Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil

F.A.M. Echevarria, G. Gettinby, S. Hazelwood

Research output: Contribution to journal › Article

10 Citations (Scopus)

Abstract

A computer model developed to study Ostertagia circumcincta resistance to anthelmintics in UK sheep flocks has been adapted for use with Haemonchus contortus under southern Brazilian conditions. The model simulates the effect of different anthelmintic control regimens on the year-to-year pattern of resistance in breeding ewes. The nematode control regimen most used by Brazilian sheep farmers was found to increase the frequency of genes which confer resistance from approximately 3% to 14% in an H. contortus population over a 20 year period. The effect of early versus late season anthelmintic treatment was investigated. This indicated that early season treatment would select for resistance rapidly, whereas late season treatments would not, owing to large numbers of untreated parasites accumulating at the beginning of the season. A model which can predict the development of anthelmintic resistance in parasites of ewes is a valuable tool in the understanding of the effect of different strategies on nematode control programmes and merits further consideration.
LanguageEnglish
Pages315-325
Number of pages11
JournalVeterinary Parasitology
Volume47
Issue number3-4
Publication statusPublished - May 1993

Fingerprint

Haemonchus
Anthelmintics
Haemonchus contortus
anthelmintics
Brazil
nematode control
prediction
Population
ewes
Sheep
Parasites
Ostertagia
sheep
parasites
Teladorsagia circumcincta
Gene Frequency
computer simulation
Computer Simulation
Breeding
gene frequency

Keywords

  • anthelmintic resistance
  • Brazil
  • computer simulation
  • gene frequency
  • sheep
  • sheep diseases
  • Haemonchiasis
  • Haemonchus contortus
  • drug resistance

Cite this

Echevarria, F.A.M. ; Gettinby, G. ; Hazelwood, S. / Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil. In: Veterinary Parasitology. 1993 ; Vol. 47, No. 3-4. pp. 315-325.
@article{e1504a34c85d44feb1954e840ec9fe4d,
title = "Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil",
abstract = "A computer model developed to study Ostertagia circumcincta resistance to anthelmintics in UK sheep flocks has been adapted for use with Haemonchus contortus under southern Brazilian conditions. The model simulates the effect of different anthelmintic control regimens on the year-to-year pattern of resistance in breeding ewes. The nematode control regimen most used by Brazilian sheep farmers was found to increase the frequency of genes which confer resistance from approximately 3{\%} to 14{\%} in an H. contortus population over a 20 year period. The effect of early versus late season anthelmintic treatment was investigated. This indicated that early season treatment would select for resistance rapidly, whereas late season treatments would not, owing to large numbers of untreated parasites accumulating at the beginning of the season. A model which can predict the development of anthelmintic resistance in parasites of ewes is a valuable tool in the understanding of the effect of different strategies on nematode control programmes and merits further consideration.",
keywords = "anthelmintic resistance, Brazil, computer simulation, gene frequency, sheep, sheep diseases, Haemonchiasis, Haemonchus contortus, drug resistance",
author = "F.A.M. Echevarria and G. Gettinby and S. Hazelwood",
note = "I have added a scanned copy of the document",
year = "1993",
month = "5",
language = "English",
volume = "47",
pages = "315--325",
journal = "Veterinary Parasitology",
issn = "0304-4017",
number = "3-4",

}

Echevarria, FAM, Gettinby, G & Hazelwood, S 1993, 'Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil' Veterinary Parasitology, vol. 47, no. 3-4, pp. 315-325.

Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil. / Echevarria, F.A.M.; Gettinby, G.; Hazelwood, S.

In: Veterinary Parasitology, Vol. 47, No. 3-4, 05.1993, p. 315-325.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil

AU - Echevarria, F.A.M.

AU - Gettinby, G.

AU - Hazelwood, S.

N1 - I have added a scanned copy of the document

PY - 1993/5

Y1 - 1993/5

N2 - A computer model developed to study Ostertagia circumcincta resistance to anthelmintics in UK sheep flocks has been adapted for use with Haemonchus contortus under southern Brazilian conditions. The model simulates the effect of different anthelmintic control regimens on the year-to-year pattern of resistance in breeding ewes. The nematode control regimen most used by Brazilian sheep farmers was found to increase the frequency of genes which confer resistance from approximately 3% to 14% in an H. contortus population over a 20 year period. The effect of early versus late season anthelmintic treatment was investigated. This indicated that early season treatment would select for resistance rapidly, whereas late season treatments would not, owing to large numbers of untreated parasites accumulating at the beginning of the season. A model which can predict the development of anthelmintic resistance in parasites of ewes is a valuable tool in the understanding of the effect of different strategies on nematode control programmes and merits further consideration.

AB - A computer model developed to study Ostertagia circumcincta resistance to anthelmintics in UK sheep flocks has been adapted for use with Haemonchus contortus under southern Brazilian conditions. The model simulates the effect of different anthelmintic control regimens on the year-to-year pattern of resistance in breeding ewes. The nematode control regimen most used by Brazilian sheep farmers was found to increase the frequency of genes which confer resistance from approximately 3% to 14% in an H. contortus population over a 20 year period. The effect of early versus late season anthelmintic treatment was investigated. This indicated that early season treatment would select for resistance rapidly, whereas late season treatments would not, owing to large numbers of untreated parasites accumulating at the beginning of the season. A model which can predict the development of anthelmintic resistance in parasites of ewes is a valuable tool in the understanding of the effect of different strategies on nematode control programmes and merits further consideration.

KW - anthelmintic resistance

KW - Brazil

KW - computer simulation

KW - gene frequency

KW - sheep

KW - sheep diseases

KW - Haemonchiasis

KW - Haemonchus contortus

KW - drug resistance

UR - http://www.ncbi.nlm.nih.gov/pubmed/8333136

M3 - Article

VL - 47

SP - 315

EP - 325

JO - Veterinary Parasitology

T2 - Veterinary Parasitology

JF - Veterinary Parasitology

SN - 0304-4017

IS - 3-4

ER -

Echevarria FAM, Gettinby G, Hazelwood S. Model predictions for anthelmintic resistance amongst Haemonchus contortus populations in southern Brazil. Veterinary Parasitology. 1993 May;47(3-4):315-325.

Access to Document