Tropical biomedicine最新文献

Due to their proximity and association, cats play a dual role in humans' lives, serving as common companion animals as well as strays. However, they also serve as a significant reservoir for various parasites, including gastrointestinal (GI) parasites. The global prevalence of GI parasites in cats is relatively high, raising concerns about their potential transmission to humans and the risk of causing diseases. Cat droppings are frequently found contaminating the environment and, admittedly, more often in low-income housing areas, posing additional risks to this marginalised group. Therefore, this study aimed to survey the preliminary environmental prevalence of GI parasites in the faecal samples of cats collected from urban poor neighbourhoods in Klang Valley, Malaysia. A total of one hundred cat faecal samples were collected from 10 low-cost housing neighbourhoods across Klang Valley, Malaysia. The samples were then screened using direct smear, concentration techniques, and Harada-Mori to determine the parasitic prevalence. The overall prevalence was 73.0% (n=73), with at least one parasite species infecting the cats. A total of six GI parasites were recovered, including Hookworm (n=63, 63.0%), Toxocara spp. (n=26, 26.0%), Cystoisospora spp. (n=7, 7.0%), Ascaris spp. (n=2, 2.0%), Balantidium coli (n=1, 1.0%), and Trichuris spp. (n=1, 1.0%). Understanding the prevalence of these parasites is crucial, particularly in marginalised communities where poor environmental hygiene and overcrowding are prevalent, to ensure that appropriate preventive and control measures are implemented due to the zoonotic potential of these infections.

Chikungunya is a mosquito-borne viral disease caused by chikungunya virus (CHIKV), characterised by fever, polyarthralgia, myalgia, rash, and headache, with chronic arthralgia persisting for months or years. Although vaccine is recently available, it is not widely used, and treatment focuses on symptom relief. Many natural products or their active compounds have been investigated for their anti-CHIKV activities on Vero cells which is irrelevant in CHIKV pathogenesis in human. Tualang Honey has also been shown to exert anti-CHIKV in Vero cells. This study advances the evaluation of Tualang honey's antiviral activity against CHIKV by utilising human fibroblast-like synoviocyte (HFLS) cells, a model more reflective of joint pathology in chronic infection. The maximum non-toxic dose (MNTD) of honey was determined using XTT assay. The effects of different concentrations and incubation times of honey were explored using pre-treatment and post-treatment assays, while anti-adsorption and anti-entry assays were used to investigate its antiviral activities. The MNTD of Tualang honey on HFLS cells was determined to be 50 mg/mL. Tualang honey at concentrations < 20 mg/mL exhibited variable prophylactic activity in the pre-treatment assay, reducing viral titres by 29.21% to 94.87%. Significant CHIKV inhibition (p < 0.05) was observed with 10 and 15 mg/mL pre-treatment for 6 and 12 hours before infection, respectively. Notably, its anti-CHIKV effects were stronger during pre-treatment than post-treatment assay. Posttreatment with honey caused minimal to strong CHIKV inhibition, lowering viral titres by 6.67%-72.46%, depending on the concentration and incubation time, although it was not statistically significant. Tualang honey showed stronger anti-entry than anti-adsorption effects, decreasing viral titres by up to 90.45% and 66.89%, respectively. This study highlights Tualang honey's anti-CHIKV activity through various mechanisms, although further research is needed to confirm its clinical relevance. Importantly, the effects of concentration and incubation time are essential factors in determining antiviral efficacy.

Cryptococcus neoformans, a ubiquitous fungus commonly found in bird droppings, poses a significant health risk by causing cryptococcal meningitis especially in immunocompromised individuals. In Malaysia, clinical reports from 1964-2010 documented an increasing incidence of C. neoformans cases, even in healthy individuals. Nevertheless, studies focusing on C. neoformans occurrence in birds are limited, with the last study conducted in 2005, focusing solely on the Klang Valley region. We aimed to update the molecular epidemiology and antifungal susceptibility of C. neoformans in bird droppings from public areas and zoological gardens across Peninsular Malaysia. Molecular identifications were performed using nested-PCR with CNLAC1 outer and inner primer pairs for the primary and secondary PCR. Antifungal susceptibility tests were conducted against Amphotericin B, Fluconazole, and Itraconazole. The hygiene and environmental conditions of the zoological gardens were recorded. A total of 509 bird droppings were collected: 257 (50.5%) from public places and 252 (49.5%) from zoological gardens. Most samples from public areas were from common pigeons (n = 144; 56.0%), while samples from Mandarin ducks predominated in zoological gardens (n = 40; 15.9%). The overall prevalence of C. neoformans was 42.6% (217/509), with a higher prevalence in zoological gardens (116/252; 46.0%) versus public places (101/257; 39.3%) (P = 0.125). Notably, common pigeons in zoological gardens showed a significantly higher carrier rate (80.8%) versus in public places (54.9%) (P = 0.013). Other species with high carrier rates in zoological garden included Indian peafowls (61.9%) and budgie birds (61.3%). In public areas, apart from pigeons; doves (43.5%) also exhibited a high prevalence. Enclosure density and Columbidae family were found to be associated with high positivity rate in zoological gardens. Two strains were identified: C. neoformans var. neoformans (serotype D) and C. neoformans var. grubii (serotype A). One isolate exhibited resistance to Itraconazole. This study highlights the need for ongoing public health surveillance and preventive measures particularly in settings where human-bird interactions are frequent.

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is a T-cell inactivation receptor and has been found to be elevated in Tuberculosis (TB) patients. The functional polymorphisms in CTLA-4 gene, including CTLA4+49A/G (rs231775) and CTLA-4+6230A/G (rs3087243) have been reported to be associated with the risk for many diseases. The two aforementioned functional polymorphisms in the CTLA-4 gene were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in order to investigate the possible susceptibility to pulmonary TB (PTB) in a Thai population. In this study, TB patients were grouped as 1) PTB with and without comorbidity of other diseases (PTB) 2) PTB without comorbidity of other diseases (PTBWO) 3) PTB comorbidity with other diseases (PTBD). We demonstrated that the allele frequency of CTLA-4+49A was higher in PTB, PTBWO, and PTBD groups than in healthy controls subjects (HCS), but no significant association of CTLA-4+49A/G polymorphisms with PTB, PTBWO and PTBD were seen. Whereas the CTLA-4+6230A allele was significantly higher in PTB, PTBWO and PTBD groups than in HCS, and the CTLA-4+6230A allele was found to be significantly associated with PTB, PTBWO and PTBD (P=0.007, OR 2.111, 95%CI(1.220-3.652); P=0.0218, OR 2, 95%CI(1.100-635); P=0.0439, OR 2.5, 95%CI(1.004-6.227) for PTB, PTBWO and PTBD respectively), as well as CTLA-4+6230AG genotype was found to be significantly associated with PTB and PTBWO (P=0.0432, OR 2.259, 95%CI(1.018-5.014); P=0.0392, OR 2.464, 95%CI(1.034-5.874) for PTB and PTBWO respectively). For the combination of CTLA-4+49A/G+6230A/G genotypes, +49AA+6230AA and +49AG+6230AG genotypes was more frequent in PTB and PTBWO groups. This study is the first to investigate CTLA-4+49A/G and +6230A/G polymorphisms in PTB patients in Thailand, The A allele and AG genotype of CTLA-4+6230A/G was significantly associated with PTB, suggesting a possible genetic influence on TB susceptibility. These findings indicate that CTLA-4 polymorphisms, especially CTLA4+6230A/G, may play a role in PTB risk in the Thai population.

This study evaluated the antifungal efficacy of a non-thermal plasma (NTP) jet against environmental isolates of Cryptococcus neoformans, a pathogenic fungus commonly found in pigeon droppings and associated with serious infections in immunocompromised individuals. Given the increasing concern over environmental fungal contamination and drug-resistant strains, this research aimed to identify optimized plasma conditions for effective fungal inactivation without relying on chemical disinfectants. Environmental C. neoformans isolates were cultured on Sabouraud dextrose agar and subjected to NTP treatment under systematically varied parameters: input power (30, 50, and 70 W), exposure time (30 s, 1, 2, and 3 min), and air flow rates (1, 1.5, and 2 LPM) mixed with a constant 12 LPM argon gas. Following treatment, plates were incubated at 37°C for 24 hours, and antifungal activity was assessed by measuring the inhibition zone. The highest antifungal effect was achieved at 70 W, with a 3-minute exposure and Ar:Air flow ratio of 12:2 LPM, producing a clear zone of 0.93 ± 0.05 cm². This value corresponded to 28.6% of the inhibition zone produced by the Amphotericin B positive control (3.25 ± 0.08 cm²). All treatment conditions exhibited statistically significant inhibition (p < 0.05), with increased efficacy at higher airflow and longer exposure durations. The generation of reactive oxygen and nitrogen species (RONS) is believed to be the primary mechanism underlying fungal inactivation. These findings demonstrate that Argon-Air-based NTP jet systems offer a promising, eco-friendly, and non-chemical approach for controlling fungal pathogens in environmental settings. The method has potential for application in urban sanitation and public health contexts where fungal contamination from bird droppings poses ongoing risks.

Tuberculosis (TB) is one of the top 10 causes of death and the leading cause of morbidity from a single infectious agent. Tuberculous meningitis (TBM) is a subtype of tuberculosis which constitutes about 5% of all extrapulmonary tuberculosis and about 1-2% of active tuberculosis. This study was conducted to analyse the annual incidence of TBM in Malaysia from 2015-2020. Through this study we were also able to study the demographic characteristics and clinical profiles of TBM patients. It was a cross sectional study using data collected from Malaysia national case-based TB registry (MyTB) between year 2015 and 2020. Descriptive analysis was used and univariate analysis was performed using binary logistic regression. All the statistical analyses with p-value less than 0.05 is considered significant with the 95% confidence interval. There were total of 2072 TBM cases from year 2015 until 2020, which comprised of 1.38% of total TB cases within 6 years. Most of the patients were Malaysian (1682 cases (81.2%)) while only 390 (18.8%) cases were reported among foreigners. Most cases were detected among the age group of 35-44 with average of 77.8 (22.5%) cases per year, followed by age group 35-44 with average of 66.8 (19.35%) cases per year. Of all the TBM cases, 23.2% patients were known case of HIV while 1.45% diagnosed as HIV later. TBM is a disease with poor prognosis as the consequence of the half of the affected patient is death or severe disability which is evidenced by 42.7% patients passed away. TBM imposes a great challenge in both diagnosis and management, as most affected patients will be left with severe long-term complications even with treatment. It is important to understand the epidemiology and characteristics of tuberculous meningitis in Malaysia to improve the management and enhance the control of this deadly disease.

The productive outdoor larval habitats of dengue vectors are widespread, cryptic and hard-to-reach. It is a challenge to larvicide such habitats using traditional manual sprayers. A wide-area treatment with Bacillus thuringiensis israelensis (Bti) microdroplets dispersed from a motorized backpack sprayer into such habitats is a proven method to suppress the vector population and interrupt disease transmission. This paper provides the answers to the constant inquiries by program operators on the characteristics of a Bti wide-area spray from a motorized backpack sprayer. The Bti spray mix can be either 125g or 250g in 10 liters water with a walking speed of 1m in 6 secs or 1m in 3 secs, respectively, to achieve the recommended dose of 400g/ha-500g/ha. The spray dispersed at a flowrate of 567mL-650mL through the No. 2 sprayer orifice, reached a 16m swath. A 90%-100% larval mortality was obtained in containers that were left outdoors for 7 to 14 days post spray under a shade, exposed to ambient temperature and sunlight. Higher Bti doses, at 2x and 3x to the recommended dose, achieved 90%-100% mortality in containers left outdoors for more than 14 days, but higher doses are not recommended in areas with persistent rainfall.

Blastocystis is a ubiquitous intestinal protist of humans and animals. It is a genetically diverse organism whose part in the health and disease is still uncertain. This study provides information on Blastocystis STs in cattle, goats, and sheep in Perak, Malaysia, and the likely role of livestock animals in Blastocystis transmission to humans in Malaysia. Faecal samples from a total of 151 livestock animals consisting of cattle, goats, and sheep from Perak were examined by PCR analysis of the barcode region. Blastocystis ST10, ST14, and ST21 were identified in this study, and ST10 was common to all three ruminant livestock animal groups involved. Findings from previously published studies on Blastocystis in ruminant and non-ruminant livestock animals in Malaysia support indications that livestock animals may serve as reservoirs of human infections, being as one or more of the following Blastocystis subtypes: ST1, ST2, ST3, ST4, ST5, and ST6, have been isolated from both humans and livestock animals within similar regions of the country. Animal handlers are, therefore, advised to exercise proper hygiene to prevent possible transmission of Blastocystis from their animals, while further studies on the genetic variants of Blastocystis in farm animals and their keepers are required to better understand the role of these animals in human Blastocystis.

Nowadays, there has been a noticeable rise in the utilization of nanoparticles in a diverse array of fields, including medicine and industry. The current research seeks to evaluate the in vivo therapeutic efficacy of bioconjugated Linalool-zinc oxide nanoparticles (ZOP) in the treatment of G. lamblia infection. The impact of Linalool-ZOP at dosages of 20 mg/kg and 40 mg/kg, both individually and in conjunction with metronidazole (MTZ, 7.5 mg/kg) on the number and viability of Giardia cysts, the serum level of electrolytes of sodium (Na+) and potassium (K+), as well as the NF-kB signaling-related genes ((Tumor Necrosis Factor-alpha (TNF-a), Interleukin-1 (IL-1), IL-10, Nuclear Factor kappa B p65 (NF-kB p65), and Toll-like Receptor 4 (TLR4)) were assessed. We found that the average diameter of Linalool-ZOP was determined to be 105 nm. Following a seven-day treatment of G. lamblia-infected mice with LinaloolZOP mainly in conjunction with MTZ, the number and viability of G. lamblia cysts was significantly decreased (P<0.001). Linalool-ZOP, particularly in combination with MTZ, notably modulated the serum levels of Na and K in the infected mice (P < 0.001). The Linalool-ZOP, particularly in conjunction with MTZ independently led to a notable drop in the TNF-a, IL-1, NF-kB p65, and TLR4 genes, as well as a marked increase in IL-10 gene expression (P< 0.001) with no toxicity on vital organs in mice. The present study revealed that the Linalool-ZOP, mainly in combination with MTZ, significantly alleviated Giardia infection in murine models by reducing inflammation and rectifying serum electrolyte imbalances. Should additional mechanisms be clarified and subsequent clinical trials involving human subjects produce positive outcomes, these compounds could be considered potential candidates for developing a new therapeutic approach for giardiasis. Furthermore, we advocate for the initiation of human clinical trials and a more comprehensive assessment of the toxicity of Linalool-ZOP in more intricate models.

Leishmaniasis is an infectious disease caused by protozoan parasites of the genus Leishmania, transmitted through the bite of infected female phlebotomine sandflies. As a neglected tropical disease, it has recently garnered significant attention. Cutaneous leishmaniasis (CL) is a priority for disease control by the World Health Organization (WHO) in Saudi Arabia, among other countries. This narrative review focuses on the history of the disease, its epidemiological and entomological aspects, high-risk populations, and hard-to-reach areas. The review is based on a comprehensive analysis of literature published in English on leishmaniasis in Saudi Arabia. Articles were systematically filtered to ensure relevance to the scope of this paper. Findings from these studies were summarized and categorized geographically into five main regions: Northern, Southern, Eastern, Western, and Central Saudi Arabia.