Displaying publications 1 - 20 of 52 in total

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  1. Khan SM, Wells C, Christou N, Tan CY, Mathur P, El-Hussuna A
    Surgery, 2023 Jul;174(1):46-51.
    PMID: 37156647 DOI: 10.1016/j.surg.2023.04.001
    BACKGROUND: Anastomosis leak is one of the significant postoperative complications after colorectal surgery. The aim of this systematic review was to synthesize the evidence relative to the preoperative assessment of the colon and rectum blood supply and to investigate its role in predicting anastomosis leak.

    METHOD: This systematic review was conducted according to the recommendations of the Cochrane Handbook for Reviews of Interventions and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, Embase, and the Cochrane Library were searched to identify eligible studies. The main outcome variable was the preoperative assessment of patterns of blood supply to the colon and the impact of these patterns on anastomosis leak. The quality of bias control in the studies was assessed using the Newcastle-Ottawa Scale. Due to the heterogeneous nature of the included studies, no meta-analysis was conducted.

    RESULTS: Fourteen studies were included. The study covered a period from 1978 to 2021. A significant degree of variation in the arterial and/or venous supply of the colon and rectum might influence anastomosis leak rates. Calcification in great blood vessels can be assessed with a preoperative computed tomography scan, which may predict anastomosis leak rates. This is supported by many experimental studies that showed increased rates of anastomosis leak after preoperative ischemia, but the extent of this impact is not well established.

    CONCLUSION: Preoperative assessment of blood supply to the colon and rectum might help in planning the surgical intervention to reduce anastomosis leak rates. Calcium scoring of major arteries might predict anastomosis leak and thus play a crucial role in intraoperative decision-making.

  2. Tan HT, Tan CY, Teong CS, Ratnasingam J, Goh KJ
    J Clin Neurophysiol, 2020 Aug 05.
    PMID: 32773648 DOI: 10.1097/WNP.0000000000000766
    PURPOSE: Thyrotoxic periodic paralysis is characterized by recurrent episodes of reversible, severe proximal muscle weakness associated with hypokalemia and hyperthyroidism. Prolonged exercise test is an easy, noninvasive method of demonstrating abnormal muscle membrane excitability in periodic paralyses. Although abnormal in thyrotoxic periodic paralysis patients, the effects thyroid hormone levels in non-thyrotoxic periodic paralysis thyrotoxicosis patients have not been well studied. The study aims to evaluate thyrotoxicosis patients (regardless of thyrotoxic periodic paralysis history) with prolonged exercise test and correlate it with their thyroid status.

    METHODS: This is a prospective, cross-sectional study of consecutive thyrotoxicosis patients seen at the endocrine clinic of a tertiary medical center. Thyroid status was determined biochemically before prolonged exercise test. Compound muscle action potential (CMAP) amplitudes postexercise were compared against pre-exercise amplitudes and recorded as percentage of mean baseline CMAP amplitude. Comparisons of time-dependent postexercise CMAP amplitudes and mean CMAP amplitude decrement were made between hyperthyroid and nonhyperthyroid groups.

    RESULTS: Seventy-four patients were recruited, 23 (31%) men, 30 (41%) Chinese, and the mean age was 48.5 ± 16.8 years. Of 74 patients, 32 (43%) were hyperthyroid and 42 (57%) were nonhyperthyroid viz. euthyroid and hypothyroid. Time-dependent CMAP amplitudes from 10 to 45 minutes after exercise were significantly lower in hyperthyroid patients compared with nonhyperthyroid patients (P < 0.01). Mean CMAP amplitude decrement postexercise was significantly greater in hyperthyroid than nonhyperthyroid patients (23.4% ± 11.4% vs. 17.3% ± 10.5%; P = 0.02).

    CONCLUSIONS: Compound muscle action potential amplitude declines on prolonged exercise test were significantly greater in hyperthyroid patients compared with nonhyperthyroid patients. Muscle membrane excitability is highly influenced by thyroid hormone level. Thyrotoxic periodic paralysis occurs from increased levels of thyroid hormone activity in susceptible patients.

  3. Low SC, Md Sari NA, Tan CY, Ahmad-Annuar A, Wong KT, Law WC, et al.
    Neuromuscul Disord, 2021 07;31(7):642-650.
    PMID: 34059423 DOI: 10.1016/j.nmd.2021.03.008
    We report the clinical and genetic characteristics of hereditary transthyretin amyloidosis in the multi-ethnic Malaysian population. Subjects with genetically confirmed transthyretin amyloidosis seen between 2001 till August 2020 were included. There were 30 patients and 14 asymptomatic carriers, of which 26 (59.1%) were men. The majority (86.7%) were ethnic Chinese while two (6.7%) each were Malay and Sri Lankan Tamil ethnicity respectively. Among patients, mean age of symptom-onset was 55.9 ± 9.8 years with mean duration from symptom-onset to diagnosis of 3.2 ± 2.5 years. Common presenting symptoms were sensory symptoms of upper limbs (43.3%), symmetric sensory symptoms of both lower limbs (16.7%) and autonomic symptoms (16.7%). Nerve conduction studies showed sensorimotor polyneuropathy in 25 (83.3%) patients (22, axonal). Abnormal echocardiograms were seen in 24 (80%) patients, although 15 were asymptomatic. Of six different TTR mutations found, Ala97Ser was the commonest, and found exclusively in 84.6% of Chinese patients. Other mutations among Chinese patients were Val30Met, Ala25Thr and Asp39Val. Our Malay and Tamil patients had Glu54Lys and Gly47Val mutations respectively. In conclusion, TTR Ala97Ser is the commonest mutation among ethnic Chinese Malaysians which presented with late-onset progressive sensorimotor polyneuropathy, autonomic dysfunction and subclinical cardiac involvement.
  4. Tan CY, Shahrizaila N, Goh KJ
    J Oral Facial Pain Headache, 2017 10 27;31(4):e15-e20.
    PMID: 29073667 DOI: 10.11607/ofph.1793
    AIMS: To describe the clinical characteristics of trigeminal neuralgia (TN) in a multi-ethnic Malaysian population and to relate them to standardized measures of pain severity, anxiety, depression, and quality of life (QoL).

    METHODS: Patients fulfilling the International Headache Society (IHS) criteria for TN were prospectively interviewed for their demographic and clinical data. Pain intensity was rated with a visual analog scale (VAS), anxiety and depression were determined by the Hospital Anxiety and Depression Scale (HADS), and QoL was assessed by the Short-Form 36 (SF-36) questionnaire. Chi-square, Mann-Whitney U, and Spearman correlation tests were used to test for differences considering a significance level of P < .05.

    RESULTS: Of the 75 included patients, 52 (69.3%) were women with a mean ± standard deviation (SD) onset age of 52.0 ± 12.7 years, and 57.3% were Chinese, 24.0% Malay, and 18.7% Indian. Pain was more common on the right side (69.3%) and in the maxillary and mandibular divisions. VAS scores for pain at its worst were higher in anxious/borderline anxious patients compared to non-anxious patients (89.5 ± 15.9 vs 80.9 ± 17.2, respectively; P < .05), and VAS scores for pain at its least were higher in depressed/borderline depressed subjects compared to non-depressed subjects (38.4 ± 25.8 vs 23.0 ± 19.2, respectively; P < .05). Chinese patients had lower VAS scores for pain at its least compared to Indian patients (19.7 ± 16.1 vs 39.9 ± 24.7; P < .01). TN patients scored lower in all eight domains of the SF-36 compared to the general population. Indian patients had lower scores in role limitations due to physical health (8.9 ± 23.2 vs 49.4 ± 43.8; P < .01) and social function (56.3 ± 13.6 vs 76.5 ± 23.6; P < .01) than Chinese patients, and Malay patients had lower mental health scores compared to Chinese patients (59.1 ± 19.5 vs 73.0 ± 21.0; P < .01).

    CONCLUSION: Clinical characteristics of TN patients were similar to those of other populations. There were differences in pain ratings and QoL between TN patients of different ethnicities, as well as between those with anxiety and depression.

  5. Kew Y, Tan CY, Ng CJ, Thang SS, Tan LH, Khoo YK, et al.
    Rheumatol Int, 2017 Apr;37(4):633-639.
    PMID: 28013358 DOI: 10.1007/s00296-016-3633-x
    The prevalence of neuropathic low back pain differs in different ethnic populations. The aims of the study are to determine its frequency and associations in a multi-ethnic cohort of Asian low back pain patients. This was a cross-sectional study of low back patients seen at the University of Malaya Medical Centre, Kuala Lumpur, Malaysia. Neuropathic low back pain patients were identified using the painDETECT questionnaire and compared with non-neuropathic (unclear or nociceptive) low back pain patients, in terms of socio-demographic and clinical factors, pain severity (numerical pain rating scale, NPRS), disability (Roland Morris Disability Questionnaire, RMDQ), as well as anxiety and depression (Hospital Anxiety and Depression Scale, HADS). Of 210 patients, 26 (12.4%) have neuropathic low back pain. Neuropathic pain is associated with non-Chinese ethnicity, higher body mass index and pain radiation below the knee. Patients with neuropathic pain have significantly higher NPRS and RMDQ scores, and there are more subjects with anxiety on HADS. However, there are no differences between the groups in age, gender, pain duration or underlying diagnosis of low back pain. The prevalence of neuropathic low back pain in a multi-ethnic Malaysian cohort is lower than previously reported in other populations with possible differences between ethnic groups. It is associated with greater pain severity, disability and anxiety.
    Study site: Spine Clinic, University of Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
  6. Tan JY, Tan CY, Yahya MA, Shahrizaila N, Goh KJ
    Muscle Nerve, 2024 May;69(5):597-603.
    PMID: 38488306 DOI: 10.1002/mus.28081
    INTRODUCTION/AIMS: Muscle strength, functional status, and muscle enzymes are conventionally used to evaluate disease status in idiopathic inflammatory myopathies (IIM). This study aims to investigate the role of quantitative muscle ultrasound in evaluating disease status in IIM patients.

    METHODS: Patients with IIM, excluding inclusion body myositis, were recruited along with age- and sex-matched healthy controls (HC). All participants underwent muscle ultrasound and clinical assessments. Six limb muscles were unilaterally scanned using a standardized protocol, measuring muscle thickness (MT) and echo intensity (EI). Results were compared with HC, and correlations were made with outcome measures.

    RESULTS: Twenty IIM patients and 24 HC were recruited. The subtypes of IIM were dermatomyositis (6), necrotizing myositis (6), polymyositis (3), antisynthetase syndrome (3), and nonspecific myositis (2). Mean disease duration was 8.7 ± 6.9 years. There were no significant differences in demographics and anthropometrics between patients and controls. MT of rectus femoris in IIM patients was significantly lower than HC. Muscle EI of biceps brachii and vastus medialis in IIM patients were higher than HC. There were moderate correlations between MT of rectus femoris and modified Rankin Scale, Physician Global Activity Assessment, and Health Assessment Questionnaire, as well as between EI of biceps brachii and Manual Muscle Testing-8.

    DISCUSSION: Muscle ultrasound can detect proximal muscle atrophy and hyperechogenicity in patients with IIM. The findings correlate with clinical outcome measures, making it a potential tool for evaluating disease activity of patients with IIM in the late phase of the disease.

  7. Schee JP, Tan JS, Tan CY, Shahrizaila N, Wong KT, Goh KJ
    J Clin Neurol, 2024 Jul;20(4):422-430.
    PMID: 38951975 DOI: 10.3988/jcn.2023.0265
    BACKGROUND AND PURPOSE: Multiple acyl-CoA dehydrogenase deficiency (MADD) is an inherited disorder of fatty acid oxidation that causes lipid storage myopathy (LSM). This is the first report on MADD that describes the phenotypic and genetic features of a Malaysian cohort.

    METHODS: Among the >2,500 patients in a local muscle biopsy database, patients with LSM were identified and their genomic DNA were extracted from muscle samples and peripheral blood. All 13 exons of the electron-transfer flavoprotein dehydrogenase gene (ETFDH) were subsequently sequenced. Fifty controls were included to determine the prevalence of identified mutations in the normal population.

    RESULTS: Fourteen (82%) of the 17 LSM patients had MADD with ETFDH mutations. Twelve (86%) were Chinese and two were Malay sisters. Other unrelated patients reported that they had no relevant family history. Nine (64%) were females. The median age at onset was 18.5 years (interquartile range=16-37 years). All 14 demonstrated proximal limb weakness, elevated serum creatine kinase levels, and myopathic changes in electromyography. Three patients experienced a metabolic crisis at their presentation. Sanger sequencing of ETFDH revealed nine different variants/mutations, one of which was novel: c.998A>G (p.Y333C) in exon 9. Notably, 12 (86%) patients, including the 2 Malay sisters, carried a common c.250G>A (p.A84T) variant, consistent with the hotspot mutation reported in southern China. All of the patients responded well to riboflavin therapy.

    CONCLUSIONS: Most of our Malaysian cohort with LSM had late-onset, riboflavin-responsive MADD with ETFDH mutations, and they demonstrated phenotypic and genetic features similar to those of cases reported in southern China. Furthermore, we report a novel ETFDH mutation and possibly the first ever MADD patients of Malay descent.

  8. Tan JY, Tan CY, Gengadharan PN, Shahrizaila N, Goh KJ
    J Clin Neurol, 2024 Jul;20(4):412-421.
    PMID: 38951974 DOI: 10.3988/jcn.2023.0285
    BACKGROUND AND PURPOSE: Myasthenia gravis (MG) is clinically heterogeneous and can be classified into subgroups according to the clinical presentation, antibody status, age at onset, and thymic abnormalities. This study aimed to determine the clinical characteristics and outcomes of generalized MG (GMG) patients based on these subgroups.

    METHODS: Medical records of MG patients from 1976 to 2023 were reviewed retrospectively. Patients with pure ocular MG were excluded. Data on demographic, clinical characteristics, laboratory features, and outcomes were analyzed.

    RESULTS: This study included 120 GMG patients. There was a slight preponderance of female patients over male patients (male:female ratio=1:1.3), with the age at onset exhibiting a bimodal distribution. Female patients peaked at a lower age (21-30 years) whereas male patients peaked at a higher age (61-70 years). Most (92%, 105 of 114) patients had positive anti-acetylcholine receptor antibodies. Five patients were also tested for anti-muscle-specific tyrosine kinase antibodies, with two showing positivity. Thymectomy was performed in 62 (52%) patients, of which 30 had thymoma, 16 had thymic hyperplasia, 7 had an involuted thymus, and 6 had a normal thymus. There were significantly more female patients (68% vs. 45%, p=0.011) with early-onset disease (<50 years old) and thymic hyperplasia (33% vs. 0%, p<0.025). Most (71%) of the patients had a good outcome based on the Myasthenia Gravis Foundation of America postintervention status. GMG patients with early-onset disease had a significantly better outcome than patients with a late onset in univariate (58% vs. 37%, p=0.041) and multivariate (odds ratio=4.68, 95% confidence interval=1.17-18.64, p=0.029) analyses.

    CONCLUSIONS: Female patients with early-onset MG and thymic hyperplasia had significantly better outcomes, but only early-onset disease was independently associated with a good outcome. These findings are comparable with those of other studies.

  9. Tan SY, Tan CY, Yahya MA, Low SC, Shahrizaila N, Goh KJ
    Neurol Sci, 2024 Jan 25.
    PMID: 38270729 DOI: 10.1007/s10072-024-07340-y
    INTRODUCTION: There is an increasing need for a reproducible and sensitive outcome measure in patients with hereditary transthyretin amyloidosis (ATTRv) with polyneuropathy (PN) due to the emergence of disease modifying therapies. In the current study, we aimed to investigate the role of quantitative muscle ultrasound (QMUS) as a disease biomarker in ATTRv-PN.

    METHODS: Twenty genetically confirmed ATTRv amyloidosis patients (nine symptomatic, 11 pre-symptomatic) were enrolled prospectively between January to March 2023. Muscle ultrasound was performed on six muscles at standardized locations. QMUS parameters included muscle thickness (MT) and muscle echo intensity (EI). Twenty-five age- and sex-matched healthy controls were recruited for comparison. Significant QMUS parameters were correlated with clinical outcome measures.

    RESULTS: Muscle volume of first dorsal interosseus (FDI) muscle [measured as cross-sectional area (CSA)] was significantly lower in symptomatic patients compared to healthy controls and pre-symptomatic carriers (98.3 ± 58.0 vs. 184.4 ± 42.5 vs. 198.3 ± 56.8, p 

  10. Leonhard SE, Tan CY, van der Eijk AA, Reisin RR, Franken SC, Huizinga R, et al.
    J Peripher Nerv Syst, 2021 Sep 22.
    PMID: 34549484 DOI: 10.1111/jns.12469
    Half of the world's population is at risk of arthropod-borne virus (arbovirus) infections. Several arbovirus infections have been associated with Guillain-Barré syndrome (GBS). We investigated whether arboviruses are driving GBS beyond epidemic phases of transmission and studied the antibody response to glycolipids. The protocol of the International Guillain-Barré syndrome Outcome Study (IGOS), an observational prospective cohort study, was adapted to a case-control design. Serum samples were tested for a recent infection with Zika virus (ZIKV), dengue virus (DENV), chikungunya (CHIKV) virus, hepatitis E virus, Epstein-Barr virus (EBV), cytomegalovirus (CMV), Campylobacter jejuni, and Mycoplasma pneumoniae, and for antibodies to glycolipids. Forty-nine patients were included from Brazil (63%), Argentina (14%), and Malaysia (22%). Evidence of a recent infection was found in 27/49 (55%) patients: C jejuni (n = 15, 31%), M pneumoniae (n = 5, 10%), CHIKV (n = 2, 4%), EBV (n = 1, 2%), C jejuni and M pneumoniae (n = 2, 4%), CMV and DENV (n = 1, 2%), and C jejuni and DENV (n = 1, 2%). In 22 patients, 35 paired controls were collected. Odds ratio for recent infections did not significantly differ between cases and controls. No typical anti-ganglioside antibody binding was associated with recent arbovirus infection. We conclude that arbovirus infections occur in GBS patients outside of epidemic viral transmission, although not significantly more than in controls. Broad infection and anti-ganglioside antibody serology are important to establish the most likely pathogenic trigger in GBS patients. Larger studies are necessary to determine the association between arboviruses and GBS.
  11. Kamgang J, Tétinou F, Zolo Y, Tan CY, Wambo C, Fongang EJN, et al.
    Neurol Res Int, 2021;2021:9948990.
    PMID: 34221504 DOI: 10.1155/2021/9948990
    Introduction: Stroke recurrence accounts for a great percentage of catastrophic complications, yet no comprehensive study has analyzed the factors associated with stroke recurrence in Cameroon. We carried out this case-control study to better understand the factors associated with the stroke recurrence in Cameroon.

    Methods: We collected sociodemographic, clinical, neuroimaging, laboratory, and therapeutic data of eligible patients who consulted the neurology and cardiology department of the Yaounde Central Hospital in Cameroon. We included all patients at least five years removed from their first stroke event who consulted the authors' institution as of January 15, 2019. Wilcoxon signed-rank and Fisher's exact tests were used. Also, a Cox regression model was used to identify confounders.

    Results: We recruited 100 patients; seven out of ten patients had hypertension, while six out of 10 had a sedentary lifestyle. Half of the patients consumed alcohol regularly, while one patient out of five had diabetes. Most patients presented with their first stroke event, and a quarter had a stroke recurrence. Stroke recurrence was associated with right handedness (OR = 0.23, 95% CI = 0.16-0.33), congestive heart failure (OR = 3.45, 95% CI = 1.16-10.28), gout (OR = 4.34, 95% CI = 1.09-18.09), dysarthria (OR = 4.34, 95% CI = 1.30-14.54), and facial palsy (OR = 3.96, 95% CII = 1.49 - 10.51), as well as modifiable factors such as elevated abdominal circumference (P 

  12. Amran A, Tan CY, Tan KL, Ho RM, Anand AK, Leong CW
    Clin Pharmacol Drug Dev, 2021 12;10(12):1514-1518.
    PMID: 34107173 DOI: 10.1002/cpdd.964
    A newly developed branded generic of a moxifloxacin (MOX) 400-mg tablet formulation was manufactured prior to this study. A bioequivalence (BE) study was done to assess the pharmacokinetics of the formulation using a randomized, open-label, 2-period crossover, 2-sequence, and single-dose experiment. Thirty healthy male volunteers were recruited. The test formulation, Flonoxin 400 mg, was compared with the reference formulation, Avelox 400 mg. The pharmacokinetic parameters of MOX were calculated based on the plasma drug concentration-time profile. Noncompartmental analysis was performed to determine its safety and tolerability. The 90% confidence intervals (CIs) were 88.5%-104.6%, 96.1%-101.1%, and 96.8%-100.7% for Cmax , AUC0-t , and AUC0-inf , respectively. All CIs were within the 80.0%-125.0% boundary, thus fulfilling the acceptable BE criteria according to the ASEAN guidelines.
  13. Tan CY, Wafiatul NMH, Chang SMW, Tee AX, Lim AW
    Med J Malaysia, 2023 Nov;78(6):793-802.
    PMID: 38031223
    INTRODUCTION: There has been an observed number of readmissions after an index COVID-19 admission, including admissions after an initial home quarantine. The purpose of this study was to identify the clinical characteristics and outcomes of COVID-19 patients who were readmitted or admitted after an initial home quarantine between 21 and 90 days of illness.

    MATERIALS AND METHODS: This was a single-centre retrospective cohort study comprising patients admitted to a state hospital in Selangor, Malaysia, between August and October 2021. The demographic data, clinical characteristics, presenting complaints, laboratory tests, organ dysfunction, use of invasive ventilation, intensive care unit (ICU) admissions, length of hospitalisation and mortality were collected and analysed.

    RESULTS: The analysis involved a total of 195 cases. More than a quarter of the cases (52 [26.7%]) were related to the initial COVID-19 infection. Nine cases (4.6%) required mechanical ventilation, while eight cases (4.1%) were admitted to the ICU. The overall mortality was 17 cases (8.7%). Surviving patients were younger (49.5 vs. 58.4 years), less likely to have diabetes mellitus (48.3% vs. 82.4%), or chronic kidney disease (12.9% vs. 41.2%); had higher levels of admission haemoglobin (12.6 vs. 9.1g/dL) and albumin (33.0 vs. 21.0g/L); lower white blood cells (10.2 vs. 13.0 × 109/L), creatinine (81.2 vs. 151.9μmol/L) and C-reactive protein (18.2 vs. 135.0mg/L) at admission; less likely to have MI (6.7% vs. 23.5%), sepsis (3.4% vs. 47.1%), or acute kidney injury (3.4% vs. 17.6%) and organ dysfunction (25.3% vs. 94.1%).

    CONCLUSION: Approximately a quarter of patients were admitted or readmitted due to direct COVID-19 complications between 21 and 90 days of illness. The baseline oxygen requirements at admission were independently associated with mortality, invasive mechanical ventilation and ICU admissions. Further research is needed to establish a risk model for patients returning to a hospital to predict their risk of post-COVID complications.

  14. Mohd Fauzi NA, Abdullah S, Tan AH, Mohd Ramli N, Tan CY, Lim SY
    Parkinsonism Relat Disord, 2020 06;75:110-113.
    PMID: 30846242 DOI: 10.1016/j.parkreldis.2019.02.025
    We report a case of relapsing-remitting opsoclonus-myoclonus-ataxia syndrome (OMAS) in a patient with Hashimoto's encephalopathy, diagnosed after comprehensive evaluation. OMAS as a manifestation of Hashimoto's encephalopathy has been reported once previously. It is hoped that recognition of this entity and early initiation of immunotherapy will improve clinical outcomes for patients.
  15. Tan AH, Low SC, Tan CY, Lim KS, Tan CT, Lim SY
    Parkinsonism Relat Disord, 2016 11;32:137-139.
    PMID: 27688197 DOI: 10.1016/j.parkreldis.2016.09.019
  16. Osahor AN, Tan CY, Sim EU, Lee CW, Narayanan K
    Anal Biochem, 2014 Oct 1;462:26-8.
    PMID: 24929088 DOI: 10.1016/j.ab.2014.05.030
    When recombineering bacterial artificial chromosomes (BACs), it is common practice to design the ends of the donor molecule with 50 bp of homology specifying its insertion site. We demonstrate that desired recombinants can be produced using intermolecular homologies as short as 15 bp. Although the use of shorter donor end regions decreases total recombinants by several fold, the frequency of recombinants with correctly inserted donor molecules was high enough for easy detection by simple polymerase chain reaction (PCR) screening. This observation may have important implications for the design of oligonucleotides for recombineering, including significant cost savings, especially for high-throughput projects that use large quantities of primers.
  17. Tan CY, Lin CN, Ooi PT
    Transbound Emerg Dis, 2021 Nov;68(6):2915-2935.
    PMID: 34110095 DOI: 10.1111/tbed.14185
    Porcine circovirus 3 (PCV3) was first discovered in 2016, almost concomitantly by two groups of researchers in the United States. The novel case was reported in a group of sows with chronic reproductive problems with clinical presentation alike porcine dermatitis and nephropathy syndrome (PDNS), where metagenomic sequencing revealed a genetically divergent porcine circovirus designated PCV3. The discovery of PCV3 in a PDNS case, which used to be considered as part of PCVAD attributed to PCV2 (porcine circovirus 2), has garnered attention and effort in further research of the novel virus. Just when an infectious molecular DNA clone of PCV3 has been developed and successfully used in an in vivo pathogenicity study, yet another novel PCV strain surfaced, designated PCV4 (porcine circovirus 4). So far, PCV3 has been reported in domestic swine population globally at low to moderate prevalence, from almost all sample types including organ tissues, faecal, semen and colostrum samples. PCV3 has been associated with a myriad of clinical presentations, from PDNS to porcine respiratory disease complex (PRDC). This review paper summarizes the studies on PCV3 to date, with focus on diagnosis.
  18. 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.
  19. Tan CY, Opaskornkul K, Thanawongnuwech R, Arshad SS, Hassan L, Ooi PT
    PLoS One, 2020;15(7):e0235832.
    PMID: 32706778 DOI: 10.1371/journal.pone.0235832
    Porcine circovirus type 3 (PCV3) is a newly emerging virus in the swine industry, first reported recently in 2016. PCV3 assembles into a 2000 bp circular genome; slightly larger than PCV1 (1758-1760 bp), PCV2 (1766-1769 bp) and PCV4 (1770 bp). Apart from being associated with porcine dermatitis and nephropathy syndrome (PDNS), PCV3 has been isolated from pigs with clinical signs of reproductive failures, myocarditis, porcine respiratory disease complex (PRDC) and neurologic disease. Given that PCV3 is increasingly reported in countries including Thailand and U.S. with whom Malaysia shares trade and geographical relationship; and that PCV3 is associated with several clinical presentations that affect productivity, there is a need to study the presence and molecular characteristics of PCV3 in Malaysian swine farms. Twenty-four commercial swine farms, three abattoirs and retail shops in Peninsular Malaysia were sampled using convenience sampling method. A total of 281 samples from 141 pigs, including 49 lung archive samples were tested for PCV3 by conventional PCR. Twenty-eight lung samples from wild boar population in Peninsular Malaysia were also included. Nucleotide sequences were analyzed for maximum likelihood phylogeny relationship and pairwise distances. Results revealed that PCV3 is present in Peninsular Malaysia at a molecular prevalence of 17.02%, with inguinal lymph nodes and lungs showing the highest molecular detection rates of 81.82% and 71.43% respectively. Despite wide reports of PCV3 in healthy animals and wild boars, no positive samples were detected in clinically healthy finishers and wild boar population of this study. PCV3 strain A1 and A2 were present in Malaysia, and Malaysian PCV3 strains were found to be phylogenetically related to Spanish, U.S. and Mexico strains.
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