MERIAL ANIMAL HEALTH
AUCKLAND – NZ
OCTOBER/2005
HELMINTHIC
RESISTANCE TO
DRUGS IN
RUMINANTSE. L. BORDIN
DVM, Pathologist
38.9 %
20.7 %
18.4 %
18.2 %
3.8 %
MOST IMPORTANT PARASITES (VETERINARY PERCEPTION)
TICKSTICKS
INTERNAL PARASITESINTERNAL PARASITES
HORN FLY HORN FLY
OTHER FLIES/MYIASISOTHER FLIES/MYIASIS
LICE – MANGELICE – MANGE
NO NO DATA YES
NO NO DATA YES
*FAO (papers and reports)
REPORT ON HELMINTHIC RESISTANCE*
MORE THAN TWO SPECIES*
< 2 PARASITE SPECIES
> 2 PARASITE SPECIES
< 2 PARASITE SPECIES
> 2 PARASITE SPECIES
*FAO
Sheeps and Goats : Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia circumcincta
to BDZ, IVM, LEV/MOR., and MOX
Horses : Small strongyles to all groups but IVM/MOX. Ascarid to ivermectin ( lactones ?)
Cattle: Already described for Fasciola hepatica and Haemonchus spp to BDZ , Fasciola hepatica to closantel and
to rafoxanide. Potential resistance to nitroxinil.
Nematode resistance already described to Nematode resistance already described to macrociclic lactonesmacrociclic lactones
Adapted from Prichard, R, (2002)
HELMINTHS PARASITES
RESISTANCE
Spreading*South America,
EurasiaCooperia spp.Cattle
SpreadWorldwideHaemonchus
contortusSheeps
and Goats
ExtensionRegionNematodeAnimal
Spreading*South AmericaH. placei, T. colubriformis, Nematodirus spp
Cattle
Unknown *North AmericaParascaris equorum
Horses
RESISTANCE TO IVERMECTIN
Adapted from Prichard, R, (2002)
* Based on field evidences, on FEC and other experimental confirmations
* Cooperia oncophora, Cooperia spp, Trichostrongylus sp, Haemonchus spp
A) Echevarria, et al.
B) Vermunt, et al; Fiel, et al.
C) Paiva, et al.
D) Anziani, O.S; Suarez V.
E) Costa, Alvimar.
F) Lima, W; Malaco, M; Bordin, E.L. (not published)
Brazil – E/F2004
FECRT / Larval CultureArgentina - D2003FECRT / Larval Culture / Necropsy
FECRT / Larval MotilityBrazil - C2001
FECRT / NecropsyArgentina - B2000
FECRT / Larval CultureBrazil - A1999
FECRT / NecropsyNew Zealand1998
FECRTUnited Kingdom1996
DIAGNOSIS / METHODPLACE YEAR
CHRONOLOGY OF SOME REPORTS OF NEMATODE RESISTANCE+ TO MLs ON CATTLE
*Coprocultures** NecropsiesAnziani, O; Fiel, C. A.
Province Drug Genera* Species**
Santa Fe Avermectins Cooperia C. pectinata
Buenos Aires – West/Middle
AvermectinsBDZ
CooperiaHaemonchus
C. oncophoraH. contortus
Buenos Aires – North; Entre
Rios, Corrientes
Avermectins Cooperia Not determinated
La Pampa Avermectins Cooperia Not determinated
Santa Fe – Middle
AvermectinsBDZ
HaemunchosCooperia
H. placei, C. oncophora, C. pectinata
Cordoba Avermectins and BDZ
HaemunchosCooperia
Ostertagia
C. punctata, H. placei, O.ostertagi, C.
oncophora, C. punctata
CATTLE NEMATODE RESISTANCE TO ANTHELMINTHICS IN ARGENTINAAPRIL 2000 – NOVEMBER 2003
FEC – Comparative – Field StudyBRAZIL
40% reduction 1225 735Ivermectin 3,5%
45% reduction750 410Doramectin 1%
36% reduction620 394Ivermectin 3,15%
7% reduction915 850
Control
Comparative Results (0-29)
Mean FEC
Day “0” +29
Treatment Group
Number of Parasite Larvae(Days 0 – 29)
100% reduction020Oesophagostomun
Increase of 33%3332Haemonchus
Increase of 139%6748Cooperia
Ivermectin 3,5%
100% reduction026Oesophagostomun
Increase of 247% 8936Haemonchus
Reduction of 71%1138Cooperia
Doramectin 1,0 %
100% reduction014Oesophagostomun
Reduction of 62%1540Haemonchus
Increase of 85%8546Cooperia
Ivermectin 3,15%
Country Farms (n)Antihelminthics: % resistant parasites (farms)
Alben Iver Lev Rfx Clos B+L Mean
South Africaa 80 79 73 23 89 - - 98
Paraguayb 37 70 67 47 - - - ?
Uruguayc 242 61 1 29 - - - 93
Brazild 182 68 7 19 - 20 15 97
Argentinae 65 37 2 8 - - 5 46
aVan Wyk et al. (1999); bMaciel et al. (1996); cNari et al. (1996); dEchevarria et al. (1996); eEddi et al. (1996).
Haemonchus spp RESISTANCE TO SEVERAL ANTIHELMINTHICS: COMPARISON BETWEEN THE SITUATION OF SOUTH AFRICA AND COUNTRIES
OF SOUTH AMERICA (1999)
Herd Place A Place B LVZ ABZ IVM LVZ ABZ IVM
1 91 5454 100 81 4444 94
2 93 94 100 94 94 3232
3 94 2020 5858 95 8787 8484
4 99 00 95 5252 100 100
5 97 88 96 100 100 100
6 8080 90 100 92 7777 100
7 92 100 100 91 100 100
8 97 96 99 100 100 93
9 7575 6868 97 100 100 100
Mean 9191 6868 9494 8989 8989 8989
(Barreto, M. A et al, 2002)
EFFICACY (%) OF SEVERAL FORMULATIONS BASED ON THE COMPARISON OF EGG COUNTS OF GI PARASITES IN GOATS (FECRT) - BRAZIL
Herd Place A Place BLVZ ABZ IVM LVZ ABZ IVM
1 96 6262 91 95 7171 94
2 97 8787 92 9090 1818 97
3 96 6969 7777 98 6666 97
4 92 7373 6666 94 00 90
5 3131 00 00 99 8585 99
6 95 6363 7070 98 8787 98
7 4343 2525 4848 99 6161 7979
8 7676 00 2727 95 6363 98
9 8686 3434 4848 98 33 97
Mean 7979 4646 5858 9696 5050 9494
(Barreto, M. A et al, 2002)
EFFICACY (%) OF SEVERAL FORMULATIONS BASED ON THE COMPARISON OF EGG COUNTS OF GI PARASITES IN GOATS (FECRT) - BRAZIL
Insistence on treating all the animals in the herd
Emphasis on the reiterated control that ignores the crucial role of refugia
Fail on distinguishing maximum production X
optimal
“We have to admit that our previously efforts on the administration of resistance were useless at
the best and contra-productive at worst”
MAJOR PROBLEMS IN SHEEPS
(BARGER, I., Australia)
ConclusionsSheep/Goats – Markets - Brazil
• Parasite Resistance has reached its maximum level.• Producers start to adopt FEC for monitoring andFAMACHA®/PCP just for sensible animals.• Product combinations (Triton® is strongly included in PCP).• Producers are adopting a moving/treating management.• When available a cattle/sheep combined pasturing has beenrecommended.• It is necessary an urgent product registration harmonization.• Sheep and goats markets are growing. • Sheep and goat population: 40 MM• Average meat consumption – 0,7 kg/year
ConclusionsCattle Market - Brazil
• Less expensive avermectin generics available (More than 60).• Avermectin generics mostly used to control OPs and SPsresistant tick strain.• Haemonchus spp. and Cooperia spp. more involved.• Diagnostic of resistance based on FEC and larvae culture.• Helminthic resistance is still incipient but potentially a shorttime threat.• Market needs a combined formulation (LVS plus AVM?).• PCPs for young animals has been claimed to avoid resistance.• It is necessary an urgent product registration harmonization.
CONCLUSION
The resistance tends to increase, forboth parasites, internal and external,
but can be mitigatedthrough the use of drugs, or
combinations of drugs, effectively used in oriented and
monitored protocols
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