Displaying publications 241 - 260 of 573 in total

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  1. Rama Rao S, Liew TS, Yow YY, Ratnayeke S
    PLoS One, 2018;13(5):e0196582.
    PMID: 29734361 DOI: 10.1371/journal.pone.0196582
    Invasive snails in the genus Pomacea have spread across Southeast Asia including Peninsular Malaysia. Their effects on natural and agricultural wetlands are appreciable, but species-specific effects are less clear because of morphological similarity among the species. Our objective was to establish diagnostic characteristics of Pomacea species in Malaysia using genetic and morphological criteria. The mitochondrial COI gene of 52 adult snails from eight localities in Peninsular Malaysia was amplified, sequenced, and analysed to verify species and phylogenetic relationships. Shells were compared using geometric morphometric and covariance analyses. Two monophyletic taxa, P. canaliculata and P. maculata, occurred in our samples. The mean ratio of shell height: aperture height (P = 0.042) and shell height: shell width (P = 0.007) was smaller in P. maculata. P. maculata co-occurred with P. canaliculata in five localities, but samples from three localities contained only P. canaliculata. This study is the first to confirm the presence of two of the most invasive species of Pomacea in Peninsular Malaysia using a molecular technique. P. canaliculata appears to be the more widespread species. Despite statistical differences, both quantitative and qualitative morphological characteristics demonstrated much interspecific overlap and intraspecific variability; thus, shell morphology alone cannot reliably verify species identity. Molecular techniques for distinguishing between these two highly invasive Pomacea species are needed to understand their specific ecological niches and to develop effective protocols for their management.
    Matched MeSH terms: Species Specificity
  2. 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.

    Matched MeSH terms: Species Specificity
  3. Bakar AA, Adamson EAS, Juliana LH, Nor Mohd SA, Wei-Jen C, Man A, et al.
    PLoS One, 2018;13(9):e0202945.
    PMID: 30183729 DOI: 10.1371/journal.pone.0202945
    Management of wild fisheries resources requires accurate knowledge on which species are being routinely exploited, but it can be hard to identify fishes to species level, especially in speciose fish groups where colour patterns vary with age. Snappers of the genus Lutjanus represent one such group, where fishes can be hard to identify and as a result fisheries statistics fail to capture species-level taxonomic information. This study employs traditional morphological and DNA barcoding approaches to identify adult and juvenile Lutjanus species harvested in Malaysian waters. Our results reveal a suite of species that differs markedly from those that have previously been considered important in the Malaysian wild-capture fishery and show that official fisheries statistics do not relate to exploitation at the species level. Furthermore, DNA barcoding uncovered two divergent groups of bigeye snapper ('Lutjanus lutjanus') distributed on either side of the Malay Peninsula, displaying a biogeographical pattern similar to distributions observed for many co-occurring reef-distributed fish groups. One of these bigeye snapper groups almost certainly represents an unrecognized species in need of taxonomic description. The study demonstrates the utility of DNA barcoding in uncovering overlooked diversity and for assessing species catch composition in a complicated but economically important taxonomic group.
    Matched MeSH terms: Species Specificity
  4. Bittleston LS, Wolock CJ, Yahya BE, Chan XY, Chan KG, Pierce NE, et al.
    Elife, 2018 08 28;7.
    PMID: 30152327 DOI: 10.7554/eLife.36741
    The 'pitchers' of carnivorous pitcher plants are exquisite examples of convergent evolution. An open question is whether the living communities housed in pitchers also converge in structure or function. Using samples from more than 330 field-collected pitchers of eight species of Southeast Asian Nepenthes and six species of North American Sarracenia, we demonstrate that the pitcher microcosms, or miniature ecosystems with complex communities, are strikingly similar. Compared to communities from surrounding habitats, pitcher communities house fewer species. While communities associated with the two genera contain different microbial organisms and arthropods, the species are predominantly from the same phylogenetic clades. Microbiomes from both genera are enriched in degradation pathways and have high abundances of key degradation enzymes. Moreover, in a manipulative field experiment, Nepenthes pitchers placed in a North American bog assembled Sarracenia-like communities. An understanding of the convergent interactions in pitcher microcosms facilitates identification of selective pressures shaping the communities.
    Matched MeSH terms: Species Specificity
  5. Mustafar F, Harvey MA, Khani A, Arató J, Rainer G
    eNeuro, 2018 07 11;5(4).
    PMID: 30073190 DOI: 10.1523/ENEURO.0167-18.2018
    Our understanding of the neurobiological underpinnings of learning and behavior relies on the use of invasive techniques, which necessitate the use of animal models. However, when different species learn the same task, to what degree are they actually producing the same behavior and engaging homologous neural circuitry? This question has received virtually no recent attention, even as the most powerful new methodologies for measuring and perturbing the nervous system have become increasingly dependent on the use of murine species. Here, we test humans, rats, monkeys, and an evolutionarily intermediate species, tree shrews, on a three alternative, forced choice, visual contrast discrimination task. As anticipated, learning rate, peak performance, and transfer across contrasts was lower in the rat compared to the other species. More interestingly, rats exhibited two major behavioral peculiarities: while monkeys and tree shrews based their choices largely on visual information, rats tended to base their choices on past reward history. Furthermore, as the task became more difficult, rats largely disengaged from the visual stimulus, reverting to innate spatial predispositions in order to collect rewards near chance probability. Our findings highlight the limitation of muridae as models for translational research, at least in the area of visually based decision making.
    Matched MeSH terms: Species Specificity
  6. Tan KY, Liew JL, Tan NH, Quah ESH, Ismail AK, Tan CH
    J Proteomics, 2019 02 10;192:246-257.
    PMID: 30243938 DOI: 10.1016/j.jprot.2018.09.006
    The Asiatic coral snakes are basal in the phylogeny of coral snakes. Although envenoming by the Asiatic coral snakes is rarely fatal, little is known about their venom properties and variability from the American coral snakes. Integrating reverse-phase high performance liquid chromatography and nano-liquid chromatography-tandem mass spectrometry, we showed that the venom proteome of the Malaysian banded or striped coral snake (Calliophis intestinalis) was composed of mainly phospholipases A2 (PLA2, 43.4%) and three-finger toxins (3FTx, 20.1%). Within 3FTx, the cytotoxins or cardiotoxins (CTX) dominated while the neurotoxins' content was much lower. Its subproteomic details contrasted with the 3FTx profile of most Micrurus sp., illustrating a unique dichotomy of venom phenotype between the Old and the New World coral snakes. Calliophis intestinalis venom proteome was correlated with measured enzymatic activities, and in vivo it was myotoxic but non-lethal to mice, frogs and geckos at high doses (5-10 μg/g). The venom contains species-specific toxins with distinct sequences and antigenicity, and the antibodies raised against PLA2 and CTX of other elapids showed poor binding toward its venom antigens. The unique venom proteome of C. intestinalis unveiled a repertoire of novel toxins, and the toxicity test supported the need for post-bite monitoring of myotoxic complication. SIGNIFICANCE: Malaysian banded or striped coral snake (Calliophis intestinalis) has a cytotoxin (CTX)-predominating venom proteome, a characteristic shared by its congener, the Malayan blue coral snake (Calliophis bivirgata). With little neurotoxins (NTX), it illustrates a CTX/NTX dichotomy of venom phenotype between the Old World and the New World coral snakes. The low toxicity of the venom imply that C. intestinalis bite envenoming can be managed via symptomatic relief of the mild to moderate pain with appropriate analgesia. Systemically, the serum creatine kinase level of patients should be monitored serially for potential complication of myotoxicity. The distinct antigenicity of the venom proteins implies that the empirical use of heterologous antivenom is mostly inappropriate and not recommended.
    Matched MeSH terms: Species Specificity
  7. Takaoka H, Low VL, Tan TK, Ya'cob Z, Sofian-Azirun M, Dhang Chen C, et al.
    J Med Entomol, 2019 02 25;56(2):432-440.
    PMID: 30597034 DOI: 10.1093/jme/tjy222
    Simulium (Gomphostilbia) yvonneae sp. nov. is described based on adults, pupae, and mature larvae from Vietnam. This new species belongs to the Simulium duolongum subgroup in the S. batoense species-group of the subgenus Gomphostilbia Enderlein. It is distinguished by having a relatively larger number of male upper-eye facets in 16 vertical columns and 16 horizontal rows and a pupal gill with eight filaments arranged as 3+(1+2)+2 from dorsal to ventral, of which two filaments of the ventral pair are 1.8 times as long as the longest filament of the middle and dorsal triplets. Morphological comparisons are made to distinguish this new species from all 22 related species. The genetic distinctiveness of this new species in the S. duolongum subgroup is also presented based on the DNA barcoding COI gene.
    Matched MeSH terms: Species Specificity
  8. Jamaluddin JAF, Mohammed Akib NA, Ahmad SZ, Abdul Halim SAA, Abdul Hamid NK, Mohd Nor SA
    PMID: 31012766 DOI: 10.1080/24701394.2019.1597073
    A total of 74 shrimp specimens were sequenced at a 584 bp segment of the cytochrome oxidase subunit I (COI) gene to examine patterns of DNA barcode variation in a mangrove biodiversity hotspot. The Maximum Likelihood tree, barcode gap analysis, Automatic Barcode Gap Discovery analysis and sequence comparisons with data available from Barcode of Life Data System and GenBank recovered 18 taxa of which 15 were identified to species level, 2 at genus level and a single taxon at order level. Two deep mitochondrial DNA lineage divergences were found in the giant tiger prawn, Penaeus monodon. It is suggested that one of the lineages is a consequence of an introduction from aquaculture activity. These results have provided a reliable barcode library for cataloguing shrimps in this area.
    Matched MeSH terms: Species Specificity
  9. Kenzo T, Ichie T, Watanabe Y, Yoneda R, Ninomiya I, Koike T
    Tree Physiol, 2006 Jul;26(7):865-73.
    PMID: 16585032
    Variations in leaf photosynthetic, morphological and biochemical properties with increasing plant height from seedlings to emergent trees were investigated in five dipterocarp species in a Malaysian tropical rain forest. Canopy openness increased significantly with tree height. Photosynthetic properties, such as photosynthetic capacity at light saturation, light compensation point, maximum rate of carboxylation and maximum rate of photosynthetic electron transport, all increased significantly with tree height. Leaf morphological and biochemical traits, such as leaf mass per area, palisade layer thickness, nitrogen concentration per unit area, chlorophyll concentration per unit dry mass and chlorophyll to nitrogen ratio, also changed significantly with tree height. Leaf properties had simple and significant relationships with tree height, with few intra- and interspecies differences. Our results therefore suggest that the photosynthetic capacity of dipterocarp trees depends on tree height, and that the trees adapt to the light environment by adjusting their leaf morphological and biochemical properties. These results should aid in developing models that can accurately estimate carbon dioxide flux and biomass production in tropical rain forests.
    Matched MeSH terms: Species Specificity
  10. Wahid I, Sunahara T, Mogi M
    J Med Entomol, 2003 Mar;40(2):150-8.
    PMID: 12693842
    Maxillae and mandibles of males of 44 species of 12 mosquito genera and females of three autogenous genera and two partially autogenous species were examined under light microscopy and scanning electron microscopy. The maxillae and mandibles of male mosquitoes are delicate, tape-like structures with lengths characterizing genera or higher level classification units. Five patterns are recognized: (A) long maxillae and mandibles with mandibles longer than maxillae in Anopheles; (B) long maxillae and mandibles with maxillae longer than mandibles in Toxorhynchites; (C) short or intermediate lengths of maxillae with short mandibles in Aedes, Armigeres, Culex, Ochlerotatus, Orthopodomyia, and Uranotaenia; (D) short or intermediate length of maxillae with no mandibles in Mimomyia and Tripteroides; and (E) no maxillae and mandibles in Malaya and Topomyia. Maxillary and mandibular lengths of male mosquitoes show a positive correlation. Length of maxillae and mandibles of autogenous females are reduced to the same level as conspecific males. In contrast, females of partially autogenous species have complete maxillae and mandibles as in females of anautogenous species.
    Matched MeSH terms: Species Specificity
  11. Ismail SNFB, Baharum SN, Fazry S, Low CF
    J Fish Dis, 2019 Dec;42(12):1761-1772.
    PMID: 31637743 DOI: 10.1111/jfd.13093
    Discovery of species-specific interaction between the host and virus has drawn the interest of many researchers to study the evolution of the newly emerged virus. Comparative genome analysis provides insights of the virus functional genome evolution and the underlying mechanisms of virus-host interactions. The analysis of nucleotide composition signified the evolution of nodavirus towards host specialization in a host-specific mutation manner. GC-rich genome of betanodavirus was significantly deficient in UpA and UpU dinucleotides composition, whilst the AU-rich genome of gammanodavirus was deficient in CpG dinucleotide. The capsid of MrNV and PvNV of gammanodavirus retains the highest abundance of adenine and uracil at the second codon position, respectively, which were found to be very distinctive from the other genera. ENC-GC3 plot inferred the influence of natural selection and mutational pressure in shaping the evolution of MrNV RdRp and capsid, respectively. Furthermore, CAI/eCAI analysis predicts a comparable adaptability of MrNV in squid, Sepia officinalis than its natural host, Macrobrachium rosenbergii. Thus, further study is warranted to investigate the capacity of MrNV replication in S. officinalis owing to its high codon adaptation index.
    Matched MeSH terms: Species Specificity
  12. Westbury MV, Petersen B, Lorenzen ED
    PLoS One, 2019;14(9):e0222004.
    PMID: 31553763 DOI: 10.1371/journal.pone.0222004
    Fin whales (Balaenoptera physalus) and blue whales (B. musculus) are the two largest species on Earth and are widely distributed across the world's oceans. Hybrids between these species appear to be relatively widespread and have been reported in both the North Atlantic and North Pacific; they are also relatively common, and have been proposed to occur once in every thousand fin whales. However, despite known hybridization, fin and blue whales are not sibling species. Rather, the closest living relative of fin whales are humpback whales (Megaptera novaeangliae). To improve the quality of fin whale data available for analysis, we assembled and annotated a fin whale nuclear genome using in-silico mate pair libraries and previously published short-read data. Using this assembly and genomic data from a humpback, blue, and bowhead whale, we investigated whether signatures of introgression between the fin and blue whale could be found. We find no signatures of contemporary admixture in the fin and blue whale genomes, although our analyses support ancestral gene flow between the species until 2.4-1.3 Ma. We propose the following explanations for our findings; i) fin/blue whale hybridization does not occur in the populations our samples originate from, ii) contemporary hybrids are a recent phenomenon and the genetic consequences have yet to become widespread across populations, or iii) fin/blue whale hybrids are under large negative selection, preventing them from backcrossing and contributing to the parental gene pools.
    Matched MeSH terms: Species Specificity
  13. Elvert M, Sauerhering L, Maisner A
    J Infect Dis, 2020 05 11;221(Suppl 4):S395-S400.
    PMID: 31665348 DOI: 10.1093/infdis/jiz455
    During the Nipah virus (NiV) outbreak in Malaysia, pigs and humans were infected. While pigs generally developed severe respiratory disease due to effective virus replication and associated inflammation processes in porcine airways, respiratory symptoms in humans were rare and less severe. To elucidate the reasons for the species-specific differences in NiV airway infections, we compared the cytokine responses as a first reaction to NiV in primary porcine and human bronchial epithelial cells (PBEpC and HBEpC, respectively). In both cell types, NiV infection resulted in the expression of type III interferons (IFN-λ). Upon infection with similar virus doses, viral RNA load and IFN expression were substantially higher in HBEpC. Even if PBEpC expressed the same viral RNA amounts as NiV-infected HBEpC, the porcine cells showed reduced IFN- and IFN-dependent antiviral gene expression. Despite this inherently limited IFN response, the expression of proinflammatory cytokines (IL-6, IL-8) in NiV-infected PBEpC was not decreased. The downregulation of antiviral activity in the presence of a functional proinflammatory cytokine response might be one of the species-specific factors contributing to efficient virus replication and acute inflammation in the lungs of pigs infected with the Malaysian NiV strain.
    Matched MeSH terms: Species Specificity
  14. Hall DA, Plack CJ
    Hear Res, 2019 10;382:107778.
    PMID: 31470340 DOI: 10.1016/j.heares.2019.107778
    Matched MeSH terms: Species Specificity
  15. Okamoto M, Ito A, Kurosawa T, Oku Y, Kamiya M, Agatsuma T
    Int J Parasitol, 1995 Feb;25(2):221-8.
    PMID: 7622329
    The technique of isoenzyme electrophoresis was applied to Japanese wild populations of Taenia taeniaeformis (isolated from Norway rats) and three laboratory reared isolates (KRN isolated from a Malaysian Norway rat, BMM from a Belgian house mouse and ACR from a Japanese gray red-backed vole). The average heterozygosities of Japanese wild populations were fairly small and total genetic variability was 0.0499. The genetic make-up of T. taeniaeformis in Norway rats was rather uniform in the whole of Japan. In KRN isolate, each of all 10 loci examined possessed the allele which was predominant in Japanese wild populations. Similarly, each of 9 loci in BMM isolate possessed the same alleles, but one of 2 alleles at HK locus was different from that in the others. T. taeniaeformis parasitizing house mice and rats were considered to be genetically closely related to each other. In ACR isolate, 7 out of 10 loci possessed different alleles from those in the other populations. It was considered that ACR isolate was genetically distant and its phylogenetic origin in Japan should be different from worms parasitizing Norway rats.
    Matched MeSH terms: Species Specificity
  16. Wilcox JS, Kerschner A, Hollocher H
    Infect Genet Evol, 2019 11;75:103994.
    PMID: 31421245 DOI: 10.1016/j.meegid.2019.103994
    Plasmodium knowlesi is an important causative agent of malaria in humans of Southeast Asia. Macaques are natural hosts for this parasite, but little is conclusively known about its patterns of transmission within and between these hosts. Here, we apply a comprehensive phylogenetic approach to test for patterns of cryptic population genetic structure between P. knowlesi isolated from humans and long-tailed macaques from the state of Sarawak in Malaysian Borneo. Our approach differs from previous investigations through our exhaustive use of archival 18S Small Subunit rRNA (18S) gene sequences from Plasmodium and Hepatocystis species, our inclusion of insertion and deletion information during phylogenetic inference, and our application of Bayesian phylogenetic inference to this problem. We report distinct clades of P. knowlesi that predominantly contained sequences from either human or macaque hosts for paralogous A-type and S-type 18S gene loci. We report significant partitioning of sequence distances between host species across both types of loci, and confirmed that sequences of the same locus type showed significantly biased assortment into different clades depending on their host species. Our results support the zoonotic potential of Plasmodium knowlesi, but also suggest that humans may be preferentially infected with certain strains of this parasite. Broadly, such patterns could arise through preferential zoonotic transmission of some parasite lineages or a disposition of parasites to transmit within, rather than between, human and macaque hosts. Available data are insufficient to address these hypotheses. Our results suggest that the epidemiology of P. knowlesi may be more complicated than previously assumed, and highlight the need for renewed and more vigorous explorations of transmission patterns in the fifth human malarial parasite.
    Matched MeSH terms: Species Specificity
  17. Matsui M, Nishikawa K, Eto K, Hossman MY
    Zoolog Sci, 2020 Feb;37(1):91-101.
    PMID: 32068378 DOI: 10.2108/zs190078
    Two lineages of stream toads in the genus Ansonia from Malaysian Borneo have long been suspected to be specifically distinct on the basis of molecular data. We assessed the taxonomic status of these lineages using morphological and additional genetic data. In mtDNA phylogeny, each lineage-one from Bario, Kelabit Highlands of Sarawak, the other from Mt. Mulu of Sarawak and the Crocker Range of Sabah-is separated from other congeners by large genetic distances, comparable with those observed between heterospecific species in the genus. These lineages are also morphologically distinguishable from other species, and are considered to represent valid, independently evolving species. We therefore describe them as A. kelabitensis sp. nov. and A. kanak sp. nov.
    Matched MeSH terms: Species Specificity
  18. Tilker A, Abrams JF, Mohamed A, Nguyen A, Wong ST, Sollmann R, et al.
    Commun Biol, 2019;2:396.
    PMID: 31701025 DOI: 10.1038/s42003-019-0640-y
    Habitat degradation and hunting have caused the widespread loss of larger vertebrate species (defaunation) from tropical biodiversity hotspots. However, these defaunation drivers impact vertebrate biodiversity in different ways and, therefore, require different conservation interventions. We conducted landscape-scale camera-trap surveys across six study sites in Southeast Asia to assess how moderate degradation and intensive, indiscriminate hunting differentially impact tropical terrestrial mammals and birds. We found that functional extinction rates were higher in hunted compared to degraded sites. Species found in both sites had lower occupancies in the hunted sites. Canopy closure was the main predictor of occurrence in the degraded sites, while village density primarily influenced occurrence in the hunted sites. Our findings suggest that intensive, indiscriminate hunting may be a more immediate threat than moderate habitat degradation for tropical faunal communities, and that conservation stakeholders should focus as much on overhunting as on habitat conservation to address the defaunation crisis.
    Matched MeSH terms: Species Specificity
  19. Wadhwa R, Pandey P, Gupta G, Aggarwal T, Kumar N, Mehta M, et al.
    Curr Top Med Chem, 2019;19(28):2593-2609.
    PMID: 31746290 DOI: 10.2174/1568026619666191026105308
    BACKGROUND: Candida species are the important etiologic agents for candidiasis, the most prevalent cause of opportunistic fungal infections. Candida invasion results in mucosal to systemic infections through immune dysfunction and helps in further invasion and proliferation at several sites in the host. The host defence system utilizes a wide array of the cells, proteins and chemical signals that are distributed in blood and tissues which further constitute the innate and adaptive immune system. The lack of antifungal agents and their limited therapeutic effects have led to high mortality and morbidity related to such infections.

    METHODS: The necessary information collated on this review has been gathered from various literature published from 1995 to 2019.

    RESULTS: This article sheds light on novel drug delivery approaches to target the immunological axis for several Candida species (C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, C. rugose, C. hemulonii, etc.).

    CONCLUSION: It is clear that the novel drug delivery approaches include vaccines, adoptive transfer of primed immune cells, recombinant cytokines, therapeutic antibodies, and nanoparticles, which have immunomodulatory effects. Such advancements in targeting various underpinning mechanisms using the concept of novel drug delivery will provide a new dimension to the fungal infection clinic particularly due to Candida species with improved patient compliance and lesser side effects. This advancement in knowledge can also be extended to target various other similar microbial species and infections.

    Matched MeSH terms: Species Specificity
  20. Fungfuang W, Udom C, Tongthainan D, Kadir KA, Singh B
    Malar J, 2020 Oct 01;19(1):350.
    PMID: 33004070 DOI: 10.1186/s12936-020-03424-0
    BACKGROUND: Certain species of macaques are natural hosts of Plasmodium knowlesi and Plasmodium cynomolgi, which can both cause malaria in humans, and Plasmodium inui, which can be experimentally transmitted to humans. A significant number of zoonotic malaria cases have been reported in humans throughout Southeast Asia, including Thailand. There have been only two studies undertaken in Thailand to identify malaria parasites in non-human primates in 6 provinces. The objective of this study was to determine the prevalence of P. knowlesi, P. cynomolgi, P. inui, Plasmodium coatneyi and Plasmodium fieldi in non-human primates from 4 new locations in Thailand.

    METHODS: A total of 93 blood samples from Macaca fascicularis, Macaca leonina and Macaca arctoides were collected from four locations in Thailand: 32 were captive M. fascicularis from Chachoengsao Province (CHA), 4 were wild M. fascicularis from Ranong Province (RAN), 32 were wild M. arctoides from Prachuap Kiri Khan Province (PRA), and 25 were wild M. leonina from Nakornratchasima Province (NAK). DNA was extracted from these samples and analysed by nested PCR assays to detect Plasmodium, and subsequently to detect P. knowlesi, P. coatneyi, P. cynomolgi, P. inui and P. fieldi.

    RESULTS: Twenty-seven of the 93 (29%) samples were Plasmodium-positive by nested PCR assays. Among wild macaques, all 4 M. fascicularis at RAN were infected with malaria parasites followed by 50% of 32 M. arctoides at PRA and 20% of 25 M. leonina at NAK. Only 2 (6.3%) of the 32 captive M. fascicularis at CHA were malaria-positive. All 5 species of Plasmodium were detected and 16 (59.3%) of the 27 macaques had single infections, 9 had double and 2 had triple infections. The composition of Plasmodium species in macaques at each sampling site was different. Macaca arctoides from PRA were infected with P. knowlesi, P. coatneyi, P. cynomolgi, P. inui and P. fieldi.

    CONCLUSIONS: The prevalence and species of Plasmodium varied among the wild and captive macaques, and between macaques at 4 sampling sites in Thailand. Macaca arctoides is a new natural host for P. knowlesi, P. inui, P. coatneyi and P. fieldi.

    Matched MeSH terms: Species Specificity
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