purpose of this study was to determine the effect of four anthelmintics to control infection in sheep in central Italy. Fifty sheep with fecal egg counts (FEC) > or =150 eggs per gram were selected on each of three farms (n = 150 total sheep) which were randomly allocated to one of five groups. Groups were treated with febantel, levamisole, ivermectin, or moxidectin while the fifth group acted as the control group. A FEC reduction test (FECRT) was conducted on each animal and the mean FEC of each treatment group was compared to that of the control group within farm. Resistance was declared when percentage reduction (R) <95% and the lower 95% confidence interval was <90%. Levamisole (mean R = 89%) resistance was found on all farms and ivermectin (mean R = 93%) resistance was found on two of the three farms. Posttreatment larval cultures showed the presence of Teladorsagia (Ostertagia) circumcincta and Trichostrongylus spp. larvae. Febantel (mean R = 96%) and moxidectin (mean R = 100%) remained effective. This study suggests that drug resistance in sheep gastrointestinal trichostrongyles is present in central Italy and a potential problem which would justify a broader nationwide geographical investigation.
Traversa
Donato
D
Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, University of Teramo, Piazza Aldo Moro 45, 64100 Teramo, Italy. dtraversa@unite.it
Paoletti
Barbara
B
Otranto
Domenico
D
Miller
James
J
D000818:Animals; D000969:Antinematodal Agents / Q000494:pharmacology* / Q000627:therapeutic use; D018432:Drug Resistance, Multiple; D005243:Feces / Q000469:parasitology; D006146:Guanidines / Q000494:pharmacology / Q000627:therapeutic use; D007558:Italy; D007559:Ivermectin / Q000494:pharmacology / Q000627:therapeutic use; D007978:Levamisole / Q000494:pharmacology / Q000627:therapeutic use; D018942:Macrolides / Q000494:pharmacology / Q000627:therapeutic use; D010028:Ostertagia / Q000187:drug effects*; D010029:Ostertagiasis / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary; D010270:Parasite Egg Count; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology / Q000517:prevention & control*; D016896:Treatment Outcome; D014253:Trichostrongylosis / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary; D014254:Trichostrongylus / Q000187:drug effects*
D000969:Antinematodal Agents; D006146:Guanidines; D018942:Macrolides; D007978:Levamisole; D007559:Ivermectin; C027837:moxidectin; C017309:febantel
Vet Rec. 2001 Dec 22-29;149(25):778-9
11808671
Vet Parasitol. 2006 Apr 15;137(1-2):112-8
16426761
J Vet Intern Med. 2006 Mar-Apr;20(2):435-44
16594607
Vet Parasitol. 2004 Sep 2;123(3-4):189-99
15325045
J Helminthol. 2001 Dec;75(4):325-30
11818048
Am J Vet Res. 1964 May;25:844-6
14141529
Vet Parasitol. 1997 Nov;72(3-4):391-405; discussion 405-12
9460208
Vet Parasitol. 2001 Jun 28;97(4):253-9
11390078
Vet Parasitol. 2003 Nov 3;117(1-2):61-71
14597280
Vet Parasitol. 2002 Oct 16;109(1-2):91-9
12383628
N Z Vet J. 2003 Jun;51(3):139-41
16032313
Parasitol Res. 2006 Jun;99(1):78-83
16489471
Vet Parasitol. 2006 Jan 15;135(1):39-45
16213097
Res Vet Sci. 1992 Nov;53(3):371-4
1465512
Vet Rec. 2006 Dec 16;159(25):860
17172488
J Clin Microbiol. 2007 Sep;45(9):2937-42
17626168
Dtsch Tierarztl Wochenschr. 2001 Feb;108(2):49-50
11367880
Aust Vet J. 2001 Nov;79(11):756-61
11789911
Vet Parasitol. 1992 Sep;44(1-2):35-44
1441190
Int J Parasitol. 1999 Jan;29(1):155-64; discussion 183-4
10048828
Vet Parasitol. 2006 Mar 31;136(3-4):167-85
16427201
Parasitol Res. 2007 Aug;101(3):577-81
17356891
Vet Rec. 2002 Jan 19;150(3):87
11858150
Vet Res. 2002 Sep-Oct;33(5):465-80
12387484
Trends Parasitol. 2004 Oct;20(10):477-81
15363441