The combination of indoor residual spraying and insecticide-treated nets provides added protection against malaria compared with insecticide-treated nets alone.

Both insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS) reduce malaria in high malaria transmission areas. The combined effect of these interventions is unknown. We conducted a non-randomized prospective cohort study to determine protective efficacy of IRS with ITNs (ITN + IRS) compared with ITNs alone (ITN only) in preventing Plasmodium falciparum parasitemia. At baseline, participants provided blood samples for malaria smears, were presumptively treated for malaria, and received ITNs. Blood smears were made monthly and at sick visits. In total, 1,804 participants were enrolled. Incidence of P. falciparum parasitemia in the ITN + IRS and ITN only groups was 18 and 44 infections per 100 persons-years at risk, respectively (unadjusted rate ratio = 0.41; 95% confidence interval [CI] = 0.31-0.56). Adjusted protective efficacy of ITN + IRS compared with ITN only was 62% (95% CI = 0.50-0.72). The combination of IRS and ITN might be a feasible strategy to further reduce malaria transmission in areas of persistent perennial malaria transmission.

[1]  Nicolas Moiroux,et al.  Pyrethroid resistance in African anopheline mosquitoes: what are the implications for malaria control? , 2011, Trends in parasitology.

[2]  J. Morgan,et al.  Pyrethroid Resistance in an Anopheles funestus Population from Uganda , 2010, PloS one.

[3]  J. Morgan,et al.  High Level of Pyrethroid Resistance in an Anopheles funestus Population of the Chokwe District in Mozambique , 2010, PloS one.

[4]  B. Sharp,et al.  Indoor residual spraying for preventing malaria. , 2010, The Cochrane database of systematic reviews.

[5]  E. Walker,et al.  Anopheles gambiae: historical population decline associated with regional distribution of insecticide-treated bed nets in western Nyanza Province, Kenya , 2010, Malaria Journal.

[6]  I. Kleinschmidt,et al.  Combining indoor residual spraying and insecticide-treated net interventions. , 2009, The American journal of tropical medicine and hygiene.

[7]  I. Kleinschmidt,et al.  Marked increase in child survival after four years of intensive malaria control. , 2009, The American journal of tropical medicine and hygiene.

[8]  R. Snow,et al.  Effect of a fall in malaria transmission on morbidity and mortality in Kilifi, Kenya , 2008, The Lancet.

[9]  Immo Kleinschmidt,et al.  Malaria vector control by indoor residual insecticide spraying on the tropical island of Bioko, Equatorial Guinea , 2007, Malaria Journal.

[10]  T. S. Awolola,et al.  Behaviour and population dynamics of the major anopheline vectors in a malaria endemic area in southern Nigeria. , 2007, Journal of vector borne diseases.

[11]  C. Lengeler,et al.  Insecticide-treated bed nets and curtains for preventing malaria. , 2004, The Cochrane database of systematic reviews.

[12]  S. P. Kachur,et al.  Efficacy of permethrin-treated bed nets in the prevention of mortality in young children in an area of high perennial malaria transmission in western Kenya. , 2003, The American journal of tropical medicine and hygiene.

[13]  S. P. Kachur,et al.  The efficacy of permethrin-treated bed nets on child mortality and morbidity in western Kenya I. Development of infrastructure and description of study site. , 2003, The American journal of tropical medicine and hygiene.

[14]  R. Hunt,et al.  Anopheles funestus resistant to pyrethroid insecticides in South Africa , 2000, Medical and veterinary entomology.

[15]  N. White,et al.  Pharmacokinetics and Pharmacodynamics of Lumefantrine (Benflumetol) in Acute Falciparum Malaria , 2000, Antimicrobial Agents and Chemotherapy.

[16]  M. Rowland.  Malaria control: bednets or spraying? Malaria control in the Afghan refugee camps of western Pakistan. , 1999, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[17]  J. Lines,et al.  Malaria control: bednets or spraying? Spray versus treated nets using deltamethrin--a community randomized trial in India. , 1999, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[18]  J. Vulule,et al.  Reduced susceptibility of Anopheles gambiae to permethrin associated with the use of permethrin‐impregnated bednets and curtains in Kenya , 1994, Medical and veterinary entomology.

[19]  F. Collins,et al.  Identification of single specimens of the Anopheles gambiae complex by the polymerase chain reaction. , 1993, The American journal of tropical medicine and hygiene.

[20]  C. Curtis,et al.  Comparison of house spraying and insecticide-treated nets for malaria control. , 2000, Bulletin of the World Health Organization.

[21]  Alain Villemeur,et al.  Methods and techniques , 1992 .

[22]  B. Grab,et al.  Impact of control measures on malaria transmission and general mortality. , 1976, Bulletin of the World Health Organization.

[23]  M. Gillies.,et al.  The Anophelinae of Africa South of the Sahara , 1968 .