Impact of different strategies to control Plasmodium infection and anaemia on the island of Bioko (Equatorial Guinea).
BACKGROUND
On the island of Bioko (Equatorial Guinea), insecticide-treated nets (ITNs) have been the main tool used to control malaria over the last 13 years. In 2004, started an indoor residual spraying (IRS) campaign to control malaria. The purpose of this study is to asses the impact of the two control strategies on the island of Bioko (Equatorial Guinea), with regards to Plasmodium infection and anaemia in the children under five years of age.


METHODS
Two transversal studies, the first one prior to the start of the IRS campaign and the second one year later. Sampling was carried out by stratified clusters. Malaria infection was measured by means of thick and thin film, and the packed cell volume (PCV) percentage. Data related to ITN use and information regarding IRS were collected. The Pearson's chi-square and logistic regression statistical tests were used to calculate odds ratios (OR).


RESULTS
In the first survey, 168 children were sampled and 433 children in the second one. The prevalence of infection was 40% in 2004, and significantly lower at 21.7% in 2005. PCV was 41% and 39%, respectively. 58% of the children surveyed in 2004 and 44.3% in 2005 had slept under an ITN. 78% of the dwellings studied in 2005 had been sprayed. In the 2005 survey, sleeping without a mosquito net meant a risk of infection 3 times greater than sleeping protected with a net hanged correctly and with no holes (p < 0.05).


CONCLUSIONS
IRS and ITNs have proven to be effective control strategies on the island of Bioko. The choice of one or other strategy is, above all, a question of operational feasibility and availability of local resources.
Pardo
Gema
G
Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III, c/Sinesio Delgado, 6, PO Box 28029, Madrid, Spain. gema-pardo@terra.es
Descalzo
Miguel Angel
MA
Molina
Laura
L
Custodio
Estefanía
E
Lwanga
Magdalena
M
Mangue
Catalina
C
Obono
Jaquelina
J
Nchama
Araceli
A
Roche
Jesús
J
Benito
Agustín
A
Cano
Jorge
J
D000740:Anemia / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D000818:Animals; D000852:Anopheles / Q000469:parasitology; D001512:Bedding and Linens; D002675:Child, Preschool; D016703:Equatorial Guinea / Q000453:epidemiology; D006801:Humans; D007306:Insecticides / Q000008:administration & dosage*; D016778:Malaria, Falciparum / Q000150:complications / Q000453:epidemiology / Q000469:parasitology / Q000517:prevention & control*; D009032:Mosquito Control / Q000379:methods*; D010963:Plasmodium falciparum
D007306:Insecticides