title: Towards malaria elimination in Mpumalanga, South Africa: a population-level mathematical modelling approach.
abstract: BACKGROUND
  Mpumalanga in South Africa is committed to eliminating malaria by 2018 and efforts are increasing beyond that necessary for malaria control. Differential Equation models may be used to study the incidence and spread of disease with an important benefit being the ability to enact exogenous change on the system to predict impact without committing any real resources. The model is a deterministic non-linear ordinary differential equation representation of the dynamics of the human population. The model is fitted to weekly data of treated cases from 2002 to 2008, and then validated with data from 2009 to 2012. Elimination-focused interventions such as the scale-up of vector control, mass drug administration, a focused mass screen and treat campaign and foreign source reduction are applied to the model to assess their potential impact on transmission.
  
  
  RESULTS
  Scaling up vector control by 10% and 20% resulted in substantial predicted decreases in local infections with little impact on imported infections. Mass drug administration is a high impact but short-lived intervention with predicted decreases in local infections of less that one infection per year. However, transmission reverted to pre-intervention levels within three years. Focused mass screen and treat campaigns at border-entry points are predicted to result in a knock-on decrease in local infections through a reduction in the infectious reservoir. This knock-on decrease in local infections was also predicted to be achieved through foreign source reduction. Elimination was only predicted to be possible under the scenario of zero imported infections in Mpumalanga.
  
  
  CONCLUSIONS
  A constant influx of imported infections show that vector control alone will not be able to eliminate local malaria as it is insufficient to interrupt transmission. Both mass interventions have a large and immediate impact. Yet in countries with a large migrant population, these interventions may fail due to the reintroduction of parasites and their impact may be short-lived. While all strategies (in isolation or combined) contributed to decreasing local infections, none was predicted to decrease local infections to zero. The number of imported infections highlights the importance of reducing imported infections at source, and a regional approach to malaria elimination.
authors.affiliation: Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa. sheetal.silal@uct.ac.za.
authors.forename: Sheetal P
authors.initials: SP
authors.lastname: Silal
authors.forename: Francesca
authors.initials: F
authors.lastname: Little
authors.forename: Karen I
authors.initials: KI
authors.lastname: Barnes
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: White
mesh_terms: D006801:Humans; D015994:Incidence; D008288:Malaria / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission; D008954:Models, Biological; D015233:Models, Statistical; D013019:South Africa / Q000453:epidemiology
references.citation: PLoS Med. 2011 Jan 25;8(1):e1000403
references.pmid: 21283605
references.citation: Trop Med Int Health. 2008 Jan;13(1):108-22
references.pmid: 18291009
references.citation: Malar J. 2016 Aug 12;15(1):409
references.pmid: 27520364
references.citation: Bull Math Biol. 2008 Jul;70(5):1272-96
references.pmid: 18293044
references.citation: Clin Microbiol Infect. 2011 Nov;17(11):1617-23
references.pmid: 21951597
references.citation: Lancet Infect Dis. 2012 Mar;12(3):191-200
references.pmid: 22172305
references.citation: Malar J. 2003 Feb 19;2:3
references.pmid: 12643812
references.citation: Malar J. 2009 Apr 17;8:68
references.pmid: 19374738
references.citation: Malar J. 2009 Oct 12;8 Suppl 1:S5
references.pmid: 19818172
references.citation: Malar J. 2008 Dec 11;7 Suppl 1:S8
references.pmid: 19091042
references.citation: Malar J. 2009 Sep 14;8:212
references.pmid: 19747403
references.citation: S Afr Med J. 1996 Jan;86(1):83-9
references.pmid: 8685790
references.citation: Lancet. 2010 Nov 6;376(9752):1592-603
references.pmid: 21035841
references.citation: S Afr Med J. 2007 Nov;97(11 Pt 3):1193-7
references.pmid: 18250936
references.citation: Malar J. 2011 Jul 21;10:202
references.pmid: 21777413
references.citation: Malar J. 2012 Dec 19;11:423
references.pmid: 23253091
references.citation: PLoS One. 2013 Oct 29;8(10):e76640
references.pmid: 24204650
references.citation: J Natl Malar Soc. 1951 Dec;10(4):327-36
references.pmid: 14908561
references.citation: Malar J. 2012 Jan 13;11:19
references.pmid: 22239855
references.citation: Malar J. 2012 Aug 22;11:294
references.pmid: 22913727
references.citation: PLoS One. 2012;7(5):e37166
references.pmid: 22662135
references.citation: Am J Trop Med Hyg. 2007 Jan;76(1):42-7
references.pmid: 17255227
references.citation: Trans R Soc Trop Med Hyg. 1958 Mar;52(2):152-68
references.pmid: 13543904
references.citation: Am J Trop Med Hyg. 1999 Jul;61(1 Suppl):4-19
references.pmid: 10432041
references.citation: Parasitol Today. 1999 Mar;15(3):105-11
references.pmid: 10322323
references.citation: Proc Natl Acad Sci U S A. 2010 Jul 6;107(27):12222-7
references.pmid: 20566870
references.citation: Malar J. 2010 Jul 22;9:213
references.pmid: 20649972
references.citation: Am J Trop Med Hyg. 1955 Sep;4(5):781-9
references.pmid: 13259002
references.citation: Trop Med Int Health. 2004 Aug;9(8):846-56
references.pmid: 15303988