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Mathematical modeling of transmission dynamics of Opisthorchis viverrini

English title Mathematical modeling of transmission dynamics of Opisthorchis viverrini
Applicant Chitnis Nakul
Number 163057
Funding scheme Project funding (Div. I-III)
Research institution Department of Epidemiology and Public Health Swiss Tropical and Public Health Institute Universität Basel
Institution of higher education University of Basel - BS
Main discipline Methods of Epidemiology and Preventive Medicine
Start/End 01.11.2015 - 31.10.2019
Approved amount 290'408.00
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All Disciplines (2)

Discipline
Methods of Epidemiology and Preventive Medicine
Mathematics

Keywords (5)

parasite transmission dynamics; liver fluke control; mathematical model; opisthorchis viverrini; epidemiology

Lay Summary (German)

Lead
Im vorliegenden Forschungsprojekt untersuchen wir mittels mathematischer Modellierungen der Einfluss von verschiedenen Bekämpfungsmassnahmen auf die Übertragung des asiatischen Leberegels (Opisthorchis viverrini). Der asiatische Leberegel ist vor allem in Südostasien äusserst häufig, vor allem in Laos, Thailand und Kambodscha. Die lokale Bevölkerung infiziert sich indem sie rohe oder ungenügend gekochte Fische und Fischgerichte konsumiert. Der Leberegel wird übertragen, wenn die Eier mit dem Stuhl in Süsswasser gelangen wo sie die obligaten Schneckenzwischenwirte befallen können. Larvenstadien, die aus den Schnecken entweichen infizieren Fische in welchen sich für den Menschen infektiöse Stadien bilden. Die Bekämpfung besteht aus dem regelmässigen behandeln der infizierten Bevölkerung in Kombination mit verbesserten Ernährungsgewohnheiten und Latrinen.
Lay summary

Trotz weit verbreiteten Bekämpfungsmassnahmen, wird der asiatische Leberegel in Laos, Thailand und Kambodscha übertragen. Der erwachsene Wurm befindet sich in den Gallengängen der Leber des Menschen und anderen Endwirten wie Hunde und Katzen. Er kann dort zu verschiedenen Leberpathologien führen, inklusive einem tödlichen Gallengangtumor (Cholangiocarcinoma).

Im vorliegenden Projekt arbeiten Forscher vom Swiss TPH mit dem laotischen Nationalen Institut für Public Health zusammen. Die Forscher werden ein mathematisches Modell entwickeln in welchem die Übertragung des asiatischen Leberegels simuliert wird. Das Modell wird durch Felddaten, die in Laos erhoben wurden, validiert. Danach wird das Modell benützt um die Einflüsse von verschiedenen Bekämpfungsstrategien zu evaluieren. Insbesondere geht es darum besser zu verstehen, (i) inwieweit die Hunde und Katzen für die Übertragung verantwortlich sind und welche Effekte die Behandlung dieser Tiere auf die Gesamtübertragung haben, (ii) welche Rolle die verschiedene Fischfangpraktiken auf die Übertragung haben und (iii) welche Effekte verschiedene Bekämpfungsstrategien haben, insbesondere die Behandlung von Menschen kombiniert mit anderen Bekämpfungsstrategien.

Direct link to Lay Summary Last update: 06.10.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
Analysis of interventions against the liver fluke, opisthorchis viverrini
Bürli Christine, Harbrecht Helmut, Odermatt Peter, Sayasone Somphou, Chitnis Nakul (2018), Analysis of interventions against the liver fluke, opisthorchis viverrini, in Mathematical Biosciences, 303, 115-125.
Mathematical analysis of the transmission dynamics of the liver fluke, Opisthorchis viverrini
Bürli Christine, Harbrecht Helmut, Odermatt Peter, Sayasone Somphou, Chitnis Nakul (2018), Mathematical analysis of the transmission dynamics of the liver fluke, Opisthorchis viverrini, in Journal of Theoretical Biology, 439, 181-194.

Collaboration

Group / person Country
Types of collaboration
Olga Federova, Siberian State Medical University Russia (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Lao Tropical and Public Health Institute Laos (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Andrea Rinaldo ,École Polytechnique Fédérale de Lausanne Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
11th European Conference on Mathematical and Theoretical Biology Talk given at a conference Population-based and individual-based modelling of Opisthorchis viverrini 23.07.2018 Lisbon, Portugal Bürli Christine;
Helminth Infection - from Transmission to Control Swiss TPH Winter Symposium 2017 Talk given at a conference Opisthorchis viverrini Transmission Models 07.12.2017 Basel, Switzerland Chitnis Nakul;
Sixth International Conference on Mathematical Modeling and Analysis of Populations in Biological Systems Talk given at a conference Mathematical Modelling of the Transmission Dynamics of Opisthorchis viverrini 20.10.2017 Tucson, AZ, United States of America Chitnis Nakul;
10th European Congress on Tropical Medicine and International Health Talk given at a conference Mathematical modelling of transmission dynamics of Opisthorchis viverrini 16.10.2017 Antwerp, Belgium Bürli Christine;
The 59th British Applied Mathematics Colloquium Talk given at a conference Mathematical Modelling of the Transmission Dynamics of Opisthorchis viverrini 10.04.2017 Guildford, Great Britain and Northern Ireland Chitnis Nakul;
Asian Neglected Tropical Disease Conference 2017 Talk given at a conference Mathematical modelling of transmission dynamics of Opisthorchis viverrini 08.03.2017 Khon Kaen, Thailand Bürli Christine;
65th Annual Meeting of the American Society of Tropical Medicine and Hygiene Talk given at a conference Mathematical Modelling of the Transmission Dynamics of Opisthorchis viverrini in Lao PDR 13.11.2016 Atlanta, GA, United States of America Chitnis Nakul;


Self-organised

Title Date Place

Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
2nd Asian Cholangiocarcinoma conference Talk 12.12.2019 Vientiane, Laos Odermatt Peter; Somphou Sayasone;
13th Lao National Health Research Forum Talk 16.10.2019 Vientiane, Laos Odermatt Peter; Somphou Sayasone;
12th Lao National Health Research Forum Talk 16.10.2018 Vientiane, Laos Somphou Sayasone; Odermatt Peter;


Abstract

Background The trematode liver fluke, Opisthorchis viverrini causes the chronic and debilitating hepatobiliary disease, opisthorchiasis, which can lead to the fatal bile-duct cancer, cholangiocarcinoma. About 8 million people are infected with O. viverrini, mostly in Thailand, Laos and Cambodia with a further 80 million at risk. O. viverrini exhibits a complex life cycle involving humans and reservoir mammalian hosts (such as dogs and cats), free-swimming aquatic stages, and intermediate host stages in faucet snails and cyprinoid fish. Humans get infected through the consumption of raw or undercooked infectious fish. The role of reservoir hosts in transmission dynamics is poorly understood but believed to be important. Control is currently based on treatment, health education on food consumption, and improved sanitation. However despite more than 20 years of control activities, prevalence remains high in foci of northeastern Thailand. In the absence of long-term control, prevalence is even higher in Laos, exceeding 60% in high endemic provinces. Large-scale control has recently started in Laos, so there is a pressing need to understand the effectiveness and cost-effectiveness of various control strategies in reducing parasite transmission and disease burden. Mathematical modeling is uniquely placed to point to provide a better understanding of this multi-host disease system, identify weak points in the transmission cycle and determine the effectiveness of combinations of interventions to provide rational advice for the planning of control activities.Goal and specific objectives We will develop and use mathematical models, calibrated with data from currently ongoing field studies and control efforts, to assess the determinants and key indicators of the transmission dynamicsof O. viverrini and estimate the effectiveness of control interventions, with the following objectives:1. Estimate the contributions of secondary mammalian hosts to the overall transmission of O. viverrini to humans.2. Determine the impact on transmission of varying fishing practices.3. Determine the effectiveness of control interventions in reducing transmission and parasite burden.Methods The study will involve:1. Developing deterministic population-based and stochastic individual-based models of the life cycle of O. viverrini including intermediate hosts, humans and reservoir mammalian hosts; and of the effects of control interventions on this system.2. Calibrating these models from available field data, literature reviews and expert opinion.3. Mathematical analyses and numerical simulations, including bifurcation and sensitivity analysis.4. Continuous dialogue with country control programs to ensure model relevance and provide useful feedback from model results.Expected results and significance The study will provide for the first time deterministic population-based and stochastic individual-based models of O. viverrini transmission. These will create a basis for comparing likely effects of different control strategies in reducing parasite transmission and burden, assessing the relative contribution ofreservoir hosts, and the impacts of varying fishing practices. This will elucidate the transmission dynamics of O. viverrini, including the role of fish in infecting humans and pets, identify data gaps to inform the design of future experiments and field studies, and will provide a basis for rational planning of control, especially in the context of a new control program in Laos. The project will lay the foundation for modeling the epidemiology and control of related food-borne trematodiasis and consequently of the morbidity associated with these parasitic infections.
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