title: A 20-year longitudinal study of Plasmodium ovale and Plasmodium malariae prevalence and morbidity in a West African population.
abstract: BACKGROUND
  Plasmodium ovale and Plasmodium malariae have long been reported to be widely distributed in tropical Africa and in other major malaria-endemic areas of the world. However, little is known about the burden caused by these two malaria species.
  
  
  RESULTS
  We did a longitudinal study of the inhabitants of Dielmo village, Senegal, between June, 1990, and December, 2010. We monitored the inhabitants for fever during this period and performed quarterly measurements of parasitemia. We analyzed parasitological and clinical data in a random-effect logistic regression model to investigate the relationship between the level of parasitemia and the risk of fever and to establish diagnostic criteria for P. ovale and P. malariae clinical attacks. The prevalence of P. ovale and P. malariae infections in asymptomatic individuals were high during the first years of the project but decreased after 2004 and almost disappeared in 2010 in relation to changes in malaria control policies. The average incidence densities of P. ovale and P. malariae clinical attacks were 0.053 and 0.093 attacks per person per year in children <15 years and 0.024 and 0.009 attacks per person per year in adults ≥ 15 years, respectively. These two malaria species represented together 5.9% of the malaria burden.
  
  
  CONCLUSIONS
  P. ovale and P. malariae were a common cause of morbidity in Dielmo villagers until the recent dramatic decrease of malaria that followed the introduction of new malaria control policies. P. ovale and P. malariae may constitute an important cause of morbidity in many areas of tropical Africa.
authors: Laboratoire de Paludologie et Zoologie Médicale, Institut de Recherche pour le Développement, Dakar, Senegal.
authors: Clémentine
authors: C
authors: Roucher
authors: Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal ; Institut Pasteur de Madagascar, Antananarivo, Madagascar.
authors: Christophe
authors: C
authors: Rogier
authors: Laboratoire de Paludologie et Zoologie Médicale, Institut de Recherche pour le Développement, Dakar, Senegal.
authors: Cheikh
authors: C
authors: Sokhna
authors: Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal.
authors: Adama
authors: A
authors: Tall
authors: Laboratoire de Paludologie et Zoologie Médicale, Institut de Recherche pour le Développement, Dakar, Senegal.
authors: Jean-François
authors: JF
authors: Trape
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005334:Fever / Q000209:etiology; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008137:Longitudinal Studies; D008288:Malaria / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000469:parasitology*; D009017:Morbidity; D018512:Parasitemia / Q000453:epidemiology / Q000469:parasitology; D010963:Plasmodium falciparum; D010965:Plasmodium malariae / Q000502:physiology*; D041122:Plasmodium ovale / Q000502:physiology*; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D012675:Senegal / Q000453:epidemiology; D055815:Young Adult