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Implementing school malaria surveys in Kenya: towards a national surveillance system.

Gitonga CW, Karanja PN, Kihara J, Mwanje M, Juma E, Snow RW, Noor AM, Brooker S - Malar. J. (2010)

Bottom Line: RDT positive results were corrected by microscopy and all results were adjusted for clustering using random effect regression modelling. 49,975 children in 480 schools were sampled, at an estimated cost of US$ 1,116 per school.The prevalence of infection showed marked variation across the country, with prevalence being highest in Western and Nyanza provinces, and lowest in Central, North Eastern and Eastern provinces.Nationally, 2.3% of schools had reported ITN use >60%, and low reported ITN use was a particular problem in Western and Nyanza provinces.

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Affiliation: Malaria Public Health & Epidemiology Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya. cgitonga@nairobi.kemri-wellcome.org

ABSTRACT

Objective: To design and implement surveys of malaria infection and coverage of malaria control interventions among school children in Kenya in order to contribute towards a nationwide assessment of malaria.

Methods: The country was stratified into distinct malaria transmission zones based on a malaria risk map and 480 schools were visited between October 2008 and March 2010. Surveys were conducted in two phases: an initial opportunistic phase whereby schools were selected for other research purposes; and a second phase whereby schools were purposively selected to provide adequate spatial representation across the country. Consent for participation was based on passive, opt-out consent rather than written, opt-in consent because of the routine, low-risk nature of the survey. All children were diagnosed for Plasmodium infection using rapid diagnostic tests, assessed for anaemia and were interviewed about mosquito net usage, recent history of illness, and socio-economic and household indicators. Children's responses were entered electronically in the school and data transmitted nightly to Nairobi using a mobile phone modem connection. RDT positive results were corrected by microscopy and all results were adjusted for clustering using random effect regression modelling.

Results: 49,975 children in 480 schools were sampled, at an estimated cost of US$ 1,116 per school. The overall prevalence of malaria and anaemia was 4.3% and 14.1%, respectively, and 19.0% of children reported using an insecticide-treated net (ITN). The prevalence of infection showed marked variation across the country, with prevalence being highest in Western and Nyanza provinces, and lowest in Central, North Eastern and Eastern provinces. Nationally, 2.3% of schools had reported ITN use >60%, and low reported ITN use was a particular problem in Western and Nyanza provinces. Few schools reported having malaria health education materials or ongoing malaria control activities.

Conclusion: School malaria surveys provide a rapid, cheap and sustainable approach to malaria surveillance which can complement household surveys, and in Kenya, show that large areas of the country do not merit any direct school-based control, but school-based interventions, coupled with strengthened community-based strategies, are warranted in western and coastal Kenya. The results also provide detailed baseline data to inform evaluation of school-based malaria control in Kenya.

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The geographical distribution of (a) Malaria infection in 480 schools, (b) anaemia adjusted for age, sex and altitude in 399 schools, and (c) reported insecticide net use among school children in 480 schools across Kenya, September 2008-March 2010. Note: Haemoglobin was not assessed in some schools in the North Eastern Kenya. Classification based on the WHO categories of anaemia for public health importance (WHO, 2001).
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Figure 3: The geographical distribution of (a) Malaria infection in 480 schools, (b) anaemia adjusted for age, sex and altitude in 399 schools, and (c) reported insecticide net use among school children in 480 schools across Kenya, September 2008-March 2010. Note: Haemoglobin was not assessed in some schools in the North Eastern Kenya. Classification based on the WHO categories of anaemia for public health importance (WHO, 2001).

Mentions: The overall prevalence of infection, based on slide-corrected RDT positivity, was 4.3 (95% CI, 3.3 - 5.2). The vast majority (96.8%) of these infections were P. falciparum, with the remainder being either P. ovale (0.1%) or P. malariae (0.6%) or mixed infections (2.6%); no P. vivax was detected. Prevalence was significantly higher in children aged 5-9 and 10-14 years old (4.4%) than children older than 15 years (2.8%, p < 0.0001), but did not significantly differ between males and females (4.3% vs. 4.2%, p = 0.53). The prevalence of malaria infection by province is shown in Table 2 and the geographical distribution of malaria is shown in Figure 3a. Prevalence varied markedly by school (0 - 70.9%) and by province, being highest in Western Province (21.6%, 95% CI: 14.6 - 28.7%) and lowest in Central and North Eastern provinces, where no child was found to be infected in any school (Table 2). Prevalence was <5% in all other provinces, except Nyanza Province (9.3%, 95% CI: 6.8 - 11.9%). Eleven (2.3%) schools had a parasite prevalence ≥ 40% and all of these were located around Lake Victoria (Figure 3a).


Implementing school malaria surveys in Kenya: towards a national surveillance system.

Gitonga CW, Karanja PN, Kihara J, Mwanje M, Juma E, Snow RW, Noor AM, Brooker S - Malar. J. (2010)

The geographical distribution of (a) Malaria infection in 480 schools, (b) anaemia adjusted for age, sex and altitude in 399 schools, and (c) reported insecticide net use among school children in 480 schools across Kenya, September 2008-March 2010. Note: Haemoglobin was not assessed in some schools in the North Eastern Kenya. Classification based on the WHO categories of anaemia for public health importance (WHO, 2001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2984573&req=5

Figure 3: The geographical distribution of (a) Malaria infection in 480 schools, (b) anaemia adjusted for age, sex and altitude in 399 schools, and (c) reported insecticide net use among school children in 480 schools across Kenya, September 2008-March 2010. Note: Haemoglobin was not assessed in some schools in the North Eastern Kenya. Classification based on the WHO categories of anaemia for public health importance (WHO, 2001).
Mentions: The overall prevalence of infection, based on slide-corrected RDT positivity, was 4.3 (95% CI, 3.3 - 5.2). The vast majority (96.8%) of these infections were P. falciparum, with the remainder being either P. ovale (0.1%) or P. malariae (0.6%) or mixed infections (2.6%); no P. vivax was detected. Prevalence was significantly higher in children aged 5-9 and 10-14 years old (4.4%) than children older than 15 years (2.8%, p < 0.0001), but did not significantly differ between males and females (4.3% vs. 4.2%, p = 0.53). The prevalence of malaria infection by province is shown in Table 2 and the geographical distribution of malaria is shown in Figure 3a. Prevalence varied markedly by school (0 - 70.9%) and by province, being highest in Western Province (21.6%, 95% CI: 14.6 - 28.7%) and lowest in Central and North Eastern provinces, where no child was found to be infected in any school (Table 2). Prevalence was <5% in all other provinces, except Nyanza Province (9.3%, 95% CI: 6.8 - 11.9%). Eleven (2.3%) schools had a parasite prevalence ≥ 40% and all of these were located around Lake Victoria (Figure 3a).

Bottom Line: RDT positive results were corrected by microscopy and all results were adjusted for clustering using random effect regression modelling. 49,975 children in 480 schools were sampled, at an estimated cost of US$ 1,116 per school.The prevalence of infection showed marked variation across the country, with prevalence being highest in Western and Nyanza provinces, and lowest in Central, North Eastern and Eastern provinces.Nationally, 2.3% of schools had reported ITN use >60%, and low reported ITN use was a particular problem in Western and Nyanza provinces.

View Article: PubMed Central - HTML - PubMed

Affiliation: Malaria Public Health & Epidemiology Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya. cgitonga@nairobi.kemri-wellcome.org

ABSTRACT

Objective: To design and implement surveys of malaria infection and coverage of malaria control interventions among school children in Kenya in order to contribute towards a nationwide assessment of malaria.

Methods: The country was stratified into distinct malaria transmission zones based on a malaria risk map and 480 schools were visited between October 2008 and March 2010. Surveys were conducted in two phases: an initial opportunistic phase whereby schools were selected for other research purposes; and a second phase whereby schools were purposively selected to provide adequate spatial representation across the country. Consent for participation was based on passive, opt-out consent rather than written, opt-in consent because of the routine, low-risk nature of the survey. All children were diagnosed for Plasmodium infection using rapid diagnostic tests, assessed for anaemia and were interviewed about mosquito net usage, recent history of illness, and socio-economic and household indicators. Children's responses were entered electronically in the school and data transmitted nightly to Nairobi using a mobile phone modem connection. RDT positive results were corrected by microscopy and all results were adjusted for clustering using random effect regression modelling.

Results: 49,975 children in 480 schools were sampled, at an estimated cost of US$ 1,116 per school. The overall prevalence of malaria and anaemia was 4.3% and 14.1%, respectively, and 19.0% of children reported using an insecticide-treated net (ITN). The prevalence of infection showed marked variation across the country, with prevalence being highest in Western and Nyanza provinces, and lowest in Central, North Eastern and Eastern provinces. Nationally, 2.3% of schools had reported ITN use >60%, and low reported ITN use was a particular problem in Western and Nyanza provinces. Few schools reported having malaria health education materials or ongoing malaria control activities.

Conclusion: School malaria surveys provide a rapid, cheap and sustainable approach to malaria surveillance which can complement household surveys, and in Kenya, show that large areas of the country do not merit any direct school-based control, but school-based interventions, coupled with strengthened community-based strategies, are warranted in western and coastal Kenya. The results also provide detailed baseline data to inform evaluation of school-based malaria control in Kenya.

Show MeSH
Related in: MedlinePlus