Pyrethroid treatment of cattle for tsetse control: reducing its impact on dung fauna

PLoS Negl Trop Dis. 2015 Mar 4;9(3):e0003560. doi: 10.1371/journal.pntd.0003560. eCollection 2015 Mar.

Abstract

Background: African trypansomiases of humans and animals can be controlled by attacking the vectors, various species of tsetse fly. Treatment of cattle with pyrethroids to kill tsetse as they feed is the most cost-effective method. However, such treatments can contaminate cattle dung, thereby killing the fauna which disperse the dung and so play an important role in soil fertility. Hence there is a need to identify cost-effective methods of treating cattle with minimal impact on dung fauna.

Methodology/principal findings: We used dung beetles to field bioassay the levels of dung contamination following the use of spray and pour-on formulations of deltamethrin, applied to various parts of the body of cattle in Zimbabwe. Results suggested that dung was contaminated by contact with insecticide on the body surface as the cattle defecated, and by ingestion of insecticide as the cattle licked themselves. Death of dung beetles was reduced to negligible levels by using only the spray and applying it to the legs and belly or legs alone, i.e., places where most tsetse feed.

Conclusion/significance: The restricted applications suitable for minimising the impact on dung fauna have the collateral benefits of improving the economy and convenience of cattle treatments for tsetse control. The demonstration of collateral benefits is one of the surest ways of promoting environmentally friendly procedures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Coleoptera* / drug effects
  • Feces / parasitology*
  • Insect Control / methods*
  • Insecticides / pharmacology*
  • Nitriles / pharmacology
  • Pyrethrins / pharmacology*
  • Zimbabwe

Substances

  • Insecticides
  • Nitriles
  • Pyrethrins
  • decamethrin

Grant support

Financial support was received from the DFID Animal Health Programme (Project nos. R7539, R7987), the DFID/RCUK programme on Zoonoses and Emerging Livestock Systems (ZELS, BBSRC grant no.BB/L019035/1), and the ICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR). Financial support was received from the DFID Animal Health Programme (Project nos. R7539, R7987), the DFID/RCUK programme on Zoonoses and Emerging Livestock Systems (ZELS, BBSRC grant no.BB/L019035/1), and the ICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR). The funders had no role in study design, data collection and analyses, decision to publish, or preparation of the manuscript.