Tropical biomedicine最新文献

Plasmodium knowlesi, primarily a zoonotic malaria species is the most common malaria pathogen in the Southeast Asia especially in Malaysian Borneo, Malaysia. Due to morphological resemblance of P. knowlesi to other human Plasmodium, the sensitivity for microscopic detection of P. knowlesi, which is the gold standard, is compromised. Thus, efforts have been made in finding alternatives for the disease diagnosis. This study described the potential use of anti-PkTRAMP polyclonal antibodies in sandwich ELISA for P. knowlesi detection. Anti-PkTRAMP polyclonal antibodies raised from mice and rabbit were first evaluated for their binding capability towards native proteins in P. knowlesi lysates using Western blot. These mice and rabbit polyclonal antibodies were then used in the sandwich ELISA as capture and detection antibodies, respectively. P. knowlesi A1H1 culture was utilised to determine the limit of detection (LOD) of this assay. Its clinical performance was determined by testing with archived human malaria and uninfected samples. Western blot analysis affirmed the polyclonal antibodies reactivity to P. knowlesi. The LOD obtained from three replicated assays was at 0.015% parasitaemia. The assay has 76% sensitivity and 75% specificity for P. knowlesi. Its positive and negative predictive values were 76% and 75%, respectively. No cross reactivity with P. falciparum and healthy samples was observed, except for P. vivax where 10 out of 12 samples were detected. In conclusion, anti-PkTRAMP polyclonal antibodies can be useful in detecting P. knowlesi. Regardless, the full potential of anti-PkTRAMP antibodies for diagnostic purposes need to be explored further.

Toxoplasmosis is an infectious disease caused by the intracellular protozoan parasite, Toxoplasma gondii. While the infection is typically asymptomatic in healthy individuals, it can progress to cerebral toxoplasmosis, especially in those with human immunodeficiency virus (HIV) or weakened immune systems. In this communication, we present a case of a newly diagnosed HIV infection patient who presented with neurological symptoms. The patient was later diagnosed with probable cerebral toxoplasmosis. The case depicts the severe consequences of toxoplasmosis in immunocompromised patients, highlighting the urgent need to identify those at high risk of contracting the disease and the importance of prophylactic treatment. This requires the necessity for early HIV diagnosis and close monitoring of HIV-positive patients.

The study has generated visible aerosols with the diameter of 11 to 35 µm from the kenaf cellulose nanofiber (KCNF) impregnated with the temephos (KCNF+T) in water suspension. The study aimed to determine whether the KCNF+T aerosols are capable to elicit neurotoxicity in the adult mosquitoes via the respiratory exposure route by observing their behavioural response and measuring its body acetylcholine esterase (AChE) activity. Adult Aedes aegypti mosquitoes were assigned to one negative control group and three treatment groups namely, distilled water (vehicle control), KCNF and KCNF+T. The study adopted the MS1911 whereby the aerosols generated are released into the insecticide bioassay glass chamber (IBGC) separately to achieve four different aerosols concentrations of 6.4 ml/m³, 12.8 ml/m³, 19.2 ml/m³, and 25.6 ml/m³. Then the 20 sugar-fed mosquitoes were released free-flying into each IBGC to observe its behavioural response (knockdown) at 30, 60, 120, 180, 240, 300 minutes intervals and 24^th hour mortality. Results showed that only mosquitoes exposed to KCNF+T aerosols exhibited persistent knockdown. There was significant difference (p< 0.05) between observation intervals with the cumulative knockdown of 84.8%, 92.8%, 99.0%, 100.0%, 100.0%, 100.0% compared with the KCNF aerosols. Further, it was distinctive that only KCNF+T is capable to cause the female mosquitoes moribund/mortality at the 24th hour with 90% at the lowest aerosol concentration of 6.4 ml/m³. The neuroenzyme assay on the mosquito that died from the KCNF+T exposure verified to have reduced AChE enzyme activity. The behavioural response and reduction of the AChE activity strongly suggests the temephos from the KCNF+T aerosols has been released into the mosquito body causing the neurotoxicity but KCNF alone is not neurotoxic.

Dengue fever is one of the most common diagnoses in patients presenting with acute febrile illness in tropical countries. Borrelia, on the other hand, is the cause of vector-borne infections of relapsing fever and Lyme disease. While co-infections of dengue with chikungunya, Zika, malaria, influenza and typhoid have been reported, clinical cases of Borrelia infections have never been reported in Malaysia. Based on available evidence, this is the first case series to report dengue fever and Borrelia spp. co-infection. All three patients in this report were admitted to medical wards on day 3 to day 8 of illness for dengue fever as evidenced by a positive dengue NS1 antigen test. The clinical manifestations were typical of dengue fever, with all patients having high grade fever, myalgia, and arthralgia. All patients also had thrombocytopenia. Features of severe dengue, such as shock, hemorrhage and impaired consciousness were absent. Borrelia DNA were detected in the blood samples of the patients. However, all the patients denied having skin lesions and a history of insect bites. All the patients were given intravenous fluid therapy and were discharged after 3 to 5 days of hospitalization.

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.

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.

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.