Quality of Sterile Male Tsetse after Long Distance Transport as Chilled, Irradiated Pupae

PLoS Negl Trop Dis. 2015 Nov 12;9(11):e0004229. doi: 10.1371/journal.pntd.0004229. eCollection 2015 Nov.

Abstract

Background: Tsetse flies transmit trypanosomes that cause human and African animal trypanosomosis, a debilitating disease of humans (sleeping sickness) and livestock (nagana). An area-wide integrated pest management campaign against Glossina palpalis gambiensis has been implemented in Senegal since 2010 that includes a sterile insect technique (SIT) component. The SIT can only be successful when the sterile males that are destined for release have a flight ability, survival and competitiveness that are as close as possible to that of their wild male counterparts.

Methodology/principal findings: Tests were developed to assess the quality of G. p. gambiensis males that emerged from pupae that were produced and irradiated in Burkina Faso and Slovakia (irradiation done in Seibersdorf, Austria) and transported weekly under chilled conditions to Dakar, Senegal. For each consignment a sample of 50 pupae was used for a quality control test (QC group). To assess flight ability, the pupae were put in a cylinder filtering emerged flies that were able to escape the cylinder. The survival of these flyers was thereafter monitored under stress conditions (without feeding). Remaining pupae were emerged and released in the target area of the eradication programme (RF group). The following parameter values were obtained for the QC flies: average emergence rate more than 69%, median survival of 6 days, and average flight ability of more than 35%. The quality protocol was a good proxy of fly quality, explaining a large part of the variances of the examined parameters.

Conclusions/significance: The quality protocol described here will allow the accurate monitoring of the quality of shipped sterile male tsetse used in operational eradication programmes in the framework of the Pan-African Tsetse and Trypanosomosis Eradication Campaign.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Austria
  • Burkina Faso
  • Cold Temperature
  • Humans
  • Male
  • Pest Control, Biological / methods*
  • Pupa / physiology
  • Pupa / radiation effects
  • Senegal
  • Slovakia
  • Survival Analysis
  • Transportation / methods*
  • Tsetse Flies / growth & development
  • Tsetse Flies / physiology*
  • Tsetse Flies / radiation effects

Grants and funding

The work presented in this article was supported by the Government of Senegal, the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, the Department of Technical Cooperation of the IAEA, the CIRAD (Project “Integrated Vector Management: innovating to improve control and reduce environmental impacts” of Institut Carnot Santé Animale (ICSA) excellence network) and the US State Department. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.