A distribution model for Glossina brevipalpis and Glossina austeni in Southern Mozambique, Eswatini and South Africa for enhanced area-wide integrated pest management approaches

PLoS Negl Trop Dis. 2021 Nov 29;15(11):e0009989. doi: 10.1371/journal.pntd.0009989. eCollection 2021 Nov.

Abstract

Background: Glossina austeni and Glossina brevipalpis (Diptera: Glossinidae) are the sole cyclical vectors of African trypanosomes in South Africa, Eswatini and southern Mozambique. These populations represent the southernmost distribution of tsetse flies on the African continent. Accurate knowledge of infested areas is a prerequisite to develop and implement efficient and cost-effective control strategies, and distribution models may reduce large-scale, extensive entomological surveys that are time consuming and expensive. The objective was to develop a MaxEnt species distribution model and habitat suitability maps for the southern tsetse belt of South Africa, Eswatini and southern Mozambique.

Methodology/principal findings: The present study used existing entomological survey data of G. austeni and G. brevipalpis to develop a MaxEnt species distribution model and habitat suitability maps. Distribution models and a checkerboard analysis indicated an overlapping presence of the two species and the most suitable habitat for both species were protected areas and the coastal strip in KwaZulu-Natal Province, South Africa and Maputo Province, Mozambique. The predicted presence extents, to a small degree, into communal farming areas adjacent to the protected areas and coastline, especially in the Matutuíne District of Mozambique. The quality of the MaxEnt model was assessed using an independent data set and indicated good performance with high predictive power (AUC > 0.80 for both species).

Conclusions/significance: The models indicated that cattle density, land surface temperature and protected areas, in relation with vegetation are the main factors contributing to the distribution of the two tsetse species in the area. Changes in the climate, agricultural practices and land-use have had a significant and rapid impact on tsetse abundance in the area. The model predicted low habitat suitability in the Gaza and Inhambane Provinces of Mozambique, i.e., the area north of the Matutuíne District. This might indicate that the southern tsetse population is isolated from the main tsetse belt in the north of Mozambique. The updated distribution models will be useful for planning tsetse and trypanosomosis interventions in the area.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Distribution
  • Animals
  • Cattle
  • Cattle Diseases / epidemiology
  • Cattle Diseases / transmission
  • Ecosystem
  • Eswatini / epidemiology
  • Glossinidae / classification
  • Glossinidae / physiology*
  • Insect Control / methods*
  • Insect Vectors / classification
  • Insect Vectors / physiology*
  • Mozambique / epidemiology
  • South Africa / epidemiology

Grants and funding

CdB and GV received funding for this work from the Joint Food and Agriculture Organization of the United Nations (FAO)/ International Atomic Energy Agency (IAEA) Centre of Nuclear Techniques in Food and Agriculture and the IAEA’s Department of Technical Cooperation. AD received funding from the IAEA’s Department of Technical Cooperation for model developing. Field collections in South Africa were funded by the Department of Science and Technology. LG and JB received funding from the GeosAf project (www.rp-pcp.org/projects/) implemented by the ACP Group of States. This publication has been produced with the assistance of the European Union or that of the funders. The contents of this publication are the sole responsibility of authors and can in no way be taken to reflect the views of the European Union. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work was also conducted within the framework of the Research Platform « Production and Conservation in Partnership » (www.rp-pcp.org).