Impact of indoor residual spraying with lambda-cyhalothrin on malaria parasitemia and anemia prevalence among children less than five years of age in an area of intense, year-round transmission in Malawi.
Little is known about the impact of indoor residual spraying (IRS) in areas with intense malaria transmission such as sub-Saharan Africa. In Malawi, IRS with lambda-cyhalothrin has been applied annually in an area of intense year-long transmission since 2007. We evaluated the impact of IRS on parasitemia and anemia prevalence in children less than five years of age by using a cross-sectional household survey conducted in 2009, six months after the second IRS spray round. We measured malaria parasitemia and anemia (hemoglobin level < 11 g/dL) in 899 children less than five years of age and used binomial regression to assess the impact of IRS by comparing children living in a household sprayed with IRS (direct IRS) with those in a household not sprayed with IRS, but in an IRS area (indirect IRS) and those living in a household not sprayed with IRS and not in an IRS area (no IRS). In the IRS area, 77% of households reported receiving IRS. Adjusting for bed net use, house construction, and socioeconomic status, we found that receiving direct IRS and indirect IRS were significantly associated with a 33% (95% confidence interval [CI] = 1-54%) and 46% (95% CI = 20-64%) reduction in parasitemia and a 21% (95% CI = 4-34%) and 30% (95% CI = 12-45%) reduction in anemia prevalence, respectively.
Jacek
J
Skarbinski
Dyson
D
Mwandama
Adam
A
Wolkon
Madalitso
M
Luka
James
J
Jafali
Alison
A
Smith
Themba
T
Mzilahowa
John
J
Gimnig
Carl
C
Campbell
John
J
Chiphwanya
Doreen
D
Ali
Don P
DP
Mathanga
D000740:Anemia / Q000453:epidemiology* / Q000517:prevention & control; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D006801:Humans; D007306:Insecticides / Q000494:pharmacology*; D008288:Malaria / Q000453:epidemiology* / Q000635:transmission; D008295:Malawi / Q000453:epidemiology; D009032:Mosquito Control / Q000379:methods; D009570:Nitriles / Q000494:pharmacology*; D018512:Parasitemia / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D015995:Prevalence; D011722:Pyrethrins / Q000494:pharmacology*
D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C037304:cyhalothrin