Determinants of MDA impact and designing MDAs towards malaria elimination

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Tables

Table 1

Factor	Meaning	Values
Teams	Number of teams performing prevalence surveys and distributing ACTs simultaneously. Translated into coverage speed in square brackets, that is, the number of days it takes to perform one MDA round in a region of 1000 villages.	15 [267] 25 [160] 50 [80] 100 [40] 200 [20] 400 [10]
Prevalence	Mean initial malaria u-PCR prevalence across all villages.	0.5, 0.1, 0.15, 0.2, 0.25, 0.3
Resistance	Mean initial proportion of parasites which are artemisinin resistant.	0.1, 0.2, 0.3
Distribution	Transmission heterogeneity distribution, underlying spatial heterogeneity of malaria transmission, manifested by differential mosquito density distributions.	Gaussian, Log-normal, Pareto
Mobility	Describes the intensity of population movement in the general population. Indicates the per person average daily probability of moving to places other than their home village for short-term visits (see Mobility section in the Simulation Protocol). that is a population of individuals whose short-term movement occurs on average 25 times per year (25/365) has a relatively static population with low mobility.	5/365 25/365 125/365 250/365
Campaigns	The number of MDA Campaigns	1, 2
Peaks	The number of annual seasonal peaks	1, 2

Table 2

#	Name	Description	Value	Reference
1	V	Set of villages	|V| = 1000
2	N	Set of individuals across all villages	|N| = 314,795	-
3	ml	Proportion of males in the population	0.48	(National Institute of Statistics, 2008)
4	maxage	Maximum age	80 years	-
5	beta	Biting rate	variable*	-
6	previ	Initial proportion of infectious people	variable*	-
7	resit	Initial proportion of artemisinin resistant infections	variable*	-
8	netuse	Proportion of individuals that own an insecticide treated bed net	0.5	-
9	itneffect	proportional decrease of individual susceptibility/infectiousness related to ITN usage	0.2	-
10	ovstay	Mean number of nights spent somewhere when undertaking short-term population movement	3	-
11	crit	Critical distance below which overnight stays somewhere other than your home are made very unlikely	4 km	-
12	timecomp	Mean time to complete ACT routine treatment	4 days	Best guess
13	fullcourse	Proportion that receives treatment full course	0.8	(Yeung et al., 2008)
14	covab	Proportion of symptomatic cases that receive antimalarials	0.6	(Yeung et al., 2008)
15	nomp	Relative probability of receiving treatment in a non-malaria post village	0.1	Best guess
16	asymtreat	Relative probability of receiving treatment without clinical symptom	10−4	-
17	tauab	Daily probability of receiving ACT in a village under MDA	1/1.5	-
18	gamma	Mean liver stage duration	5 days	(Collins and Jeffery, 1999; Eyles and Young, 1951)
19	sigma	Mean time to infectiousness after liver emergence	15 days	(Jeffery and Eyles, 1955)
20	mellow	Mean duration of symptoms	3 days	(Church et al., 1997)
21	xa0	Daily probability of going below the minimum effective artemisinin concentration	1/7	(Karbwang et al., 1998)
22	xai	Daily probability losing the DHA effect as part of ACT	1/3	(Rijken et al., 2011; Tarning et al., 2008)
23	xab	Daily probability of going below the minimum effective piperaquine concentration	1/30	(Rijken et al., 2011; Tarning et al., 2008)
24	xpr	Daily probability of going below the minimum effective primaquine concentration	1/2	(Burgess and Bray, 1961)
25	delta	Mean duration of a malaria untreated infection	160 days	(Eyles and Young, 1951; Babiker et al., 1998; Franks et al., 2001)
26	imm_min	Minimum clinical immunity period	40 days	Best guess
27	alpha	Average permanence in each immunity level	60 days	-
28	phic	Relative infectiousness of symptomatic infections compared to sub-patent ones	1	-
29	mdi	Mosquito daily probability of dying while infectious	1/7	(Dawes et al., 2009)
30	mdn	Mosquito daily probability of dying while infected but not yet infectious	1/20	(Dawes et al., 2009)
31	mgamma	Mean extrinsic incubation period	14 days	(Smith et al., 2014)
32	amp	Amplitude of mosquito density seasonal variation	0.6	Best guess
33	process	Days needed to administer a full ACT course in one village	4 days	Optimistic guess
34	rounds	Number of drug rounds in an MDA campaign	3	Standard practice
35	btrounds	Number of days between drug rounds in an MDA campaign	32	Standard practice
36	vcefficacy	Vector control efficacy	variable*	-
37	$c_{b\bullet r0\bullet a}$	Daily probability of clearing blood stage drug sensitive parasites with circulating dha	1/5	(Adjuik et al., 2004; Pukrittayakamee et al., 2004)
38	$c_{b\bullet ra\bullet a}$	Daily probability of clearing blood stage artemisinin resistant parasites with dha	0.27*$c_{b\bullet r0\bullet a}$ (0.05)	(Dondorp et al., 2009)
39	$c_{i\bullet r0\bullet a}$	Daily probability of clearing infectious stage drug sensitive parasites with circulating dha	1/3	(Adjuik et al., 2004; Pukrittayakamee et al., 2004)
40	$c_{i\bullet ra\bullet a}$	Daily probability of clearing infectious stage artemisinin resistant parasites with dha	0.27*$c_{i\bullet r0\bullet a}$ (0.09)	(Dondorp et al., 2009)
41	$c_{b\bullet ro\bullet ab}$	Daily probability of clearing blood stage drug sensitive parasites with circulating dha- piperaquine	1/3	(Adjuik et al., 2004; Pukrittayakamee et al., 2004)
42	$c_{b\bullet ra\bullet ab}$	Daily probability of clearing blood stage artemisinin resistant parasites with dha- piperaquine	0.27*$c_{b\bullet ro\bullet ab}$ + (1.0–0.27)*$c_{b\bullet r0\bullet b}$ (0.33)	(Dondorp et al., 2009)
43	$c_{i\bullet r0\bullet ab}$	Daily probability of clearing infectious stage drug sensitive parasites with circulating dha- piperaquine	1/3	(Bustos et al., 2013)
44	$c_{i\bullet ra\bullet ab}$	Daily probability of clearing infectious stage artemisinin resistant parasites with dha- piperaquine	0.27*$c_{i\bullet r0\bullet ab}$ + (1.0–0.27)*$c_{i\bullet r0\bullet b}$ (0.126)	-
45	$c_{b\bullet r0\bullet b}$	Daily probability of clearing blood stage drug sensitive parasites with circulating piperaquine	1/3	(Chen et al., 1982)
46	$c_{b\bullet ra\bullet b}$	Daily probability of clearing blood stage artemisinin resistant parasites with piperaquine	1/3	(Chen et al., 1982)
47	$c_{i\bullet r0\bullet b}$	Daily probability of clearing infectious stage drug sensitive parasites with circulating piperaquine	1/20	(Myint et al., 2007)
48	$c_{i\bullet ra\bullet b}$	Daily probability of clearing infectious stage artemisinin resistant parasites with piperaquine	1/20	(Myint et al., 2007)
49	$c_{i\bullet r0\bullet p}$	Daily probability of clearing infectious stage drug sensitive parasites with primaquine	1/1.5	(Burgess and Bray, 1961; Smithuis et al., 2010)
50	$c_{i\bullet ra\bullet p}$	Daily probability of clearing infectious stage artemisinin resistant parasites with primaquine	1/1.5	-
51	k	Steepness of susceptibility increase with age	0.14	(Aguas et al., 2008)
52	r	Amplitude of susceptibility increase with age	0.99	(Aguas et al., 2008)

1. ^*the values are varied in different simulation settings. Their values are given in the description of each set of experiments and the set of possible values is given in Table 1.

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