Displaying publications 61 - 80 of 212 in total

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  1. Hin HS, Ramalingam R, Chunn KY, Ahmad N, Ab Rahman J, Mohamed MS
    Am J Trop Med Hyg, 2012 Oct;87(4):737-40.
    PMID: 22826499 DOI: 10.4269/ajtmh.2012.12-0165
    Co-infection of melioidosis and leptospirosis is uncommon. We report here four such cases, confirmed by blood culture for melioidosis and blood polymerase-chain reaction for leptospirosis, which occurred among rescuers involved in a search and rescue operation for a young man who was suspected to have drowned in Lubuk Yu, a recreational forest in Pahang, Malaysia. Despite treatment, three of the patients died from the co-infection.
  2. Horstick O, Jaenisch T, Martinez E, Kroeger A, See LL, Farrar J, et al.
    Am J Trop Med Hyg, 2014 Sep;91(3):621-34.
    PMID: 24957540 DOI: 10.4269/ajtmh.13-0676
    The 1997 and 2009 WHO dengue case classifications were compared in a systematic review with 12 eligible studies (4 prospective). Ten expert opinion articles were used for discussion. For the 2009 WHO classification studies show: when determining severe dengue sensitivity ranges between 59-98% (88%/98%: prospective studies), specificity between 41-99% (99%: prospective study) - comparing the 1997 WHO classification: sensitivity 24.8-89.9% (24.8%/74%: prospective studies), specificity: 25%/100% (100%: prospective study). The application of the 2009 WHO classification is easy, however for (non-severe) dengue there may be a risk of monitoring increased case numbers. Warning signs validation studies are needed. For epidemiological/pathogenesis research use of the 2009 WHO classification, opinion papers show that ease of application, increased sensitivity (severe dengue) and international comparability are advantageous; 3 severe dengue criteria (severe plasma leakage, severe bleeding, severe organ manifestation) are useful research endpoints. The 2009 WHO classification has clear advantages for clinical use, use in epidemiology is promising and research use may at least not be a disadvantage.
  3. Huang SS, Hassan AK, Choo KE, Ibrahim MI, Davis TM
    Am J Trop Med Hyg, 2004 Oct;71(4):444-50.
    PMID: 15516641
    To determine the prevalence of Helicobacter pylori antigen carriage in stool in the Penan ethnic minority in Malaysian Borneo, we studied 295 Penans 0.6-89.0 years of age from 1) the remote Limbang Division, 2) Mulu regional center, and 3) Belaga village. Overall, 37.7% of the subjects tested positive. Peak prevalence was reached by 10 years of age. There were no differences in age, sex, body mass index, and socioeconomic/domestic variables between antigen-positive and antigen-negative subjects. In a logistic regression analysis, subjects from Limbang were least likely to be antigen-positive (odds ratio [OR] = 0.23, 95% confidence interval [CI] = 0.12-0.44 versus other sites, P < 0.001). Availability of a flushing toilet was protective against H. pylori carriage (OR = 0.51, 95% CI = 0.27-0.95, P = 0.031). Infection with H. pylori among the Penan was less than reported in other low socioeconomic groups. The lowest prevalence in the most remote setting suggests that the infection has been a recent arrival in previously isolated communities.
  4. Intapan PM, Chotmongkol V, Tantrawatpan C, Sanpool O, Morakote N, Maleewong W
    Am J Trop Med Hyg, 2011 Jun;84(6):994-7.
    PMID: 21633039 DOI: 10.4269/ajtmh.2011.10-0675
    Previously, we reported the presence of imported trichinellosis in a Thai worker returning from Malaysia, who presented with progressive generalized muscle hypertrophy and weakness after eating wild boar meat. This work analyzed a partial small subunit of a mitochondrial ribosomal RNA gene of Trichinella larvae isolated from the patient. The results showed complete identity with a mitochondrial RNA gene of Trichinella papuae (GenBank accession no. EF517130). This is the first report of imported trichinellosis in Thailand caused by T. papuae. It is possible that T. papuae is widely distributed in the wildlife of Southeast Asia.
  5. Javaid A, Ahmad N, Afridi AK, Basit A, Khan AH, Ahmad I, et al.
    Am J Trop Med Hyg, 2018 06;98(6):1629-1636.
    PMID: 29611497 DOI: 10.4269/ajtmh.17-0936
    To evaluate the predictive value of time to sputum culture conversion (SCC) in predicting cure and factors associated with time to SCC and cure in multidrug-resistant tuberculosis (MDR-TB) patients, a retrospective study was conducted at programmatic management unit of drug resistant tuberculosis (TB), Peshawar. A total of 428 pulmonary MDR-TB patients enrolled at the study site from January 1, 2012 to August 31, 2014 were followed until treatment outcome was recorded. Survival analysis using Cox proportional hazards model and multivariate binary logistic regression were, respectively, used to identify factors associated with time to SCC and cure. A P value < 0.05 was considered statistically significant. Overall, 90.9% patients achieved SCC, and 76.9% were cured. Previous use of second-line drugs (SLDs) (hazard ratio [HR] = 0.637; 95% confidence interval [CI] = 0.429-0.947), ofloxacin resistance (HR = 0.656; 95% CI = 0.522-0.825) and lung cavitation (HR = 0.744; 95% CI = 0.595-0.931) were significantly associated with time to SCC. In predicting cure, sensitivities of SCC at 2, 4, and 6 months were 64.1% (95% CI = 58.69-69.32), 93.0% (95% CI = 89.69-95.52), and 97.6% (95% CI = 95.27-98.94), respectively, whereas specificities were 67.7% (95% CI = 57.53-76.73), 51.5% (95% CI = 41.25-61.68), and 44.4% (95% CI = 34.45-54.78), respectively. Furthermore, patients' age of 41-60 (odds ratio [OR] = 0.202; 95% CI = 0.067-0.605) and > 60 years (OR = 0.051; 95% CI = 0.011-0.224), body weight > 40 kg (OR = 2.950; 95% CI = 1.462-5.952), previous SLD use (OR = 0.277; 95% CI = 0.097-0.789), lung cavitation (OR = 0.196; 95% CI = 0.103-0.371) and ofloxacin resistance (OR = 0.386; 95% CI = 0.198-0.749) were significantly associated with cure. Association of SCC with cure was substantially stronger at 6 months (OR = 32.10; 95% CI = 14.34-71.85) than at 4 months (OR = 14.13; 95% CI = 7.92-25.21). However in predicting treatment outcomes, the combined sensitivity and specificity of SCC at 4 months was comparable to SCC at 6 months. Patients with risk factors for delayed SCC were also at high risk of unsuccessful outcomes.
  6. Jeffree SM, Ahmed K, Safian N, Hassan R, Mihat O, Lukman KA, et al.
    Am J Trop Med Hyg, 2018 Jan;98(1):45-50.
    PMID: 29141714 DOI: 10.4269/ajtmh.17-0081
    Sabah is a Malaysian state situated in the northern part of Borneo, and it is endemic for malaria. The incidence of malaria is the lowest (0.05/1,000 population) in Penampang districts of Sabah. In June 26, 2012, two Plasmodium falciparum malaria cases were notified to public health department from a village in Penampang. Immediate investigation was initiated to identify the risk factors and to institute control measures. We performed active case finding by asking household members of all houses in the village regarding malaria symptoms and by examining blood smears. Environmental investigation was performed by collecting samples to detect mosquito breeding sites and to identify malaria transmitting vector mosquitoes. A case-control study with a ratio of 1:4 (11 cases and 44 controls) was conducted using self-administered questionnaire. The microscopic examination of blood smear for malarial parasite and entomology sampling was carried out. The malarial attack rate was 2.3%, 6/11 smears have gametocyte, and the case fatality rate was 9.1%. One case was a migrant rubber tapper from Indonesia which happened to be the first case with gametocyte positive. Overall, the incidence of malaria was higher (6/11) among rubber tappers. The odds of cases for those living nearby stagnant water were 7.3 [95% confidence interval: 1.2-43.5] times higher. In conclusion, an outbreak of P. falciparum malaria was introduced into a malaria-free village by a migrant rubber tapper, by whom the imported parasite was introduced to the community via vector Anopheles balabacensis. Living near stagnant water bodies was the risk factor in this outbreak.
  7. Jegathesan M, Paramasivam T
    Am J Trop Med Hyg, 1976 Jan;25(1):201-2.
    PMID: 943960
    Vibrio parahaemolyticus was isolated from 47 of 2,699 stools examined primarily for the exclusion of cholera. All strains grew well in alkaline peptone water containing 0.5% NaCl and in Monsur's medium. Serotyping showed them to be of various types. Adults were mainly affected. The importance of looking for V. parahaemolyticus in clinical specimens from cases of diarrhea is emphasized.
  8. Jikal M, Mori D, Yusoff AF, Rai SB, Mukhsam MH, Ali I, et al.
    Am J Trop Med Hyg, 2021 07 12;105(3):777-782.
    PMID: 34255740 DOI: 10.4269/ajtmh.21-0036
    Foodborne outbreaks of hepatitis A virus (HAV) are most commonly associated with fresh and frozen produce and with various types of shellfish. Alcoholic beverage-borne outbreaks of hepatitis A are extremely rare. Here, we report an outbreak of hepatitis A associated with the consumption of a traditional wine at a funeral ceremony in the Sabah state of Malaysian Borneo. Confirmed cases were determined by serum anti-HAV immunoglobulin M and/or for fecal HAV by reverse transcription polymerase chain reaction (RT-PCR). The amplicons of RT-PCR were subjected to nucleotide sequencing followed by phylogenetic analysis. We conducted a 1:2 case-control study to identify the possible exposure that led to the outbreak. Sixteen patients met the case definition, they were 18 to 58 years old and 90% of them were males. The case-control study showed that the consumption of nipa palm wine during the ceremony was significantly associated (P = 0.0017) with hepatitis A infection (odds ratio, 5.44; 95% CI, 1.80-16.43). Untreated river water was used to dilute the traditional wine, which was assumed to be the source of the infection. Phylogenetically, these viruses belonged to genotype IA and formed an independent cluster with strains from Taiwan, Japan, and the Philippines. This strain might be an emerging HAV in Asian countries. Environmental assessments were performed and environmental samples were negative for HAV. The incidence of hepatitis A in Sabah was also determined and it was 0.795/100,000 population. Strict monitoring of traditional wine production should be implemented by the local authority to prevent future outbreaks.
  9. Joseph PG, Anwar M, Jegathesan M
    Am J Trop Med Hyg, 1978 May;27(3):562-6.
    PMID: 354419
    A total of 860 Salmonella isolations were made in Peninsular Malaysia from 15 animal species (domestic and wild), eggs, molluscs, flies, and animal feed. The isolations were distributed among 31 serotypes in eight groups. The most common serotype isolated was Salmonella pullorum, followed by S. choleraesuis and S. infantis. S. typhimurium had the widest zoological distribution. The importance of controlling animal salmonellosis is emphasized.
  10. Kan SP, Prathap K, Dissanaike AS
    Am J Trop Med Hyg, 1979 Jul;28(4):634-42.
    PMID: 111569
    The ultrastructure of the cyst wall and zoites of a species of Sarcocystis from the skeletal muscles of a naturally-infected Malaysian long-tailed monkey, Macaca fascicularis, is described in detail. The wavy, electron-dense primary cyst wall is thin (55 nm) and invaginated. Cytophaneres are absent. The ground substance contains electron-dense granules and bundles of parallel, fibrillar elements in some areas. Thin trabeculae are present. The zoites measure 1.2 X 4.7 microns and have an interior conoid, 22 subpellicular microtubules, 50-60 micronemes, 4-6 rhoptries, and a posteriorly situated nucleus. Some ultrastructural aspects of the cyst wall and the zoites of this parasite resemble those of Sarcocystis species of the moonrat, rhesus monkey, tamarin, and baboon. The light microscopic appearance of this species from M. fascicularis also bears some resemblance to that of parasites from the four cases of human Sarcocystis reported in Malaysia. The cyst in all these human cases were thin-walled, with no cytophaners. Although the final hosts of these species of Sarcocystis are not known, it is quite possible that man, monkeys, and perhaps the moonrat (an insectivore) may serve as common intermediate hosts for one or several species of Sarcocystis.
  11. Kavana N, Sonaimuthu P, Kasanga C, Kassuku A, Al-Mekhlafi HM, Fong MY, et al.
    Am J Trop Med Hyg, 2016 Oct 05;95(4):874-876.
    PMID: 27481059 DOI: 10.4269/ajtmh.16-0211
    In this study, the seroprevalence of sparganosis and its relationship with sociodemographic factors in northern Tanzania have been assessed. A total of 216 serum samples from two rural districts, Monduli and Babati, were tested for sparganosis using an enzyme-linked immunosorbent assay. The seroprevalence of anti-sparganum IgG antibodies was 62.5% (95% confidence interval [CI] = 56.1-68.9) in all age groups. There were significant associations between district (relative risk [RR] = 1.95, 95% CI = 1.42-2.69), education (RR = 1.40, 95% CI = 1.15-1.70), and pet ownership with seropositivity (RR = 1.48, 95% CI = 1.02-2.16) based on univariate analysis. However, only the district was significantly associated with seropositivity (odds ratio = 4.20, 95% CI = 1.89-9.32) in binary logistic regression analysis. Providing health education to people residing in sparganosis-endemic areas is likely to improve the efficacy of preventative measures and reduce human disease burden.
  12. Kelly DJ, Wong PW, Gan E, Chye CT, Cowan D, Lewis GE
    Am J Trop Med Hyg, 1990 Sep;43(3):301-7.
    PMID: 2121057
    Scrub typhus is a major cause of febrile illness throughout the Asia-Pacific region. It is commonly undiagnosed, partly because of the lack of a simple, reliable diagnostic test which can be used in clinical laboratories. The indirect immunoperoxidase technique, configured into a test kit, was provided to technicians who were trained in its use. They used the kit during a 2 year field trial in their respective clinical hospital laboratories throughout Malaysia. In an evaluation using 1,722 consecutive sera tested in those laboratories, the kit was found to have a median sensitivity for IgG detection of 0.85 (range 0.33-0.95), a median specificity of 0.94 (range 0.88-1.00), reproducibility of 0.86, and efficiency of 0.92 when compared to the reference laboratory. In a proficiency survey in which 10 laboratories received 3 coded test samples, all but 2 laboratories had results within 1 dilution of the reference laboratory in quantitating specific IgG, whereas 7 laboratories were within 1 dilution in quantitating IgM. The shelf life of the kit was at least 1 year at 4 degrees C.
  13. Kelly DJ, Wong PW, Gan E, Lewis GE
    Am J Trop Med Hyg, 1988 Mar;38(2):400-6.
    PMID: 3128129 DOI: 10.4269/ajtmh.1988.38.400
    An indirect immunoperoxidase test was compared with an indirect fluorescent antibody test and the Weil-Felix OXK test for serodiagnosis of scrub typhus by measuring the rickettsial antigen specific activity of IgG, IgM, and whole globulin. Acute and convalescent sera from 50 Rickettsia tsutsugamushi isolate-positive scrub typhus patients and from 45 febrile patients diagnosed as having diseases other than scrub typhus were tested. The receiver operating characteristic for each test showed that the indirect immunoperoxidase and indirect fluorescent antibody tests were more sensitive and specific than the Weil-Felix test using convalescent and acute as well as paired sera. The indirect immunoperoxidase test showed no cross-reactivity when R. tsutsugamushi antigen was tested against sera collected from patients living outside the scrub typhus-endemic area with diseases other than scrub typhus. The indirect immunoperoxidase and indirect fluorescent antibody tests were comparable in measured response to R. tsutsugamushi, R. typhi, and TT-118 (spotted fever group) antigen. Thus the indirect immunoperoxidase test represents a sensitive, specific, reproducible, and practical semiquantitative test for rickettsial disease diagnosis.
  14. Khalil I, Colombara DV, Forouzanfar MH, Troeger C, Daoud F, Moradi-Lakeh M, et al.
    Am J Trop Med Hyg, 2016 Dec 07;95(6):1319-1329.
    PMID: 27928080 DOI: 10.4269/ajtmh.16-0339
    Diarrheal diseases (DD) are leading causes of disease burden, death, and disability, especially in children in low-income settings. DD can also impact a child's potential livelihood through stunted physical growth, cognitive impairment, and other sequelae. As part of the Global Burden of Disease Study, we estimated DD burden, and the burden attributable to specific risk factors and particular etiologies, in the Eastern Mediterranean Region (EMR) between 1990 and 2013. For both sexes and all ages, we calculated disability-adjusted life years (DALYs), which are the sum of years of life lost and years lived with disability. We estimate that over 125,000 deaths (3.6% of total deaths) were due to DD in the EMR in 2013, with a greater burden of DD in low- and middle-income countries. Diarrhea deaths per 100,000 children under 5 years of age ranged from one (95% uncertainty interval [UI] = 0-1) in Bahrain and Oman to 471 (95% UI = 245-763) in Somalia. The pattern for diarrhea DALYs among those under 5 years of age closely followed that for diarrheal deaths. DALYs per 100,000 ranged from 739 (95% UI = 520-989) in Syria to 40,869 (95% UI = 21,540-65,823) in Somalia. Our results highlighted a highly inequitable burden of DD in EMR, mainly driven by the lack of access to proper resources such as water and sanitation. Our findings will guide preventive and treatment interventions which are based on evidence and which follow the ultimate goal of reducing the DD burden.
  15. Khalilpour A, Sadjjadi SM, Moghadam ZK, Yunus MH, Zakaria ND, Osman S, et al.
    Am J Trop Med Hyg, 2014 Nov;91(5):994-9.
    PMID: 25200268 DOI: 10.4269/ajtmh.14-0170
    Cystic echinococcosis (CE) caused by infection with Echinococcus granulosus is of major concern for humans in many parts of the world. Antigen B was prepared from E. granulosus hydatid fluid, and Western blots confirmed eight batches showing a band corresponding to the 8-/12-kDa subunit with positive serum and no low-molecular mass band (< 15 kDa) with negative serum. The batches were pooled and used to prepare lateral flow immunoglobulin G4 (IgG4) and IgG dipsticks. Diagnostic sensitivity was determined using serum samples from 21 hydatidosis patients, and diagnostic specificity was established using sera from 17 individuals infected with other parasites and 15 healthy people. IgG4 dipstick had a diagnostic sensitivity of 95% (20 of 21) and a specificity of 100% (32 of 32). The IgG dipstick had a sensitivity of 100% (21 of 21) and a specificity of 87.5% (28 of 32). Thus, both IgG and IgG4 dipsticks had high sensitivities, but IgG4 had greater specificity for the diagnosis of human CE.
  16. Kho KL, Koh FX, Singh HK, Zan HA, Kukreja A, Ponnampalavanar S, et al.
    Am J Trop Med Hyg, 2016 10 05;95(4):765-768.
    PMID: 27402519
    Limited information is available on the etiological agents of rickettsioses in southeast Asia. Herein, we report the molecular investigation of rickettsioses in four patients attending a teaching hospital in Malaysia. DNA of Rickettsia sp. RF2125, Rickettsia typhi, and a rickettsia closely related to Rickettsia raoultii was detected in the blood samples of the patients. Spotted fever group rickettsioses and murine typhus should be considered in the diagnosis of patients with nonspecific febrile illness in this region.
  17. Khoo HY, Lee HY, Khor CS, Tan KK, Bin Hassan MR, Wong CM, et al.
    Am J Trop Med Hyg, 2022 Jul 25;107(3):560-8.
    PMID: 35895331 DOI: 10.4269/ajtmh.21-0988
    Zika virus (ZIKV) has had a history in Malaysia since its first isolation in 1966. However, it is believed that the immunity status among forest fringe communities has been underreported. We conducted cross-sectional surveillance of forest fringe communities from 10 Orang Asli villages and their peripheral communities in Perak, Pahang, and Sabah in Malaysia. A total of 706 samples were collected from 2019 to 2020 and screened for ZIKV exposure using an anti-ZIKV IgG ELISA kit. A neutralization assay against ZIKV was used to confirm the reactive samples. The seroprevalence results reported from the study of this population in Malaysia were 21.0% (n = 148, 95% CI, 0.183-0.273) after confirmation with a foci reduction neutralization test. The presence of neutralizing antibodies provides evidence that the studied forest fringe communities in Malaysia have been exposed to ZIKV. Multivariate analysis showed that those older than 44 years and those with an education below the university level had been exposed significantly to ZIKV. In addition, higher seropositivity rates to ZIKV were also reported among secondary school students from Bentong (Pahang) and residents from Segaliud (Sabah). No associations were identified between Zika seropositivity and gender, household size, house radius to the jungle, and income level. The presence of neutralizing antibodies against ZIKV among the study population might indicate that the causative pathogen had already circulated widely in forest fringe regions. Intervention for vector control, protection from mosquito bites, and awareness improvement should be encouraged in this population.
  18. Kobayashi N, Thayan R, Sugimoto C, Oda K, Saat Z, Vijayamalar B, et al.
    Am J Trop Med Hyg, 1999 Jun;60(6):904-9.
    PMID: 10403318
    To characterize the dengue epidemic that recently occurred in Malaysia, we sequenced cDNAs from nine 1993-1994 dengue virus type-3 (DEN-3) isolates in Malaysia (DEN-3 was the most common type in Malaysia during this period). Nucleic acid sequences (720 nucleotides in length) from the nine isolates, encompassing the precursor of membrane protein (preM) and membrane (M) protein genes and part of the envelope (E) protein gene were aligned with various reference DEN-3 sequences to generate a neighbor-joining phylogenetic tree. According to the constructed tree, the nine Malaysian isolates were grouped into subtype II, which comprises Thai isolates from 1962 to 1987. Five earlier DEN-3 virus Malaysian isolates from 1974 to 1981 belonged to subtype I. The present data indicate that the recent dengue epidemic in Malaysia was due to the introduction of DEN-3 viruses previously endemic to Thailand.
  19. Kono Y, Tsukamoto K, Abd Hamid M, Darus A, Lian TC, Sam LS, et al.
    Am J Trop Med Hyg, 2001 5 19;63(1-2):94-101.
    PMID: 11358004
    A new virus named Sitiawan virus (SV) was isolated from sick broiler chicks in chicken embryos. The virus replicated well with cytopathogenic effect (CPE) in the chicken B-lymphocyte cell line LSCC-BK3. The virus was an enveloped RNA virus of approximately 41 nm in size with hemagglutinating activity (HA) to goose erythrocytes. It was cross-reactive with Japanese encephalitis virus (JEV), a member of flaviviruses by HA inhibition tests but not by cross-virus neutralization tests. The cDNA fragment of NS5 gene was amplified with primers corresponding to NS5 gene of flaviviruses. The nucleotide sequences were 92% homologous to Tembusu virus, a member of the mosquito-borne virus cluster of the genus Flavivirus. In cross-neutralization tests with Tembusu virus, antiserum to SV did not neutralize Tembusu virus, and antiserum to Tembusu virus neutralized more weakly to SV than against homologous virus. These results indicate that SV is a new virus which can be differentiated serologically from Tembusu virus but is otherwise similar with respect to nucleotide sequence. The virus causes encephalitis, growth retardation, and increased blood glucose levels in inoculated chicks.
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