1.Chikungunya virus infection.
The Medical journal of Malaysia 2006;61(2):264-9
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus which causes epidemic fever, rash and polyarthralgia in Africa and Asia. Two outbreaks have been reported in Malaysia, in Klang, Selangor (1998) and Bagan Panchor, Perak (2006). It is not known if the outbreaks were caused by the recent introduction of CHIKV, or if the virus was already circulating in Malaysia. Seroprevalence studies from the 1960s suggested previous disease activity in certain parts of the country. In Asia, CHIKV is thought to be transmitted by the same mosquitoes as dengue, Aedes aegypti and Ae. albopictus. Due to similarities in clinical presentation with dengue, limited awareness, and a lack of laboratory diagnostic capability, CHIKV is probably often underdiagnosed or misdiagnosed as dengue. Treatment is supportive. The prognosis is generally good, although some patients experience chronic arthritis. With no vaccine or antiviral available, prevention and control depends on surveillance, early identification of outbreaks, and vector control. CHIKV should be borne in mind in sporadic cases, and in patients epidemiologically linked to ongoing local or international outbreaks or endemic areas.
increasing incidence
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Dengue
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Chikungunya virus
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Infection as complication of medical care
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control
2.Sample size determination in an epidemiologic study using the EpiTools web-based calculator.
Villarta Romeo L ; Asaad Abubakar S
Acta Medica Philippina 2014;48(1):42-46
OBJECTIVES: To evaluate the utility of using a web-based sample size calculator in the preparation of a research proposal.
METHODS: EpiTools, a free web-based calculator for sample size determination, was used in various study designs.
RESULTS: Computations of sample size needed for several simple epidemiologic study designs were calculated using different assumptions. The calculator was straightforward to use and user- friendly. The results were calculated quickly. Comparison of the computed sample size using different assumptions may be done to assist in evaluating research project feasibility. The input data and output of the sample size calculation may be transformed into a report for inclusion in the written research proposal.
CONCLUSION: The EpiTools web-based calculators is a convenient tool for sample size determination in the design of research protocols in relatively simple study designs. It may be used in evaluating the feasibility of the computed sample size needed by the study design.
.sample Size ; Research Design ; Epidemiologic Research Design ; Writing ; Computers ; Epidemiologic Studies ; Internet
3.Isolation and Identification of an Emerging Pathogen, Kocuria marina, from Rattus rattus diardii
Loong, S.K. ; Johari, J. ; Che Mat Seri, N.A.A. ; AbuBakar, S.
Tropical Biomedicine 2016;33(3):589-593
Members of the genus Kocuria are commonly found in the environment and they
are also commensals of the mammalian skin and oropharynx mucosa. Human infections,
although rare, are increasingly being reported recently suggesting that this genus has mostly
been overlooked or misidentified. Its transmission route however, is still not known. We
report here the isolation and identification of a Kocuria marina isolate from the lung of a
wild urban rat (Rattus rattus diardii) caught at a wet market. The isolate was susceptible to
most of the commonly used antibiotics. The finding suggests a possibility that rats could be
a vector for K. marina.
4.A Report of Vancomycin-susceptible, Teicoplanin-resistant Enterococcus faecalis ST6 in Malaysia
Loong, S.K. ; Che Mat Seri, N.A.A. ; Mahfodz, N.H. ; Akbar, S.Z. ; AbuBakar, S.
Tropical Biomedicine 2016;33(3):577-582
The ability to acquire antibiotic resistance and virulence has propelled Enterococcus
faecalis to become a major nosocomial pathogen. In Malaysia, data on the antibiotic resistance
determinants and virulence of Enterococcus circulating strains are still scarce. This study
aimed to assess the genotype of an E. faecalis isolate initially identified as Streptococcus
uberis, examine the antibiotic resistance genotypes, analyze the genetic variations within
Tn1546 and investigate the presence of virulence genes. The E. faecalis isolate was genetically
characterized using multilocus sequence typing (MLST). Minimum inhibitory concentrations
to vancomycin and teicoplanin were determined. Antibiotic resistance and other virulence
genes were amplified using nucleic acid polymerase chain reaction. Mapping of the Tn1546
transposon was performed and compared to the prototype sequences. The E. faecalis isolate
was found to have a MLST profile corresponding to sequence type 6. The isolate was resistant
to teicoplanin but susceptible to vancomycin. Its genome consisted the vanA and vanC1
genes. Novel genetic variations in the vanS, vanS-vanH intergenic region and vanY genes
were present and six virulence genes were detected. The detection of the vanC1 gene,
thought to be non-transferable, suggests the potential emergence of inter-species enterococcal
vanC1 gene transfer. The peculiar antibiotics resistance phenotype of this E. faecalis isolate
could be associated to the novel genetic variations found. This study highlights the presence
of E. faecalis belonging to the high-risk clonal complex with multiple virulence factors in
Malaysia.
5.Emergence of Enterococcus gallinarum carrying vanA gene cluster displaying atypical phenotypes
Loong, S.K. ; Che Mat Seri, N.A.A. ; Mahfodz, N.H. ; Teoh, B.T. ; AbuBakar, S.
Tropical Biomedicine 2016;33(4):837-841
Motile enterococci such as Enterococcus gallinarum has the ability to acquire
and transfer antibiotic resistance genes to other enterococci. Even though infections caused
by E. gallinarum are rare, the discovery of this bacteria in food sources and in clinical
environments is disturbing. Here, we report the isolation and identification of E. gallinarum
from the wound of a hospital in-patient. The isolate was identified using 16S rDNA sequencing.
Isolate 146 harboured the vanA and vanC1 gene clusters, was vancomycin-susceptible, and
displayed resistance to ampicillin, penicillin, erythromycin and teicoplanin. This isolate also
showed intermediate resistance to linezolid and sequencing of the 23S rRNA peptidyl
transferase region did not unveil any known mutations associated to the conferment of
linezolid resistance. The presence of vanA did not confer resistance to vancomycin. Structural
analyses into the Tn1546 transposon carrying the vanA gene revealed distinct genetic variations
in the vanS, vanY and vanS-vanH intergenic region that could be associated to the atypical
antibiotic resistance phenotypes of isolate 146. Finding from this study are suggestive of the
occurrence of interspecies horizontal gene transfer and that similarities in genotypic
characteristic may not necessarily correlate with actual antibiotic resistance pattern of E.
gallinarum.
6.Evaluation of land cover and prevalence of dengue in Malaysia
Tiong, V. ; Abd-Jamil, J. ; Mohamed Zan, H.A. ; Abu-Bakar, R.S. ; Ew, C.L. ; Jafar, F.L. ; Nellis, S. ; AbuBakar, S.
Tropical Biomedicine 2015;32(4):587-597
Serological confirmation of dengue in 1,410 school-going children aged 7-18 years
provided prevalence data for 16 different sites in Malaysia. These sites ranged from highly
urbanized cities to small towns. We found that at least ~7 % of children in the study group had
been exposed to dengue by age 12 and ~16% by age 18. Here we report that the dengue
seroprevalence correlates with i) increasing land development and decreased vegetation,
and ii) the overall population growth. Water bodies did not significantly affect dengue
prevalence. High prevalence of dengue was also recorded in few of the non-urban sites
suggesting the expanding geographical locality of those who get dengue in Malaysia in
tandem with increased land usage activities. These findings highlight the need to give closer
consideration to future urban planning and development, taking into consideration the
changing demography and the importance of built environment to mitigate the increasing
incidence of dengue in the non-urban areas of Malaysia.
7.Valuation for cigarettes among University of the Philippines Manila students through stated preference methods.
delos Trinos John Paul Ceasar R. ; Lobo Liana Mae J. ; Cabana Charmaine Joy A. ; De Leon Shermaine Anne B. ; Guinez Abigail Ann A. ; Asaad Abubakar S.
Acta Medica Philippina 2014;48(3):72-78
OBJECTIVE:The study aimed to assess the valuation for cigarettes among UP Manila students aged 18-24 through direct and indirect stated preference methods.
METHODS: Direct (iterative bidding) and indirect (discrete choice experiment) stated preference methods were utilized to determine the smokers' Willingness-to-Pay (WTP) and non-smokers' Willingness-to-Accept (WTA). Median and interquartile range were used in describing both WTP and WTA. Fisher's Exact Test and T-test were performed using STATA v12 to determine the association between the identified factors.
RESULTS: Of the 212 respondents, 21 (9.91%) were smokers. The smokers' direct and indirect WTP for a cigarette stick were PhP 6.00 and PhP 12.43, respectively. There was a significant difference (p=0.01) between the results of the two methods. Meanwhile, 40.84% of the non-smokers could be induced to smoke with PhP 0.00 as their WTA. No significant association was found between the smokers' stated preference and their smoking status and allowance. The WTP of the smokers was higher than the December 2013 retail prices of cigarettes.
CONCLUSION: The increased cigarette prices brought about by the Sin Tax Law were insufficient in stopping the selected UP Manila students to smoke. In addition, forty percent of non-smokers in the study could be induced to smoke. Thus, further price increase of cigarettes, as well as other tobacco control measures, is recommended to discourage smoking among the youth such as college students, specifically in UP Manila.
Human ; Male ; Female ; Adult ; Adolescent ; Tobacco ; Smoking ; Smoke ; Tobacco Use Disorder ; Choice Behavior ; Students ; Surveys And Questionnaires
8.Average treatment effects of a single-dose antenatal corticosteroid on the respiratory morbidity of Filipino preterm neonates
Alvin Duke R. Sy ; Abubakar S. Asaad
Acta Medica Philippina 2022;56(16):71-77
Introduction:
Prematurity-related respiratory disorders are an important public health concern that should be
treated efficiently and effectively. Antenatal corticosteroid (ACS) therapy has been recommended to hasten fetal
lung maturation in pregnancies at risk but has not been delivered adequately in low to middle-income countries. This study aimed to estimate the treatment effects associated with the use of a single-dose antenatal corticosteroid on the incidence of respiratory-associated morbidity among prematurely delivered neonates.
Methods:
This was a retrospective cohort study of neonates delivered at 24 to 33 weeks gestation at a tertiary
hospital comparing outcomes in those given single-dose ACS with those given no ACS. Association was estimated using logistic and propensity score (PS) analyses, as well as average treatment effect (ATE) and among those treated (ATET).
Results:
Most neonates (78.11%) received a single dose before delivery (single-dose ACS group) and only a few
(21.89%) did not receive any dose (no ACS dose group). The odds ratio of respiratory morbidity in the single-dose ACS group was 0.44 (0.23-0.84) from an adjusted logistic regression model and 0.33 (0.17-0.80) from the PS matching model. The latter model was used to estimate that the average treatment effect from a single-ACS dose on the entire sample was -0.09 (-0.03 to -0.15), while its effect among the actual recipients was -0.08 (-0.02 to -0.15).
Conclusion
There is a small benefit attributed to the single-dose ACS, reinforcing the need for dose administration and completion. Future studies are recommended to clarify the estimated association and improve on the methodological constraints encountered.
Morbidity
;
Propensity Score
9.Propensity score approaches in quantifying effects of treatment from observational data
Alvin Duke R. Sy ; Abubakar S. Asaad
Acta Medica Philippina 2022;56(16):96-107
Introduction:
Despite the growing popularity of utilizing observational studies for determining associations with public health implications, there is limited literature using them for examining and quantifying the effects of exposures or treatments: The study compared traditional regression with scoring approaches in estimating treatment effects considering the noted limitations in the dataset.
Methods:
We conducted a secondary analysis of previously collected retrospective cohort data derived from
maternal-neonatal dyads delivered prematurely in a tertiary hospital. Propensity scores (PS) were estimated using logistic and boosting regression. These scores were implemented into matching, stratification, and weighting models. The estimated measures of effect from traditional regression and PS-adjusted models were compared using certain metrics (i.e., the width of CI, SE, AIC, BIC). Sensitivity analysis was also performed.
Results:
We included data from 562 patients (123 untreated and 439 treated). Both the estimated scores demonstrated satisfactory fit and reduction in the standardized differences between the groups. However, the logit-estimated scores had better prediction (AUC: 0.71 vs 0.66) and forecasting properties (Brier: 0.15 vs 0.17) than the boosting-estimated scores. All generated statistical models demonstrated a reduction in the occurrence of respiratory morbidity among preterm neonates exposed to a single-dose antenatal corticosteroid (ACS) (ORs ranged from 0.37 to 0.59). The estimated average treatment effects (ATE) and effect among those treated (ATET) from various models suggested a small benefit attributed to the single-dose ACS (ATEs range from -0.09 to -0.41; ATETs range from -0.07 to -0.17).
Conclusion
PS estimated using logistic regression performed better than those estimated using machine learning strategies. The matching model using the said scores demonstrated better fit and parsimony over conventional and propensity-adjusted models. Future studies are recommended to improve the application of these analytic techniques in real-world data.
Propensity Score
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Machine Learning
;
Logistic Models
10. Anti-TB drug resistance in Tanga, Tanzania: A cross sectional facility-base prevalence among pulmonary TB patients
Abubakar S. HOZA ; Brigitte KÖNIG ; Abubakar S. HOZA ; Sayoki G.M. MFINANGA
Asian Pacific Journal of Tropical Medicine 2015;8(11):907-913
Objective: To determine the prevalence and risk factors associated with drug resistance tuberculosis (TB) at facility-base level in Tanga, Tanzania. Methods: A total of 79 Mycobacterium tuberculosis (MTB) isolates included in the study were collected from among 372 (312 new and 60 previously treated) TB suspects self-referred to four TB clinics during a prospective study conducted from November 2012 to January 2013. Culture and drug susceptibility test of the isolates was performed at the institute of medical microbiology and epidemiology of infectious diseases, University hospital, Leipzig, Germany. Data on the patient's characteristics were obtained from structured questionnaire administered to the patients who gave informed verbal consent. Unadjusted bivariate logistic regression analysis was performed to assess the risk factors for drug resistant-TB. The significance level was determined at P < 0.05. Results: The overall proportions of any drug resistance and MDR-TB were 12.7% and 6.3% respectively. The prevalence of any drug resistance and MDR-TB among new cases were 11.4% and 4.3% respectively, whereas among previously treated cases was 22.2% respectively. Previously treated patients were more likely to develop anti-TB drug resistance. There was no association between anti-TB drug resistances (including MDR-TB) with the risk factors analysed. Conclusions: High proportions of anti-TB drug resistance among new and previously treated cases observed in this study suggest that, additional efforts still need to be done in identifying individual cases at facility-base level for improved TB control programmes and drug resistance survey should continuously be monitored in the country.