Preliminary Results: The Effect on Malaria Burden after a Change in Insecticide for Indoor Residual Spraying in Zimbabwe Beth Brennan, Ben Johns, Allison Belemvire, Shadreck Sande, Dr. Joseph Mberikunashe, Elana Fiekowsky, Hieronymo Masendu APHA 143rd Annual Meeting November 3, 2015

No relationships to disclose Disclosure Statement Elana Fiekowsky The following personal financial relationships with commercial interests relevant to this presentation existed during the past 12 months: No relationships to disclose

Agenda Background Objective Methods Analysis Limitations Conclusions

PMI Africa Indoor Residual Spraying (AIRS) Project President’s Malaria Initiative (PMI) 17 countries in Africa Aug 2014-2017 Over 10m people protected, 3m structures sprayed, 10k people trained per year

Objective The study is intended to assess if using organophosphates insecticides (OPs) in IRS has an effect on the number of confirmed malaria cases at health facilities (HFs).

Known Mosquito Resistance Objective - 2 Table 1. Summary characteristics of intervention (OP) and comparison IRS districts Analysis Group No. Province District Insecticide Type Known Mosquito Resistance 2011-2013 2014-2015 1 Manicaland Mutare PY OP PY, carbamates resistance Chimanimani No data Mutasa Nyanga 2 Buhera DDT Makoni Chipinge 3 Mashonaland Central (Comparison areas) Bindura Centenary Guruve Mazowe Mbire Mt Darwin Shamva

Methods Data was collected from 4 PMI-supported (OP) districts and compared to government-sprayed districts with PY and DDT insecticides. Figure 1: Proportion of districts with missing data, by month

Results Analysis 1. The number of confirmed malaria cases in health facilities in the four intervention districts in 2013-2014 (PYs) and 2014-2015 (OPs) Results show a marked drop in the incidence of test positive cases in all ages associated with the change from PYs to OPs in the four PMI-supported intervention districts. Figure 2: The number of test positive cases per 1,000 people diagnosed at HFs in the four intervention districts, by month and age category * p < 0.05; ** p < 0.01

Results - 2 Analysis 1. The number of confirmed malaria cases in health facilities in the four intervention districts in 2013-2014 (PYs) and 2014-2015 (OPs) Unadjusted results present a potential case for IRS with OP insecticide having an effect on malaria burden in these four districts. On average, in high transmission, the incidence rate of test positive cases per 1,000 people in 2015 was 38% of what it was in the same period in 2014 for all ages. Table 2. The average number of test positive cases per month (per 1,000 people) diagnosed at HFs in the four intervention districts, by period and age category Period Age group PY (2014) OP (2015) Unadjusted IRR Mean 95% CI p-value January-June (high transmission) U5s 5.4 2.1 0.39 0.22 to 0.68 0.001** All 30.6 11.5 0.38 0.22 to 0.66 February-April (peak transmission) 7.5 2.7 0.36 0.17 to 0.78 0.01* 45.6 15.6 0.34 0.17 to 0.71 0.004** * p < 0.05; ** p < 0.01

Results - 3 Analysis 2. The number of confirmed malaria cases in HFs in 4 intervention districts in 2013- 14 (PYs) and 2014-15 (OPs) to 10 other districts Figure 3. The number of test positive cases per 1,000 people diagnosed at health facilities, by comparison group, month and all ages IRS

Results - 4 Analysis 2 cont. Figure 4. The number of test positive cases per 1,000 people diagnosed at health facilities, by comparison group, month and children under 5 years of age

Results - 5 Analysis 2 Cont. Table 3. The number of test positive cases per 1,000 people diagnosed at health, by comparison category, period, and age category Area For January to June high transmission period For February to April peak transmission period 2013/14 2014/15 Risk difference Unadjusted IRR All ages   Known resistance, switch to OPs in 14/15 30.6 11.5 19.1* 0.38** 45.6 15.6 30.0* 0.34** Other Manicaland 17.6 7.5 10.1* 0.43** 24.8 9.1 15.7* 0.37* Mash Central comparison areas 21.0 12.4 8.6* 0.59* 28.0 15.0 13.0 0.54* Children under 5 years of age 5.4 2.1 3.3* 0.39** 2.7 4.8 0.36* 3.0 1.2 1.8* 0.40** 4.1 1.4 2.7* 0.34* 3.2 1.1 0.66 4.0 2.5 1.5 0.62

Limitations These are preliminary unadjusted results Results do not control for other factors (i.e. other malaria interventions, individual districts, data reporting, month of peak season, etc.) Questionable data quality and limited time frame for analysis

Conclusions Decline in malaria burden reported to HFs in the 4 intervention districts and comparison districts from 2014-2015. Greatest decline observed in the 4 intervention districts that switched to OPs when there was vector resistance to PYs.

Questions? Thank you! www.pmi.gov www.africairs.net Elana_Fiekowsky@abtassoc.com