High Incidence of Plasmodium knowlesi Infection in the Interior Division of Sabah, Malaysian Borneo

Lau, Tiek Ying; Joveen-Neoh, Wan.Fen; Chong, Ka Lung

doi:10.7763/ijbbb.2011.v1.30

Cited by 7 publications

(13 citation statements)

References 20 publications

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“…Thirty-five infections diagnosed as P. malariae by microscopic examination were found to be P. knowlesi . This finding was similar to the studies carried out by other researchers in Malaysian Borneo [7,10,28,35], reporting that most microscopy-positive P. malariae infections were actually proven to be P. knowlesi infections when molecular approach was used. However, the transmission dynamics of this infection still remain unknown despite wide distribution of this parasite in Malaysian Borneo.…”

Section: Discussionsupporting

confidence: 91%

“…Note: The location of human P. knowlesi detected in this study is marked by triangles. Stars represented the distribution of this parasite reported by previous studies [10,35-38]. …”

Section: Resultsmentioning

confidence: 90%

“…Recently, P. knowlesi cases had been reported in the Interior division and north-eastern state of Sabah [10,28,35]. It is obvious that the prevalence of P. knowlesi in Sabah has increased markedly and studies reported on the discovery of this parasite by using molecular approaches have greatly increased recently.…”

Section: Discussionmentioning

confidence: 99%

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Increased detection of Plasmodium knowlesi in Sandakan division, Sabah as revealed by PlasmoNex™

Goh

Lim

Vythilingam

et al. 2013

Malar J

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BackgroundPlasmodium knowlesi is a simian malaria parasite that is widespread in humans in Malaysian Borneo. However, little is known about the incidence and distribution of this parasite in the Sandakan division, Malaysian Borneo. Therefore, the aim of the present epidemiological study was to investigate the incidence and distribution of P. knowlesi as well as other Plasmodium species in this division based on a most recent developed hexaplex PCR system (PlasmoNex™).MethodsA total of 189 whole blood samples were collected from Telupid Health Clinic, Sabah, Malaysia, from 2008 to 2011. All patients who participated in the study were microscopically malaria positive before recruitment. Complete demographic details and haematological profiles were obtained from 85 patients (13 females and 72 males). Identification of Plasmodium species was conducted using PlasmoNex™ targeting the 18S ssu rRNA gene.ResultsA total of 178 samples were positive for Plasmodium species by using PlasmoNex™. Plasmodium falciparum was identified in 68 samples (38.2%) followed by 64 cases (36.0%) of Plasmodium vivax, 42 (23.6%) cases of P. knowlesi, two (1.1%) cases of Plasmodium malariae and two (1.1%) mixed-species infections (i e, P. vivax/P. falciparum). Thirty-five PlasmoNex™ positive P. knowlesi samples were misdiagnosed as P. malariae by microscopy. Plasmodium knowlesi was detected in all four districts of Sandakan division with the highest incidence in the Kinabatangan district. Thrombocytopaenia and anaemia showed to be the most frequent malaria-associated haematological complications in this study.ConclusionsThe discovery of P. knowlesi in Sandakan division showed that prospective studies on the epidemiological risk factors and transmission dynamics of P. knowlesi in these areas are crucial in order to develop strategies for effective malaria control. The availability of advanced diagnostic tool PlasmoNex™ enhanced the accuracy and accelerated the speed in the diagnosis of malaria.

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Section: Discussionsupporting

confidence: 91%

“…Note: The location of human P. knowlesi detected in this study is marked by triangles. Stars represented the distribution of this parasite reported by previous studies [10,35-38]. …”

Section: Resultsmentioning

confidence: 90%

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Increased detection of Plasmodium knowlesi in Sandakan division, Sabah as revealed by PlasmoNex™

Goh

Lim

Vythilingam

et al. 2013

Malar J

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“…Monkeys were positive with mono-infection of P. knowlesi. The prevalence of high incidence of P. knowlesi was among the patients in the age group of 21 to 40 years, more in males and in people who spent nights in forested areas for their lively hood (Lau et al 2011). In Singapore molecular epidemiological studies identified P. knowlesi infection in humans who visited forest and in longtailed monkeys from forests but not in monkeys from national reserve park (Jeslyn et al 2011).…”

Section: P Knowlesi Transmission Cycles and Its Site Of Transmissionmentioning

confidence: 99%

“…All the cases that were identified as P. malariae microscopically were identified as P. knowlesi by the nested polymerase chain reaction (PCR) that was developed by the investigators (Singh et al 1999(Singh et al , 2004. Identification of more cases in the following years from different hospitals in Sarawak (Cox- , high incidence in the interior divisions of Sabah (Lau et al 2011) and severe cases from a tertiary hospital in Sabah (Willam et al 2011) established that the entire Malaysian Borneo has P. knowlesi cases. Vythillingam et al (2008) reported cases from Peninsular Malaysia.…”

Section: Natural P Knowlesi Infections In Humansmentioning

confidence: 99%

Centenary celebrations article

Subbarao

2011

J Parasit Dis

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The identification of a large focus of Plasmodium knowlesi in Malaysian Borneo and subsequent reports from several countries in South-east Asia has led its recognition as the fifth human malaria parasite. The natural preferred hosts of this species still continue to be macaque monkeys that live in broad-leaf rain forests. This review describes the distribution of macaque monkeys, the Anopheles species belonging to the Leucosphyrus Group that have been incriminated as vectors, morphological and clinical features of this parasite, and the transmission cycles that have been identified for this parasite. As the North-eastern states of India share their borders with P. knowlesi malaria endemic countries and because travelers from countries in South-east Asia visit India and vice versa, risks of this parasite entering India and its spread are also discussed.

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Genetic diversity in the C-terminus of merozoite surface protein 1 among Plasmodium knowlesi isolates from Selangor and Sabah Borneo, Malaysia

Yap

Goh

Koehler

et al. 2017

Infection, Genetics and Evolution

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Plasmodium knowlesi, a malaria parasite of macaques, has emerged as an important parasite of humans. Despite the significance of P. knowlesi malaria in parts of Southeast Asia, very little is known about the genetic variation in this parasite. Our aim here was to explore sequence variation in a molecule called the 42kDa merozoite surface protein-1 (MSP-1), which is found on the surface of blood stages of Plasmodium spp. and plays a key role in erythrocyte invasion. Several studies of P. falciparum have reported that the C-terminus (a 42kDa fragment) of merozoite surface protein-1 (MSP-1; consisting of MSP-1 and MSP-1) is a potential candidate for a malaria vaccine. However, to date, no study has yet investigated the sequence diversity of the gene encoding P. knowlesi MSP-1 (comprising Pk-msp-1 and Pk-msp-1) among isolates in Malaysia. The present study explored this aspect. Twelve P. knowlesi isolates were collected from patients from hospitals in Selangor and Sabah Borneo, Malaysia, between 2012 and 2014. The Pk-msp-1 gene was amplified by PCR and directly sequenced. Haplotype diversity (Hd) and nucleotide diversity (л) were studied among the isolates. There was relatively high genetic variation among P. knowlesi isolates; overall Hd and л were 1±0.034 and 0.01132±0.00124, respectively. A total of nine different haplotypes related to amino acid alterations at 13 positions, and the Pk-MSP-1 sequence was found to be more conserved than Pk-msp-1. We have found evidence for negative selection in Pk-msp- as well as the 33kDa and 19kDa fragments by comparing the rate of non-synonymous versus synonymous substitutions. Future investigations should study large numbers of samples from disparate geographical locations to critically assess whether this molecule might be a potential vaccine target for P. knowlesi.

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High Incidence of Plasmodium knowlesi Infection in the Interior Division of Sabah, Malaysian Borneo

Cited by 7 publications

References 20 publications

Increased detection of Plasmodium knowlesi in Sandakan division, Sabah as revealed by PlasmoNex™

Increased detection of Plasmodium knowlesi in Sandakan division, Sabah as revealed by PlasmoNex™

Centenary celebrations article

Genetic diversity in the C-terminus of merozoite surface protein 1 among Plasmodium knowlesi isolates from Selangor and Sabah Borneo, Malaysia

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