Kapit Division Research Articles

Spatio-temporal distribution and hotspots of Plasmodium knowlesi infections in Sarawak, Malaysian Borneo

Plasmodium knowlesi infections in Malaysia are a new threat to public health and to the national efforts on malaria elimination. In the Kapit division of Sarawak, Malaysian Borneo, two divergent P. knowlesi subpopulations (termed Cluster 1 and Cluster 2) infect humans and are associated with long-tailed macaque and pig-tailed macaque hosts, respectively. It has been suggested that forest-associated activities and environmental modifications trigger the increasing number of knowlesi malaria cases. Since there is a steady increase of P. knowlesi infections over the past decades in Sarawak, particularly in the Kapit division, we aimed to identify hotspots of knowlesi malaria cases and their association with forest activities at a geographical scale using the Geographic Information System (GIS) tool. A total of 1064 P. knowlesi infections from 2014 to 2019 in the Kapit and Song districts of the Kapit division were studied. Overall demographic data showed that males and those aged between 18 and 64 years old were the most frequently infected (64%), and 35% of infections involved farming activities. Thirty-nine percent of Cluster 1 infections were mainly related to farming surrounding residential areas while 40% of Cluster 2 infections were associated with activities in the deep forest. Average Nearest Neighbour (ANN) analysis showed that humans infected with both P. knowlesi subpopulations exhibited a clustering distribution pattern of infection. The Kernel Density Analysis (KDA) indicated that the hotspot of infections surrounding Kapit and Song towns were classified as high-risk areas for zoonotic malaria transmission. This study provides useful information for staff of the Sarawak State Vector-Borne Disease Control Programme in their efforts to control and prevent zoonotic malaria.

Macaca fascicularis and Macaca nemestrina infected with zoonotic malaria parasites are widely distributed in Sarawak, Malaysian Borneo

Human infections with Plasmodium knowlesi, a malaria parasite of Macaca fascicularis and Macaca nemestrina (long-tailed and pig-tailed macaques respectively), occur throughout Southeast Asia, especially Malaysian Borneo. Other naturally-acquired human infections with malaria parasites from macaques in Southeast Asia are P. cynomolgi, P. inui-like, P. coatneyi and P. simiovale. In Sarawak, Malaysian Borneo, M. fascicularis and M. nemestrina from only the Kapit Division have been examined previously for malaria parasites. In order to determine the distribution of P. knowlesi and other zoonotic malaria parasites, 73 macaque blood samples derived from 7 other administrative divisions in Sarawak were studied. Of 45 blood samples from M. fascicularis and 28 from M. nemestrina tested by nested PCR assays, 23 (51.1%) M. fascicularis and 15 (53.6%) M. nemestrina samples were positive for Plasmodium DNA. Thirty-two of these macaques from 7 divisions sampled, harboured either single (n = 12), double (n = 9), triple (n = 7) or quadruple (n = 4) infections of P. knowlesi, P. inui, P. cynomolgi and P. coatneyi, while the infecting species of Plasmodium could not be identified for 6 samples. P. knowlesi was detected in 15.5% (7/45) M. fascicularis and in 7.1% (2/28) M. nemestrina sampled. Despite the small number of samples analysed from each administrative division, the current study indicates that macaques infected with the zoonotic malaria parasites P. knowlesi, P. cynomolgi, P. inui and P. coatneyi are widely distributed throughout Sarawak, Malaysian Borneo. Travelers to forested areas in Sarawak should be made aware of the potential risk of acquiring zoonotic malaria.

PERSEPSI GURU TERHADAP PEMBELAJARAN SAMBIL BERMAIN MENGGUNAKAN GAJET DI PRASEKOLAH

Ministry of Education in Malaysia has urged the implementation of 21st-century learning starting from 2014 to fulfil the needs of education in Malaysia. The use of gadgets in learning is normal in this century but to some rural schools in Malaysia. This study was conducted to identify the teachers’ perception towards play-based learning using gadgets in rural preschool in the Kapit Division of Sarawak. This study focused on 3 important aspects which are the usage of gadgets and their effects in teaching and learning, and the challenges faced by the preschool teachers in using gadgets during their teaching and learning process. The samples of this descriptive research involved 40 teachers from Song and Kapit districts in Sarawak. The research instrument used for this study was a structured questionnaire which consisted of 10 items using five points Likert scale. The reliability coefficient value of Alpha Cronbach is 0.65. The data was analysed using SPSS to get the frequency and percentage values. It showed that preschool teachers have positive perceptions towards play-based learning using gadgets in preschools. Despite that, using gadgets in play-based learning has some cons such as students’ unfamiliarity with using gadgets and poor internet coverage in rural areas. This study enables preschool teachers to vary their teaching methods and approaches to ensure their students have an equal education as those who are in the urban area.

A review of Megalogomphus sumatranus (Krüger, 1899) and its allies in Sundaland with a description of a new species from Borneo (Odonata: Anisoptera: Gomphidae).

Megalogomphus sumatranus (Krüger, 1899) and its allies in Sundaland are reviewed. The accessory genitalia of the males of this genus, hardly considered previously, are found to be taxonomically informative. The taxon from Borneo previously treated as M. sumatranus is described from both sexes as M. buddi sp. nov. (holotype ♂ Sungai Datai, Nanga Bloh, Lanjak Entimau Wildlife Sanctuary, Kapit Division, Sarawak, Malaysia, 22 viii 2013, leg. J. anak Awan M. anak Adau; deposited at the Naturalis Biodiversity Center, Leiden, the Netherlands). Megalogomphus borneensis (Laidlaw, 1914), described as a subspecies of M. icterops (Martin, 1903) and subsequently relegated to the synonymy of that species, is considered to be a distinct species. Megalogomphus icterops is however considered to be a junior synonym of M. sumatranus. A re-description of the holotype of Megalogomphus borneensis is provided as is the first description of the female. Descriptive notes with illustrations of Megalogomphus sumatranus are given.

Naturally Acquired Human Plasmodium cynomolgi and P. knowlesi Infections, Malaysian Borneo

To monitor the incidence of Plasmodium knowlesi infections and determine whether other simian malaria parasites are being transmitted to humans, we examined 1,047 blood samples from patients with malaria at Kapit Hospital in Kapit, Malaysia, during June 24, 2013–December 31, 2017. Using nested PCR assays, we found 845 (80.6%) patients had either P. knowlesi monoinfection (n = 815) or co-infection with other Plasmodium species (n = 30). We noted the annual number of these zoonotic infections increased greatly in 2017 (n = 284). We identified 6 patients, 17–65 years of age, with P. cynomolgi and P. knowlesi co-infections, confirmed by phylogenetic analyses of the Plasmodium cytochrome c oxidase subunit 1 gene sequences. P. knowlesi continues to be a public health concern in the Kapit Division of Sarawak, Malaysian Borneo. In addition, another simian malaria parasite, P. cynomolgi, also is an emerging cause of malaria in humans.

Efficient Surveillance of Plasmodium knowlesi Genetic Subpopulations, Malaysian Borneo, 2000-2018.

Population genetic analysis revealed that Plasmodium knowlesi infections in Malaysian Borneo are caused by 2 divergent parasites associated with long-tailed (cluster 1) and pig-tailed (cluster 2) macaques. Because the transmission ecology is likely to differ for each macaque species, we developed a simple genotyping PCR to efficiently distinguish between and survey the 2 parasite subpopulations. This assay confirmed differences in the relative proportions in areas of Kapit division of Sarawak state, consistent with multilocus microsatellite analyses. Analyses of 1,204 human infections at Kapit Hospital showed that cluster 1 caused approximately two thirds of cases with no significant temporal changes from 2000 to 2018. We observed an apparent increase in overall numbers in the most recent 2 years studied, driven mainly by increased cluster 1 parasite infections. Continued monitoring of the frequency of different parasite subpopulations and correlation with environmental alterations are necessary to determine whether the epidemiology will change substantially.

Human Plasmodium knowlesi infections in South-East Asian countries.

Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east Malaysia where two Malaysian states namely Sabah and Sarawak are situated. In 2004, Polymerase Chain Reaction (PCR) was applied for diagnosing knowlesi malaria in the Kapit Division of Sarawak, Malaysia, so that human P. knowlesi infections could be detected correctly while blood film microscopy diagnosed incorrectly as Plasmodium malariae. This parasite is transmitted from simian hosts to humans via Anopheles vectors. Indonesia is the another country in South East Asia where knowlesi malaria is moderately prevalent. In the last decade, Sarawak and Sabah, the two states of east Malaysia became the target of P. knowlesi research due to prevalence of cases with occasional fatal infections. The host species of P. knowlesi are three macaque species namely Macaca fascicularis, Macaca nemestrina and Macaca leonina while the vector species are the Leucosphyrus Complex and the Dirus Complex of the Leucophyrus Group of Anopheles mosquitoes. Rapid diagnostic tests (RDT) are non-existent for knowlesi malaria although timely treatment is necessary for preventing complications, fatality and drug resistance. Development of RDT is essential in dealing with P. knowlesi infections in poor rural healthcare services. Genetic studies of the parasite on possibility of human-to-human transmission of P. knowlesi were recommended for further studies.

Macroinvertebrates of the Tributaries of Upper Baleh River, Sarawak

Studies on Baleh River with respect to aquatic fauna currently remains limited. Hence, this paper presents thespecies richness and composition of macroinvertebrates14 tributaries of Upper Baleh River in Kapit Division,Sarawak. A total of 1,154 individuals from 10 orders, 43 families and 66 genera of macroinvertebrates werecollected. The highest number of macroinvertebrate was taken from Naah River (201 individuals) and the leastfrom Ukit River (15 individuals). The order Ephemeroptera was the most abundant, with 45% of the totalindividuals caught, followed by Trichoptera (23%), Hemiptera (10%), and Coleoptera (9%). Three biologicalindices were used to measure the diversity of macroinvertebrate of which the values of the indices were low:Shannon diversity index (1.54–2.54), Shannon evenness index (0.33–0.89) and Margalef richness index (1.67–4.90). The composition of functional feeding groups varies between first and fourth order streams, which ispossibly an indication of ecological effects of siltation due to logging activities in the area.

Evidence of asymptomatic submicroscopic malaria in low transmission areas in Belaga district, Kapit division, Sarawak, Malaysia

BackgroundMalaysia has declared its aim to eliminate malaria with a goal of achieving zero local transmission by the year 2020. However, targeting the human reservoir of infection, including those with asymptomatic infection is required to achieve malaria elimination. Diagnosing asymptomatic malaria is not as straightforward due to the obvious lack of clinical manifestations and often subpatent level of parasites. Accurate diagnosis of malaria is important for providing realistic estimates of malaria burden and preventing misinformed interventions. Low levels of parasitaemia acts as silent reservoir of transmission thus remains infectious to susceptible mosquito vectors. Hence, the aim of this study is to investigate the prevalence of asymptomatic submicroscopic malaria (SMM) in the District of Belaga, Sarawak.MethodsIn 2013, a total of 1744 dried blood spots (DBS) were obtained from residents of 8 longhouses who appeared healthy. Subsequently, 251 venous blood samples were collected from residents of 2 localities in 2014 based on the highest number of submicroscopic cases from prior findings. Thin and thick blood films were prepared from blood obtained from all participants in this study. Microscopic examination were carried out on all samples and a nested and nested multiplex PCR were performed on samples collected in 2013 and 2014 respectively.ResultsNo malaria parasites were detected in all the Giemsa-stained blood films. However, of the 1744 samples, 29 (1.7%) were positive for Plasmodium vivax by PCR. Additionally, of the 251 samples, the most prevalent mono-infection detected by PCR was Plasmodium falciparum 50 (20%), followed by P. vivax 39 (16%), P. knowlesi 9 (4%), and mixed infections 20 (8%).ConclusionsThis research findings conclude evidence of Plasmodium by PCR, among samples previously undetectable by routine blood film microscopic examination, in local ethnic minority who are clinically healthy. SMM in Belaga district is attributed not only to P. vivax, but also to P. falciparum and P. knowlesi. In complementing efforts of programme managers, there is a need to increase surveillance for SMM nationwide to estimate the degree of SMM that warrant measures to block new transmission of malaria.

Serological Prevalence of Leptospirosis Among Rural Communities in the Rejang Basin, Sarawak, Malaysia.

Leptospirosis is an important zoonotic disease globally and is endemic in Malaysia. A study was conducted in the Rejang basin of Sarawak from June 2011 to May 2013 to determine the seroprevalence of leptospirosis among the communities and dominant infecting Leptospira serovars. A total of 508 human sera were analyzed using ELISA and the microscopic agglutination test (MAT). The seroprevalence of leptospirosis in the study area was 37.4%, with the highest prevalence in Kapit division. More women were positive for leptospirosis (59.5%), and the mean age of seropositive individuals was 42.2 (SD = 18.7) years. Antibody titers between 1:50 and 1:1600 were reported, and serovars djasiman (22.1%), shermani (13.2%), and pomona (7.9%) predominated, with varied distribution between geographical locations. This study highlighted the endemicity and diversity of existing Leptospira serovars within the community. This information should be communicated to local health personnel and communities at risk, and rapid diagnostic capability should be made available to local health facilities.

Revision of the genus Devadatta Kirby, 1890 in Borneo based on molecular and morphological methods, with descriptions of four new species(Odonata: Zygoptera: Devadattidae).

Species of Devadatta from Borneo are studied using both morphological and molecular methods. As well as D. podolestoides Laidlaw, four new species are recognised from the island: D. aran spec. nov. (holotype ♂, from Pulong Tau National Park, Miri division, Sarawak, Malaysia, deposited in RMNH), D. clavicauda spec. nov. (holotype ♂, from Bukit Mina, Bukit Mina Wildlife Corridor, Sarawak Planted Forest Project, Bintulu division, Sarawak, Malaysia, deposited in RMNH), D. somoh spec. nov. (holotype ♂, from the Sungai Kahei area, Ulu Balui, Kapit division, Sarawak, Malaysia, deposited in RMNH) and D. tanduk spec. nov. (holotype ♂, from Poring Hot Springs, Kinabalu National Park, West Coast division, Sabah, Malaysia, deposited in RMNH). The Philippine taxon D. basilanensis Laidlaw is considered a good species rather than a subspecies of D. podolestoides. The Bornean species plus D. basilanensis are provisionally considered to form a species group, the podolestoides-group, within Devadatta. The species of the podolestoides-group are so similar in morphology and colouration that they are close to truly cryptic species. Two species appear to exhibit character displacement where their ranges overlap with other Devadatta species. A molecular analysis using four markers (COI, 16S, ITS and 28S) is presented. This analysis includes specimens of all species from the podolestoides-group and two Devadatta species from mainland Asia.

Chlorogomphus manausp. nov. from Sarawak, Malaysia (Odonata: Chlorogomphidae)

Chlorogomphus manau sp. nov. (holotype ♂: Borneo, Sarawak, Kapit Division, Hose Mountains, 15 April 2011, RMNH) from Malaysia is described from the male and compared with other regional Chlorogomphus species.

Plasmodium knowlesi: Reservoir Hosts and Tracking the Emergence in Humans and Macaques

Plasmodium knowlesi, a malaria parasite originally thought to be restricted to macaques in Southeast Asia, has recently been recognized as a significant cause of human malaria. Unlike the benign and morphologically similar P. malariae, these parasites can lead to fatal infections. Malaria parasites, including P. knowlesi, have not yet been detected in macaques of the Kapit Division of Malaysian Borneo, where the majority of human knowlesi malaria cases have been reported. In order to extend our understanding of the epidemiology and evolutionary history of P. knowlesi, we examined 108 wild macaques for malaria parasites and sequenced the circumsporozoite protein (csp) gene and mitochondrial (mt) DNA of P. knowlesi isolates derived from macaques and humans. We detected five species of Plasmodium (P. knowlesi, P. inui, P. cynomolgi, P. fieldi and P. coatneyi) in the long-tailed and pig-tailed macaques, and an extremely high prevalence of P. inui and P. knowlesi. Macaques had a higher number of P. knowlesi genotypes per infection than humans, and some diverse alleles of the P. knowlesi csp gene and certain mtDNA haplotypes were shared between both hosts. Analyses of DNA sequence data indicate that there are no mtDNA lineages associated exclusively with either host. Furthermore, our analyses of the mtDNA data reveal that P. knowlesi is derived from an ancestral parasite population that existed prior to human settlement in Southeast Asia, and underwent significant population expansion approximately 30,000–40,000 years ago. Our results indicate that human infections with P. knowlesi are not newly emergent in Southeast Asia and that knowlesi malaria is primarily a zoonosis with wild macaques as the reservoir hosts. However, ongoing ecological changes resulting from deforestation, with an associated increase in the human population, could enable this pathogenic species of Plasmodium to switch to humans as the preferred host.

Two new Platystictidae (Odonata: Zygoptera) from Sarawak, Malaysian Borneo

Two new members of the Platystictidae are described from Sarawak: Drepanosticta sbong, holotype male: Malaysia, Sarawak, Kapit division, Sungai Sbong, 11–II–2008; and Protosticta tubau, holotype male: Malaysia, Sarawak, Bintulu division, Planted Forest Zone, Tubau area, block E2K, 16–VIII–2009; both to be deposited in the RMNH Leiden, The Netherlands.

Bionomics of Anopheles latens in Kapit, Sarawak, Malaysian Borneo in relation to the transmission of zoonotic simian malaria parasite Plasmodium knowlesi

BackgroundA large focus of human infections with Plasmodium knowlesi, a simian parasite naturally found in long-tailed and pig-tailed macaques was discovered in the Kapit Division of Sarawak, Malaysian Borneo. A study was initiated to identify the vectors of malaria, to elucidate where transmission is taking place and to understand the bionomics of the vectors in Kapit.MethodsThree different ecological sites in the forest, farm and longhouse in the Kapit district were selected for the study. Mosquitoes were collected by human landing collection at all sites and at the forest also by monkey-baited-traps situated on three different levels. All mosquitoes were identified and salivary glands and midguts of anopheline mosquitoes were dissected to determine the presence of malaria parasites.Results and DiscussionsOver an 11-month period, a total of 2,504 Anopheles mosquitoes comprising 12 species were caught; 1,035 at the farm, 774 at the forest and 425 at the longhouse. Anopheles latens (62.3%) and Anopheles watsonii (30.6%) were the predominant species caught in the forested ecotypes, while in the farm Anopheles donaldi (49.9%) and An. latens (35.6%) predominated. In the long house, An. latens (29.6%) and An. donaldi (22.8%) were the major Anopheline species. However, An. latens was the only mosquito positive for sporozoites and it was found to be attracted to both human and monkey hosts. In monkey-baited net traps, it preferred to bite monkeys at the canopy level than at ground level. An. latens was found biting early as 18.00 hours.ConclusionAnopheles latens is the main vector for P. knowlesi malaria parasites in the Kapit District of Sarawak, Malaysian Borneo. The study underscores the relationship between ecology, abundance and bionomics of anopheline fauna. The simio-anthropophagic and acrodendrophilic behaviour of An. latens makes it an efficient vector for the transmission of P. knowlesi parasites to both human and monkey hosts.

Is a Monkey Malaria from Borneo an Emerging Human Disease?

In 2004, a team of researchers from Malaysia surprised the medical community by reporting that a significant number of people on the island of Borneo were becoming infected with a malaria parasite of monkeys, Plasmodium knowlesi [1]. The world was still unaware of the extent of the problem until 2008 when the same research group gave us a clear view of the gravity of the situation [2]. They found that P. knowlesi infections accounted for 71% of the cases of malaria in one regional hospital. Of even more concern, the team has shown that this form of malaria is potentially life threatening. The medical community is now asking whether P. knowlesi is a ‘fifth human malaria’ with the potential to spread to other parts of Southeast Asia and beyond. Many species of malaria parasite that naturally infect monkeys will also develop in humans. As early as the 1930s, human infections by monkey malarias were studied under controlled conditions in a number of laboratories, including extensive studies carried out in the USA and Romania. These studies showed that although the infections were not initially life threatening, they became increasingly virulent when cycled through humans in the absence of an intermediate passage through mosquitoes [William C, Pers. Comm] [3]. The virulence associated with the Malaysian infections raises the possibility that a new and more virulent strain of P. knowlesi is involved as well as the possibility that, in the cases of more virulent infection, some means of parasite transmission other than that initiated by the bite of an infected mosquito is playing a role. First reported in the Lancet in 2004, Singh and collaborators described their investigation of 208 cases of malaria from the Kapit division of Malaysian Borneo [1]. Their interest had arisen because of the severity of the disease in patients that had been diagnosed as being infected with Plasmodium malariae, which causes a relatively benign form of human malaria. They found that over half of these cases were the result of infection with a monkey malaria, P. knowlesi. In 2008, the group published the results of a more extensive study on the distribution of human infection by P. knowlesi in Sarawak and Sabah in Borneo and Pahang peninsular Malaysia. They demonstrated that these infections are occurring in significant numbers in many of the district hospitals. Furthermore, their investigation of four deaths in the region indicated high levels of infection with P. knowlesi and hepatorenal dysfunction, which is often associated with high parasitemias. This suggested that infection with P. knowlesi is potentially life threatening. Singh, Cox-Singh and Conway now proceed with their ground-breaking research on several fronts, including epidemiological studies to unravel the complicated story of how this emerging disease is being transmitted and further investigation of fatalities in the region to determine the extent to which the threat presents to the people of their region.

A large focus of naturally acquired Plasmodium knowlesi infections in human beings

About a fifth of malaria cases in 1999 for the Kapit division of Malaysian Borneo had routinely been identified by microscopy as Plasmodium malariae, although these infections appeared atypical and a nested PCR assay failed to identify P malariae DNA. We aimed to investigate whether such infections could be attributable to a variant form of P malariae or a newly emergent Plasmodium species. We took blood samples from 208 people with malaria in the Kapit division between March, 2000, and November, 2002. The small subunit ribosomal RNA and the circumsporozoite protein genes were sequenced for eight isolates that had been microscopically identified as P malariae. All blood samples were characterised with a genus-specific and species-specific nested PCR assay together with newly designed P knowlesi-specific primers. All DNA sequences were phylogenetically indistinguishable from those of P knowlesi, a malaria parasite of long-tailed macaque monkeys, but were significantly different from other malaria parasite species. By PCR assay, 120 (58%) of 208 people with malaria tested positive for P knowlesi, whereas none was positive for P malariae. P knowlesi parasites in human erythrocytes were difficult to distinguish from P malariae by microscopy. Most of the P knowlesi infections were in adults and we did not note any clustering of cases within communities. P knowlesi infections were successfully treated with chloroquine and primaquine. Naturally acquired P knowlesi infections, misdiagnosed by microscopy mainly as P malariae, accounted for over half of all malaria cases in our study. Morphological similarities between P knowlesi and P malariae necessitate the use of molecular methods for correct identification. Further work is needed to determine whether human P knowlesi infections in the Kapit division are acquired from macaque monkeys or whether a host switch to human beings has occurred.

Constraints to Rural Community Involvement and “Success” in Non‐agricultural Activities: Some Evidence from Sarawak, Malaysia

The Iban are the largest ethnic group in Sarawak. This paper analyses their participation in one of the most common forms of rural non‐agricultural activities in Sarawak, namely commercial handicraft production (CHP). Traditionally, the Iban produce handicrafts for personal use. With the introduction of the Iban to the cash economy, the presence of demand for their handicrafts, and the growing insecurities in the rural economy one would expect Iban craftspersons to participate actively in RNAE and produce handicrafts for commercial purposes. Some Iban craftspersons have taken up CHP, while others have not. Some have achieved economic “success” while others have failed. This suggests that there are different responses to, and impact of non‐agricultural activities (particularly CHP) on the Iban in rural Sarawak. This paper addresses the following key questions: What are the factors preventing rural communities from taking up and/or succeeding in RNAE, particularly commercial handicraft production? Is it due to the lack of willingness among Iban craftspersons to participate in commercial activities? Is it due to limited access to market and institutional support? This paper is based on a survey conducted on 200 Iban craftspersons from eleven longhouses in Kapit Division, Sarawak between 1993 until 1996