MERIAL ANIMAL HEALTH AUCKLAND NZ OCTOBER2005 HELMINTHIC RESISTANCE TO DRUGS IN RUMINANTS

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MERIAL ANIMAL HEALTH AUCKLAND NZ OCTOBER/2005
HELMINTHIC RESISTANCE TO DRUGS IN RUMINANTS
E. L. BORDIN DVM, Pathologist
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MOST IMPORTANT PARASITES (VETERINARY PERCEPTION)
3.8
18.2
38.9
TICKS INTERNAL PARASITES HORN FLY OTHER
FLIES/MYIASIS LICE MANGE
18.4
20.7
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REPORT ON HELMINTHIC RESISTANCE

• NO
• NO DATA
• YES

FAO (papers and reports)
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MORE THAN TWO SPECIES
FAO

• lt 2 PARASITE SPECIES
• gt 2 PARASITE SPECIES

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HELMINTHS PARASITES RESISTANCE

• 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
macrociclic lactones
Adapted from Prichard, R, (2002)
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RESISTANCE TO IVERMECTIN
Based on field evidences, on FEC and other
experimental confirmations
Adapted from Prichard, R, (2002)
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CHRONOLOGY OF SOME REPORTS OF NEMATODE
RESISTANCE TO MLs ON CATTLE
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)
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CATTLE NEMATODE RESISTANCE TO ANTHELMINTHICS IN
ARGENTINAAPRIL 2000 NOVEMBER 2003
Coprocultures Necropsies Anziani, O Fiel, C.
A.
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FEC Comparative Field StudyBRAZIL
Comparative Results (0-29)
Mean FEC Day 0 29
Treatment Group
7 reduction
915 850
Control
36 reduction
620 394
Ivermectin 3,15
45 reduction
750 410
Doramectin 1
40 reduction
1225 735
Ivermectin 3,5
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Number of Parasite Larvae(Days 0 29)
Increase of 85
85
46
Cooperia
Ivermectin 3,15
Reduction of 62
15
40
Haemonchus
100 reduction
0
14
Oesophagostomun
Reduction of 71
11
38
Cooperia
Doramectin 1,0
Increase of 247
89
36
Haemonchus
100 reduction
0
26
Oesophagostomun
Increase of 139
67
48
Cooperia
Ivermectin 3,5
Increase of 33
33
32
Haemonchus
100 reduction
0
20
Oesophagostomun
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Haemonchus spp RESISTANCE TO SEVERAL
ANTIHELMINTHICS COMPARISON BETWEEN THE SITUATION
OF SOUTH AFRICA AND COUNTRIES OF SOUTH AMERICA
(1999)
aVan Wyk et al. (1999) bMaciel et al. (1996)
cNari et al. (1996) dEchevarria et
al. (1996) eEddi et al. (1996).
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EFFICACY () OF SEVERAL FORMULATIONS BASED ON THE
COMPARISON OF EGG COUNTS OF GI PARASITES IN GOATS
(FECRT) - BRAZIL
(Barreto, M. A et al, 2002)
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EFFICACY () OF SEVERAL FORMULATIONS BASED ON THE
COMPARISON OF EGG COUNTS OF GI PARASITES IN GOATS
(FECRT) - BRAZIL
(Barreto, M. A et al, 2002)
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(No Transcript)
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ConclusionsSheep/Goats Markets - Brazil

• Parasite Resistance has reached its maximum
  level.
• Producers start to adopt FEC for monitoring and
• FAMACHA/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 been
• recommended.
• 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

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ConclusionsCattle Market - Brazil

• Less expensive avermectin generics available
  (More than 60).
• Avermectin generics mostly used to control OPs
  and SPs
• resistant 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 short
• time 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.

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CONCLUSION
The resistance tends to increase, for both
parasites, internal and external, but can be
mitigated through the use of drugs,
or combinations of drugs, effectively used in
oriented and monitored protocols