Displaying publications 1 - 20 of 106 in total

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  1. Abdul-Nasir AS, Mashor MY, Mohamed Z
    Comput Math Methods Med, 2012;2012:637360.
    PMID: 23082089 DOI: 10.1155/2012/637360
    Malaria is one of the serious global health problem, causing widespread sufferings and deaths in various parts of the world. With the large number of cases diagnosed over the year, early detection and accurate diagnosis which facilitates prompt treatment is an essential requirement to control malaria. For centuries now, manual microscopic examination of blood slide remains the gold standard for malaria diagnosis. However, low contrast of the malaria and variable smears quality are some factors that may influence the accuracy of interpretation by microbiologists. In order to reduce this problem, this paper aims to investigate the performance of the proposed contrast enhancement techniques namely, modified global and modified linear contrast stretching as well as the conventional global and linear contrast stretching that have been applied on malaria images of P. vivax species. The results show that the proposed modified global and modified linear contrast stretching techniques have successfully increased the contrast of the parasites and the infected red blood cells compared to the conventional global and linear contrast stretching. Hence, the resultant images would become useful to microbiologists for identification of various stages and species of malaria.
    Matched MeSH terms: Malaria/diagnosis*
  2. Abegunde AT
    Lancet, 2004;364(9441):1217.
    PMID: 15464180 DOI: 10.1016/S0140-6736(04)17132-8
    Comment on: Singh B, Kim Sung L, Matusop A, Radhakrishnan A, Shamsul SS, Cox-Singh J, Thomas A, Conway DJ. A large focus of naturally acquired Plasmodium knowlesi infections in human beings. Lancet. 2004 Mar 27;363(9414):1017-24. PubMed PMID: 15051281.
    Matched MeSH terms: Malaria/diagnosis
  3. Amir A, Russell B, Liew JW, Moon RW, Fong MY, Vythilingam I, et al.
    Sci Rep, 2016 Apr 21;6:24623.
    PMID: 27097521 DOI: 10.1038/srep24623
    Plasmodium knowlesi is extensively used as an important malaria model and is now recognized as an important cause of human malaria in Malaysia. The strains of P. knowlesi currently used for research were isolated many decades ago, raising concerns that they might no longer be representative of contemporary parasite populations. We derived a new P. knowlesi line (University Malaya line, UM01), from a patient admitted in Kuala Lumpur, Malaysia, and compared it with a human-adapted laboratory line (A1-H.1) derived from the P. knowlesi H strain. The UM01 and A1-H.1 lines readily invade human and macaque (Macaca fascicularis) normocytes with a preference for reticulocytes. Whereas invasion of human red blood cells was dependent on the presence of the Duffy antigen/receptor for chemokines (DARC) for both parasite lines, this was not the case for macaque red blood cells. Nonetheless, differences in invasion efficiency, gametocyte production and the length of the asexual cycle were noted between the two lines. It would be judicious to isolate and characterise numerous P. knowlesi lines for use in future experimental investigations of this zoonotic species.
    Matched MeSH terms: Malaria/diagnosis
  4. Amir A, Cheong FW, De Silva JR, Lau YL
    Parasit Vectors, 2018 01 23;11(1):53.
    PMID: 29361963 DOI: 10.1186/s13071-018-2617-y
    Every year, millions of people are burdened with malaria. An estimated 429,000 casualties were reported in 2015, with the majority made up of children under five years old. Early and accurate diagnosis of malaria is of paramount importance to ensure appropriate administration of treatment. This minimizes the risk of parasite resistance development, reduces drug wastage and unnecessary adverse reaction to antimalarial drugs. Malaria diagnostic tools have expanded beyond the conventional microscopic examination of Giemsa-stained blood films. Contemporary and innovative techniques have emerged, mainly the rapid diagnostic tests (RDT) and other molecular diagnostic methods such as PCR, qPCR and loop-mediated isothermal amplification (LAMP). Even microscopic diagnosis has gone through a paradigm shift with the development of new techniques such as the quantitative buffy coat (QBC) method and the Partec rapid malaria test. This review explores the different diagnostic tools available for childhood malaria, each with their characteristic strengths and limitations. These tools play an important role in making an accurate malaria diagnosis to ensure that the use of anti-malaria are rationalized and that presumptive diagnosis would only be a thing of the past.
    Matched MeSH terms: Malaria/diagnosis*
  5. Anthony C, Mahmud R, Lau YL, Syedomar SF, Sri La Sri Ponnampalavanar S
    Trop Biomed, 2013 Sep;30(3):459-66.
    PMID: 24189676 MyJurnal
    Battling malaria will be a persistent struggle without the proper means to diagnose the parasitic infection. However, the inherent limitations of microscopy, the conventional method of diagnosing malaria, affect the accuracy of diagnosis. The present study aimed to compare the accuracy of two different set of primers targeting the small subunit ribosomal RNA (ssRNA) and the dihydrofolate reductase-thymidylate synthase linker region (dhfr-ts) in detecting species specific malaria infections by nested PCR. The sensitivity and specificity of nested PCR assay using the two primers were calculated with reference to microscopy as the 'gold standard'. The results show that 18S rRNA primers had 91.9% sensitivity and 100% specificity in detecting human Plasmodium species as opposed to dhfr-ts primers which had 51.4% sensitivity and 100% specificity. The higher sensitivity of 18S rRNA primers suggests that it may be a better diagnostic tool for detecting human malaria.
    Matched MeSH terms: Malaria/diagnosis*
  6. Antinori S, Galimberti L, Milazzo L, Corbellino M
    Acta Trop, 2013 Feb;125(2):191-201.
    PMID: 23088834 DOI: 10.1016/j.actatropica.2012.10.008
    Plasmodium knowlesi was initially identified in the 30s as a natural Plasmodium of Macaca fascicularis monkey also capable of experimentally infecting humans. It gained a relative notoriety in the mid-30s as an alternative to Plasmodium vivax in the treatment of the general paralysis of the insane (neurosyphilis). In 1965 the first natural human infection was described in a US military surveyor coming back from the Pahang jungle of the Malaysian peninsula. P. knowlesi was again brought to the attention of the medical community when in 2004, Balbir Singh and his co-workers reported that about 58% of malaria cases observed in the Kapit district of the Malaysian Borneo were actually caused by P. knowlesi. In the following years several reports showed that P. knowlesi is much more widespread than initially thought with cases reported across Southeast Asia. This infection should also be considered in the differential diagnosis of any febrile travellers coming back from a recent travel to forested areas of Southeast Asia. P. knowlesi can cause severe malaria with a rate of 6-9% and with a case fatality rate of 3%. Respiratory distress, acute renal failure, shock and hyperbilirubinemia are the most frequently observed complications of severe P. knowlesi malaria. Chloroquine is considered the treatment of choice of uncomplicated malaria caused by P. knowlesi.
    Matched MeSH terms: Malaria/diagnosis
  7. Azidah AK, Mohd Faizal MA, Lili HY, Zeehaida M
    Trop Biomed, 2014 Mar;31(1):31-5.
    PMID: 24862042 MyJurnal
    Plasmodium knowlesi has been recently identified as the "fifth human malaria species" following the discovery in Malaysian Borneo of a large focus of this simian malaria parasite in humans. Even though it shares microscopic similarities with Plasmodium malariae, it may cause severe illness with risk of fatality. We describe a case of P. knowlesi infection causing multi-organ failure in a patient who was successfully managed due to early recognition of the infection. Clinicians in this region should be more aware of the infection as it is not as rare as previously thought. This case write up highlight the case of severe malaria infection which presented with multi organ involvement which is caused by P. knowlesi.
    Matched MeSH terms: Malaria/diagnosis*
  8. Azira NM, Zairi NZ, Amry AR, Zeehaida M
    Trop Biomed, 2012 Sep;29(3):398-404.
    PMID: 23018503 MyJurnal
    Plasmodium knowlesi is a simian malaria parasite and is recently recognized as the fifth malaria parasite infecting humans. Manifestation of the infection may resemble other infection particularly dengue fever leading to inappropriate management and delay in treatment. We reported three cases of naturally acquired P. knowlesi in Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia. Clinical manifestations were quite similar in those cases. Microscopically, the diagnosis might be challenging. These cases were confirmed by polymerase chain reaction method which serves as a gold standard.
    Matched MeSH terms: Malaria/diagnosis*
  9. Barber BE, William T, Grigg MJ, Yeo TW, Anstey NM
    Malar J, 2013;12:8.
    PMID: 23294844 DOI: 10.1186/1475-2875-12-8
    In areas co-endemic for multiple Plasmodium species, correct diagnosis is crucial for appropriate treatment and surveillance. Species misidentification by microscopy has been reported in areas co-endemic for vivax and falciparum malaria, and may be more frequent in regions where Plasmodium knowlesi also commonly occurs.
    Matched MeSH terms: Malaria/diagnosis*
  10. Barber BE, William T, Jikal M, Jilip J, Dhararaj P, Menon J, et al.
    Emerg Infect Dis, 2011 May;17(5):814-20.
    PMID: 21529389 DOI: 10.3201/eid1705.101489
    Plasmodium knowlesi can cause severe malaria in adults; however, descriptions of clinical disease in children are lacking. We reviewed case records of children (age <15 years) with a malaria diagnosis at Kudat District Hospital, serving a largely deforested area of Sabah, Malaysia, during January-November 2009. Sixteen children with PCR-confirmed P. knowlesi monoinfection were compared with 14 children with P. falciparum monoinfection diagnosed by microscopy or PCR. Four children with knowlesi malaria had a hemoglobin level at admission of <10.0 g/dL (minimum lowest level 6.4 g/dL). Minimum level platelet counts were lower in knowlesi than in falciparum malaria (median 76,500/μL vs. 156,000/mL; p = 0.01). Most (81%) children with P. knowlesi malaria received chloroquine and primaquine; median parasite clearance time was 2 days (range 1-5 days). P. knowlesi is the most common cause of childhood malaria in Kudat. Although infection is generally uncomplicated, anemia is common and thrombocytopenia universal. Transmission dynamics in this region require additional investigation.
    Matched MeSH terms: Malaria/diagnosis
  11. Barber BE, William T, Grigg MJ, Piera K, Yeo TW, Anstey NM
    J Clin Microbiol, 2013 Apr;51(4):1118-23.
    PMID: 23345297 DOI: 10.1128/JCM.03285-12
    Plasmodium knowlesi can cause severe and fatal human malaria in Southeast Asia. Rapid diagnosis of all Plasmodium species is essential for initiation of effective treatment. Rapid diagnostic tests (RDTs) are sensitive for detection of uncomplicated and severe falciparum malaria but have not been systematically evaluated in knowlesi malaria. At a tertiary referral hospital in Sabah, Malaysia, we prospectively evaluated the sensitivity of two combination RDTs for the diagnosis of uncomplicated and severe malaria from all three potentially fatal Plasmodium species, using a pan-Plasmodium lactate dehydrogenase (pLDH)-P. falciparum histidine-rich protein 2 (PfHRP2) RDT (First Response) and a pan-Plasmodium aldolase-PfHRP2 RDT (ParaHIT). Among 293 hospitalized adults with PCR-confirmed Plasmodium monoinfection, the sensitivity of the pLDH component of the pLDH-PfHRP2 RDT was 74% (95/129; 95% confidence interval [CI], 65 to 80%), 91% (110/121; 95% CI, 84 to 95%), and 95% (41/43; 95% CI, 85 to 99%) for PCR-confirmed P. knowlesi, P. falciparum, and P. vivax infections, respectively, and 88% (30/34; 95% CI, 73 to 95%), 90% (38/42; 95% CI, 78 to 96%), and 100% (12/12; 95% CI, 76 to 100%) among patients tested before antimalarial treatment was begun. Sensitivity in severe malaria was 95% (36/38; 95% CI, 83 to 99), 100% (13/13; 95% CI, 77 to 100), and 100% (7/7; 95% CI, 65 to 100%), respectively. The aldolase component of the aldolase-PfHRP2 RDT performed poorly in all Plasmodium species. The pLDH-based RDT was highly sensitive for the diagnosis of severe malaria from all species; however, neither the pLDH- nor aldolase-based RDT demonstrated sufficiently high overall sensitivity for P. knowlesi. More sensitive RDTs are needed in regions of P. knowlesi endemicity.
    Matched MeSH terms: Malaria/diagnosis*
  12. Boo YL, Lim HT, Chin PW, Lim SY, Hoo FK
    Parasitol Int, 2016 Feb;65(1):55-57.
    PMID: 26454133 DOI: 10.1016/j.parint.2015.10.003
    Plasmodium knowlesi, a zoonotic malaria, is now considered the fifth species of Plasmodium causing malaria in humans. With its 24-hour erythrocytic stage of development, it has raised concern regarding its high potential in replicating and leading to severe illness. Spleen is an important site for removal of parasitized red blood cells and generating immunity. We reported a case of knowlesi malaria in a non-immune, splenectomized patient. We observed the delay in parasite clearance, high parasitic counts, and severe illness at presentation. A thorough search through literature revealed several case reports on falciparum and vivax malaria in splenectomized patients. However, literature available for knowlesi malaria in splenectomized patient is limited. Further studies need to be carried out to clarify the role of spleen in host defense against human malaria especially P. knowlesi.
    Matched MeSH terms: Malaria/diagnosis
  13. Britton S, Cheng Q, Grigg MJ, William T, Anstey NM, McCarthy JS
    Am J Trop Med Hyg, 2016 07 06;95(1):120-2.
    PMID: 27162264 DOI: 10.4269/ajtmh.15-0670
    The simian parasite Plasmodium knowlesi is now the commonest cause of malaria in Malaysia and can rapidly cause severe and fatal malaria. However, microscopic misdiagnosis of Plasmodium species is common, rapid antigen detection tests remain insufficiently sensitive and confirmation of P. knowlesi requires polymerase chain reaction (PCR). Thus available point-of-care diagnostic tests are inadequate. This study reports the development of a simple, sensitive, colorimetric, high-throughput loop-mediated isothermal amplification assay (HtLAMP) diagnostic test using novel primers for the detection of P. knowlesi. This assay is able to detect 0.2 parasites/μL, and compared with PCR has a sensitivity of 96% for the detection of P. knowlesi, making it a potentially field-applicable point-of-care diagnostic tool.
    Matched MeSH terms: Malaria/diagnosis*
  14. Bronner U, Divis PC, Färnert A, Singh B
    Malar J, 2009 Jan 16;8:15.
    PMID: 19146706 DOI: 10.1186/1475-2875-8-15
    Plasmodium knowlesi is typically found in nature in macaques and has recently been recognized as the fifth species of Plasmodium causing malaria in human populations in south-east Asia. A case of knowlesi malaria is described in a Swedish man, who became ill after returning from a short visit to Malaysian Borneo in October 2006. His P. knowlesi infection was not detected using a rapid diagnostic test for malaria, but was confirmed by PCR and molecular characterization. He responded rapidly to treatment with mefloquine. Evaluation of rapid diagnostic kits with further samples from knowlesi malaria patients are necessary, since early identification and appropriate anti-malarial treatment of suspected cases are essential due to the rapid growth and potentially life-threatening nature of P. knowlesi. Physicians should be aware that knowlesi infection is an important differential diagnosis in febrile travellers, with a recent travel history to forested areas in south-east Asia, including short-term travellers who tested negative with rapid diagnostic tests.
    Matched MeSH terms: Malaria/diagnosis*
  15. Brown GW, Shirai A, Jegathesan M, Burke DS, Twartz JC, Saunders JP, et al.
    Am J Trop Med Hyg, 1984 Mar;33(2):311-5.
    PMID: 6324601
    We studied 1,629 febrile patients from a rural area of Malaysia, and made a laboratory diagnosis in 1,025 (62.9%) cases. Scrub typhus was the most frequent diagnosis (19.3% of all illnesses) followed by typhoid and paratyphoid (7.4%); flavivirus infection (7.0%); leptospirosis (6.8%); and malaria (6.2%). The hospital mortality was very low (0.5% of all febrile patients). The high prevalence of scrub typhus in oil palm laborers (46.8% of all febrile illnesses in that group) was confirmed. In rural Malaysia, therapy with chloramphenicol or a tetracycline would be appropriate for undiagnosed patients in whom malaria has been excluded. Failure to respond to tetracycline within 48 hours would usually suggest a diagnosis of typhoid, and indicate the need for a change in therapy.
    Matched MeSH terms: Malaria/diagnosis*
  16. Chen Y, Chan CK, Kerishnan JP, Lau YL, Wong YL, Gopinath SC
    BMC Infect Dis, 2015;15:49.
    PMID: 25656928 DOI: 10.1186/s12879-015-0786-2
    Plasmodium knowlesi was identified as the fifth major malaria parasite in humans. It presents severe clinical symptoms and leads to mortality as a result of hyperparasitemia in a short period of time. This study aimed to improve the current understanding of P. knowlesi and identify potential biomarkers for knowlesi malaria.
    Matched MeSH terms: Malaria/diagnosis*
  17. Cheong FW, Lau YL, Fong MY, Mahmud R
    Am J Trop Med Hyg, 2013 May;88(5):835-40.
    PMID: 23509118 DOI: 10.4269/ajtmh.12-0250
    Plasmodium knowlesi is now known as the fifth Plasmodium species that can cause human malaria. The Plasmodium merozoite surface protein (MSP) has been reported to be potential target for vaccination and diagnosis of malaria. MSP-1(33) has been shown to be immunogenic and its T cell epitopes could mediate cellular immune protection. However, limited studies have focused on P. knowlesi MSP-133. In this study, an approximately 28-kDa recombinant P. knowlesi MSP-1(33) (pkMSP-1(33)) was expressed by using an Escherichia coli system. The purified pkMSP-1(33) reacted with serum samples of patients infected with P. knowlesi (31 of 31, 100%) and non-P. knowlesi malaria (27 of 28, 96.43%) by Western blotting. The pkMSP-1(33) also reacted with P. knowlesi (25 of 31, 80.65%) and non-P. knowlesi malaria sera (20 of 28, 71.43%) in an enzyme-linked immunosorbent assay (ELISA). Most of the non-malarial infection (49 of 52 in by Western blotting and 46 of 52 in the ELISA) and healthy donor serum samples (65 of 65 by Western blotting and ELISA) did not react with recombinant pkMSP-1(33).
    Matched MeSH terms: Malaria/diagnosis*
  18. Chew CH, Lim YA, Lee PC, Mahmud R, Chua KH
    J Clin Microbiol, 2012 Dec;50(12):4012-9.
    PMID: 23035191 DOI: 10.1128/JCM.06454-11
    Malaria remains one of the major killers of humankind and persists to threaten the lives of more than one-third of the world's population. Given that human malaria can now be caused by five species of Plasmodium, i.e., Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, and the recently included Plasmodium knowlesi, there is a critical need not only to augment global health efforts in malaria control but also, more importantly, to develop a rapid, accurate, species-sensitive/species-specific, and economically effective diagnostic method for malaria caused by these five species. Therefore, in the present study, a straightforward single-step hexaplex PCR system targeting five human Plasmodium 18S small-subunit rRNAs (ssu rRNAs) was designed, and the system successfully detected all five human malaria parasites. In addition, this system enables the differentiation of single infection as well as mixed infections up to the two-species level. This assay was validated with 50 randomly blinded test and 184 clinical samples suspected to indicate malaria. This hexaplex PCR system is not only an ideal alternative for routine malaria diagnosis in laboratories with conventional PCR machines but also adds value to diagnoses when there is a lack of an experienced microscopist or/and when the parasite morphology is confusing. Indeed, this system will definitely enhance the accuracy and accelerate the speed in the diagnosis of malaria, as well as improve the efficacy of malaria treatment and control, in addition to providing reliable data from epidemiological surveillance studies.
    Matched MeSH terms: Malaria/diagnosis*
  19. Cho SJ, Lee J, Lee HJ, Jo HY, Sinniah M, Kim HY, et al.
    Int J Biol Sci, 2016;12(7):824-35.
    PMID: 27313496 DOI: 10.7150/ijbs.14408
    Rapid diagnostic tests (RDTs) can detect anti-malaria antibodies in human blood. As they can detect parasite infection at the low parasite density, they are useful in endemic areas where light infection and/or re-infection of parasites are common. Thus, malaria antibody tests can be used for screening bloods in blood banks to prevent transfusion-transmitted malaria (TTM), an emerging problem in malaria endemic areas. However, only a few malaria antibody tests are available in the microwell-based assay format and these are not suitable for field application. A novel malaria antibody (Ab)-based RDT using a differential diagnostic marker for falciparum and vivax malaria was developed as a suitable high-throughput assay that is sensitive and practical for blood screening. The marker, merozoite surface protein 1 (MSP1) was discovered by generation of a Plasmodium-specific network and the hierarchical organization of modularity in the network. Clinical evaluation revealed that the novel Malaria Pf/Pv Ab RDT shows improved sensitivity (98%) and specificity (99.7%) compared with the performance of a commercial kit, SD BioLine Malaria P.f/P.v (95.1% sensitivity and 99.1% specificity). The novel Malaria Pf/Pv Ab RDT has potential for use as a cost-effective blood-screening tool for malaria and in turn, reduces TTM risk in endemic areas.
    Matched MeSH terms: Malaria/diagnosis*
  20. Chong SE, Mohamad Zaini RH, Suraiya S, Lee KT, Lim JA
    Malar J, 2017 01 03;16(1):2.
    PMID: 28049485 DOI: 10.1186/s12936-016-1666-y
    BACKGROUND: Dengue and malaria are two common, mosquito-borne infections, which may lead to mortality if not managed properly. Concurrent infections of dengue and malaria are rare due to the different habitats of its vectors and activities of different carrier mosquitoes. The first case reported was in 2005. Since then, several concurrent infections have been reported between the dengue virus (DENV) and the malaria protozoans, Plasmodium falciparum and Plasmodium vivax. Symptoms of each infection may be masked by a simultaneous second infection, resulting in late treatment and severe complications. Plasmodium knowlesi is also a common cause of malaria in Malaysia with one of the highest rates of mortality. This report is one of the earliest in literature of concomitant infection between DENV and P. knowlesi in which a delay in diagnosis had placed a patient in a life-threatening situation.

    CASE PRESENTATION: A 59-year old man staying near the Belum-Temengor rainforest at the Malaysia-Thailand border was admitted with fever for 6 days, with respiratory distress. His non-structural protein 1 antigen and Anti-DENV Immunoglobulin M tests were positive. He was treated for severe dengue with compensated shock. Treating the dengue had so distracted the clinicians that a blood film for the malaria parasite was not done. Despite aggressive supportive treatment in the intensive care unit (ICU), the patient had unresolved acidosis as well as multi-organ failure involving respiratory, renal, liver, and haematological systems. It was due to the presentation of shivering in the ICU, that a blood film was done on the second day that revealed the presence of P. knowlesi with a parasite count of 520,000/μL. The patient was subsequently treated with artesunate-doxycycline and made a good recovery after nine days in ICU.

    CONCLUSIONS: This case contributes to the body of literature on co-infection between DENV and P. knowlesi and highlights the clinical consequences, which can be severe. Awareness should be raised among health-care workers on the possibility of dengue-malaria co-infection in this region. Further research is required to determine the real incidence and risk of co-infection in order to improve the management of acute febrile illness.

    Matched MeSH terms: Malaria/diagnosis*
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