Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)

A published study used a stochastic branching process to derive equations for the mean and variance of the probability of, and time to, extinction in population of tsetse flies (Glossina spp) as a function of adult and pupal mortality, and the probabilities that a female is inseminated by a fertile...

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Main Authors: Damian, Kajunguri, Elisha B., Are, John W., Hargrove
Format: Article
Published: PLOS 2019
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Online Access:http://hdl.handle.net/20.500.12493/147
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author Damian, Kajunguri
Elisha B., Are
John W., Hargrove
author_facet Damian, Kajunguri
Elisha B., Are
John W., Hargrove
author_sort Damian, Kajunguri
collection KAB-DR
description A published study used a stochastic branching process to derive equations for the mean and variance of the probability of, and time to, extinction in population of tsetse flies (Glossina spp) as a function of adult and pupal mortality, and the probabilities that a female is inseminated by a fertile male. The original derivation was partially heuristic and provided no proofs for inductive results. We provide these proofs, together with a more compact way of reaching the same results. We also show that, while the published equations hold good for the case where tsetse produce male and female offspring in equal proportion, a different solution is required for the more general case where the probability (β) that an offspring is female lies anywhere in the interval (0, 1). We confirm previous results obtained for the special case whereβ= 0.5 and show that extinction probability is at a minimum for β>0.5 by an amount that increases with increasing adult female mortality. Sensitivity analysis showed that the extinction probability was affected most by changes in adult female mortality, followed by the rate of production of pupae. Because females only produce a single offspring approximately every 10 days, imposing a death rate of greater than about 3.5% per day will ensure the eradication of any tsetse population. These mortality levels can be achieved for some species using insecticide-treated targets or cattle— providing thereby a simple, effective and cost-effective method of controlling and eradicating tsetse, and also human and animal trypanosomiasis. Our results are of further interest in the modern situation where increases in temperature are seeing the real possibility that tsetse will go extinct in some areas, without the need for intervention, but have an increased chance of surviving in other areas where they were previously unsustainable due to low temperatures.
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spelling oai:idr.kab.ac.ug:20.500.12493-1472024-01-17T04:50:36Z Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp) Damian, Kajunguri Elisha B., Are John W., Hargrove Neglected Tropical Diseases A published study used a stochastic branching process to derive equations for the mean and variance of the probability of, and time to, extinction in population of tsetse flies (Glossina spp) as a function of adult and pupal mortality, and the probabilities that a female is inseminated by a fertile male. The original derivation was partially heuristic and provided no proofs for inductive results. We provide these proofs, together with a more compact way of reaching the same results. We also show that, while the published equations hold good for the case where tsetse produce male and female offspring in equal proportion, a different solution is required for the more general case where the probability (β) that an offspring is female lies anywhere in the interval (0, 1). We confirm previous results obtained for the special case whereβ= 0.5 and show that extinction probability is at a minimum for β>0.5 by an amount that increases with increasing adult female mortality. Sensitivity analysis showed that the extinction probability was affected most by changes in adult female mortality, followed by the rate of production of pupae. Because females only produce a single offspring approximately every 10 days, imposing a death rate of greater than about 3.5% per day will ensure the eradication of any tsetse population. These mortality levels can be achieved for some species using insecticide-treated targets or cattle— providing thereby a simple, effective and cost-effective method of controlling and eradicating tsetse, and also human and animal trypanosomiasis. Our results are of further interest in the modern situation where increases in temperature are seeing the real possibility that tsetse will go extinct in some areas, without the need for intervention, but have an increased chance of surviving in other areas where they were previously unsustainable due to low temperatures. Kabale University 2019-04-29T08:09:09Z 2019-04-29T08:09:09Z 2019 Article KajunguriD, Are EB, HargroveJW (2019) Improvedestimates for extinction probabilities and times to extinction for populationsof tsetse (Glossina spp). PLoS Negl Trop Dis 13(4): e0006973 http://hdl.handle.net/20.500.12493/147 application/pdf PLOS
spellingShingle Neglected Tropical Diseases
Damian, Kajunguri
Elisha B., Are
John W., Hargrove
Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)
title Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)
title_full Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)
title_fullStr Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)
title_full_unstemmed Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)
title_short Improved estimates for extinction probabilities and times to extinction for populations of tsetse (Glossina spp)
title_sort improved estimates for extinction probabilities and times to extinction for populations of tsetse glossina spp
topic Neglected Tropical Diseases
url http://hdl.handle.net/20.500.12493/147
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AT elishabare improvedestimatesforextinctionprobabilitiesandtimestoextinctionforpopulationsoftsetseglossinaspp
AT johnwhargrove improvedestimatesforextinctionprobabilitiesandtimestoextinctionforpopulationsoftsetseglossinaspp