An Observational Analysis of the Impact of IRS in the

Ségou Region of Mali: 2012 - 2014Joseph Wagman1*, Christelle Gogue1, Kenzie Tynuv1, Jules Mihigo2, Diadier Diallo3, Elie Bankineza4, Mamadou Bah4, Andrew Saibu5, Jason Richardson6 ,Diakalkia Kone7, Seydou

Fomba7, Laurence Slutsker1, Molly Robertson1

1PATH, Washington, DC, USA, 2US President’s Malaria Initiative, Bamako, Mali, 3MEASURE Evaluation, Bamako, Mali, 4Abt Associates, AIRS Project, Bamako, Mali,

5Abt Associates, NgenIRS Project, Accra, Ghana, 6IVCC, Washington, DC, USA,7Programme National de Lutte contre le Paludisme, Ministère de la Sante, Bamako, Mali; *jwagman@path.org

Introduction

#1129

Project Partners

The annual IRS campaigns from 2012 – 2015 in Ségou were good public health

investments

o Around 500,000 people protected for 3 years at around $7 USD or less per

person per year, regardless of which chemical was sprayed

o Around 300,000 cases of malaria were likely averted,

PMI/Abt entomological surveillance results 3 indicate that the IRS campaigns were

also broadly associated in time and space with reductions in overall An. gambiae

s.l. indoor resting and biting densities.

It is encouraging that, despite the continued and obvious need for an

expanded IRS toolkit, campaigns with currently available non-pyrethroid

products (including 3rd generation IRS products) can have a sizable, cost-

effective impact in areas of high pyrethroid resistance and widespread use of

LLINs.

Additionally, this work highlights the critical importance of quality-assured,

validated, routine surveillance and well defined observational analyses to asses the

impact of malaria control interventions in various operational settings – helping to

empower evidence-based decisions and to grow the evidence base needed to

better understand when and where to utilize new vector control tools as they

become available.

*The NgenIRS (Next Generation IRS) project is a partnership, led by IVCC, that includesthe US President’s Malaria Initiative, Abt Associates, and PATH. NgenIRS works in close

collaboration with leading insecticide manufacturers, national malaria control programs,

the Global Fund, and other stakeholders to save lives and protect health by reducingtransmission of malaria through affordable indoor residual spraying of long lasting, non-

pyrethroid insecticides. It is funded by UNITAID. For more information please visit

www.ngenirs.com or email David McGuire (david.mcguire@ivcc.com).

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Fig. 1. (a) The location of Mali in West Africa, with Ségou Region highlighted. (b) The locations of the community health facilities inSégou that reported malaria rapid diagnostic test results during the months analyzed here (Jan 2012 to Jan 2016). The IRS Districts ofBarouéli and Bla are shown in dark and light green, respectively; non-IRS comparator districts are shown in blue.

References1 2015 Estimates; Direction Nationale de la Population, Republique du Mali

2 2013 DHS3 PMI, 2016. Mali: Entomological Monitoring of 2015 IRS Activities

4 Cisse, et al. 2015. Mal J. 14:327, 5 Noor, et al. 2015. PLoS One;10e0136919

6 Johns and Cico, 2016. PM/AID-OAA-TO-14-000357 PMI. The PMI Africa IRS (AIRS) Project IRS 2 Task Order Four

Mali Entomological Monitoring Reports. 2012 – 2014. https://www.pmi.gov/where-we-work/mali

Table 1. Summary of the malaria control landscape in Ségou Region, Mali 2012 - 2015

1 Active Ingredient. CA = Carbamate; OP = organophosphate 2 % of structures targeted for IRS that were sprayed3 Universal Distribution Campaigns undertaken in 2012 and 2015 4 % of target population receiving at least 2 courses of SMC with SP+A

A set of retrospective, observational (ecological), time-series analyses were

performed using 1,382,202 RDT-confirmed cases of malaria reported by routine

health systems (Système Numérique d'Information Sanitaire Intégré) from January

2012 to January 2016.

Weather Station

Mauritania

Senegal

Guinea

Côte d’Ivoire

Burkina Faso

Niger

Algeria

Non-IRS DistrictsIRS 2012-2015

Community Health FacilityIRS 2012-2014

50km

a. b.

PMI/AIRS Entomological Surveillance Site

• 9,138 monthly reports from 202 community health centers in Ségou

• Community health center catchment area population estimates obtained from

the Ministry of Health

• Health center incidence rates per 10,000 person-months at risk were

stratified by IRS status for comparative analyses

• Total population ~3 million; ~590K

under 5 years old (u5)1

• 2013 u5 malaria prevalence = 56%2

• Malaria transmission highly seasonal,

typically highest June - October

• Primary vector is Anopheles gambiae

s.s.

• High levels of pyrethroid and DDT

resistance widely reported3,4

• High access to and use of LLINs2

o 90% of households with at least 1

LLIN

o 60% of total population report

sleeping under the LLIN

• Scale up of seasonal malaria chemo-

prevention (SMC) began in 2013

• 7 total administrative districts (cercles),

similar to one another in terms of 5

o Population density

o Rainfall patterns

o Malaria transmission seasonality

o Malaria prevalence

• 2 districts, Barouéli and Bla, participated

in the PMI/AIRS project during the study

period

o Bendiocarb WP (Ficam®; Bayer

CropScience) sprayed in 2012 &

2013

o Pyrimiphos-methyl CS (Actellic®300

CS; Syngenta AG) sprayed in 2014 &

2015

Ségou Region

Study Location

Approach Results, continued

Fig. 2. Epidemiological curves showingthe monthly incidence of RDT+confirmed malaria cases in Ségou,stratified by district IRS status. Thearea of the tan curve illustrates thedifference between the incidencerates observed in the IRS districts(green) and the non-IRS districts(blue). The duration of each year’s IRScampaign is also illustrated.

Also shown are the cumulativeincidence reductions observed in IRSdistricts, relative to non-IRS districts,during the 6 months that followedeach year’s IRS campaign.

321.3 fewer cases per

10,000 person-months

289.7 fewer cases per

10,000 person-months

491.5 fewer cases per

10,000 person-months

Table 2. A crude estimate of the cost-effectiveness of IRS in Bla and Barouéli Districts, 2012 - 2014

Estimates of the cost-effectiveness of IRS

Reported IRS expenditures and costs were compiled from Revised PMI Obligation

Tables and the PMI IRS Country Programs 2015 Comparative Cost Analysis6.

Crude estimates of the cost-effectiveness for each year’s IRS campaign were

calculated using the corresponding PMI/AIRS cost estimates for that year, adjusted

for the proportional number of structures sprayed per district included in this

analysis.

Results

Conclusions

Fig. 3. Comparing the entomologicaland epidemiological trends showingthe impact of IRS in Ségou Region,2012-2014. The monthly malariaincidence curves are presented withthe results of routine PMI/Abt AIRSentomological surveillance activities7.

*Bendiocarb was sprayed in 2012 and2013, while pirimiphos methyl wassprayed in 2014

Transmission Season 1

Reduced Incidence Observed in IRS

Districts (number of RDT+ cases per

10,000 person-months)

Total Population of IRS

Districts

Estimated Cases

Averted 2

Estimated Cost of IRS

Campaign 3

Crude Cost

per person

covered

Crude Cost

per case

averted

2012 321.3 563,359 108,604 $ 3,426,834.00 $6.08 $31.55

2013 289.7 586,125 101,880 $ 4,339,328.78 $7.40 $42.59

2014 491.5 258,598 76,261 $ 1,778,893.77 $6.88 $23.33

Total 1102.5 1,408,082 286,745 $ 9,545,056.55 $6.78 $33.29

1 Defined here as the six months following the IRS campaign2 (Reduced incidence)*(population of IRS districts)*(6 months)3 Annual Revised PMI Expenditures from Africa Indoor Residual Spray (AIRS) Mali Program,

in adjusted 2014 USD, multiplied by proportional number of houses sprayed per district analyzed

2012 2013 2014 2015

IRS IRS IRS IRS

District AI1

Coverage

Estimate2

LLINs

Distributed3 SMC4 AI1

Coverage

Estimate2

LLINs

Distributed3 SMC4 AI1

Coverage

Estimate2

LLINs

Distributed3 SMC4 AI1

Coverage

Estimate2

LLINs

Distributed3 SMC4

Barouéli CA 98% Universal - CA 98% ANC/EPI - OP 96% ANC/EPI - OP 98% Universal 86%

Bla CA 99% Universal - CA 98% ANC/EPI - OP 98% ANC/EPI 104% none - Universal 98%

Macina none - Universal - none - ANC/EPI - none - ANC/EPI - none - Universal 82%

Segou none - Universal - none - ANC/EPI - none - ANC/EPI - none - Universal 82%

Niono none - Universal - none - ANC/EPI - none - ANC/EPI - none - Universal 68%

San none - Universal - none - ANC/EPI 94% none - ANC/EPI 102% none - Universal Unknown

Tominian none - Universal - none - ANC/EPI - none - ANC/EPI - none - Universal 96%

The widespread adoption of new products for indoor residual spraying (IRS) is

challenged by concerns about increased cost as well as gaps in the evidence

needed to evaluate their public health impact and cost-effectiveness across various

malaria transmission settings. To provide evidence to address this gap, we present

a retrospective, observational analysis of the epidemiological and entomological

impact of IRS with two different non-pyrethroid insecticides using routine indicators

of malaria transmission in the Ségou Region of Mali.