Displaying publications 41 - 60 of 201 in total

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  1. Zamiri R, Abbastabar Ahangar H, Zakaria A, Zamiri G, Shabani M, Singh B, et al.
    Chem Cent J, 2015;9:28.
    PMID: 26089982 DOI: 10.1186/s13065-015-0099-y
    In this paper a template-free precipitation method was used as an easy and low cost way to synthesize Ag2S semiconductor nanoparticles. The Kramers-Kronig method (K-K) and classical dispersion theory was applied to calculate the optical constants of the prepared samples, such as the reflective index n(ω) and dielectric constant ε(ω) in Far-infrared regime.
  2. Menon BS, Abdullah S, Mahamud F, Morgan UM, Malik AS, Choo KE, et al.
    PMID: 11556583
    The aim of this prospective study was to determine the prevalence of Cryptosporidium parvum in hospitalized children in Kota Bharu, Malaysia. Over a 19 month study period, 258 stool samples were examined from 159 children; 109 with diarrhea and 50 controls without diarrhea. Modified Ziehl-Neelsen staining method and a polymerase chain reaction (PCR) assay were used to detect C. parvum and the samples were also examined for the presence of other intestinal parasites. Only 1 of the 109 (0.9%) children with acute diarrhea was positive for C. parvum by microscopy and PCR. Thirty-one percent of children were infested with other intestinal parasites, the most common being Ascaris lumbricoides and Trichuris trichiura. In conclusion, we found C. parvum to be an uncommon infective agent in hospitalized children with or without diarrhea in Kota Bharu, Malaysia.
  3. Othman SS, Abdul Kadir K, Hassan J, Hong GK, Singh BB, Raman N
    Aust N Z J Psychiatry, 1994 Dec;28(4):620-4.
    PMID: 7794205
    The thyroid status of 249 patients with chronic schizophrenia (males = 136, females = 113) with a median age of 36 years (range: 16 to 58 years) and a median duration of hospitalisation of 10 years (range: 1 to 30 years) was assessed. Thyroid antibodies (TAb) were found in 51 patients (20%). In female patients, 32 (28%) were TAb positive compared to 13% (n = 152, p = 0.01) in healthy female blood donors. In male patients, the prevalence of TAb was 14% compared to 7% (n = 449, p = 0.01) in healthy male blood donors. Of the 183 patients who had thyroid hormone measurements, 60% had normal test, 5% had elevated TSH and 17% had low TSH. The T4, FT41 and FT31 were significantly lower in those with low or high TSH (p < 0.001) compared to those with normal TSH. Of the 143 patients with normal TSH, 33 (23%) had low T3. In conclusion, there is a spectrum of thyroid function test abnormalities in chronic schizophrenia; this may be related to an abnormality in the central regulation of the hypothalamo-pituitary thyroid axis as well as at the peripheral level. However the association between chronic schizophrenia and the presence of thyroid antibodies, and the clinical relevance of these biochemical abnormalities, are still not clear.
  4. Singh B, Cox-Singh J, Miller AO, Abdullah MS, Snounou G, Rahman HA
    Trans R Soc Trop Med Hyg, 1996 9 1;90(5):519-21.
    PMID: 8944260
    A modified nested polymerase chain reaction (PCR) method for detection of Plasmodium falciparum, P. vivax and P. malariae was combined with a simple blood collection and deoxyribonucleic acid (DNA) extraction method and evaluated in Malaysia. Finger-prick blood samples from 46 hospital patients and 120 individuals living in malaria endemic areas were spotted on filter papers and dried. The simple Chelex method was used to prepare DNA templates for the nested PCR assay. Higher malaria prevalence rates for both clinical (78.2%) and field samples (30.8%) were obtained with the nested PCR method than by microscopy (76.1% and 27.5%, respectively). Nested PCR was more sensitive than microscopy in detecting mixed P. falciparum and P. vivax infections, detected 5 more malaria samples than microscopy on the first round of microscopical examination, and detected malaria in 3 microscopically negative samples. Nested PCR failed to detect parasite DNA in 2 microscopically positive samples, an overall sensitivity of 97.4% compared to microscopy. The nested PCR method, when coupled with simple dried blood spot sampling, is a useful tool for collecting accurate malaria epidemiological data, particularly in remote regions of the world.
  5. Divis PCS, Duffy CW, Kadir KA, Singh B, Conway DJ
    Mol Ecol, 2018 02;27(4):860-870.
    PMID: 29292549 DOI: 10.1111/mec.14477
    Plasmodium knowlesi is a significant cause of human malaria transmitted as a zoonosis from macaque reservoir hosts in South-East Asia. Microsatellite genotyping has indicated that human infections in Malaysian Borneo are an admixture of two highly divergent sympatric parasite subpopulations that are, respectively, associated with long-tailed macaques (Cluster 1) and pig-tailed macaques (Cluster 2). Whole-genome sequences of clinical isolates subsequently confirmed the separate clusters, although fewer of the less common Cluster 2 type were sequenced. Here, to analyse population structure and genomic divergence in subpopulation samples of comparable depth, genome sequences were generated from 21 new clinical infections identified as Cluster 2 by microsatellite analysis, yielding a cumulative sample size for this subpopulation similar to that for Cluster 1. Profound heterogeneity in the level of intercluster divergence was distributed across the genome, with long contiguous chromosomal blocks having high or low divergence. Different mitochondrial genome clades were associated with the two major subpopulations, but limited exchange of haplotypes from one to the other was evident, as was also the case for the maternally inherited apicoplast genome. These findings indicate deep divergence of the two sympatric P. knowlesi subpopulations, with introgression likely to have occurred recently. There is no evidence yet of specific adaptation at any introgressed locus, but the recombinant mosaic types offer enhanced diversity on which selection may operate in a currently changing landscape and human environment. Loci responsible for maintaining genetic isolation of the sympatric subpopulations need to be identified in the chromosomal regions showing fixed differences.
  6. Davis TM, Singh B, Choo KE, Ibrahim J, Sulaiman SA, Kadir ZA, et al.
    J Intern Med, 1998 May;243(5):349-54.
    PMID: 9651556
    OBJECTIVES: To investigate the dynamic parathyroid response to rapidly induced, sustained hypocalcaemia in patients with acute malaria and in healthy volunteers.

    DESIGN: Serum intact parathormone (PTH) concentrations were measured on samples taken before and during a variable-rate tri-sodium citrate infusion designed to 'clamp' the whole blood ionised calcium concentration 0.20 mmol L-1 below baseline for 120 min.

    SUBJECTS: Six Malaysian patients aged 17-42 years with acute malaria, four of whom were restudied in convalescence, and 12 healthy controls aged 19-36 years.

    MAIN OUTCOME MEASURES: Whole-blood ionised calcium and serum intact PTH concentrations.

    RESULTS: The mean (SD baseline ionised calcium was lower in the malaria patients than in controls (1.09 +/- 0.06 vs. 1.18 +/- 0.03 mmol L-1, respectively; P = 0.01) but PTH concentrations were similar (3.0 +/- 1.8 vs. 3.3 +/- 1.3 pmol L(-1); P = 0.33). Target whole-blood ionised calcium concentrations were achieved more rapidly in the controls than the patients (within 15 vs. 30 min) despite significantly more citrate being required in the patients (area under the citrate infusion-time curve 0.95 (0.25 vs. 0.57 +/- 0.09 mmol kg-1; P < 0.01). The ratio of the change in serum PTH to that in ionised calcium (delta PTH/ delta Ca2+), calculated to adjust for differences in initial rate of fall of ionised calcium, was similar during the first 5 min of the clamp (132 +/- 75 x 10(-6) vs. 131 +/- 43 x 10(-6) in patients and controls, respectively, P > 0.05), as were steady-state serum PTH levels during the second hour (7.0 +/- 2.2 pmol L-1 in each case). Convalescent patients had normal basal ionised calcium levels but the lowest serum intact PTH levels before and during the clamp, consistent with an increase in skeletal PTH sensitivity after treatment.

    CONCLUSIONS: There is a decreased ionised calcium 'set point' for basal PTH secretion but a normal PTH response to acute hypocalcaemia in malaria. Skeletal resistance may attenuate the effects of the PTH response but patients with malaria appear relatively resistant to the calcium chelating effects of citrated blood products.

  7. Sachdev Manjit Singh B, Wan SA, Cheong YK, Chuah SL, Teh CL, Jobli AT
    J Med Case Rep, 2021 Feb 23;15(1):94.
    PMID: 33618728 DOI: 10.1186/s13256-020-02642-z
    BACKGROUND: Arthritis is rarely reported as a paraneoplastic manifestation of occult malignancy. We report herein two cases of paraneoplastic arthritis due to occult malignancy. CASE 1: The patient was a 65-year-old woman of asian descent who was a former smoker with a history of spine surgery performed for L4/L5 degenerative disc disease. She presented with a 1-month history of oligoarthritis affecting both ankle joints and early morning stiffness of about 3 hours. Laboratory tests were positive for antinuclear antibody at a titer of 1:320 (speckled) but negative for rheumatoid factor. She was treated for seronegative spondyloarthritis and started on prednisolone without much improvement. A routine chest radiograph incidentally revealed a right lung mass which was found to be adenocarcinoma of the lung. She was treated with gefitinib and her arthritis resolved. CASE 2: The patient was a 64-year-old woman of asian descent, nonsmoker, who presented with a chief complaint of asymmetrical polyarthritis involving her right wrist, second and third metacarpophalangeal joints, and first to fifth proximal interphalangeal joints. She was treated for seronegative rheumatoid arthritis (RA) and started on sulfasalazine, with poor clinical response. Six months later, she developed abdominal pain which was diagnosed as ovarian carcinoma by laparotomy. Her arthritis resolved following treatment of her malignancy with chemotherapy.

    CONCLUSION: In summary, paraneoplastic arthritis usually presents in an atypical manner and responds poorly to disease-modifying antirheumatic drugs. Accordingly, we recommend screening for occult malignancy in patients presenting with atypical arthritis.

  8. Cox-Singh J, Lu HY, Davis TM, Ilett KF, Hackett LP, Matusop A, et al.
    Int J Parasitol, 2003 Nov;33(13):1545-52.
    PMID: 14572517
    Thirty-two patients reporting to the Lundu District Hospital, Sarawak, Malaysian Borneo, with uncomplicated falciparum malaria were recruited into a multifaceted study to assess treatment response. Following combined chloroquine and sulphadoxine/pyrimethamine treatment the patients were followed for 28 days according to the World Health Organisation in vivo drug response protocol. The in vivo study revealed that 13 (41%) of the patients had a sensitive response to treatment, five (16%) cleared asexual stage parasites but had persistent gametocytes, 11 (34%) had RI type resistance and three (9%) had RII type resistance requiring quinine intervention before day 7 for parasite clearance. Although clinically insignificant, patients with persistent gametocytes, surviving chloroquine and sulphadoxine/pyrimethamine treatment during maturation, were placed in the reduced response to treatment group for analysis. Allelic typing detected 100% prevalence of the pfcrt K76T marker associated with chloroquine resistance and 78% prevalence of the pfdhfr NRNL haplotype associated with sulphadoxine/pyrimethamine treatment failure. High serum chloroquine levels and pfdhfr haplotypes with
  9. Cox-Singh J, Pomrehn AS, Wolfe ND, Rahman HA, Lu HY, Singh B
    Int J Parasitol, 2000 Oct;30(11):1177-9.
    PMID: 11027784
    The blood filtration method was used as the gold standard to determine the detection level of simple blood-spot sampling and nested-polymerase chain reaction (PCR) for Brugia malayi. Of 100 samples, 48 were filtration-positive. Of these, 26 had microfilaria counts that were low enough (<1-29 microfilariae/ml) to accurately assess the limit of detection by nested-PCR. Nested-PCR consistently detected B. malayi DNA in samples with > or = 10 microfilariae/ml. Post-filtration, microfilaria-depleted, blood-spots from microfilaria-positive samples were screened by nested-PCR and B. malayi specific 'free' DNA was detected in 51.7% of these samples. There was no evidence for 'free' DNA in microfilaria-negative individuals from this endemic community.
  10. Cox-Singh J, Pomrehn AS, Rahman HA, Zakaria R, Miller AO, Singh B
    Int J Parasitol, 1999 May;29(5):717-21.
    PMID: 10404266
    In the absence of a suitable Brugia malayi antigen detection assay, PCR remains one of the more sensitive alternatives to Giemsa-stained thick blood films for B. malayi detection. The need for refrigerated storage and transportation of blood has limited the use of PCR for large-scale epidemiology studies in remote endemic areas. Here we report simple finger-prick blood-spot collection, a one-tube DNA template extraction method and the development of a B. malayi-specific nested PCR assay. The assay was tested on 145 field samples and was positive for all 30 microscopy-positive samples and for an additional 13 samples which were microscopy-negative.
  11. Gamalo LE, Dimalibot J, Kadir KA, Singh B, Paller VG
    Malar J, 2019 Apr 24;18(1):147.
    PMID: 31014342 DOI: 10.1186/s12936-019-2780-4
    BACKGROUND: Macaca fascicularis (long-tailed macaque) is the most widespread species of macaque in Southeast Asia and the only species of monkey found naturally in the Philippines. The species is the natural host for the zoonotic malaria species, Plasmodium knowlesi and Plasmodium cynomolgi and for the potentially zoonotic species, Plasmodium inui. Moreover, other Plasmodium species such as Plasmodium coatneyi and Plasmodium fieldi are also natural parasites of M. fascicularis. The aims of this study were to identify and determine the prevalence of Plasmodium species infecting wild and captive long-tailed macaques from the Philippines.

    METHODS: A total of 95 blood samples from long-tailed macaques in the Philippines were collected from three locations; 30 were from captive macaques at the National Wildlife Rescue and Rehabilitation Center (NWRRC) in Luzon, 25 were from captive macaques at the Palawan Wildlife Rescue and Conservation Center (PWRCC) in Palawan and 40 were from wild macaques from Puerto Princesa Subterranean River National Park (PPSRNP) in Palawan. The Plasmodium spp. infecting the macaques were identified using nested PCR assays on DNA extracted from these blood samples.

    RESULTS: All 40 of the wild macaques from PPSRNP in Palawan and 5 of 25 captive macaques from PWRCC in Palawan were Plasmodium-positive; while none of the 30 captive macaques from the NWRRC in Luzon had any malaria parasites. Overall, P. inui was the most prevalent malaria parasite (44.2%), followed by P. fieldi (41.1%), P. cynomolgi (23.2%), P. coatneyi (21.1%), and P. knowlesi (19%). Mixed species infections were also observed in 39 of the 45 Plasmodium-positive macaques. There was a significant difference in the prevalence of P. knowlesi among the troops of wild macaques from PPSRNP.

    CONCLUSION: Wild long-tailed macaques from the island of Palawan, the Philippines are infected with P. knowlesi, P. inui, P. coatneyi, P. fieldi and P. cynomolgi. The prevalence of these Plasmodium spp. varied among the sites of collection and among troops of wild macaques at one site. The presence of these simian Plasmodium parasites, especially P. knowlesi and P. cynomolgi in the long-tailed macaques in Palawan presents risks for zoonotic transmission in the area.

  12. Ang JXD, Kadir KA, Mohamad DSA, Matusop A, Divis PCS, Yaman K, et al.
    Parasit Vectors, 2020 Sep 15;13(1):472.
    PMID: 32933567 DOI: 10.1186/s13071-020-04345-2
    BACKGROUND: Plasmodium knowlesi is a significant cause of human malaria in Sarawak, Malaysian Borneo. Only one study has been previously undertaken in Sarawak to identify vectors of P. knowlesi, where Anopheles latens was incriminated as the vector in Kapit, central Sarawak. A study was therefore undertaken to identify malaria vectors in a different location in Sarawak.

    METHODS: Mosquitoes found landing on humans and resting on leaves over a 5-day period at two sites in the Lawas District of northern Sarawak were collected and identified. DNA samples extracted from salivary glands of Anopheles mosquitoes were subjected to nested PCR malaria-detection assays. The small subunit ribosomal RNA (SSU rRNA) gene of Plasmodium was sequenced, and the internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of the mosquitoes were sequenced from the Plasmodium-positive samples for phylogenetic analysis.

    RESULTS: Totals of 65 anophelines and 127 culicines were collected. By PCR, 6 An. balabacensis and 5 An. donaldi were found to have single P. knowlesi infections while 3 other An. balabacensis had either single, double or triple infections with P. inui, P. fieldi, P. cynomolgi and P. knowlesi. Phylogenetic analysis of the Plasmodium SSU rRNA gene confirmed 3 An. donaldi and 3 An. balabacensis with single P. knowlesi infections, while 3 other An. balabacensis had two or more Plasmodium species of P. inui, P. knowlesi, P. cynomolgi and some species of Plasmodium that could not be conclusively identified. Phylogenies inferred from the ITS2 and/or cox1 sequences of An. balabacensis and An. donaldi indicate that they are genetically indistinguishable from An. balabacensis and An. donaldi, respectively, found in Sabah, Malaysian Borneo.

    CONCLUSIONS: Previously An. latens was identified as the vector for P. knowlesi in Kapit, central Sarawak, Malaysian Borneo, and now An. balabacensis and An. donaldi have been incriminated as vectors for zoonotic malaria in Lawas, northern Sarawak.

  13. Conway DJ, Machado RL, Singh B, Dessert P, Mikes ZS, Povoa MM, et al.
    Mol Biochem Parasitol, 2001 Jul;115(2):145-56.
    PMID: 11420101
    Comparing patterns of genetic variation at multiple loci in the genome of a species can potentially identify loci which are under selection. The large number of polymorphic microsatellites in the malaria parasite Plasmodium falciparum are available markers to screen for selectively important loci. The Pfs48/45 gene on Chromosome 13 encodes an antigenic protein located on the surface of parasite gametes, which is a candidate for a transmission blocking vaccine. Here, genotypic data from 255 P. falciparum isolates are presented, which show that alleles and haplotypes of five single nucleotide polymorphisms (SNPs) in the Pfs48/45 gene are exceptionally skewed in frequency among different P. falciparum populations, compared with alleles at 11 microsatellite loci sampled widely from the parasite genome. Fixation indices measuring inter-population variance in allele frequencies (F(ST)) were in the order of four to seven times higher for Pfs48/45 than for the microsatellites, whether considered (i) among populations within Africa, or (ii) among different continents. Differing mutational processes at microsatellite and SNP loci could generally affect the population structure at these different types of loci, to an unknown extent which deserves further investigation. The highly contrasting population structure may also suggest divergent selection on the amino acid sequence of Pfs48/45 in different populations, which plausibly indicates a role for the protein in determining gamete recognition and compatibility.
  14. Supandi FN, Singh B, Thamutaram H, Lim KF, Yusoff AR
    Ann Hepatobiliary Pancreat Surg, 2021 Jun 30;25(Suppl 1):S388.
    PMID: 34230285 DOI: 10.14701/ahbps.EP-189
    Introduction: Pancreatic cancer has a relative 5-year survival of less than 10%. The most common neoplasm of the pancreas is ductal adenocarcinoma, which comprises 85% of all malignant pancreatic tumours. Primary pancreatic sarcomas are extremely rare which account for less than 0.1% of all pancreatic malignancies and pancreatic angiosarcomas attribute to 1% of all tissue sarcomas. Sarcomas of the pancreas are more aggressive and have a dismal prognosis.

    Methods: A 69-year-old lady presented with obstructive jaundice, abdominal discomfort and associated constitutional symptoms. She was investigated and found to have obstructive jaundice with normal tumor marker assays. An endoscopic ultrasound was done followed by a needle biopsy which confirmed a pancreatic head angiosarcoma followed by an ERCP and a stent placement. A CT abdomen done revealed a pancreatic head and uncinate tumor with a stent in the common bile duct.

    Results: Patient underwent a pylorus preserving pancreaticoduodenectomy with an uneventful post-operative recovery. She defaulted her oncology appointments and was followed up with serial imaging. She developed a local recurrence 18 months after surgery and succumbed to her disease after 3 years.

    Conclusions: Pancreatic angiosarcoma is an aggressive tumor compared to other pancreatic malignancies. For a definite diagnosis of angiosarcoma, histopathologic and immunohistochemical analysis are necessary. Surgical resection offers the only possible cure, while oncological treatment has variable outcome. Currently, there are no treatment protocols available due to the small number of cases present in literature.

  15. Jain A, Sharma G, Ghoshal G, Kesharwani P, Singh B, Shivhare US, et al.
    Int J Pharm, 2018 Jul 30;546(1-2):97-105.
    PMID: 29715533 DOI: 10.1016/j.ijpharm.2018.04.061
    The work entails a novel strategy of formulating the lycopene loaded whey protein isolate nanoparticles (LYC-WPI-NPs) solely using the rational blend of biomacromolecule without using equipment-intensive techniques. The LYC-WPI-NPs were fabricated as a substantial drug delivery platform, with maximum entrapment, spatial and controlled release manners, exceptional plasma concentration, and perspective for discrepancy delivery of therapeutics. Prepared nano-formulations were measured in ultra-fine size (100-350 nm) with sphere-shaped. The percent lycopene entrapment of prepared LYC-WPI-NPs was estimated in the range to 50 and 65%. In vitro percent cumulative release study demonstrated deaden and extended release i.e. approximately 75% following 16th h. The in vitro percent cell survival (cytotoxicity study) of prepared nanoparticles was evaluated against MCF-7 breast cancer cells by MTT based colorimetric assay. Sub-cellular localization of lycopene when delivered by LYC-WPI-NPs was assessed by HPLC (high performance liquid chromatography). The WPI-NPs enhance the oral bioavailability of lycopene by controlling its release from nano-formulation and facilitating its absorption through lymphatic pathways. Prophylactic anticancer efficacy of LYC-WPI-NPs was evaluated thereafter on experimentally induced breast cancer animal model. Conclusively, it may quite reasonable that lycopene loaded protein nanoparticles are competent to improve the biopharmaceutical attributes of lycopene and demonstrated prophylactic anticancer activity, decrease tumor proliferation and increase the survival rate of treated animals, thus signifying their feasible usefulness in cancer therapeutic and intervention.
  16. Sabatino A, Regolisti G, Karupaiah T, Sahathevan S, Sadu Singh BK, Khor BH, et al.
    Clin Nutr, 2017 06;36(3):663-671.
    PMID: 27371993 DOI: 10.1016/j.clnu.2016.06.007
    BACKGROUND & AIMS: Protein-Energy Wasting (PEW) is the depletion of protein/energy stores observed in the most advanced stages of Chronic Kidney Disease (CKD). PEW is highly prevalent among patients on chronic dialysis, and is associated with adverse clinical outcomes, high morbidity/mortality rates and increased healthcare costs. This narrative review was aimed at exploring the pathophysiology of PEW in end-stage renal disease (ESRD) on hemodialysis. The main aspects of nutritional status evaluation, intervention and monitoring in this clinical setting were described, as well as the current approaches for the prevention and treatment of ESRD-related PEW.

    METHODS: An exhaustive literature search was performed, in order to identify the relevant studies describing the epidemiology, pathogenesis, nutritional intervention and outcome of PEW in ESRD on hemodialysis.

    RESULTS AND CONCLUSION: The pathogenesis of PEW is multifactorial. Loss of appetite, reduced intake of nutrients and altered lean body mass anabolism/catabolism play a key role. Nutritional approach to PEW should be based on a careful and periodic assessment of nutritional status and on timely dietary counseling. When protein and energy intakes are reduced, nutritional supplementation by means of specific oral formulations administered during the hemodialysis session may be the first-step intervention, and represents a valid nutritional approach to PEW prevention and treatment since it is easy, effective and safe. Omega-3 fatty acids and fibers, now included in commercially available preparations for renal patients, could lend relevant added value to macronutrient supplementation. When oral supplementation fails, intradialytic parenteral nutrition can be implemented in selected patients.

  17. Nada Raja T, Hu TH, Zainudin R, Lee KS, Perkins SL, Singh B
    BMC Evol. Biol., 2018 04 10;18(1):49.
    PMID: 29636003 DOI: 10.1186/s12862-018-1170-9
    BACKGROUND: Non-human primates have long been identified to harbour different species of Plasmodium. Long-tailed macaques (Macaca fascicularis), in particular, are reservoirs for P. knowlesi, P. inui, P. cynomolgi, P. coatneyi and P. fieldi. A previous study conducted in Sarawak, Malaysian Borneo, however revealed that long-tailed macaques could potentially harbour novel species of Plasmodium based on sequences of small subunit ribosomal RNA and circumsporozoite genes. To further validate this finding, the mitochondrial genome and the apicoplast caseinolytic protease M genes of Plasmodium spp. were sequenced from 43 long-tailed macaque blood samples.

    RESULTS: Apart from several named species of malaria parasites, long-tailed macaques were found to be potentially infected with novel species of Plasmodium, namely one we refer to as "P. inui-like." This group of parasites bifurcated into two monophyletic clades indicating the presence of two distinct sub-populations. Further analyses, which relied on the assumption of strict co-phylogeny between hosts and parasites, estimated a population expansion event of between 150,000 to 250,000 years before present of one of these sub-populations that preceded that of the expansion of P. knowlesi. Furthermore, both sub-populations were found to have diverged from a common ancestor of P. inui approximately 1.5 million years ago. In addition, the phylogenetic analyses also demonstrated that long-tailed macaques are new hosts for P. simiovale.

    CONCLUSIONS: Malaria infections of long-tailed macaques of Sarawak, Malaysian Borneo are complex and include a novel species of Plasmodium that is phylogenetically distinct from P. inui. These macaques are new natural hosts of P. simiovale, a species previously described only in toque monkeys (Macaca sinica) in Sri Lanka. The results suggest that ecological factors could affect the evolution of malaria parasites.

  18. Sugiarto SR, Baird JK, Singh B, Elyazar I, Davis TME
    Malar J, 2022 Nov 14;21(1):327.
    PMID: 36372877 DOI: 10.1186/s12936-022-04366-5
    Kalimantan is a part of Indonesia, which occupies the southern three-quarters of the island of Borneo, sharing a border with the Malaysian states of Sabah and Sarawak. Although most areas of Kalimantan have low and stable transmission of Plasmodium falciparum and Plasmodium vivax, there are relatively high case numbers in the province of East Kalimantan. Two aspects of malaria endemicity in Kalimantan differentiate it from the rest of Indonesia, namely recent deforestation and potential exposure to the zoonotic malaria caused by Plasmodium knowlesi that occurs in relatively large numbers in adjacent Malaysian Borneo. In the present review, the history of malaria and its current epidemiology in Kalimantan are examined, including control and eradication efforts over the past two centuries, mosquito vector prevalence, anti-malarial use and parasite resistance, and the available data from case reports of knowlesi malaria and the presence of conditions which would support transmission of this zoonotic infection.
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