title: Elimination of visceral leishmaniasis in the Indian subcontinent: a comparison of predictions from three transmission models.
abstract: We present three transmission models of visceral leishmaniasis (VL) in the Indian subcontinent (ISC) with structural differences regarding the disease stage that provides the main contribution to transmission, including models with a prominent role of asymptomatic infection, and fit them to recent case data from 8 endemic districts in Bihar, India. Following a geographical cross-validation of the models, we compare their predictions for achieving the WHO VL elimination targets with ongoing treatment and vector control strategies. All the transmission models suggest that the WHO elimination target (<1 new VL case per 10,000 capita per year at sub-district level) is likely to be met in Bihar, India, before or close to 2020 in sub-districts with a pre-control incidence of 10 VL cases per 10,000 people per year or less, when current intervention levels (60% coverage of indoor residual spraying (IRS) of insecticide and a delay of 40days from onset of symptoms to treatment (OT)) are maintained, given the accuracy and generalizability of the existing data regarding incidence and IRS coverage. In settings with a pre-control endemicity level of 5/10,000, increasing the effective IRS coverage from 60 to 80% is predicted to lead to elimination of VL 1-3 years earlier (depending on the particular model), and decreasing OT from 40 to 20days to bring elimination forward by approximately 1year. However, in all instances the models suggest that L. donovani transmission will continue after 2020 and thus that surveillance and control measures need to remain in place until the longer-term aim of breaking transmission is achieved.
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. Electronic address: e.lerutte@erasmusmc.nl.
authors.forename: Epke A
authors.initials: EA
authors.lastname: Le Rutte
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, United Kingdom.
authors.forename: Lloyd A C
authors.initials: LAC
authors.lastname: Chapman
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Luc E
authors.initials: LE
authors.lastname: Coffeng
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Jervis
authors.affiliation: Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium.
authors.forename: Epco C
authors.initials: EC
authors.lastname: Hasker
authors.affiliation: CARE India Solutions for Sustainable Development, Patna, Bihar, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Dwivedi
authors.affiliation: CARE India Solutions for Sustainable Development, Patna, Bihar, India.
authors.forename: Morchan
authors.initials: M
authors.lastname: Karthick
authors.affiliation: CARE India Solutions for Sustainable Development, Patna, Bihar, India.
authors.forename: Aritra
authors.initials: A
authors.lastname: Das
authors.affiliation: CARE India Solutions for Sustainable Development, Patna, Bihar, India.
authors.forename: Tanmay
authors.initials: T
authors.lastname: Mahapatra
authors.affiliation: CARE India Solutions for Sustainable Development, Patna, Bihar, India.
authors.forename: Indrajit
authors.initials: I
authors.lastname: Chaudhuri
authors.affiliation: Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium.
authors.forename: Marleen C
authors.initials: MC
authors.lastname: Boelaert
authors.affiliation: London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
authors.forename: Graham F
authors.initials: GF
authors.lastname: Medley
authors.affiliation: CARE India Solutions for Sustainable Development, Patna, Bihar, India.
authors.forename: Sridhar
authors.initials: S
authors.lastname: Srikantiah
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, United Kingdom.
authors.forename: T Deirdre
authors.initials: TD
authors.lastname: Hollingsworth
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Sake J
authors.initials: SJ
authors.lastname: de Vlas
mesh_terms: D000981:Antiprotozoal Agents / Q000627:therapeutic use; D060740:Disease Eradication; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D007306:Insecticides; D007898:Leishmaniasis, Visceral / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission*; D008962:Models, Theoretical
chemical_list: D000981:Antiprotozoal Agents; D007306:Insecticides
keywords: Detection and treatment; Elimination; Indian subcontinent; Indoor residual spraying; Kala-azar; Mathematical modelling; Neglected tropical disease; Predictions; Sandfly; Transmission dynamics; Visceral leishmaniasis