Displaying publications 1 - 20 of 724 in total

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  1. Baharin SNAN, Tan SL, Sam IC, Chan YF
    Trop Biomed, 2023 Dec 01;40(4):478-485.
    PMID: 38308836 DOI: 10.47665/tb.40.4.014
    Hand, foot, and mouth disease (HFMD) is a contagious childhood disease caused by enteroviruses including enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6) and CV-A16 transmitted via direct and indirect contact. Different types of toy surfaces can affect the stability of viruses. Understanding the stability of enteroviruses on toys provides insightful data for effective disinfection in kindergartens or homes. Porous (ethylene-vinyl acetate mat foam, paper, pinewood, polyester fabric, and squishy polyurethane foam) and non-porous (acrylonitrile butadiene styrene plastic and stainless-steel coin) surfaces were inoculated with EV-A71 at 4, 24, and 35°C, and coxsackieviruses at 24°C. Infectious enteroviruses were recovered and titred in median tissue culture infectious dose assay (TCID50). Atomic force microscopy (AFM) images were taken from surfaces to examine association of surface roughness with virus stability. Overall, infectious enteroviruses were persistent on all non-porous and porous surfaces. Virus persistence was longest at 4°C followed by 24°C and 35°C. EV-A71 half-lives ranged between 6.4-12.8 hours at 4°C, 2.4-6.7 hours at 24°C, and 0.13-2.7 hours at 35°C. At lower virus titres exposed to 24°C, half-lives of enteroviruses ranged from 0.1-1.4 hours. Surface roughness values from AFM suggested smooth surfaces of non-porous surfaces were associated with better virus stability. Temperature, enterovirus concentration, and type of surface affected persistence and stability of enteroviruses. Our findings suggest both porous and non-porous surfaces in kindergartens allow enterovirus persistence and should be frequently disinfected to curb HFMD outbreaks in kindergartens.
  2. Al-Madhagi WM, Sharhan O, Jadan B, Hashim NM, Awadh N, Othman R
    Trop Biomed, 2023 Dec 01;40(4):486-496.
    PMID: 38308837 DOI: 10.47665/tb.40.4.015
    Much of the new research and investigation in pharmacy sciences are concerned with developing therapeutic agents, and identifying and finding new drugs with their chemical structure to treat different human diseases such as infectious diseases from natural products. Therefore, the present findings relate to isolating five new compounds the dichloromethane extract of Peperomia blanda (Jacq.) Kunth grown on Socotra Island, Yemen. two new secolignans; which have been proposed as peperomin I & J. These compounds were isolated together with the other two polyketides presented as surinone D and dindygulerione F. The chemical structures were elucidated and confirmed with nuclear magnetic resonance (NMR) and liquid chromatography-mass spectroscopy (LCMS) analysis. These compounds were first isolated and reported from this plant. These new compounds' antimicrobial activity has been evaluated, and minimum inhibitory concentration has been recorded in the range of 125-250 µg/mL. The pharmacotherapeutic spectrum of compounds was predicated using PASS software which showed potential activity.
  3. Boonsuya A, Chitpitaklert P, Pechdee P, Srithongklang W, Thanchonnang C, La N, et al.
    Trop Biomed, 2023 Dec 01;40(4):471-477.
    PMID: 38308835 DOI: 10.47665/tb.40.4.013
    Entamoeba gingivalis is present in the oral cavity of humans and is associated with periodontal disease. Consequently, this study aimed to comprehensively investigate the E. gingivalis infection and the associated risk factors among individuals suffering from periodontal conditions. A cross-sectional descriptive study was carried out within a cohort of periodontal patients. Dental plaque specimens were meticulously collected and subsequently subjected to thorough examination using the polymerase chain reaction (PCR)-based technique targeting the small subunit ribosomal RNA (SrRNA) gene of the organism. The occurrence of risk factors for E. gingivalis infection was analyzed by the chi-square test and binary logistic regression. Out of the 230 participants, 60 were clinically diagnosed with periodontitis, while 170 were afflicted with gingivitis. Out of the 230 patients, 25 (10.9%) tested positive for E. gingivalis infections. An in-depth analysis unveiled that a significant majority of infections were recorded within subgroups characterized by a marital status (15.45%), manifestation of periodontitis (25.00%), and concomitant presence of underlying disease (20.83%). Furthermore, the high risk factor associated with E. gingivalis infection was the female (ORadj = 13.65, 95% CI = 1.08-173.21), followed by periodontitis (ORadj = 3.30, 95% CI = 1.21-9.00), respectively. The study employs a molecular diagnostic approach to screen for E. gingivalis enrichment within a subset of periodontal patients with advancing disease. The findings emphasize the necessity for further research to elucidate the pathogenesis of E. gingivalis and advocate for vigilant surveillance within a substantial population of periodontal patients.
  4. Subejano MSE, Penuliar G
    Trop Biomed, 2023 Dec 01;40(4):422-429.
    PMID: 38308829 DOI: 10.47665/tb.40.4.007
    Campylobacteriosis is a human infection primarily caused by Campylobacter jejuni and Campylobacter coli. Consumption of contaminated chicken and poultry products is the main mode of transmission. These bacteria possess virulence factors, including adhesins and toxins, which contribute to their pathogenesis. Moreover, their large genomes undergo frequent genetic recombination, resulting in a high degree of genetic diversity. However, limited information is available regarding the virulence and genotypic diversity profiles of these microorganisms in the Philippines. The objective of this study was to address this knowledge gap by characterizing Campylobacter isolates obtained from chicken offal sold in wet markets in Metro Manila, Philippines. Multilocus Sequence Typing (MLST) analysis was performed to determine the sequence types, resulting in the identification of 13 unique sequence types, including nine previously unreported ones, and three clonal complexes. Notably, the widespread sequence type ST-305 was found in samples from different markets. Furthermore, six isolates deposited in the Campylobacter PubMLST database were identified as C. coli based on allele profiles. Profiling using 10 selected virulence genes revealed that more than half of the isolates carried these genes. The most prevalent virulence gene was cadF (100%), followed by flaA (95%), racR, cdtA, cdtB, and cdtC (85%). The genes dnaJ and ceuE were also present in 75% of the isolates. Despite the limited sample size, the findings of this study reveal a significant level of genotypic diversity among the Campylobacter isolates. This diversity has important implications for source attribution studies and the identification of strains involved in campylobacteriosis outbreaks. Furthermore, the investigation of virulence factors associated with colonization and invasion of the avian gut can provide insights for the development of practical applications in Campylobacter control strategies. Understanding and addressing these factors are crucial steps toward mitigating the risk of Campylobacter infections and enhancing public health efforts.
  5. Teh ZH, Lim BH, See Too WC, Few LL
    Trop Biomed, 2023 Dec 01;40(4):430-438.
    PMID: 38308830 DOI: 10.47665/tb.40.4.008
    Entamoeba histolytica is the parasite responsible for amoebiasis, which can result in amoebic colitis or amoebic liver abscess. Metronidazole has been the conventional treatment for intestinal amoebiasis, but concerns regarding resistance have emerged due to the identification of resistance pathways in E. histolytica. This study investigates a novel anti-amoebic approach targeting the CDP-choline pathway. Inhibition studies were conducted using potential choline kinase (CK) inhibitors to inhibit the EhCK enzyme, and RNA interference was employed to knock down the EhCK gene. Km and Vmax of purified EhCK and hCKa2 proteins were determined by pyruvate kinase-lactate dehydrogenase (PK-LDH) coupled assay. The IC50 values for EhCK and hCKa2 were determined with several commercial CK inhibitors. Selected inhibitors were incubated with E. histolytica trophozoites for 48 hours to determine the EC50 for each inhibitor. Silencing of gene encoding EhCK was carried out using duplex siRNA and the gene expression level was measured by real-time qPCR. Based on the IC50 values, three of the inhibitors, namely CK37, flavopiridol and H-89 were more potent against EhCK than hCKa2. Trophozoites growth inhibition showed that only HDTAB, H-89 and control drug metronidazole could penetrate and induce cell death after 48-hour incubation. siRNA concentration of 10 µg/mL was used for the transfection of positive control GAPDH, EhCK, and non-targeting GFP siRNAs. RNAi experiment concluded with positive control GAPDH downregulated by 99% while the level of EhCK mRNA was downregulated by 47%. In this study, potential inhibitors of EhCK and siRNA have been identified, paving the way for further refinement and testing to enhance their potency against EhCK while sparing hCK. The utilization of these specific inhibitors and siRNA targeting EhCK represents a novel approach to impede the growth of E. histolytica by disrupting its phospholipid synthesis pathway.
  6. Zhao L, Wu HY, Xie D, Mo LM, Yang FF, Gao Y, et al.
    Trop Biomed, 2023 Dec 01;40(4):439-443.
    PMID: 38308831 DOI: 10.47665/tb.40.4.009
    The study of children who experienced with febrile seizures(FS) as a result of COVID-19 infection to gain insight into the clinical characteristics and prognosis of neurological damage, with the aim of improving prevention, diagnosis, and the treatment of neurological complications. This study investigated the clinical features of 53 children with FS who were admitted to Sanya Women and Children's Hospital from December 1, 2022, to January 31, 2023. The results indicated that the duration of convulsion in the case and control group was 7.90±8.91 and 2.67±1.23 (minutes) respectively. The analysis reveals that convulsions occurred within 24 hours in 39 cases (95.12%) of the case group, and in 8 cases (66.7%) of the control group. The difference was statistically significant (P<0.05). Additionally, the case group presented lower counts of WBC and NEU compared to the control group (p<0.05). The findings indicate that convulsions manifest at earlier stages of COVID-19 in children and the last longer than in the control group. It is therefore crucial for healthcare workers to remain attentive to patients with COVID-19 who report fever within 24 hours, and act promptly to implement preventive measures, particularly in cases of prolonged fever. It is essential to integrate the clinical manifestation, particularly convulsions, and the continuous numerical changes of inflammatory factors to assess COVID-19 linked with febrile seizures. In addition, larger-scale multi-center and systematic research are necessary to aid clinicians in monitoring neuropathological signals and biological targets, enabling more equitable diagnosis and treatment plans.
  7. John DV, Sreenivas N, Deora H, Purushottam M, Debnath M, Mahadevan A, et al.
    Trop Biomed, 2023 Dec 01;40(4):406-415.
    PMID: 38308827 DOI: 10.47665/tb.40.4.005
    The pathogenesis of chronic parasitic central nervous system (CNS) infections, including granulomatous amoebic meningoencephalitis (GAE), cerebral toxoplasmosis (CT), and neurocysticercosis (NCC), is primarily due to an inflammatory host reaction to the parasite. Inflammatory cytokines produced by invading T cells, monocytes, and CNS resident cells lead to neuroinflammation which underlie the immunopathology of these infections. Immune molecules, especially cytokines, can therefore emerge as potential biomarker(s) of CNS parasitic infections. In this study, cerebral spinal fluid (CSF) samples from suspected patients with parasitic infections were screened for pathogenic free-living amoebae by culture (n=2506) and PCR (n=275). Six proinflammatory cytokines in smear and culture-negative CSF samples from patients with GAE (n = 2), NCC (n = 7), and CT (n = 23) as well as control (n = 7) patients were measured using the Multiplex Suspension assay. None of the CSF samples tested was positive for neurotropic free-living amoebae by culture and only two samples showed Acanthamoeba 18S rRNA by PCR. Of the six cytokines measured, only IL-6 and IL-8 were significantly increased in all three infection groups compared to the control group. In addition, TNFa levels were higher in the GAE and NCC groups and IL-17 in the GAE group compared to controls. The levels of IL-1b and IFNg were very low in all the infection groups and the control group. There was a correlation between CSF cellularity and increased levels of IL-6, IL-8, and TNFa in 11 patients. Thus, quantifying inflammatory cytokine levels in CSF might help with understanding the level of neuroinflammation in patients with neurotropic parasitic diseases. Further studies with clinico-microbiological correlation in the form of reduction of cytokine levels with treatment and the correlation with neurological deficits are needed.
  8. Kazim AR, Houssaini J, Tappe D, Heo CC, Vellayan S
    Trop Biomed, 2023 Dec 01;40(4):416-421.
    PMID: 38308828 DOI: 10.47665/tb.40.4.006
    We report two new records of chewing lice from avian pets in Peninsular Malaysia: Colpocephalum apivorus Tendeiro, 1958 from an Oriental honey buzzard (Pernis ptilorhynchus (Temminck, 1821)), and Myrsidea splendenticola Klockenhoff, 1973 from an albino house crow (Corvus splendens Vieillot, 1817). The scarcity of louse records from avian pets and wild birds, and the lack of louse research in Malaysia are discussed.
  9. Abdullah DA, Aishah EA
    Trop Biomed, 2023 Dec 01;40(4):453-461.
    PMID: 38308833 DOI: 10.47665/tb.40.4.011
    The present study was conducted to investigate the immunomodulatory and anti-inflammatory effects of Elettaria cardamomum essential oil (ECEO) for the control of acute Toxoplasma gondii infection. The effect of ECEO on T. gondii tachyzoites was measured by the tetrazolium bromide method. Mice received ECEO orally at doses of 1-4 mg/kg/day for 14 days. Once acute toxoplasmosis was induced in mice, their mortality rate and parasite load were recorded. The level of liver antioxidant/oxidant enzymes and the level of mRNA expression of interleukin-1 beta and interferongamma were also investigated. ECEO particularly at a concentration of 150 µg/ml has promising in vitro anti-Toxoplasma effects (p<0.001). After treatment with ECEO, the mortality rate (9th day) and parasite load decreased (p<0.001) in the infected mice. ECEO markedly (p < 0.05) restored hepatic oxidant and antioxidant enzyme levels, as well as increased cytokines. These results report a significant inhibitory effect of ECEO mainly at a dose of 4 mg/mL, against the T. gondii Rh strain through strengthening the immune system and reducing inflammation and oxidative stress; however, further research is needed to verify these results.
  10. Siew ZY, Lai ZJ, Ho QY, Ter HC, Ho SH, Wong ST, et al.
    Trop Biomed, 2023 Dec 01;40(4):462-470.
    PMID: 38308834 DOI: 10.47665/tb.40.4.012
    Bats are flying mammals with unique immune systems that allow them to hold many pathogens. Hence, they are recognised as the reservoir of many zoonotic pathogens. In this study, we performed molecular detection to detect coronaviruses, paramyxoviruses, pteropine orthoreoviruses and dengue viruses from samples collected from insectivorous bats in Krau Reserve Forest. One faecal sample from Rhinolophus spp. was detected positive for coronavirus. Based on BLASTN, phylogenetic analysis and pairwise alignment-based sequence identity calculation, the detected bat coronavirus is most likely to be a bat betacoronavirus lineage slightly different from coronavirus from China, Philippines, Thailand and Luxembourg. In summary, continuous surveillance of bat virome should be encouraged, as Krau Reserve Forest reported a wide spectrum of biodiversity of insectivorous and fruit bats. Moreover, the usage of primers for the broad detection of viruses should be reconsidered because geographical variations might possibly affect the sensitivity of primers in a molecular approach.
  11. Paul BT, Jesse FAA, Kamaludeen J, Chung ELT, Mat Isa K, Azhar NA, et al.
    Trop Biomed, 2023 Dec 01;40(4):444-452.
    PMID: 38308832 DOI: 10.47665/tb.40.4.010
    This paper describes the occurrence of multiple parasitic infection with special reference to emerging haemotropic Mycoplasma ovis. A cross-sectional survey of four selected goat flocks was conducted to collect samples and management information. Blood samples were processed using microhaematocrit centrifugation to determine the packed cell volume (PCV). Detection and morphological identification of blood protozoa and haemotropic Mycoplasma ovis from Giemsa-stained smears were done microscopically. M. ovis infection was classified mild (1-29% infected cells), moderate (30-59% infected cells), or severe (above 60% infected cells). Faecal floatation and McMaster faecal egg count were used to detect and classify strongyle infections as negative (no eggs/oocysts), light (< 500 epg), Moderate (500 - 1000 epg), or severe (>1000 epg) and coccidia infection as light (<1800 opg), moderate (1800 - 6000 opg), or severe (>6000 opg). There were 149 goats with blood protozoa (57.98%; 95% CI: 51.87 - 63.85) and 204 goats with GI parasites (79.38%; 95% CI: 74.02 - 83.87) involved in single (15.8%; 95% CI: 11.7 - 21.0) or multiple (84.2%; 95% CI: 79.0 - 88.3) infections. The risk of Strongyles increases by 2.49 (95% CI: 1.24 - 4.99) in females versus males and 6.79 (95% CI: 3.25 - 14.18, p =0.000) in adults versus young. The risk of Eimeria species increases by 7.32 (95% CI: 3.45 - 15.50, p =0.000) in adults versus young, while M. ovis coinfection risk increases by 4.51 (95% CI: 1.40 - 14.50, p =0.000) in female versus males. Thin animals had a significantly higher (p<0.05) mean burden of Strongyle (1370.37 ± 345.49) and Eimeria (1594.12 ± 695.26) than the moderate and fat goats. The PCV was negatively associated with mean faecal egg count (FEC) (p<0.05) such that a lower PCV was recorded in animals with a higher Strongyle epg output. A severe burden of M. ovis was accompanied by an increased nematode FEC and decreased haematocrit (p<0.05). Coinfections of Strongyles, or Eimeria species involving M. ovis were associated with a higher parasitaemia compared with single infections (p<0.05). This study highlights the importance of M. ovis and Strongyle or Eimeria species coinfections among goat flocks and provides valuable data for developing and implementing an integrated herd health management program for parasite control among low-input smallholder flocks.
  12. La N, Leng M, Arunsan P, Pechdee P, Boonsuya A, Thanchonnang C, et al.
    Trop Biomed, 2023 Dec 01;40(4):383-391.
    PMID: 38308824 DOI: 10.47665/tb.40.4.002
    The southeast Asian fluke Opisthorchis viverrini remains endemic, particularly in Thailand, Lao PDR, Cambodia, Vietnam, and Myanmar. However, there is a lack of data on the prevalence of liver fluke infection in Kratie Province in northeastern Cambodia. The present study aimed to detect O. viverrini DNA in fecal specimens by using the internal transcribed spacer 2 (ITS2) region of ribosomal DNA (rDNA) based on polymerase chain reaction (PCR). The prevalence and percentage of O. viverrini infection were described by data analysis. Bivariate binary logistic regression analysis was used to look at the related prevalence of O. viverrini infection. A total of 6.89% from 377 fecal samples were found positive of O. viverrini DNA. The prevalence of O. viverrini infection was found to be higher in men (8.92%) than in women (5.45%), and to be associated more frequently with younger age groups (13.40%), illiteracy (8.74%), participation in other careers (non-specific occupations) (11.63%), and residence in the Trapaing Srae village (9.94%) of the Snuol district, Kratie Province. Age groups under 20 years old were significantly linked with O. viverrini infection, with ORadj=0.601, 95% CI=0.410-0.882, p=0.009 and significant value established at (P<0.05). This study demonstrates that O. viverrini infection is distributed in rural areas located near freshwater reservoirs. Therefore, active surveillance, clinical examination of association with hepatobiliary, cholangiocarcinoma, and health education are needed.
  13. Goa Y, Du JG, Jirapattharasate C, Galon E, Ji SW, Ran ZG, et al.
    Trop Biomed, 2023 Dec 01;40(4):400-405.
    PMID: 38308826 DOI: 10.47665/tb.40.4.004
    Beta toxin (CPB) is a lethal toxin and plays a key role in enterotoxemia of ruminants caused by Clostridium perfringens type C strain. The existing vaccines based on crude CPB need time-consuming detoxification and difficult quality control steps. In this study, we synthesized the rCPBm4 of C. perfringens type C strain and small ubiquitin-like modifier (SUMO)-tag CPBm4 (rSUMO-CPBm4) by introducing four amino acid substitutions: R212E, Y266A, L268G, and W275A. Compared with rCPBm4, rSUMO-CPBm4 was expressed with higher solubility in Escherichia coli BL21 (DE3). Neither rCPBm4 nor rSUMO-CPBm4 was lethal to mice. Although rCPBm4 and rSUMO-CPBm4 were reactogenic with polyclonal antibodies against crude CPB, rabbits vaccinated with rSUMO-CPBm4 developed significant levels of toxin-neutralizing antibody (TNA) titers that conferred protection against crude toxin challenge. These data suggest that genetically detoxified rSUMO-CPBm4 is a promising subunit vaccine candidate for C. perfringens type C beta enterotoxemia.
  14. Sanggari A, Attah AO, Yahaya ZS, Farah Haziqah MT
    Trop Biomed, 2023 Dec 01;40(4):392-399.
    PMID: 38308825 DOI: 10.47665/tb.40.4.003
    Blastocystis is a prevalent infectious agent found in the gastrointestinal tract of humans and animals. While the morphology of Blastocystis has been extensively studied, there is still a lack of comprehensive research on its ultrastructure, especially regarding surface characteristics and their correlation with pathogenic potential. Additionally, the subtyping of Blastocystis does not provide information on the isolate's pathogenicity. This study aimed to examine the morphology and the cell surface of Blastocystis in avian and non-human primates, including peafowl, pheasant, and lion-headed tamarin. By employing light microscopy and scanning electron microscopy (SEM), this study provides the first evidence of the cellular and surface features of Blastocystis in these animal species. Our findings revealed distinct variations in cell size, shape, and surface morphology among the different host species. Notably, the isolates from peafowl exhibited larger cell sizes compared to the isolates from the pheasant. However, interestingly, both animal species were found to exhibit the same Blastocystis ST6. It was also observed that the surface structure of Blastocystis from different hosts displayed a diverse range of patterns, including mesh-like appearances, deep indentations, and attachments to bacteria. Additionally, findings also revealed the presence of a rough surface structure in peafowl, a characteristic that has been previously linked to pathogenicity and symptomatic infection in animals, as indicated by earlier studies. The findings contribute to our understanding of the morphological features and the surface characteristic of Blastocystis in different host species, shedding light on the parasite's adaptations and potential implications for host health.
  15. Trop Biomed, 2023 Dec 01;40(4):375-382.
    PMID: 38308823 DOI: 10.47665/tb.40.4.001
    Bovine anaplasmosis, caused by Anaplasma marginale, is a significant infectious disease affecting cattle populations globally. However, the prevalence and distribution of bovine anaplasmosis vary across regions, making it crucial to assess its global burden systematically. This study aims to provide a comprehensive understanding of the global prevalence of bovine anaplasmosis and synthesized data from diverse geographic regions. A literature search was conducted to identify all relevant published articles reporting the prevalence of bovine anaplasmosis and a total of 164 studies were found eligible for final systematic review and meta-analysis. Meta-analysis was conducted using meta package of R software and summary estimates of the prevalence were calculated. Meta-analysis of 129,851 samples from 42 countries was conducted and the overall estimated prevalence of bovine anaplasmosis was found to be 38% (100% CI = 33% - 42%). The prevalence was found to be higher in cattle (39.9%) in comparison to yaks (6.4%). Diagnosis using serology (40.2%) yielded a higher prevalence compared to molecular testing (38.3%) and blood smears (22.4%) methods. Additionally, there were significant differences in the prevalence of bovine anaplasmosis between different countries (p<0.05). This study will inform evidence-based strategies for control and prevention of bovine anaplasmosis on a global scale by discovering the true extent of the disease and identifying high-prevalence areas.
  16. Tan CY, Thanawongnuwech R, Arshad SS, Hassan L, Lee CY, Low SE, et al.
    Trop Biomed, 2023 Sep 01;40(3):301-306.
    PMID: 37897162 DOI: 10.47665/tb.40.3.005
    Porcine circovirus type 4 (PCV4) is the newest member in the porcine circovirus family, first reported in 2020. To date, the presence of PCV4 has only been reported in China, South Korea and most recently in Thailand. Detection of PCV4 have been reported in various production stages of pigs from piglets, finishers to sows; associated with a myriad of clinical manifestations including porcine dermatitis and nephropathy syndrome (PDNS), postweaning multisystemic wasting syndrome (PMWS), respiratory, enteric and neurological diseases. While successful virus isolation and culture has yet to be reported, pathogenicity of PCV4 has been demonstrated through infectious clone studies. The objective of this study is to investigate the presence of PCV4 in Malaysian porcine population to update the epidemiology of porcine circoviruses in Malaysia. A total of 49 samples from commercial intensive pig farms, abattoir and wild boar population were subjected to conventional polymerase chain reaction assay to detect PCV4 capsid (cap) genome. Resulting cap nucleotide sequences were analyzed for maximum likelihood phylogeny relationship. Results revealed that PCV4 is present in Peninsular Malaysia at a molecular prevalence of 4.08% (2 / 49 samples). Both PCV4 positive samples originated from clinically healthy finishers. Malaysian PCV4 strains were classified as genotype PCV4b, and were found to be phylogenetically distinct from the China, South Korea and Thailand strains. With this latest update of the novel PCV4 in Malaysia, it is clear that more attention needs to be given to the investigation of novel porcine circoviruses (PCV) and management of PCV diseases.
  17. Wahab AA, Nurazizah SMA, Ding CH, Muttaqillah NAS, Nordashima AS, Kori N, et al.
    Trop Biomed, 2023 Sep 01;40(3):290-294.
    PMID: 37897160 DOI: 10.47665/tb.40.3.003
    Melioidosis is endemic in Southeast Asia, including Malaysia. Liver abscess is not uncommon in melioidosis, but it is usually associated with bacteremia. We presented a case of a 55-year-old gentleman with underlying end-stage renal failure who presented with non-specific abdominal pain for three months. Initial blood investigations showed leukocytosis and increased C-reactive protein. Computed tomography (CT) of the abdomen revealed multiple hypodense lesions in the liver and spleen. The culture of the liver specimen obtained through the ultrasound-guided isolated Burkholderia pseudomallei. He was given an adjusted dose of intravenous ceftazidime due to underlying renal failure. Melioidosis serology also returned positive for IgM with titer >1:1280. His blood cultures were reported negative three times. Despite on antibiotics for five weeks, there was no significant improvement of the liver abscesses was observed. He was unfortunately infected with the SARS-CoV-2 virus during his admission and passed away due to severe COVID-19 pneumonia.
  18. Sabrina DL, Latiffah H, Reuben SKS, Ooi PT
    Trop Biomed, 2023 Sep 01;40(3):281-289.
    PMID: 37897159 DOI: 10.47665/tb.40.3.002
    The intake of food and water containing the Sarcocystis parasite has been linked to a number of outbreaks worldwide, including Malaysia. Nevertheless, the lack of surveys and epidemiological data on Sarcocystis infections in Malaysia makes it difficult to estimate its occurrence in humans and animals. A cross-sectional study was conducted to determine the prevalence of Sarcocystis and the risk factors associated with infection among village chickens and pigs reared under different farm managements in Peninsular Malaysia. Phylogenetic trees were constructed using partial fragments of the 18S rRNA gene and ITS1 sequences. In the present study, 680 sera samples were collected from village chickens (n=250) and commercial pigs (n=433) and anti-Sarcocystis antibodies were screened using the enzymelinked immunosorbent assays (ELISA) kit. At the animal level, the prevalence of Sarcocystis was 9.2% (95% CI: 5.92-13.48) and at the farm level, it was 64.0% (95% CI: 42.52-82.03) in village chickens. The animal-level seroprevalence of Sarcocystis for pigs was 3.7% (95% CI: 2.13-5.93) and 36.8% (95% CI: 16.29-61.64) at the farm-level. Polymerase Chain Reaction (PCR) was conducted on meat samples from various parts of village chickens (n=250) consisting of brain, heart, lung, and pectoralis muscle tissues, and pork (n=121) consisting of intercostal muscle, diaphragm, and tongue. Sarcocystis DNA was detected in 6.4% (95% CI: 4.60-11.60) of village chicken samples but zero in pork samples. A total of 11 unique Sarcocystis haplotypes were isolated from these tissue samples. Multivariable logistic regression analysis of the putative risk factors showed a statistically significant association between Sarcocystis infection in pigs and uncovered storage of feed. Although no zoonotic Sarcocystis was isolated in this study, we reported the first discovery of S. wenzeli in Malaysia.
  19. Gilbert M, Mohamed M, Choong SS, Baqi A, Kumaran JV, Sani I, et al.
    Trop Biomed, 2023 Sep 01;40(3):273-280.
    PMID: 37897158 DOI: 10.47665/tb.40.3.001
    Most of the public health importance coronaviruses, such as Severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2 are likely originated from bats and spread to humans through intermediate hosts; civet cats, dromedary camel and Malayan pangolin, respectively. SARS-CoV-2-like coronaviruses were detected in Thailand, which is neighbouring with Kelantan in East Coast Malaysia. To date, there is no report on the presence of public health concerns (SARS-CoV, SARS-CoV-2 and MERS-CoV) coronaviruses in bats from Malaysia. This study was aimed to elucidate the presence of these coronaviruses in bat samples from East Coast, Malaysia. A total of hundred seventy oropharyngeal swab samples were collected from three states of East Coast Malaysia. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was conducted based on partial 3' Untranslated region (3'UTR) or ORF10 gene and the products were sequenced. The sequences were compared with all coronavirus sequences from the National Center for Biotechnology Information-GenBank (NCBI-GenBank) using NCBI-Basic Local Alignment Search Tool (NCBI-BLAST) software. A phylogenetic tree was constructed to determine the genetic relationship among the detected coronaviruses with the reference coronaviruses from the NCBI-GenBank. Our results showed that SARSCoV-2-like viruses were present in 3% (5/170) of the bats from East Coast Malaysia that have 98-99% sequence identities and are genetically related to SARS-CoV-2 from humans. This finding indicates the presence of SARS-CoV-2-like viruses in bats from East Coast Malaysia that may become a public health concern in the future.
  20. Lim YZ, Teoh BT, Sam SS, Azizan NS, Khor CS, Nor'e SS, et al.
    Trop Biomed, 2023 Sep 01;40(3):313-319.
    PMID: 37897164 DOI: 10.47665/tb.40.3.007
    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus with widespread distribution across the globe. Since 2016, CHIKV re-emerged in several countries including Indian subcontinent and Southeast Asia. A proper diagnostic tool for early diagnosis of CHIKV infection is crucial to facilitate patient management and control virus transmission at the earliest stage of outbreak. Therefore, a TaqMan minor groove binder (MGB) probe-based quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was developed to detect and quantify the CHIKV. The primers and probe were designed based on a conserved genomic region of 730 global CHIKV sequences that is located between nsP1 and nsP2 genes. The nucleotide mismatches of primers and probe with 730 global CHIKV sequences and 13 alphaviruses were then analysed in silico. In this study, the last 5 nucleotides at 3' end of primers and 5' end of probe were considered to be the critical regions for priming. In silico analysis revealed that the critical regions of primers and probe were at least 99.6% matched with the 730 global CHIKV sequences. Besides, the primers and probe showed at least 5/20 (25.0%) and 4/17 (23.5%) nucleotide mismatches with 13 alphaviruses respectively. The amplification efficiency of qRT-PCR assay was 100.59% (95% CI= 93.06, 109.33) with a R2 score of 0.957. Its limit of detection (LOD) at 95% probability level was 16.6 CHIKV RNA copies (95% CI= 12.9, 28.9). The qRT-PCR assay was specific to CHIKV without cross-reacting with all dengue virus serotypes, Getah virus, Tembusu virus and Zika virus. The diagnostic results of qRT-PCR assay were perfectly agreed (k=1.000, p=0.003) with a commercial trioplex assay, with sensitivity of 100% (95% CI= 61, 100) and specificity of 100% (95% CI= 44, 100). Overall, the developed qRT-PCR assay is ideal for rapid, sensitive and specific detection as well as quantification of CHIKV.
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