title: Plasmodium malariae Infection Associated with a High Burden of Anemia: A Hospital-Based Surveillance Study.
abstract: BACKGROUND
  Plasmodium malariae is a slow-growing parasite with a wide geographic distribution. Although generally regarded as a benign cause of malaria, it has been associated with nephrotic syndrome, particularly in young children, and can persist in the host for years. Morbidity associated with P. malariae infection has received relatively little attention, and the risk of P. malariae-associated nephrotic syndrome is unknown.
  
  
  RESULTS
  We used data from a very large hospital-based surveillance system incorporating information on clinical diagnoses, blood cell parameters and treatment to describe the demographic distribution, morbidity and mortality associated with P. malariae infection in southern Papua, Indonesia. Between April 2004 and December 2013 there were 1,054,674 patient presentations to Mitra Masyarakat Hospital of which 196,380 (18.6%) were associated with malaria and 5,097 were with P. malariae infection (constituting 2.6% of all malaria cases). The proportion of malaria cases attributable to P. malariae increased with age from 0.9% for patients under one year old to 3.1% for patients older than 15 years. Overall, 8.5% of patients with P. malariae infection required admission to hospital and the median length of stay for these patients was 2.5 days (Interquartile Range: 2.0-4.0 days). Patients with P. malariae infection had a lower mean hemoglobin concentration (9.0 g/dL) than patients with P. falciparum (9.5 g/dL), P. vivax (9.6g/dL) and mixed species infections (9.3g/dL). There were four cases of nephrotic syndrome recorded in patients with P. malariae infection, three of which were in children younger than 5 years old, giving a risk in this age group of 0.47% (95% Confidence Interval; 0.10% to 1.4%). Overall, 2.4% (n = 16) of patients hospitalized with P. malariae infection subsequently died in hospital, similar to the proportions for the other endemic Plasmodium species (range: 0% for P. ovale to 1.6% for P. falciparum).
  
  
  CONCLUSIONS
  Plasmodium malariae infection is relatively uncommon in Papua, Indonesia but is associated with significant morbidity from anemia and a similar risk of mortality to patients hospitalized with P. falciparum and P. vivax infection. In our large hospital database, one in 200 children under the age of 5 years with P. malariae infection were recorded as having nephrotic syndrome.
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Casuarina, Darwin, Northern Territory, Australia.
authors.forename: Siobhan
authors.initials: S
authors.lastname: Langford
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Casuarina, Darwin, Northern Territory, Australia.|Division of Medicine, Christchurch Hospital, Christchurch, New Zealand.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Douglas
authors.affiliation: Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lampah
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Simpson
authors.affiliation: Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia.|Mimika District Health Authority, Timika, Papua, Indonesia.
authors.forename: Enny
authors.initials: E
authors.lastname: Kenangalem
authors.affiliation: Rumah Sakit Mitra Masyarakat, Timika, Papua, Indonesia.
authors.forename: Paulus
authors.initials: P
authors.lastname: Sugiarto
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Casuarina, Darwin, Northern Territory, Australia.|Division of Medicine, Royal Darwin Hospital, Darwin, Australia.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Anstey
authors.affiliation: Timika Malaria Research Program, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia.|Mimika District Health Authority, Timika, Papua, Indonesia.|Department of Child Health, Faculty of Medicine, University Gadjah Mada, Yogyakarta, Indonesia.
authors.forename: Jeanne Rini
authors.initials: JR
authors.lastname: Poespoprodjo
authors.affiliation: Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Casuarina, Darwin, Northern Territory, Australia.|Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Ric N
authors.initials: RN
authors.lastname: Price
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000740:Anemia / Q000150:complications / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D015897:Comorbidity; D062665:Epidemiological Monitoring; D005260:Female; D006761:Hospitals; D006801:Humans; D007214:Indonesia / Q000453:epidemiology; D007223:Infant; D008288:Malaria / Q000150:complications* / Q000453:epidemiology* / Q000469:parasitology; D016778:Malaria, Falciparum / Q000150:complications / Q000453:epidemiology; D016780:Malaria, Vivax / Q000150:complications / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000302:isolation & purification; D010965:Plasmodium malariae / Q000302:isolation & purification*; D010966:Plasmodium vivax / Q000302:isolation & purification; D055815:Young Adult