title: The rise and fall of malaria in a West African rural community, Dielmo, Senegal, from 1990 to 2012: a 22 year longitudinal study.
abstract: BACKGROUND
  A better understanding of the effect of malaria control interventions on vector and parasite populations, acquired immunity, and burden of the disease is needed to guide strategies to eliminate malaria from highly endemic areas. We monitored and analysed the changes in malaria epidemiology in a village community in Senegal, west Africa, over 22 years.
  
  
  METHODS
  Between 1990 and 2012, we did a prospective longitudinal study of the inhabitants of Dielmo, Senegal, to identify all episodes of fever and investigate the relation between malaria host, vector, and parasite. Our study included daily medical surveillance with systematic parasite detection in individuals with fever. We measured parasite prevalence four times a year with cross-sectional surveys. We monitored malaria transmission monthly with night collection of mosquitoes. Malaria treatment changed over the years, from quinine (1990-94), to chloroquine (1995-2003), amodiaquine plus sulfadoxine-pyrimethamine (2003-06), and finally artesunate plus amodiaquine (2006-12). Insecticide-treated nets (ITNs) were introduced in 2008.
  
  
  RESULTS
  We monitored 776 villagers aged 0-101 years for 2 378 150 person-days of follow-up. Entomological inoculation rate ranged from 142·5 infected bites per person per year in 1990 to 482·6 in 2000, and 7·6 in 2012. Parasite prevalence in children declined from 87% in 1990 to 0·3 % in 2012. In adults, it declined from 58% to 0·3%. We recorded 23 546 fever episodes during the study, including 8243 clinical attacks caused by Plasmodium falciparum, 290 by Plasmodium malariae, and 219 by Plasmodium ovale. Three deaths were directly attributable to malaria, and two to severe adverse events of antimalarial drugs. The incidence of malaria attacks ranged from 1·50 attacks per person-year in 1990 to 2·63 in 2000, and to only 0·046 in 2012. The greatest changes were associated with the replacement of chloroquine and the introduction of ITNs.
  
  
  CONCLUSIONS
  Malaria control policies combining prompt treatment of clinical attacks and deployment of ITNs can nearly eliminate parasite carriage and greatly reduce the burden of malaria in populations exposed to intense perennial malaria transmission. The choice of drugs seems crucial. Rapid decline of clinical immunity allows rapid detection and treatment of novel infections and thus has a key role in sustaining effectiveness of combining artemisinin-based combination therapy and ITNs despite increasing pyrethroid resistance.
  
  
  BACKGROUND
  Pasteur Institutes of Dakar and Paris, Institut de Recherche pour le Développement, and French Ministry of Cooperation.
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal. Electronic address: jean-francois.trape@ird.fr.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Trape
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal.
authors.forename: Adama
authors.initials: A
authors.lastname: Tall
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Cheikh
authors.initials: C
authors.lastname: Sokhna
authors.affiliation: Ministry of Health, Dakar, Sénégal.
authors.forename: Alioune Badara
authors.initials: AB
authors.lastname: Ly
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Nafissatou
authors.initials: N
authors.lastname: Diagne
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Ousmane
authors.initials: O
authors.lastname: Ndiath
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Catherine
authors.initials: C
authors.lastname: Mazenot
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal.
authors.forename: Vincent
authors.initials: V
authors.lastname: Richard
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Badiane
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Fambaye
authors.initials: F
authors.lastname: Dieye-Ba
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal.
authors.forename: Joseph
authors.initials: J
authors.lastname: Faye
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Gora
authors.initials: G
authors.lastname: Ndiaye
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal.
authors.forename: Fatoumata
authors.initials: F
authors.lastname: Diene Sarr
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Clémentine
authors.initials: C
authors.lastname: Roucher
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Charles
authors.initials: C
authors.lastname: Bouganali
authors.affiliation: Institut de Recherche pour le Développement, Laboratoire de Paludologie, Dakar, Sénégal.
authors.forename: Hubert
authors.initials: H
authors.lastname: Bassène
authors.affiliation: Institut Pasteur de Dakar, Département d'Immunologie, Dakar, Sénégal.
authors.forename: Aissatou
authors.initials: A
authors.lastname: Touré-Baldé
authors.affiliation: Institut Pasteur de Dakar, Département d'Immunologie, Dakar, Sénégal; Institut Pasteur, Département de Parasitologie et Mycologie, Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Roussilhon
authors.affiliation: Institut Pasteur de Dakar, Département d'Immunologie, Dakar, Sénégal; Institut Pasteur, Département de Parasitologie et Mycologie, Paris, France.
authors.forename: Ronald
authors.initials: R
authors.lastname: Perraut
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal.
authors.forename: André
authors.initials: A
authors.lastname: Spiegel
authors.affiliation: Institut Pasteur de Dakar, Département d'Immunologie, Dakar, Sénégal.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Sarthou
authors.affiliation: Institut Pasteur, Département de Parasitologie et Mycologie, Paris, France.
authors.forename: Luiz Pereira
authors.initials: LP
authors.lastname: da Silva
authors.affiliation: Institut Pasteur, Département de Parasitologie et Mycologie, Paris, France.
authors.forename: Odile
authors.initials: O
authors.lastname: Mercereau-Puijalon
authors.affiliation: Institut Pasteur, Département de Parasitologie et Mycologie, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Druilhe
authors.affiliation: Institut Pasteur de Dakar, Département d'Epidémiologie, Dakar, Sénégal; Institut Pasteur de Madagascar, Antananarivo, Madagascar.
authors.forename: Christophe
authors.initials: C
authors.lastname: Rogier
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000852:Anopheles / Q000469:parasitology*; D000962:Antimalarials / Q000008:administration & dosage; D037621:Artemisinins / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004359:Drug Therapy, Combination; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007303:Insect Vectors / Q000469:parasitology*; D008137:Longitudinal Studies; D008288:Malaria / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000187:drug effects*; D010965:Plasmodium malariae / Q000187:drug effects*; D041122:Plasmodium ovale / Q000187:drug effects*; D015995:Prevalence; D011446:Prospective Studies; D012424:Rural Population; D012675:Senegal / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000962:Antimalarials; D037621:Artemisinins; C031327:artemisinin