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