Detecting Foci of Malaria Transmission with School Surveys: A Pilot Study in the Gambia

Background In areas of declining malaria transmission such as in The Gambia, the identification of malaria infected individuals becomes increasingly harder. School surveys may be used to identify foci of malaria transmission in the community. Methods The survey was carried out in May–June 2011, before the beginning of the malaria transmission season. Thirty two schools in the Upper River Region of The Gambia were selected with probability proportional to size; in each school approximately 100 children were randomly chosen for inclusion in the study. Each child had a finger prick blood sample collected for the determination of antimalarial antibodies by ELISA, malaria infection by microscopy and PCR, and for haemoglobin measurement. In addition, a simple questionnaire on socio-demographic variables and the use of insecticide-treated bed nets was completed. The cut-off for positivity for antimalarial antibodies was obtained using finite mixture models. The clustered nature of the data was taken into account in the analyses. Results A total of 3,277 children were included in the survey. The mean age was 10 years (SD = 2.7) [range 4–21], with males and females evenly distributed. The prevalence of malaria infection as determined by PCR was 13.6% (426/3124) [95% CI = 12.2–16.3] with marked variation between schools (range 3–25%, p<0.001), while the seroprevalence was 7.8% (234/2994) [95%CI = 6.4–9.8] for MSP119, 11.6% (364/2997) [95%CI = 9.4–14.5] for MSP2, and 20.0% (593/2973) [95% CI = 16.5–23.2) for AMA1. The prevalence of all the three antimalarial antibodies positive was 2.7% (79/2920). Conclusions This survey shows that malaria prevalence and seroprevalence before the transmission season were highly heterogeneous.

[1]  D. Conway,et al.  Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau , 2009, Malaria Journal.

[2]  D. Conway,et al.  Risk factors for house-entry by malaria vectors in a rural town and satellite villages in The Gambia , 2008, Malaria Journal.

[3]  David L Smith,et al.  Measuring malaria endemicity from intense to interrupted transmission , 2008, The Lancet. Infectious diseases.

[4]  Teun Bousema,et al.  Dried blood spots as a source of anti-malarial antibodies for epidemiological studies , 2008, Malaria Journal.

[5]  P. Magnussen,et al.  Malaria diagnosis and treatment administered by teachers in primary schools in Tanzania , 2001, Tropical medicine & international health : TM & IH.

[6]  K. Deribe,et al.  Malaria and Under-Nutrition: A Community Based Study Among Under-Five Children at Risk of Malaria, South-West Ethiopia , 2010, PloS one.

[7]  A. Holder,et al.  The Fine Specificity, but Not the Invasion Inhibitory Activity, of 19-Kilodalton Merozoite Surface Protein 1-Specific Antibodies Is Associated with Resistance to Malarial Parasitemia in a Cross-Sectional Survey in The Gambia , 2004, Infection and Immunity.

[8]  Thomas A. Smith,et al.  Rapid urban malaria appraisal (RUMA) in sub-Saharan Africa , 2005 .

[9]  S. Brooker,et al.  School-based surveys of malaria in Oromia Regional State, Ethiopia: a rapid survey method for malaria in low transmission settings , 2011, Malaria Journal.

[10]  V. do Rosário,et al.  Pre-elimination of malaria on the island of Príncipe , 2010, Malaria Journal.

[11]  R. Snow,et al.  The use of schools for malaria surveillance and programme evaluation in Africa , 2009, Malaria Journal.

[12]  A. Oduro,et al.  Antibody levels to multiple malaria vaccine candidate antigens in relation to clinical malaria episodes in children in the Kasena-Nankana district of Northern Ghana , 2011, Malaria Journal.

[13]  Robert W Snow,et al.  Implementing school malaria surveys in Kenya: towards a national surveillance system , 2010, Malaria Journal.

[14]  M. Thomson,et al.  Malaria prevalence is inversely related to vector density in The Gambia, West Africa. , 1994, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[15]  J. Stanford,et al.  Exploring the relationship between chronic undernutrition and asymptomatic malaria in Ghanaian children , 2010, Malaria Journal.

[16]  A. Benito,et al.  Nutritional and socio-economic factors associated with Plasmodium falciparum infection in children from Equatorial Guinea: results from a nationally representative survey , 2009, Malaria Journal.

[17]  Simon I. Hay,et al.  Stable and Unstable Malaria Hotspots in Longitudinal Cohort Studies in Kenya , 2010, PLoS medicine.

[18]  David L. Smith,et al.  Standardizing estimates of the Plasmodium falciparum parasite rate , 2007, Malaria Journal.

[19]  D. Conway,et al.  Continued Decline of Malaria in The Gambia with Implications for Elimination , 2010, PloS one.

[20]  C. Nishida,et al.  Development of a WHO growth reference for school-aged children and adolescents. , 2007, Bulletin of the World Health Organization.

[21]  S. Brooker,et al.  Relationships between anaemia and parasitic infections in Kenyan schoolchildren: A Bayesian hierarchical modelling approach , 2008, International journal for parasitology.

[22]  S. Brooker,et al.  Local perceptions of intermittent screening and treatment for malaria in school children on the south coast of Kenya , 2012, Malaria Journal.

[23]  C. Drakeley,et al.  Efficacy trial of malaria vaccine SPf66 in Gambian infants , 1995, The Lancet.

[24]  D. Conway,et al.  A Randomised Trial to Compare the Safety, Tolerability and Efficacy of Three Drug Combinations for Intermittent Preventive Treatment in Children , 2010, PloS one.

[25]  D. Conway,et al.  Changes in malaria indices between 1999 and 2007 in The Gambia: a retrospective analysis , 2008, The Lancet.

[26]  S. Brooker,et al.  Malaria morbidity among school children living in two areas of contrasting transmission in western Kenya. , 2004, The American journal of tropical medicine and hygiene.

[27]  A. Prentice,et al.  Impact of nutritional status on antibody responses to different vaccines in undernourished Gambian children , 2003, Acta paediatrica.

[28]  C. Drakeley,et al.  Target Antigen, Age, and Duration of Antigen Exposure Independently Regulate Immunoglobulin G Subclass Switching in Malaria , 2006, Infection and Immunity.

[29]  J. Slater,et al.  Letter: The low-lying placenta and dysmaturity. , 1975, Lancet.

[30]  Organização Mundial de Saúde,et al.  World malaria report 2011 , 2011 .

[31]  P. Byass,et al.  BED-NETS AND MALARIA SUPPRESSION , 1987, The Lancet.

[32]  R. Moy,et al.  Less diarrhoea but no change in growth: 15 years’ data from three Gambian villages , 1999, Archives of disease in childhood.

[33]  A. Kroeger,et al.  Using schoolchildren's reports of bed net use monitored by schoolteachers as a proxy of community coverage in malaria endemic areas of Uganda , 2006, Tropical medicine & international health.

[34]  P. Phillips-Howard,et al.  Malaria and nutritional status among pre-school children: results from cross-sectional surveys in western Kenya. , 2005, The American journal of tropical medicine and hygiene.

[35]  K. Bojang,et al.  A trial of intermittent preventive treatment and home-based management of malaria in a rural area of The Gambia , 2011, Malaria Journal.

[36]  J. Vulule,et al.  Parasitemia, anemia, and malarial anemia in infants and young children in a rural holoendemic Plasmodium falciparum transmission area. , 2006, The American journal of tropical medicine and hygiene.

[37]  D. Conway,et al.  Serum IgG3 to the Plasmodium falciparum merozoite surface protein 2 is strongly associated with a reduced prospective risk of malaria , 2003, Parasite immunology.

[38]  K. Brouwer,et al.  Knowledge attitudes and practices of grade three primary schoolchildren in relation to schistosomiasis, soil transmitted helminthiasis and malaria in Zimbabwe , 2011, BMC infectious diseases.

[39]  David Schellenberg,et al.  Health Centre Surveys as a Potential Tool for Monitoring Malaria Epidemiology by Area and over Time , 2011, PloS one.

[40]  Weltgesundheitsorganisation.  World malaria report , 2005 .

[41]  A. Holder,et al.  A longitudinal study of naturally acquired cellular and humoral immune responses to a merozoite surface protein (MSP1) of Plasmodium falciparum in an area of seasonal malaria transmission , 1993, Parasite immunology.

[42]  K. Jaton,et al.  Detection of Four Plasmodium Species in Blood from Humans by 18S rRNA Gene Subunit-Based and Species-Specific Real-Time PCR Assays , 2004, Journal of Clinical Microbiology.

[43]  D. Sellen,et al.  Genetics of Criminal and Antisocial Behaviour. Ciba Foundation Symposium 194. Pp. 283. Edited by G. R. Bock & J. A. Goode. (Wiley, Chichester, 1996.) £50.00. , 1998, Journal of Biosocial Science.

[44]  B. Greenwood,et al.  Comparison of two simple methods for determining malaria parasite density. , 1991, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[45]  D. Boakye,et al.  School-based participatory health education for malaria control in Ghana: engaging children as health messengers , 2010, Malaria Journal.

[46]  R. Chilengi,et al.  Humoral Responses to Plasmodium falciparum Blood-Stage Antigens and Association with Incidence of Clinical Malaria in Children Living in an Area of Seasonal Malaria Transmission in Burkina Faso, West Africa , 2007, Infection and Immunity.

[47]  J. Sachs,et al.  Malaria in São Tomé and principe: on the brink of elimination after three years of effective antimalarial measures. , 2009, The American journal of tropical medicine and hygiene.

[48]  C. Karema,et al.  Malaria Journal BioMed Central , 2009 .

[49]  W. Jarra,et al.  High sensitivity of detection of human malaria parasites by the use of nested polymerase chain reaction. , 1993, Molecular and biochemical parasitology.

[50]  J. Sexton,et al.  Malaria in primary school children and infants in kinshasa, democratic republic of the congo: surveys from the 1980s and 2000. , 2004, The American journal of tropical medicine and hygiene.

[51]  Abdullah S Ali,et al.  Impact of Artemisinin-Based Combination Therapy and Insecticide-Treated Nets on Malaria Burden in Zanzibar , 2007, PLoS medicine.

[52]  B. Cissé,et al.  Influence of wasting and stunting at the onset of the rainy season on subsequent malaria morbidity among rural preschool children in Senegal. , 2009, The American journal of tropical medicine and hygiene.

[53]  Teun Bousema,et al.  Hitting Hotspots: Spatial Targeting of Malaria for Control and Elimination , 2012, PLoS medicine.

[54]  A. Holder,et al.  Clinical immunity to Plasmodium falciparum malaria is associated with serum antibodies to the 19-kDa C-terminal fragment of the merozoite surface antigen, PfMSP-1. , 1996, The Journal of infectious diseases.

[55]  D. Conway,et al.  Effect of two different house screening interventions on exposure to malaria vectors and on anaemia in children in The Gambia: a randomised controlled trial , 2009, The Lancet.

[56]  W. Jarra,et al.  Identification of the four human malaria parasite species in field samples by the polymerase chain reaction and detection of a high prevalence of mixed infections. , 1993, Molecular and biochemical parasitology.