Epidemiology of Plasmodium knowlesi malaria in north-east Sabah, Malaysia

family clusters and wide age distribution

Bridget Barber, Timothy William, Prabakaran Dhararaj, F Anderios, Matthew Grigg, Tsin Yeo, Nicholas Anstey

Research output: Contribution to journalArticleResearchpeer-review

11 Downloads (Pure)

Abstract

Background: The simian parasite Plasmodium knowlesi is a common cause of human malaria in Malaysian Borneo, with a particularly high incidence in Kudat, Sabah. Little is known however about the epidemiology in this substantially deforested region. 

Methods: 
Malaria microscopy records at Kudat District Hospital were retrospectively reviewed from January 2009-November 2011. Demographics, and PCR results if available, were recorded for each positive result. Medical records were reviewed for patients suspected of representing family clusters, and families contacted for further information. Rainfall data were obtained from the Malaysian Meteorological Department. 

Results: “Plasmodium malariae” mixed or mono-infection was diagnosed by microscopy in 517/653 (79%) patients. Of these, PCR was performed in 445 (86%) and was positive for P. knowlesi mono-infection in 339 (76%). Patients with knowlesi malaria demonstrated a wide age distribution (median 33, IQR 20–50, range 0.7-89 years) with P. knowlesi predominating in all age groups except those <5 years old, where numbers approximated those of Plasmodium falciparum and Plasmodium vivax. Two contemporaneous family clusters were identified: a father with two children (aged 10–11 years); and three brothers (aged one-11 years), all with PCR-confirmed knowlesi malaria. Cases of P. knowlesi demonstrated significant seasonal variation, and correlated with rainfall in the preceding three to five months. 

Conclusions: 
Plasmodium knowlesi is the most common cause of malaria admissions to Kudat District Hospital. The wide age distribution and presence of family clusters suggest that transmission may be occurring close to or inside people’s homes, in contrast to previous reports from densely forested areas of Sarawak. These findings have significant implications for malaria control. Prospective studies of risk factors, vectors and transmission dynamics of P. knowlesi in Sabah, including potential for human-to-human transmission, are needed. 
Original languageEnglish
Article number401
Pages (from-to)1-8
Number of pages8
JournalMalaria Journal
Volume11
DOIs
Publication statusPublished - 2012

Fingerprint

Plasmodium knowlesi
Plasmodium malariae
Malaysia
Age Distribution
Malaria
Epidemiology
District Hospitals
Polymerase Chain Reaction
Microscopy
Borneo
Plasmodium vivax
Plasmodium falciparum
Infection
Fathers
Medical Records
Siblings
Parasites
Age Groups
Demography
Prospective Studies

Cite this

@article{ca6fab69d5d840a988ddf7ebfbc700ab,
title = "Epidemiology of Plasmodium knowlesi malaria in north-east Sabah, Malaysia: family clusters and wide age distribution",
abstract = "Background: The simian parasite Plasmodium knowlesi is a common cause of human malaria in Malaysian Borneo, with a particularly high incidence in Kudat, Sabah. Little is known however about the epidemiology in this substantially deforested region. Methods: Malaria microscopy records at Kudat District Hospital were retrospectively reviewed from January 2009-November 2011. Demographics, and PCR results if available, were recorded for each positive result. Medical records were reviewed for patients suspected of representing family clusters, and families contacted for further information. Rainfall data were obtained from the Malaysian Meteorological Department. Results: “Plasmodium malariae” mixed or mono-infection was diagnosed by microscopy in 517/653 (79{\%}) patients. Of these, PCR was performed in 445 (86{\%}) and was positive for P. knowlesi mono-infection in 339 (76{\%}). Patients with knowlesi malaria demonstrated a wide age distribution (median 33, IQR 20–50, range 0.7-89 years) with P. knowlesi predominating in all age groups except those <5 years old, where numbers approximated those of Plasmodium falciparum and Plasmodium vivax. Two contemporaneous family clusters were identified: a father with two children (aged 10–11 years); and three brothers (aged one-11 years), all with PCR-confirmed knowlesi malaria. Cases of P. knowlesi demonstrated significant seasonal variation, and correlated with rainfall in the preceding three to five months. Conclusions: Plasmodium knowlesi is the most common cause of malaria admissions to Kudat District Hospital. The wide age distribution and presence of family clusters suggest that transmission may be occurring close to or inside people’s homes, in contrast to previous reports from densely forested areas of Sarawak. These findings have significant implications for malaria control. Prospective studies of risk factors, vectors and transmission dynamics of P. knowlesi in Sabah, including potential for human-to-human transmission, are needed. ",
keywords = "rain, adolescent, adult, age distribution, aged, article, child, family assessment, female, human, infant, major clinical study, malaria falciparum, Malaysia, male, medical record review, microscopy, mixed infection, Plasmodium knowlesi malaria, Plasmodium vivax malaria, polymerase chain reaction, preschool child, retrospective study, school child, seasonal variation, Adolescent, Adult, Age Distribution, Aged, Aged, 80 and over, Child, Child, Preschool, Cluster Analysis, Family Health, Female, Humans, Infant, Infant, Newborn, Malaria, Male, Middle Aged, Plasmodium knowlesi, Retrospective Studies, Young Adult",
author = "Bridget Barber and Timothy William and Prabakaran Dhararaj and F Anderios and Matthew Grigg and Tsin Yeo and Nicholas Anstey",
year = "2012",
doi = "10.1186/1475-2875-11-401",
language = "English",
volume = "11",
pages = "1--8",
journal = "Malaria Journal",
issn = "1475-2875",
publisher = "BioMed Central",

}

Epidemiology of Plasmodium knowlesi malaria in north-east Sabah, Malaysia : family clusters and wide age distribution. / Barber, Bridget; William, Timothy; Dhararaj, Prabakaran; Anderios, F; Grigg, Matthew; Yeo, Tsin; Anstey, Nicholas.

In: Malaria Journal, Vol. 11, 401, 2012, p. 1-8.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Epidemiology of Plasmodium knowlesi malaria in north-east Sabah, Malaysia

T2 - family clusters and wide age distribution

AU - Barber, Bridget

AU - William, Timothy

AU - Dhararaj, Prabakaran

AU - Anderios, F

AU - Grigg, Matthew

AU - Yeo, Tsin

AU - Anstey, Nicholas

PY - 2012

Y1 - 2012

N2 - Background: The simian parasite Plasmodium knowlesi is a common cause of human malaria in Malaysian Borneo, with a particularly high incidence in Kudat, Sabah. Little is known however about the epidemiology in this substantially deforested region. Methods: Malaria microscopy records at Kudat District Hospital were retrospectively reviewed from January 2009-November 2011. Demographics, and PCR results if available, were recorded for each positive result. Medical records were reviewed for patients suspected of representing family clusters, and families contacted for further information. Rainfall data were obtained from the Malaysian Meteorological Department. Results: “Plasmodium malariae” mixed or mono-infection was diagnosed by microscopy in 517/653 (79%) patients. Of these, PCR was performed in 445 (86%) and was positive for P. knowlesi mono-infection in 339 (76%). Patients with knowlesi malaria demonstrated a wide age distribution (median 33, IQR 20–50, range 0.7-89 years) with P. knowlesi predominating in all age groups except those <5 years old, where numbers approximated those of Plasmodium falciparum and Plasmodium vivax. Two contemporaneous family clusters were identified: a father with two children (aged 10–11 years); and three brothers (aged one-11 years), all with PCR-confirmed knowlesi malaria. Cases of P. knowlesi demonstrated significant seasonal variation, and correlated with rainfall in the preceding three to five months. Conclusions: Plasmodium knowlesi is the most common cause of malaria admissions to Kudat District Hospital. The wide age distribution and presence of family clusters suggest that transmission may be occurring close to or inside people’s homes, in contrast to previous reports from densely forested areas of Sarawak. These findings have significant implications for malaria control. Prospective studies of risk factors, vectors and transmission dynamics of P. knowlesi in Sabah, including potential for human-to-human transmission, are needed. 

AB - Background: The simian parasite Plasmodium knowlesi is a common cause of human malaria in Malaysian Borneo, with a particularly high incidence in Kudat, Sabah. Little is known however about the epidemiology in this substantially deforested region. Methods: Malaria microscopy records at Kudat District Hospital were retrospectively reviewed from January 2009-November 2011. Demographics, and PCR results if available, were recorded for each positive result. Medical records were reviewed for patients suspected of representing family clusters, and families contacted for further information. Rainfall data were obtained from the Malaysian Meteorological Department. Results: “Plasmodium malariae” mixed or mono-infection was diagnosed by microscopy in 517/653 (79%) patients. Of these, PCR was performed in 445 (86%) and was positive for P. knowlesi mono-infection in 339 (76%). Patients with knowlesi malaria demonstrated a wide age distribution (median 33, IQR 20–50, range 0.7-89 years) with P. knowlesi predominating in all age groups except those <5 years old, where numbers approximated those of Plasmodium falciparum and Plasmodium vivax. Two contemporaneous family clusters were identified: a father with two children (aged 10–11 years); and three brothers (aged one-11 years), all with PCR-confirmed knowlesi malaria. Cases of P. knowlesi demonstrated significant seasonal variation, and correlated with rainfall in the preceding three to five months. Conclusions: Plasmodium knowlesi is the most common cause of malaria admissions to Kudat District Hospital. The wide age distribution and presence of family clusters suggest that transmission may be occurring close to or inside people’s homes, in contrast to previous reports from densely forested areas of Sarawak. These findings have significant implications for malaria control. Prospective studies of risk factors, vectors and transmission dynamics of P. knowlesi in Sabah, including potential for human-to-human transmission, are needed. 

KW - rain

KW - adolescent

KW - adult

KW - age distribution

KW - aged

KW - article

KW - child

KW - family assessment

KW - female

KW - human

KW - infant

KW - major clinical study

KW - malaria falciparum

KW - Malaysia

KW - male

KW - medical record review

KW - microscopy

KW - mixed infection

KW - Plasmodium knowlesi malaria

KW - Plasmodium vivax malaria

KW - polymerase chain reaction

KW - preschool child

KW - retrospective study

KW - school child

KW - seasonal variation

KW - Adolescent

KW - Adult

KW - Age Distribution

KW - Aged

KW - Aged, 80 and over

KW - Child

KW - Child, Preschool

KW - Cluster Analysis

KW - Family Health

KW - Female

KW - Humans

KW - Infant

KW - Infant, Newborn

KW - Malaria

KW - Male

KW - Middle Aged

KW - Plasmodium knowlesi

KW - Retrospective Studies

KW - Young Adult

UR - http://www.scopus.com/inward/record.url?scp=84870307881&partnerID=8YFLogxK

U2 - 10.1186/1475-2875-11-401

DO - 10.1186/1475-2875-11-401

M3 - Article

VL - 11

SP - 1

EP - 8

JO - Malaria Journal

JF - Malaria Journal

SN - 1475-2875

M1 - 401

ER -