Uncertainty and sensitivity analyses of extinction probabilities suggest that adult female mortality is the weakest link for populations of tsetse (Glossina spp)

• Published in: PLoS neglected tropical diseases 2020-05, Vol.14 (5), p.e0007854-e0007854
• Main Authors: Are, Elisha B, Hargrove, John W
• Format: Article
• Language: English
• Subjects: African trypanosomiasis; Biological research; Biology and Life Sciences; Branching (mathematics); Daily; Ecology and Environmental Sciences; Eradication; Expression vectors; Extinction; Extinction (Biology); Females; Fertility; Life history; Markov processes; Mathematical models; Medicine and Health Sciences; Mortality; Natural history; Parameter sensitivity; Parameters; Physical Sciences; Population (statistical); Population dynamics; Population growth; Population statistics; Probability; Probability theory; Sensitivity analysis; South Africa; Species extinction; Statistical analysis; Statistics; Tropical diseases; Tsetse fly (Glossina palpalis); Uncertainty; Uncertainty analysis; Vector-borne diseases; Vectors
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0007854

A relatively simple life history allows us to derive an expression for the extinction probability of populations of tsetse, vectors of African sleeping sickness. We present the uncertainty and sensitivity analysis of the extinction probability, to offer key insights into factors affecting the control or eradication of tsetse populations. We represent tsetse population growth as a branching process, and derive closed form estimates of population extinction from that model. Statistical and mathematical techniques are used to analyse the uncertainties in estimating extinction probability, and the sensitivity of the extinction probability to changes in input parameters representing the natural life history and vital dynamics of tsetse populations. For fixed values of input parameters, the sensitivity of extinction probability depends on the baseline parameter values. Extinction probability is most sensitive to the probability that a female is inseminated by a fertile male when daily pupal mortality is low, whereas the extinction probability is most sensitive to daily mortality rate for adult females when daily pupal mortality, and extinction probabilities, are high. Global uncertainty and sensitivity analysis show that daily mortality rate for adult females has the highest impact on the extinction probability. The high correlation between extinction probability and daily female adult mortality gives a strong argument that control techniques which increase daily female adult mortality may be the single most effective means of ensuring eradication of tsetse population.