Tropical biomedicine最新文献

To investigate co-infection of bacterial isolates associated with respiratory syncytial virus (RSV) in children aged less than two years who were admitted to hospital with confirmed lower respiratory tract infection (LRTI) in Kelantan, Malaysia. The demographic data, clinical history, case management, haematological as well as infectious parameters (white blood cell differential and count, plus C-reactive protein, CRP) of the patients were systematically recorded. Less than one-third of cases were RSV-positive (21.03% and 26.23% were diagnosed as acute bronchiolitis or pneumonia, respectively). Blood cultures from approximately 10% of patients demonstrated growth of Haemophilus influenzae, Staphylococcus aureus, coagulase-negative Staphylococcus, Pseudomonas stutzeri, haemolytic Streptococcus group A, and Bacillus subtilis. Further analysis indicated that children with positive bacterial growth had an insignificant predictive value of CRP (2.32-7.16 mg/dl). The total white cell counts were 2.97-7.33 x 10⁹sup>/L despite increased lymphocyte values in the bacteria-positive blood culture. Platelet counts were also within normal limits except for a single case of H. influenzae infection (685.50 x 10⁹sup>/L). Interestingly, 95.01% of patients were treated with antibiotics; 66.23% of RSV infection cases were administered with a combination of antibiotics and 33.77% with only a single antibiotic. The data indicate that the use of antibiotics, either singly or in combination, is not always effective in treating LRTI in infants. Alternative therapeutic regimens should be considered, especially in Asian countries that may have limited resources.

The indigenous community in Malaysia also known as Orang Asli have preserved their unique cultural identity in the face of rapid national development and modernization efforts. Over the years, poverty alleviation has become a central pillar of Malaysia development. In this review, seroprevalence report from the Orang Asli and their health status about neglected tropical diseases were collated and analyzed. The review will show the potential areas of research for future development. Specifically, the review will cover a 12-year period preceding the onset of COVID-19 pandemic, offering critical insights into the community health landscape. In depth discussion on the unique impact of the pandemic covering healthcare access, socioeconomic dynamics and community resilience. Analysis revealed the burden of parasitism is high in the community and the sustainability of certain basic access such as clean water and education remains a challenge. Different approaches to improve future intervention strategies were also discussed. The review can contribute to essential knowledge for policymakers, researchers, healthcare providers interested in enhancing the well-being of the Orang Asli community.

Tuberculosis (TB) is a critical disease that predominantly affects the lungs. This disease remains a global health threat. Currently, the incidence of TB is estimated to be 92 cases in every 100 000 population. However, latent TB infection (LTBI) cases among Malaysians are another great health concern that requires immediate steps to be taken to detect, diagnose, and treat LTBI as one of the key strategies to end TB. Although individuals with LTBI are unlikely to infect others, the threat of infection is still imminent as these individuals can potentially develop into active TB cases. As such, this study aims to identify the prevalence of LTBI among asymptomatic individuals that underwent QuantiFERON®-TB Gold Plus test from a private laboratory in Malaysia to determine the association between the risk factors and the detected LTBI cases. A retrospective study was conducted by analyzing the archive records of 3 877 samples from January 2021 to March 2022. The cases underwent QuantiFERON®-TB Gold Plus tests for LTBI at Premier Integrated Labs. This study underlines that those who were LTBI positive had a prevalence of 638/3 877 (16.46%) with males contributing to 343/638 cases (53.76%). Furthermore, the majority of the positive cases were between the age of 30-43 years old with 197/638 (30.88%), and Chinese ethnicity with 225/638 (35.27%). The risk factors significantly associated with LTBI cases were age (p = 0.001) and ethnicity (p = 0.001). The prevalence of LTBI determined through this study is considered remarkably low for an intermediate TB burden country. Although LTBI is not contagious, specific clinical and preventative considerations are needed for the diagnosis, treatment, and implementation of appropriate safety measures to curb the spread of TB in Malaysia.

Current strategies for tick control have led to the development of resistance and environmental contamination. Consequently, there is an urgent need for research into new and effective acaricides for tick control. The aim of this study was to fabricate and characterize Linalool loaded zinc oxide nanoparticles (Lin@ZNP), and to assess the acaricidal, larvacidal, and repellent activities of Lin@ ZNP against Hyalomma anatolicum, a prevalent tick species infesting cattle in Saudi Arabia. Lin@ ZNP was synthesized using an ethanolic solution of polyvinyl alcohol. The adult immersion, the larval packet, and the assessment of vertical movement behavior of tick larvae assays were utilized to examine the acaricidal, larvicidal, and repellent activities of Lin@ZNP against H. anatolicum, respectively. Furthermore, the impact of Lin@ZNP on acetylcholinesterase and oxidant/antioxidant enzyme activities was investigated. Exposure of adult H. anatolicum to different concentrations of Lin@ZNP resulted in noticeable (p<0.001) reductions in the viability rate of adults and the mean number, weight, and hatchability of eggs, compared to the control group. Lin@ZNP demonstrated significant repellent effects on H. anatolicum larvae after 60, 120, and 180 minutes of exposure. Lin@ZNP, particularly at all concentrations, markedly suppressed the acetylcholinesterase activity of the larval stage of H. anatolicum (P<0.001); but increase in malondialdehyde (MDA) levels (P<0.001) and a decrease in glutathione-S-transferase (GST) levels in H. anatolicum larvae (P<0.001). Lin@ZNP exhibited considerable acaricidal, larvicidal, and repellent effects against H. dromedarii adults and larvae in a manner dependent on the dosage. Additionally, Lin@ZNP notably reduced AChE levels and antioxidant activity, while inducing oxidative stress in H. anatolicum larvae. Nevertheless, further research is necessary to elucidate the precise mechanisms and practical efficacy of Lin@ZNP.

Hand, Foot and Mouth Disease (HFMD), a highly contagious viral disease common among infants and young children, is primarily caused by Enterovirus A71 (EV-A71) and Coxsackievirus A16 (CVA16). Nonetheless, emerging enteroviruses, such as CV-A10 and CV-A6, have also caused widespread outbreaks globally, in part due to the absence of effective antiviral therapies, and the high personto-person transmission rate. Person-to-person transmission is usually through fecal-oral or oral-oral routes, and sometimes via droplets. As the oral cavity is a primary site for early virus infection and replication, controlling oral viral shedding can mitigate the risk of transmission through this route. Povidone-iodine (PVP-I), a widely used antiseptic, has shown broad-spectrum antimicrobial properties but antiviral studies against HFMD-causing enteroviruses are limited, especially for CV-A10 and CVA6. Our study demonstrated that a 1% PVP-I solution (final concentration of 0.5%) exhibited virucidal activity against EV-A71, CV-A16, CV-A10, and CV-A6. All seven EV-A71 isolates and five CV-A16 isolates showed a significant virus titer reduction after a 1-minute incubation, while five CV-A10 isolates and two CV-A6 isolates required a 5-minute incubation to achieve this. The virucidal activity was confirmed through the EN14476:2013+A2:2019 virucidal quantitative suspension test, wherein all four viruses were completely inactivated after a 30-minute incubation with PVP-I at 37°C under both clean and dirty conditions. Western blot analysis suggested that PVP-I could affect the VP1 structural proteins of EV-A71. Our results suggest that PVP-I could serve as a potential virucidal agent to reduce the risk of person-to-person transmission of HFMD.

Giardiasis, caused by the parasite Giardia lamblia, is a prevalent and serious public health concern, particularly affecting children worldwide. The primary mode of transmission for the parasite is through contaminated food and water sources and often leads to the onset of diarrhoea in infected individuals. However, the present medications for Giardiasis treatment often come with numerous side effects, while the growing problem of drug resistance adds a significant complication. Therefore, there is an urgent need for alternative treatments. In this study, we explored the in-vitro potential of Andrographis paniculata leaf extract as a possible alternative treatment for Giardiasis. Our investigation involved assessing the impact of the ethanolic extract on Giardia trophozoites through the analysis of parameters such as cell death, morphological alterations, adherence, ROS generation, and cell cycle dynamics. A. paniculata leaf extracts demonstrated significant inhibitory activity against the growth of Giardia trophozoites. After being incubated for 24 hours, the test results revealed an IC50 value of 51.26µg/ml (95% CI 37.17- 65.35) for inducing cell death in Giardia trophozoites. We observed a substantial degradation of DNA, alteration in morphology, inhibition in adherence, ROS generation and inhibition of the cell cycle in Giardia trophozoites. The findings indicate that A. paniculata extract has the potential to be used as a therapeutic treatment for giardiasis. This approach aims to offer a natural therapeutic solution for giardiasis, minimizing side effects and reducing the risk of drug resistance.

Soil-transmitted helminths (STHs) are known as one of the neglected parasitic diseases, leading to significant health issues and associated complications. This study aims to assess the current prevalence of STH infections and the associated risk factors among rural primary schoolchildren in Malaysia. A cross-sectional study was conducted among 638 schoolchildren (7-11 years old) from 10 rural primary schools in five regions of Malaysia. The overall prevalence of STH infections among schoolchildren was 54.5%, with T. trichiura being the predominant STH species (50.9%), followed by A. lumbricoides (19.6%) and hookworms (7.4%). The highest prevalence of STH infections was recorded in the schools in Perak (96.6%), followed by Pahang (85.4%), Johor (42.1%) and Sabah (6.2%). At the same time, none of the schoolchildren in Sarawak were infected with STHs. The findings also highlighted that the older age group (10-11 years old) exhibited a higher prevalence of STH infection and T. trichiura compared to those aged 7-9 years old (P = 0.01) among the schools with a high prevalence of STH infections (>= 70%). Several variables, such as being female (1.9 [1.2, 3.0]) (Adjusted odd ratio [95% confidence interval]), low household income (30.9 [7.0, 136.5]), using untreated water supply (1.9 [1.1, 3.2]), indiscriminate defaecation (1.9 [1.1, 3.1]), indiscriminate garbage disposal (2.8 [1.3, 6.0]), eating with hands (5.9 [3.4, 10.4]) and experiencing pallor signs (2.3 [1.1, 5.0]), emerged as significant predictors of STH infections in this study population. The present study underscores that in specific rural community areas of Malaysia, STH infections continue to pose health concerns among primary schoolchildren. Hence, to ensure the sustained effectiveness of the measures taken to control STH infections, a collaborative and ongoing effort between various stakeholders is imperative to provide targeted support to rural communities, especially those in areas lacking essential amenities and healthcare services.

Simulium asakoae Takaoka and Davies has been confirmed to bite humans and has been incriminated as a vector of blood protozoan parasites of the genera Leucocytozoon and Trypanosoma, as well as an unknown filarial parasite in Thailand. However, its attraction to humans has remained uninvestigated in Malaysia. Recently, 27 black flies were collected in Pahang, Malaysia, of which 25 were captured in CO₂-baited Malaise traps and two were collected from humans during trapping activity. All specimens were morphologically identified as S. asakoae. Cytochrome c oxidase I sequences of the two specimens caught on humans showed 100% similarity with those of S. asakoae in the NCBI GenBank, confirming their morphological identity. Blood-meal analysis using a HAL·HAR^TM kit did not show the presence of domestic or wild animal DNA. However, human DNA was amplified from one engorged fly in the cytochrome b gene amplification assay, providing the first evidence of blood-feeding by S. asakoae in Malaysia.

Nsp1 in SARS-CoV-2 is a key protein that increases the virus's pathogenicity and virulence by binding to the host ribosome and blocks the 40S ribosomal subunit channel, which effectively impedes the mRNA translation as well as crippling the host immune system. Previous studies revealed that the N-terminal in Nsp1 is part and parcel of Nsp1 efficiency, and mutations in its core residues have weakened the protein's. This knowledge persuades us to carry out the in silico screening on plant compounds of Piper sarmentosum Roxb. against the five target residues which are Glu36, Glu37, Arg99, Arg124 and Lys125. Potential compounds were tested for their druggability. As a result, we identified five out of 112 compounds including stigmasterol, N-feruloyltyramine, beta-Sitosterol, 13-(1,3-benzodioxol-5-yl)- N-(2methylpropyl) trideca-2,4,12-trienamide and N-(2-methylpropyl) octadeca-2-4dienamide in Piper sarmentosum Roxb. as potential inhibitors for Nsp1. These compounds formed at least a hydrophobic, hydrogen bonding or π-cation interactions with the protein. Furthermore, SwissADME analysis and the number of bindings to the target residues suggest that N-feruloyltyramine is the ideal inhibitor candidate against SARS-CoV-2 at its N-terminal of Nsp1. Lastly, the interaction with N-feruloyltyramine increased flexibility in the loop regions of N-terminal Nsp1, especially residues 54 to 70, with residue 59 showing the highest fluctuation, potentially affecting the protein's stability and function due to the correlation between RMSF and protein function.

Malaria is an insect-borne disease transmitted by Anopheles mosquitoes or the importation of Plasmodium-infected blood, posing a serious threat to human health and life safety. This study aims to analyze the incidence of malaria in Qingdao at various stages from 1949 to 2021, to collate the control measures taken at different epidemic stages to assess the effectiveness of malaria control, and to identify a set of malaria control strategies suitable for Qingdao, while providing Chinese experience for other countries or cities in their malaria elimination efforts. A retrospective survey was used to collect information on malaria cases, control measures and prevention and control effects in Qingdao from 1949 to 2021, and to evaluate malaria control strategies and measures in Qingdao. 704 155 cases have been reported from 1949 to 2021, with three epidemic peaks: the incidence rate was 1715.9/100 000 in 1961, 1409.7/100 000 in 1965, and the most severe case occurred in 1972, with an incidence rate of 1635.6/100 000 and a case count exceeding 90 000. Throughout the various stages of malaria epidemics, Qingdao has effectively eliminated indigenous malaria by implementing diverse preventive and control measures. Since the last indigenous case of Plasmodium vivax was reported in 2002, all locally reported cases have been imported, mainly by returning migrant workers from Africa. This study examines a range of malaria prevention and control strategies and interventions that are appropriate for Qingdao. These measures have enabled Qingdao to successfully eliminate malaria and maintain malaria-free status for more than 20 years. These measures can also serve as a reference for similarly situated cities in Africa and Southeast Asia.