Influence of Obstructive Sleep Apnea on the Risk of Dental Caries: Insights from a 13-Year Population-Based Retrospective Study

KNOWLEDGE TRANSFER STATEMENT

Obstructive sleep apnea has been proven to have a great negative impact on patients, and the relationship between sleep apnea and dental caries is still inconclusive. Our study shows that patients with sleep apnea and those older than 45 y have a significant risk of dental caries.

Cardiopulmonary Protection for Bilateral Breast Irradiation: A Dosimetric Comparison between Proton and Photon Plans

PURPOSE/OBJECTIVE(S)

Recent advances in cancer treatment improve cancer survivorship. Cardiovascular disease has become the leading cause of non-cancer death in breast cancer survivors. Therefore, risk of cardiopulmonary toxicities during multimodality treatment should be assessed carefully. It remains to be defined the best scenario for proton therapy to confer meaningful cardiovascular protection in the setting of breast irradiation. We hypothesized proton therapy plan provides optimal cardiopulmonary protection during bilateral breast irradiation. The study aimed to compare cardiopulmonary dosimetric parameters of proton and photon radiotherapy plans.

MATERIALS/METHODS

We conducted a retrospective study and patients with bilateral breast cancer indicated for radiotherapy between January 01, 2010 and December 31, 2020 were included. All patients received whole breast or chest wall irradiation with or without regional nodal irradiation. The dose scheme was 50-50.4 Gy in 25-28 fractions. Boost was allowed if patients receiving breast conserving surgery or known risk factors. The dosimetric parameters included planning target volume, mean dose to the heart, the volume of whole lung receiving 5 Gy, 10 Gy, and 20 Gy. For photon therapy, volumetric modulated arc therapy using double partial arc plans was generated with Pinnacle 9.8, Elekta Synergy and tomotherapy helical plan was generated with Tomo Hi-Art planning system. For proton therapy, treatment planning was generated with Ray station 9A. All data was managed using SAS v.9.4 software. Analysis of variance (α = 0.05) was used to compute the dosimetry of different treatment modalities. The statistical significance was considered with a p-value <0.05.

RESULTS

Thirty-one patients with bilateral breast cancer were included, including 12 bilateral breast irradiation patients and 6 bilateral chest wall irradiation patients. The mean dose of heart was 53.0±43.3 cGy in proton therapy while 736.6±225.1 cGy and 869.67±241.0 cGy in Tomotherapy and volumetric modulated arc therapy respectively. The volume of whole lung receiving 5 Gy was 15.4±7.91% in proton therapy while 46.1±10.8% and 46.3±2.5% in Tomotherapy and volumetric modulated arc therapy respectively. The volume of whole lung receiving 20 Gy was 7.7±4.3% in proton therapy while 15.4±5.6% and 19±3.5% in Tomotherapy and volumetric modulated arc therapy respectively. The effects of cardiopulmonary protection were more significant for chest wall irradiation over breast irradiation.

CONCLUSION

Proton radiotherapy provided significant dose reduction for bilateral breast irradiation. The benefit is more significant is patients receiving bilateral chest wall irradiation. Further clinical validations will be warranted to confirm the clinical relevance of the finding.

Recurrent umbilical varix rupture with hemoperitoneum: a case report and review of literature

Background

Non-traumatic hemoperitoneum was a rare event with the risk of sudden death. Spontaneous rupture of hepatocellular carcinoma is the most intuitive diagnosis when hemoperitoneum occurs in cirrhotic patients who are not regularly followed up. However, other etiologies of hemoperitoneum, such as intra-abdominal varix rupture, should be kept in mind.

Case presentation

A 44-year-old man with alcoholic liver cirrhosis, Child–Pugh B was sent to our emergency department (ED) because of recurrent abdominal pain and hypovolemic shock. He had similar symptoms one month ago and was diagnosed as hepatocellular carcinoma (HCC) rupture with hemoperitoneum, therefore he underwent trans-arterial embolization (TAE). However, the follow-up magnetic resonance imaging (MRI) showed less possibility of hepatocellular carcinoma. Contrast enhanced abdominal computed tomography (CT) showed possible umbilical vein contrast agent extravasation. Exploratory laparotomy confirmed the diagnosis of rupture umbilical varix with hemoperitoneum.

Conclusion

Although umbilical varix rupture is a rare cause of hemoperitoneum, it should be kept in mind in cirrhotic patients with unexplained hemoperitoneum.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02167-3.

Statewide Efficacy Assessment of Insect Growth Regulators Against Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: An Alternative Control Strategy?

The efficacy of three groups of insect growth regulators, namely juvenile hormone mimics (methoprene and pyriproxyfen), chitin synthesis inhibitors (diflubenzuron and novaluron), and molting disruptor (cyromazine) was evaluated for the first time, against Aedes albopictus Skuse (Diptera: Culicidae) larvae from 14 districts in Sabah, Malaysia. The results showed that all field populations of Ae. albopictus were susceptible towards methoprene, pyriproxyfen, diflubenzuron, novaluron, and cyromazine, with resistance ratio values ranging from 0.50-0.90, 0.60-1.00, 0.67-1.17, 0.71-1.29, and 0.74-1.07, respectively. Overall, the efficacy assessment of insect growth regulators in this study showed promising outcomes and they could be further explored as an alternative to conventional insecticides.

Assessment of the susceptibility status of Aedes albopictus (Diptera: Culicidae) from Interior, Sandakan and Tawau divisions of Sabah, Malaysia based on WHO diagnostic doses of larvicides

Susceptibility status of Aedes albopictus (Skuse) sampled from residential areas in Interior, Sandakan and Tawau divisions of Sabah, Malaysia, was evaluated based on the WHOrecommended doses of organochlorine and organophosphate larvicides. To determine susceptibility status, larval bioassays were carried out and post 24-hour mortalities based on WHO resistance classifications were adopted. The results demonstrated that Ae. albopictus larvae were resistant toward 5 out of the 8 larvicides tested. Larvae from all populations were resistant against bromophos, fenitrothion, malathion, temephos and dichlorodiphenyltrichloroethane (DDT), with mortalities ranging from 0.00 to 89.33%. Dieldrin, on the other hand, could induce 100.00% mortalities in all populations, followed by fenthion and chlorpyrifos, with mortalities ranging from 97.33 to 100.00% and 81.33 to 100.00% respectively. Despite most populations exhibiting similitude in their resistance status, larvae from Sandakan exhibited the highest resistance level whereas the lowest level was observed in Keningau. In view of the inadequacy of some larvicides in controlling Ae. albopictus in this study, integrated management such as insecticide rotation or combination of interventions is warranted.

Residual efficacy of deltamethrin applied to foliage against Malaysian Aedes aegypti (L.) and Aedes albopictus (Skuse)

The spraying of insecticide on foliage to provide an insecticidal barrier may serve as part of the vector control measures to combat the increasing threat of Aedes-borne diseases. The effectiveness of insecticide barrier spraying was evaluated by assessing the residual efficacy of deltamethrin sprayed on foliage against Malaysian Ae. aegypti (L.) and Ae. albopictus (Skuse). In this semi-field study, landscape plants grown within the vicinity of the Institute for Medical Research (IMR), Malaysia, were treated with deltamethrin suspension concentrate (SC) with the dosage of 30 mg/m² and 50 mg/m² in three rounds of spraying. Deltamethrin residual activity on treated and untreated leaves was investigated using standard WHO cone bioassays. Wild Aedes populations at both deltamethrin-treated and untreated plant clusters were monitored by ovitrap surveillance. Ovitrap monitoring revealed that the mean number of Ae. albopictus larvae at deltamethrin-treated were significantly lower than the mean number of larvae of the same species at the untreated plant cluster. Cone bioassay results showed that the insecticide remained effective for up to 4 weeks (> 80% mortality), but the insecticide residual activity was affected by rainfall. These results suggest that insecticide barrier spraying is a promising tool and may be used along with other mosquito control tools such as indoor residual spray and space spraying to reduce the dengue burden.

PesTrapp mobile app: A trap setting application for real-time entomological field and laboratory study

Diseases such as malaria, dengue, Zika and chikungunya remain endemic in many countries. Setting and deploying traps to capture the host/vector species are fundamental to understand their density and distributions. Human effort to manage the trap data accurately and timely is an exhaustive endeavour when the study area expands and period prolongs. One stop mobile app to manage and monitor the process of targeted species trapping, from field to laboratory level is still scarce. Toward this end, we developed a new mobile app named "PesTrapp" to acquire the vector density index based on the mobile updates of ovitraps and species information in field and laboratory. This study aimed to highlight the mobile app's development and design, elucidate the practical user experiences of using the app and evaluate the preliminary user assessment of the mobile app. The mobile app was developed using mobile framework and database. User evaluation of the mobile app was based on the adjusted Mobile App Rating Scale and Standardized User Experience Percentile Rank Questionnaire. The process flows of system design and detailed screen layouts were described. The user experiences with and without the app in a project to study Aedes surveillance in six study sites in Selangor, Malaysia were elucidated. The overall mean user evaluation score of the mobile app was 4.0 out of 5 (SD=0.6), reflects its acceptability of the users. The PesTrapp, a one-stop solution, is anticipated to improve the entomological surveillance work processes. This new mobile app can contribute as a tool in the vector control countermeasure strategies.

Who writes dermatology randomized controlled trials? The need to specify the role of medical writers

Medical writers may make major contributions to the preparation of a manuscript, but are not listed as authors. We assessed the prevalence, affiliation and role of medical writers in dermatology randomized controlled trials (RCTs) published in 2019 in the top 7 medical and top 10 dermatology journals. Medical writers were identified in 39/83 trials (47%), all of which were exclusively industry-funded trials (39/47, prevalence 83%). Most studies stated their role as 'medical writing support' and/or 'editorial assistance' (35/39, 90%), but when more information was provided, four studies specified first draft preparation (50% of RCTs in general medical and 1.3% of RCTs in dermatology journals). Medical writers are common in dermatology trials but their role is often vaguely stated. In April 2020 the British Journal or Dermatology and Clinical and Experimental Dermatology adopted CRediT (Contributor Roles Taxonomy), which describes contributions of authors and may help clarify who writes trial manuscripts.

The status and outcomes of registered clinical trials for Janus kinase inhibitors in alopecia areata: are unpublished trials being overlooked?

Recent meta-analyses of Janus kinase (JAK) inhibitors in alopecia areata (AA) have excluded trial registries and may thus be subject to publication bias. This study assessed the potential for evidence selection bias and provides an overview of JAK inhibitor trials in AA. A broad search strategy of ClinicalTrials.gov was performed for AA. We also recorded whether results were published on PubMed. There were 26 trials identified, of which 9 were ongoing (mostly oral JAK inhibitors: 8 studies; 89%). Of completed/terminated trials, 4/17 (24%) had terminated prematurely, citing 'inefficacy/futility' or 'sponsor decision'. These were all topical JAK inhibitor trials (4/8, 50% termination rate), with a 0% termination rate (0/9) for oral JAK inhibitor trials. We conclude that topical JAK inhibitors may be less efficacious than has been apparent in the literature to date, with 50% of trials having terminated due to inefficacy/futility or sponsor decision and only one topical JAK inhibitor trial ongoing.

The role of breath hold intensity modulated proton therapy for a case of left-sided breast cancer with IMN involvement. How protons compare with other conformal techniques?

Purpose

To evaluate the dosimetric impact of four different radiotherapy techniques for a case of left-sided breast cancer with Internal Mammary lymph Nodes (IMN) involvement.

Materials and methods

To identify the best radiotherapy technique for this patient, four methods were compared: 3D Conformal Radiotherapy (3D-CRT), Volumetric Modulated Arc Therapy (VMAT), Tomotherapy (TOMO) and Intensity Modulated Proton Therapy (IMPT). Patient was treated using deep inspiration breath-hold (DIBH) technique. Prescribed dose was 40.05y in 15 fractions. Plan evaluation was performed on target coverage and dose to the organs-at-risk (OARs) using 3D-CRT as a baseline.

Results

TOMO has the most ideal Conformity Index (CI) at 1.139, followed by IMPT at 1.158, VMAT at 0.765, and 3D-CRT at 0.685. Using 3D-CRT as a baseline, VMAT, TOMO and IMPT all showed improved dose coverage. IMPT has the best dose coverage. TOMO has the most ideal homogeneity index (HI) and Conformity Number (CN). Mean heart dose (MHD) is lowest for IMPT at 0.55 Gy and highest for VMAT at 4.79 Gy. V20Gy of left lung is the lowest for IMPT at 11.11%, compared to 17.53% for TOMO, 18.19% for VMAT and 33.33% for 3D-CRT. V5Gy for the contralateral breast ranges from 0.01% in IMPT to 72.32% in TOMO.

Conclusion

3D-CRT compromising target coverage but achieving good OAR sparing for the contralateral right breast, left lung and right lung. Overall, IMPT performed best in terms of target coverage and OAR-sparing. Protons delivered superior target dose coverage and sparing of normal structures for this patient. As dose value parameters are expected to correlate with acute and chronic toxicities, proton therapy should be given due consideration as the preferred technique for the treatment of left-sided breast cancers with IMN involvement. Further studies with more patients can be done to evaluate the effectiveness of proton therapy on acute and chronic toxicities.

Indoor and outdoor residual spraying of a novel formulation of deltamethrin K-Othrine® (Polyzone) for the control of simian malaria in Sabah, Malaysia

Since 2000, human malaria cases in Malaysia were rapidly reduced with the use of insecticides in Indoor Residual Spray (IRS) and Long-Lasting Insecticide Net (LLIN). Unfortunately, monkey malaria in humans has shown an increase especially in Sabah and Sarawak. The insecticide currently used in IRS is deltamethrin K-Othrine® WG 250 wettable granule, targeting mosquitoes that rest and feed indoor. In Sabah, the primary vector for knowlesi malaria is An. balabacensis a species known to bite outdoor. This study evaluates an alternative method, the Outdoor Residual Spray (ORS) using a novel formulation of deltamethrin K-Othrine® (PolyZone) to examine it suitability to control knowlesi malaria vector in Sabah, compared to the current method. The study was performed at seven villages in Sabah having similar type of houses (wood, bamboo and concrete). Houses were sprayed with deltamethrin K-Othrine® (PolyZone) at two different dosages, 25 mg/m2 and 30 mg/m2 and deltamethrin K-Othrine® WG 250 wettable granule at 25 mg/m2, sprayed indoor and outdoor. Residual activity on different walls was assessed using standard cone bioassay techniques. For larval surveillances, potential breeding sites were surveyed. Larvae were collected and identified, pre and post spraying. Adult survey was done using Human Landing Catch (HLC) performed outdoor and indoor. Detection of malaria parasite in adults was conducted via microscopy and molecular methods. Deltamethrin K-Othrine® (PolyZone) showed higher efficacy when sprayed outdoor. The efficacy was found varied when sprayed on different types of wall surfaces. Deltamethrin K-Othrine® (PolyZone) at 25 mg/m2 was the most effective with regards to ability to high mortality and effective knock down (KD). The vector population was reduced significantly post-spraying and reduction in breeding sites as well. The number of simian malaria infected vector, human and simian malaria transmission were also greatly reduced.

Clinical features and prognosis of patients with idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease

<sec> <title>BACKGROUND</title> Idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) share common risk factors. They could therefore be expressed in a single patient. However, the prevalence, clinical characteristics and prognosis of individuals with comorbid IPF and COPD are not known. </sec> <sec> <title>METHOD</title> From 2003 to 2007, the Korean Interstitial Lung Disease Study Group created a register for idiopathic interstitial pneumonia using 2002 ATS/ERS (American Thoracic Society/European Respiratory Society) criteria. Of the 1546 IPF patients assessed, 143 had decreased lung function consistent with COPD (IPF-COPD). COPD was diagnosed based on age (≥40 years) and pulmonary function (forced expiratory volume in 1 sec [FEV₁]/forced vital capacity [FVC] ratio < 0.7). </sec> <sec> <title>RESULTS</title> The median age of the IPF-COPD group was 71.0 years (interquartile range 66.0-76.0); most patients were male (88.1%). FVC (%) was significantly higher in the IPF-COPD group; however, FEV₁ (%) was significantly lower in the IPF-COPD group (P < 0.001). Diffusing capacity of the lung for carbon monoxide (DL_CO) was not significantly different between the two groups. In survival analysis, age and FVC (%), but not COPD, were significantly associated with prognosis (respectively P = 0.003, 0.001 and 0.401). COPD severity was also not related to prognosis (P = 0.935). </sec> <sec> <title>CONCLUSION</title> The prevalence of IPF-COPD was estimated to be ∼9.2% among all IPF patients; prognosis of patients with IPF-COPD was not worse than those with IPF alone. </sec>.

Status of pyrethroid resistance in Aedes (Stegomyia) aegypti (Linneaus) from dengue hotspots in Klang Valley, Malaysia

The continued absence of an effective and safe tetravalent dengue vaccine and the lack of specific anti-viral treatment have made mosquito vector control using chemical insecticides as the mainstream for dengue prevention and control. However, the long-term use of chemical insecticides may induce resistance. Hence detection of insecticide resistance in dengue vectors is crucially important in ensuring the insecticide-based intervention in dengue control program is still effective and reliable. In this study, the susceptibility status of Aedes aegypti from five selected dengue hotspots in Klang Valley, Malaysia against pyrethroids was determined by employing the World Health Organization (WHO) protocol of adult bioassay. Four types of pyrethroids were tested against adult female Aedes aegypti to determine the knockdown rate, post 24-h adult mortality and resistance ratio. All field-collected Aedes aegypti strains were resistant to the four pyrethroids tested, except for the Taman Sungai Jelok (TSJ) strain. Permethrin exhibited the lowest knockdown rate against Aedes aegypti, followed by deltamethrin, cyfluthrin and lambda-cyhalothrin. This present study indicated the widespread of pyrethroid resistance in Aedes aegypti in Klang Valley, indicating the needs of implementing alternative measures in vector control program. The data in this study can be utilised as an input for insecticide resistance management of Aedes aegypti in Malaysia.

A preliminary proteomic study of permethrin resistant and susceptible Aedes aegypti (L.)

The mechanism of insecticide resistance is traditionally attributed to detoxification enzymes, target site alteration, decreased penetration of insecticides and behavioural resistance. Other form of mechanisms, such as the role of protein(s) in resistance is unknown. In the present study, the protein profiling of both IMR-PSS strain (permethrin-selected) and IMR-LS strain (laboratory-susceptible) 24 hours post exposure period to permethrin was carried out via 1D-gel electrophoresis and liquid chromatography mass spectrometry (LC-MS/ MS). The bands which appeared in the gel of 1D-electrophoresis revealed an abundance of proteins. The band pattern of both strains looked macroscopically alike and differed only in band intensity. However, LC-MS/MS analysis revealed that the IMR-PSS strain produced extra 388 peptides that were not found in the IMR-LS strain, indicating that IMR-PSS strain reacted differently from IMR-LS strain as a result of persistent exposure to permethrin. Since the complex banding patterns of 1D-gel electrophoresis were difficult to interpret the significance of the protein difference between IMR-PSS and IMR-LS strain, hence LC-MS/MS analysis is ideally suited for better protein resolution and thus will allow more in-depth comparison of the complex pattern. The findings here provide the first preliminary evidence that insecticide resistance in mosquito induces up regulation of proteins that may be protective to mosquitoes against insecticide and proteins could be another mechanism that contributes to development of resistance.

Adulticide Resistance Status of Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: A Statewide Assessment

Resistance status of Aedes albopictus (Diptera: Culicidae) collected from Sabah, East Malaysia, was evaluated against four major classes of adulticides, namely pyrethroid, carbamate, organochlorine, and organophosphate. Adult bioassays conforming to WHO standard protocols were conducted to assess knockdown and mortality rates of Ae. albopictus. Among tested pyrethroid adulticides, only cyfluthrin, lambda-cyaholthrin, and deltamethrin were able to inflict total knockdown. The other adulticide classes mostly failed to cause any knockdown; the highest knockdown rate was only 18.33% for propoxur. With regards to mortality rate, Ae. albopictus was unanimously susceptible toward all pyrethroids, dieldrin, and malathion, but exhibited resistance toward bendiocarb, propoxur, dichlorodiphenyltrichloroethane, and fenitrothion. Additionally, correlation analysis demonstrated cross-resistance between bendiocarb and propoxur, and malathion and propoxur. In conclusion, this study has disclosed that pyrethroids are still generally effective for Aedes control in Sabah, Malaysia. The susceptibility status of Ae. albopictus against pyrethroids in descending order was cyfluthrin > lambda-cyhalothrin > deltamethrin > etofenprox > permethrin.

Pteridine fluorescence in age-determination of immature Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae)

In the practice of forensic entomology, the chronological age of the maggots retrieved from the cadaver is used to determine the minimum post-mortem interval (mPMI) i.e. minimum time of death. The conventional method of aging the maggots is based on measuring the growth rate of these maggots. Although effective, the constraint associated with conventional method necessitates the development of new age determination method, such as pteridine determination. Pteridine, a by-product of protein metabolism in insects is known to correlate with the age of a variety of dipterans. A number of studies were conducted on aging the adults of forensically important flies. In this study, pteridine was extracted from Chrysomya megacephala and Chrysomya rufifacies maggots of known age using established methods and determined by measuring the fluorescence at excitation of 330nm and the emissions between 350nm and 600nm. Results exhibited significant positive linear relationships between the pteridine accumulations and age of the fly immature. Pteridine determination is a potential new age determination tool that can be used to determine mPMI.

Bioefficacy Evaluation of Commercial Mosquito Coils Containing Metofluthrin, d-Allethrin, d-Trans Allethrin, and Prallethrin Against Aedes albopictus (Diptera: Culicidae) in Malaysia

The bioefficacy of commercial mosquito coils containing four different active ingredients, namely metofluthrin, d-allethrin, d-trans allethrin, and prallethrin against Aedes albopictus (Skuse) (Diptera: Culicidae) from 10 states in Malaysia, was evaluated using the glass chamber method. In this study, Ae. albopictus exhibited various knockdown rates (50% knockdown time, KT50), ranging from 2.50 to 5.00 min, 2.50 to 7.00 min, 3.00 to 8.00 min, and 5.00 to 17.00 min for metofluthrin, d-trans allethrin, d-allethrin, and prallethrin, respectively. Overall, all strains of Ae. albopictus were most susceptible to metofluthrin, with mortality rates >80%. On the other hand, mortality rates ranging from 5.0 to 100% were observed from all populations exposed to d-trans allethrin, d-allethrin, and prallethrin. In addition, significant correlations between KT50 of metofluthrin and d-allethrin (r = 0.758, P = 0.011), metofluthrin and prallethrin (r = 0.676, P = 0.032), d-allethrin and d-trans allethrin (r = 0.832, P = 0.003), d-allethrin and prallethrin (r = 0.921, P = 0.000), and d-trans allethrin with prallethrin (r = 0.941, P = 0.000) were detected, suggesting some levels of cross-resistance within the pyrethroid insecticides. This study demonstrated that metofluthrin can induce high insecticidal activity in Ae. albopictus in Malaysia, followed by d-trans allethrin, d-allethrin, and prallethrin.

Early development of de novo hepatocellular carcinoma after direct-acting agent therapy: Comparison with pegylated interferon-based therapy in chronic hepatitis C patients

Patients with chronic hepatitis C who achieve a sustained viral response after pegylated interferon therapy have a reduced risk of hepatocellular carcinoma, but the risk after treatment with direct-acting antivirals is unclear. We compared the rates of early development of hepatocellular carcinoma after direct-acting antivirals and after pegylated interferon therapy. We retrospectively analysed 785 patients with chronic hepatitis C who had no history of hepatocellular carcinoma (211 treated with pegylated interferon, 574 with direct-acting antivirals) and were followed up for at least 24 weeks after antiviral treatment. De novo hepatocellular carcinoma developed in 6 of 574 patients receiving direct-acting antivirals and in 1 of 211 patients receiving pegylated interferon. The cumulative incidence of early hepatocellular carcinoma development did not differ between the treatment groups either for the whole cohort (1.05% vs 0.47%, P = .298) or for those patients with Child-Pugh Class A cirrhosis (3.73% vs 2.94%, P = .827). Multivariate analysis indicated that alpha-fetoprotein level >9.5 ng/mL at the time of end-of-treatment response was the only independent risk factor for early development of hepatocellular carcinoma in all patients (P < .0001, hazard ratio 176.174, 95% confidence interval 10.768-2882.473) and in patients treated with direct-acting agents (P < .0001, hazard ratio 128.402, 95% confidence interval 8.417-1958.680). In conclusion, the rate of early development of hepatocellular carcinoma did not differ between patients treated with pegylated interferon and those treated with direct-acting antivirals and was associated with the serum alpha-fetoprotein level at the time of end-of-treatment response.

Organophosphate and Organochlorine Resistance in Larval Stage of Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia

The present study aims to investigate the susceptibility status of Aedes albopictus (Skuse) collected from residential areas in Sabah, Malaysia towards eight WHO-recommended dosages of larvicides representing the classes of organophosphates and organochlorines. Field and reference strains of Ae. albopictus larvae were bioassayed in accordance to WHO standard methods using diagnostic dosages of bromophos, malathion, fenthion, fenitrothion, temephos, chlorpyrifos, dichlorodiphenyltrichloroethane (DDT), and dieldrin. The results revealed that Ae. albopictus was resistant (mortality < 90%) towards malathion, temephos, and DDT. In addition, most of the Ae. albopictus strains exhibited a wide range of susceptibilities against bromophos, with mortality ranged from 49.33 to 93.33%. On the contrary, only dieldrin was able to induce 100% mortality against all strains of Ae. albopictus. Tolerance to fenitrothion, fenthion, and chlorpyrifos, with mortality ranging from 81.33 to 97.33%, was also observed in this study.

Ovitrap surveillance in Sarawak, Malaysia: A comprehensive study

Tropical Infectious Diseases Research and Education Centre (TIDREC), University of Malaya, 50603 Kuala Lumpur, Malaysia This study reports the distribution and abundance of Aedes by using ovitrap surveillance and aims to provide the most recent information on dengue vector distribution in Sarawak State, Malaysia. The ovitrap index (OI) of Aedes larvae was found highest in urban residential area (mean OI = 90.97%), followed by suburban (69.70%), rural (65.45%) and remote (52.63%) residential areas. The mean number of Aedes larvae per ovitrap was also found to be significantly highest in urban residential area (26.47 ± 1.62) compared to other type of residential areas (p<0.05). Interestingly, no Aedes aegypti was observed in this study, but two species of Armigeres were found co-breeding with Ae. albopictus. This study reveals that Ae. albopictus is the dominant dengue vector in Sarawak State and all the surveyed residential areas are in risk of dengue transmission with OI > 10.

Comparative Efficacy of Commercial Mosquito Coils Against Aedes aegypti (Diptera: Culicidae) in Malaysia: A Nationwide Report

This study was conducted using the glass chamber method to determine the susceptibility status of the dengue vector, Aedes aegypti (L.) from 11 states in Malaysia to commercial mosquito coils containing four different active ingredients, namely metofluthrin, d-allethrin, d-trans allethrin, and prallethrin. Aedes aegypti exhibited various knockdown rates, ranging from 14.44% to 100.00%, 0.00% to 61.67%, 0.00% to 90.00%, and 0.00% to 13.33% for metofluthrin, d-allethrin, d-trans allethrin, and prallethrin, respectively. Overall, mortality rates ranging from 0.00% to 78.33% were also observed among all populations. Additionally, significant associations were detected between the knockdown rates of metofluthrin and d-allethrin, and between metofluthrin and d-trans allethrin, suggesting the occurrence of cross-resistance within pyrethroid insecticides. Overall, this study revealed low insecticidal activity of mosquito coils against Ae. aegypti populations in Malaysia, and consequently may provide minimal personal protection against mosquito bites.

Simulated field study on the efficacy of the thermal application of a synergized pyrethroid formulation against Aedes aegypti (Linn.) and Culex quinquefasciatus Say

Thermal application of a synergized pyrethroid formulation containing 0.8% w/w sbioallethrin, 18.7% w/w permethrin and 16.8% w/w piperonyl butoxide was performed to evaluate its efficacy against adult and larva of Aedes aegypti and Culex quinquefasciatus. Three cages each containing 15 mosquitoes and paper cups each containing 25 larvae in 250 ml of water were deployed at each test point between 3 and 20 feet. The formulation was diluted (formulation:water) 1:33, 1:50 and 1:100, respectively, and applied using a thermal fogger. Sixty minutes post spraying, the adult knock down rate of Ae. aegypti and Cx. quinquefasciatus at a maximum distance of 15 feet using all dilution ratios ranged from 96.67 - 100% and 43.33 - 100%, respectively. More than 70.00% adult mortalities were recorded for both mosquito species at the distance between 3 feet and 15 feet 24 hours post spraying. In contrast, complete larval mortalities of Ae. aegypti were obtained at a maximum distance of 10 feet with dilution ratio of 1:33, while more than 80.00% larval mortalities were observed for Cx. quinquefasciatus at similar maximum distance using all dilution ratios. These results showed that thermal application using synergized pyrethroid formulation was effective against both mosquito species tested especially the adult stage.

Biting behaviour of medically important mosquitoes (Diptera: Culicidae) in Peninsular Malaysia

Human-landing catch (HLC) technique was undertaken in nine selected study sites within Peninsular Malaysia to determine the biting cycle of Aedes, Armigeres, Culex, and Mansonia mosquitoes. HLC was conducted 24 hours on three different nights in a duration of one week at each study site. Aedes albopictus were found in all study sites with bimodal biting cycle, whereas the biting peak of Aedes butleri was recorded between 1600 and 1900 hr. For Armigeres, five study sites demonstrated similar biting peak hour (1900 - 2000 hr) for Ar. kesseli four study sites showed biting peak at 1800 - 1900 hr for Ar. subalbatus. Culex quinquefasciatus was collected from all study sites except in Sungai Penchala with its biting activity beginning from 1900 hr. Both Mansonia annulifera and Mansonia uniformis captured in two different study sites showed similar biting peaks (1500 - 1600 hr). It is recommended that vector control activities be carried out at dusk as almost all mosquito species captured started their biting activities at that time.