Displaying publications 1 - 20 of 59 in total

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  1. Fulltext External quality assessment of dengue and chikungunya diagnostics in the Asia Pacific region, 2015
    Soh LT, Squires RC, Tan LK, Pok KY, Yang H, Liew C, et al.
    Western Pac Surveill Response J, 2016 04 22;7(2):26-34.
    PMID: 27508088 DOI: 10.5365/WPSAR.2016.7.1.002
    OBJECTIVE: To conduct an external quality assessment (EQA) of dengue and chikungunya diagnostics among national-level public health laboratories in the Asia Pacific region following the first round of EQA for dengue diagnostics in 2013.

    METHODS: Twenty-four national-level public health laboratories performed routine diagnostic assays on a proficiency testing panel consisting of two modules. Module A contained serum samples spiked with cultured dengue virus (DENV) or chikungunya virus (CHIKV) for the detection of nucleic acid and DENV non-structural protein 1 (NS1) antigen. Module B contained human serum samples for the detection of anti-DENV antibodies.

    RESULTS: Among 20 laboratories testing Module A, 17 (85%) correctly detected DENV RNA by reverse transcription polymerase chain reaction (RT-PCR), 18 (90%) correctly determined serotype and 19 (95%) correctly identified CHIKV by RT-PCR. Ten of 15 (66.7%) laboratories performing NS1 antigen assays obtained the correct results. In Module B, 18/23 (78.3%) and 20/20 (100%) of laboratories correctly detected anti-DENV IgM and IgG, respectively. Detection of acute/recent DENV infection by both molecular (RT-PCR) and serological methods (IgM) was available in 19/24 (79.2%) participating laboratories.

    DISCUSSION: Accurate laboratory testing is a critical component of dengue and chikungunya surveillance and control. This second round of EQA reveals good proficiency in molecular and serological diagnostics of these diseases in the Asia Pacific region. Further comprehensive diagnostic testing, including testing for Zika virus, should comprise future iterations of the EQA.

    Matched MeSH terms: Chikungunya Fever/diagnosis*
  2. Differential Diagnosis of Flavivirus Infections in Horses Using Viral Envelope Protein Domain III Antigens in Enzyme-Linked Immunosorbent Assay
    Piyasena TBH, Setoh YX, Hobson-Peters J, Prow NA, Bielefeldt-Ohmann H, Khromykh AA, et al.
    Vector Borne Zoonotic Dis, 2017 12;17(12):825-835.
    PMID: 29083957 DOI: 10.1089/vbz.2017.2172
    In Australia, infection of horses with the West Nile virus (WNV) or Murray Valley encephalitis virus (MVEV) occasionally results in severe neurological disease that cannot be clinically differentiated. Confirmatory serological tests to detect antibody specific for MVEV or WNV in horses are often hampered by cross-reactive antibodies induced to conserved epitopes on the envelope (E) protein. This study utilized bacterially expressed recombinant antigens derived from domain III of the E protein (rE-DIII) of MVEV and WNV, respectively, to determine whether these subunit antigens provided specific diagnostic markers of infection with these two viruses. When a panel of 130 serum samples, from horses with known flavivirus infection status, was tested in enzyme-linked immunosorbent assay (ELISA) using rE-DIII antigens, a differential diagnosis of MVEV or WNV was achieved for most samples. Time-point samples from horses exposed to flavivirus infection during the 2011 outbreak of equine encephalitis in south-eastern Australia also indicated that the rE-DIII antigens were capable of detecting and differentiating MVEV and WNV infection in convalescent sera with similar sensitivity and specificity to virus neutralization tests and blocking ELISAs. Overall, these results indicate that the rE-DIII is a suitable antigen for use in rapid immunoassays for confirming MVEV and WNV infections in horses in the Australian context and warrant further assessment on sensitive, high-throughput serological platforms such as multiplex immune assays.
    Matched MeSH terms: West Nile Fever/diagnosis
  3. Updates on chikungunya epidemiology, clinical disease, and diagnostics
    Sam IC, Kümmerer BM, Chan YF, Roques P, Drosten C, AbuBakar S
    Vector Borne Zoonotic Dis, 2015 Apr;15(4):223-30.
    PMID: 25897809 DOI: 10.1089/vbz.2014.1680
    Chikungunya virus (CHIKV) is an Aedes-borne alphavirus, historically found in Africa and Asia, where it caused sporadic outbreaks. In 2004, CHIKV reemerged in East Africa and spread globally to cause epidemics, including, for the first time, autochthonous transmission in Europe, the Middle East, and Oceania. The epidemic strains were of the East/Central/South African genotype. Strains of the Asian genotype of CHIKV continued to cause outbreaks in Asia and spread to Oceania and, in 2013, to the Americas. Acute disease, mainly comprising fever, rash, and arthralgia, was previously regarded as self-limiting; however, there is growing evidence of severe but rare manifestations, such as neurological disease. Furthermore, CHIKV appears to cause a significant burden of long-term morbidity due to persistent arthralgia. Diagnostic assays have advanced greatly in recent years, although there remains a need for simple, accurate, and affordable tests for the developing countries where CHIKV is most prevalent. This review focuses on recent important work on the epidemiology, clinical disease and diagnostics of CHIKV.
    Matched MeSH terms: Chikungunya Fever/diagnosis
  4. Typhoid fever--important issues still remain
    Pang T, Levine MM, Ivanoff B, Wain J, Finlay BB
    Trends Microbiol., 1998 Apr;6(4):131-3.
    PMID: 9587187
    Matched MeSH terms: Typhoid Fever/diagnosis
  5. Predicting enteric fever without bacteriological culture results
    Ross IN, Abraham T
    Trans R Soc Trop Med Hyg, 1987;81(3):374-7.
    PMID: 3686631
    We used Bayes' theorem to calculate the probability of enteric fever in 260 patients presenting with undiagnosed fever, without recourse to blood or stool culture results. These individuals were divided into 110 patients with enteric fever (63 culture positive, 47 culture negative) and 150 patients with other causes of fever. Comparison of the frequencies of occurrence of 19 clinical and laboratory events, said to be helpful in the diagnosis of enteric fever, in the two groups revealed that only 8 events were significantly more frequent in enteric fever. These were: a positive Widal test at a screening dilution of 1:40; a peak temperature greater than = 39 degrees C; previous treatment for the fever; a white blood cell count less than 9 X 10(6)/litre; a polymorphonuclear leucocyte count less than 3.5 X 10(6)/litre; splenomegaly; fever duration greater than 7 d; and hepatomegaly. When the probability of enteric fever was determined prospectively in 110 patients, using only 6 of these discriminating events, the probability of patients with a positive prediction having enteric fever (diagnostic specificity) was 0.80 (95% confidence interval: 0.68 to 0.91) and the probability of those with a negative prediction not having enteric fever (diagnostic sensitivity) was 0.92 (0.85 to 0.99). Using all 19 events did not alter the diagnostic specificity or diagnostic sensitivity. This study shows that a small number of clinical and laboratory features can objectively discriminate enteric fever from other causes of fever in the majority of patients. Calculating the probability of enteric fever can aid in diagnosis, when culturing for salmonella is either unavailable or is negative.
    Matched MeSH terms: Typhoid Fever/diagnosis*
  6. Fulltext Pulsed-field gel electrophoresis as an epidemiologic tool in the investigation of laboratory acquired Salmonella typhi infection
    Koay AS, Jegathesan M, Rohani MY, Cheong YM
    Southeast Asian J. Trop. Med. Public Health, 1997 Mar;28(1):82-4.
    PMID: 9322288
    Strains of Salmonella typhi implicated in two separate cases of laboratory acquired infection from patients and the medical laboratory technologists who processed the patients' samples were analysed by pulsed-field gel electrophoresis. Although all four isolates were of bacteriophage type E1, PFGE was able to demonstrate that the strains responsible for the two laboratory acquired cases were not genetically related. The PFGE patterns of the isolates from the MLTs were found to be identical to those of the corresponding patients after digestion with restriction enzyme AvrII. This provided genetic as well as epidemiological evidence for the source of the laboratory acquired infections.
    Matched MeSH terms: Typhoid Fever/diagnosis
  7. Fulltext Retrospective review of dot enzyme immunoassay test for typhoid fever in an endemic area
    Jackson AA, Ismail A, Ibrahim TA, Kader ZS, Nawi NM
    Southeast Asian J. Trop. Med. Public Health, 1995 Dec;26(4):625-30.
    PMID: 9139364
    Typhoid fever remains a common problem in Malaysia, but for its diagnosis both blood culture and the Widal test have drawbacks. A dot enzyme immunoassay (EIA) has been developed which detects IgM and IgG antibodies to a specific 50 kDa outer membrane protein on Salmonella typhi. This study was performed among outpatients attending the university hospital in Kelantan, a state on the east coast of Peninsular Malaysia where typhoid is endemic. The dot EIA was done on 149 outpatients of all ages in whom typhoid was suspected. Of these, 60 were not analysable due to insufficient data. The other 89 were retrospectively classed as typhoid (total = 21), or not typhoid (total = 68). The criteria for diagnosis of typhoid was either, blood culture was positive, or with blood culture negative, temperature was at least 38 degrees C and Widal O and/or H titer greater than or equal to 1/160. We then compared the diagnosis with the EIA result. For the result where either IgM or IgG was positive, sensitivity was 90%, specificity 91% and negative predictive value 97%. For IgM positive, specificity was 100%. But the specificity of IgG positive alone was reduced by six false positives, which were probably due to persistence of IgG after acute infection. Other cases were found where IgG positive alone appeared in the first week of typhoid fever, probably due to rapid response in a second or subsequent infection. We also found that IgM-producing patients were significantly younger than those showing IgG alone positive.
    Study site: Community Medicine clinic, Accident & emergency department, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
    Matched MeSH terms: Typhoid Fever/diagnosis*
  8. A serological survey of scrub, tick, and endemic typhus in Sabah, East Malaysia
    Taylor AC, Hii J, Kelly DJ, Davis DR, Lewis GE
    Southeast Asian J. Trop. Med. Public Health, 1986 Dec;17(4):613-9.
    PMID: 3107139
    A seroepidemiological survey of 837 people and 383 febrile patients was performed in rural areas of Sabah. We determined that the rickettsial diseases scrub typhus and endemic typhus were uncommon causes of febrile illness, as was tick typhus, except in forest dwelling peoples. The rate of occurrence of SFGR specific antibody was 16.5% among 412 forest dwellers, indicating that tick typhus may be a frequent cause of illness in this population.
    Matched MeSH terms: Rocky Mountain Spotted Fever/diagnosis
  9. Fulltext Dot enzyme immunosorbent assay for the serodiagnosis of typhoid fever
    Ismail A, Kader ZS, Kok-Hai O
    Southeast Asian J. Trop. Med. Public Health, 1991 Dec;22(4):563-6.
    PMID: 1820645
    A nitrocellulose membrane strip dotted with a specific 50 kDa outer membrane protein of Salmonella typhi was applied for the serodiagnosis of typhoid fever. Using horseradish peroxidase conjugated IgM and IgG antibodies with 4-chloronaphthol as substrate, antibodies in typhoid patients were clearly visualised as bluish purple dots while sera from patients with non-typhoid fevers gave negative results. The detection of specific IgM and IgG antibodies in typhoid patients suggest either recent or current infection. Combined with the high specificity, reliability and rapidity of the test, the dot EIA technique provides a simple and useful method for the serodiagnosis of typhoid using a single serum specimen.
    Matched MeSH terms: Typhoid Fever/diagnosis*
  10. Fulltext Typhoid fever presenting as acute cerebellar ataxia and severe thrombocytopenia
    Cheong BM
    Med J Malaysia, 2008 Mar;63(1):77-8.
    PMID: 18935745 MyJurnal
    Typhoid fever being a systemic infection can present in a multitude of ways, involving various systems. Here we describe a case of typhoid fever presenting with acute cerebellar ataxia and marked thrombocytopenia. This atypical presentation is not common in typhoid fever and can lead to misdiagnosis as well as a delay in the initiation of appropriate therapy. Prompt clinical improvement and the return of platelet counts to normal were noted after the patient was started on IV Ceftriaxone.
    Matched MeSH terms: Typhoid Fever/diagnosis
  11. Fulltext Atypical presentation of adult rubella
    Jayaprakash B, Sudha V, Shashikiran U
    Med J Malaysia, 2006 Jun;61(2):242-4.
    PMID: 16898322 MyJurnal
    A 55 year old female presented with fever, skin rash and subconjunctival hemorrhage. She also developed hepatitis. Fever and skin rash lasted for more than three weeks. This patient was diagnosed to have rubella, highlighting the fact that rubella can present with atypical features like prolonged fever and rash, subconjunctival hemorrhage and hepatitis, especially in adults.
    Matched MeSH terms: Fever/diagnosis
  12. Fulltext Typhoid fever: present and future
    Merican I
    Med J Malaysia, 1997 Sep;52(3):299-308; quiz 309.
    PMID: 10968104
    Typhoid fever (TF), a systemic prolonged febrile illness, continues to be a worldwide health problem especially in developing countries where there is poor sanitation and poor standards of personal hygiene. The worldwide incidence of TF is estimated to be approximately 16 million cases annually with 7 million cases occurring annually in SE Asia alone. More than 600,000 people die of the disease annually. The pathogenesis of TF is beginning to be understood. The clinical features and diagnosis of TF are well known. New diagnostic methods have yet to gain universal acceptance. Traditional treatment with the first-line antibiotics (i.e. chloramphenicol, ampicillin and trimethoprim-sulphamethoxazole) though still being used in most developing countries are gradually being replaced with shorter courses of treatment with third generation cephalosporins or fluoroquinolones especially with the growing incidence of multi-drug resistant S typhi strains (MDR-ST). MDR-ST strains are particularly common in the Indian subcontinent; Pakistan and China. The presently available vaccines are far from satisfactory in terms of safety, efficacy and costs. Newer vaccines have been developed and are presently undergoing clinical trials in human volunteers.
    Matched MeSH terms: Typhoid Fever/diagnosis
  13. Fulltext Haemophagocytosis in typhoid fever
    Ramanathan M, Karim N
    Med J Malaysia, 1993 Jun;48(2):240-3.
    PMID: 8350805
    This report deals with a young man who developed features of haemophogocytosis during the course of typhoid fever. The pertinent clinical and laboratory features of typhoid-associated haemophagocytosis are discussed. The need for blood component replacement therapy in addition to specific anti-microbials to treat haemophagocytosis complicating typhoid fever is stressed.
    Matched MeSH terms: Typhoid Fever/diagnosis
  14. Criteria for confirming typhoid fever
    Ross I, Abraham T
    Med J Malaysia, 1986 Mar;41(1):51-2.
    PMID: 3796350
    Matched MeSH terms: Typhoid Fever/diagnosis*
  15. Fulltext Standardisation of the Widal test
    Cheong YM, Jegathesan M
    Med J Malaysia, 1989 Sep;44(3):267.
    PMID: 2483249
    Matched MeSH terms: Typhoid Fever/diagnosis*
  16. Some observations of the typhoid outbreak in Sungai Padang, Perlis
    Singh N, Menon V
    Med J Malaysia, 1975 Dec;30(2):93-7.
    PMID: 1228388
    Matched MeSH terms: Typhoid Fever/diagnosis
  17. Isolation of a Plesiomonas shigelloides in Malaysia
    Ampalam SD, Fang L
    Med J Malaya, 1971 Jun;25(4):282-4.
    PMID: 4261301
    Matched MeSH terms: Typhoid Fever/diagnosis
  18. Fulltext The discrimination of d-tartrate positive and d-tartrate negative S. enterica subsp. enterica serovar Paratyphi B isolated in Malaysia by phenotypic and genotypic methods
    Ahmad N, Hoon ST, Ghani MK, Tee KY
    Malays J Pathol, 2012 Jun;34(1):35-9.
    PMID: 22870596 MyJurnal
    Serotyping is not sufficient to differentiate between Salmonella species that cause paratyphoid fever from the strains that cause milder gastroenteritis as these organisms share the same serotype Salmonella Paratyphi B (S. Paratyphi B). Strains causing paratyphoid fever do not ferment d-tartrate and this key feature was used in this study to determine the prevalence of these strains among the collection of S. Paratyphi B strains isolated from patients in Malaysia. A total of 105 isolates of S. Paratyphi B were discriminated into d-tartrate positive (dT+) and d-tartrate negative (dT) variants by two lead acetate test protocols and multiplex PCR. The lead acetate test protocol 1 differed from protocol 2 by a lower inoculum size and different incubation conditions while the multiplex PCR utilized 2 sets of primers targeting the ATG start codon of the gene STM3356. Lead acetate protocol 1 discriminated 97.1% of the isolates as S. Paratyphi B dT+ and 2.9% as dT while test protocol 2 discriminated all the isolates as S. Paratyphi B dT+. The multiplex PCR test identified all 105 isolates as S. Paratyphi B dT+ strains. The concordance of the lead acetate test relative to that of multiplex PCR was 97.7% and 100% for protocol 1 and 2 respectively. This study showed that S. Paratyphi B dT+ is a common causative agent of gastroenteritis in Malaysia while paratyphoid fever appears to be relatively uncommon. Multiplex PCR was shown to be a simpler, more rapid and reliable method to discriminate S. Paratyphi B than the phenotypic lead acetate test.
    Matched MeSH terms: Paratyphoid Fever/diagnosis
  19. Rapid serologic diagnosis of pediatric typhoid fever in an endemic area: a prospective comparative evaluation of two dot-enzyme immunoassays and the Widal test
    Bhutta ZA, Mansurali N
    Am J Trop Med Hyg, 1999 Oct;61(4):654-7.
    PMID: 10548305
    We evaluated the diagnostic sensitivity and specificity of two dot-enzyme-linked immunoassays (Typhidot and Typhidot-M; Malaysian Biodiagnostic Research SDN BHD, Kuala Lumpur, Malaysia), assessing IgG and IgM antibodies against the outer membrane protein (OMP) of Salmonella typhi, and the Widal test in comparison with blood culture in a consecutive group of children with suspected typhoid fever. Of 97 children with suspected typhoid fever, the disease was confirmed bacteriologically in 46 (47%), whereas 25 (26%) were considered to have typhoid fever on clinical grounds. An alternative diagnosis was made in 26 (27%). The Typhidot and Typhidot-M were superior to the Widal test in their diagnostic sensitivity and specificity, although values (sensitivity = 85-94% and specificity = 77-89%) were significantly lower than in other regional reports. The lower specificity of the Typhidot in our series may represent regional differences in the genomic structure and plasticity of the OMP of S. typhi and merits further evaluation of these tests in diverse geographic locations.
    Matched MeSH terms: Typhoid Fever/diagnosis*
  20. Longevity of antibody responses to a Salmonella typhi-specific outer membrane protein: interpretation of a dot enzyme immunosorbent assay in an area of high typhoid fever endemicity
    Choo KE, Davis TM, Ismail A, Ong KH
    Am J Trop Med Hyg, 1997 Dec;57(6):656-9.
    PMID: 9430522
    The objective of this study was to investigate the longevity of positive dot enzyme immunosorbent assay (dot EIA) results for IgM and IgG to a Salmonella typhi outer membrane protein in Malaysian children with enteric fever. The patients were children one month to 12 years of age with clinical evidence of typhoid fever, positive blood or stool cultures for S. typhi, and/or a positive Widal test result who were admitted over a two-year period to General Hospital (Kota Bharu, Malaysia). These patients received standard inpatient treatment for enteric fever including chloramphenicol therapy for 14 days. Dot EIA tests were performed as part of clinical and laboratory assessments on admission, at two weeks, and then at 3, 6, 9, 12, 15, 18, and 21 months postdischarge. Assessment of the longevity of positive dot EIA IgM and IgG titers was done by Kaplan-Meier analysis. In 94 evaluable patients, 28% were dot EIA IgM positive but IgG negative on admission, 50% were both IgM and IgG positive, and 22% were IgM negative and IgG positive. Mean persistence of IgM dot EIA positivity was 2.6 months (95% confidence interval = 2.0-3.1 months) and that of IgG was 5.4 months (4.5-6.3 months). There were no significant differences between the three subgroups. Thus, positive IgM and IgG results determined by dot EIA within four and seven months, respectively, following documented or suspected enteric fever in a child from an endemic area should be interpreted with caution. In other clinical situations, the dot EIA remains a rapid and reliable aid to diagnosis.
    Matched MeSH terms: Typhoid Fever/diagnosis*
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