Tropical biomedicine最新文献

Bovine anaplasmosis is a tick-borne disease in cattle which is mainly caused by Anaplasma marginale and Anaplasma centrale. It poses significant economic burdens and threat on livestock industries worldwide. This study aimed to identify Anaplasma spp. infecting the commercial Mafriwal cattle in Johor, Malaysia and investigate their phylogenetic relationship in the population. In this study, polymerase chain reaction (PCR) targeting the MSP4 gene for A. marginale and the 16s rRNA gene for A. centrale were performed. These assays were conducted on blood samples collected from 242 Mafriwal cattle. BLAST analysis and phylogenetic trees were constructed to analyze the genetic relationships between the Anaplasma spp. The results revealed 57.85% of the sampled population were infected with Anaplasma spp., 21.90% with A. marginale, 9.50% with A. centrale and 26.45% with both A. marginale and A. centrale. BLAST analysis showed 100% similarities between A. marginale sequences from this study and the sequence from a goat in Brazil. Similarly, A. centrale sequences were closely related to strains from tick vector, Rhipicephalus (Boophilus) microplus in Panama with 100% similarity. Phylogenetic analysis confirmed distinct clades for A. marginale and A. centrale, indicating genetic diversity and specific species differentiation. The findings highlight the endemicity of bovine anaplasmosis in Malaysian cattle populations and potential cross-border transmission routes. Moreover, this study provides the first report of A. centrale prevalence in Malaysia, emphasizing the importance of ongoing surveillance and management efforts. Understanding the genetic diversity and species differentiation of these pathogens is crucial for designing effective control strategies and vaccine development. In conclusion, this study enhances our understanding of the prevalence and genetic dynamics of bovine anaplasmosis among Mafriwal cattle in its largest population in Malaysia for better diagnosis and effective control measures.

Dengue, caused by the dengue virus (DENV), poses a significant global health challenge. Effective vaccines and treatments for dengue are lacking due to gaps in understanding its pathogenesis and mechanisms in severe cases. This study investigates the role of immunoglobulin E (IgE) in dengue, focusing on its potential association with virus neutralization and antibody-dependent enhancement (ADE) in DENV replication. Serum samples were obtained from dengue-positive (dengue-IgG positive), SLE (dengue-IgG negative), and control (dengue-IgG and SLE-negative) individuals. SLE sera were included as a control for their high total IgE levels. Total IgE and dengue-specific IgE levels were measured using ELISA. Neutralization assays in Vero and KU812 cells were conducted to assess virus neutralization and ADE, respectively. Dengue-positive and SLE sera showed higher total IgE levels than control sera, although there was no significance seen. Dengue-positive sera showed the presence of dengue-specific IgE, whereas SLE and control sera exhibited negligible levels. Neutralization assay in dengue-positive sera revealed no correlation between IgE levels and virus inhibition. SLE sera, however, demonstrated an inverse correlation between total IgE levels and DENV neutralization, suggesting a potential involvement of total IgE in DENV replication in the context of SLE. Seventy-eight percent of SLE sera, 65% of denguepositive and 54% of control sera exhibited enhanced virus replication in KU812 cells with serum compared to virus alone, indicating the highest occurrence of ADE in SLE, followed by dengue-positive and control sera. DENV expression in KU812 cells was notably higher in SLE sera, indicating increased ADE risk. However, no association was found between IgE levels and virus expression in KU812 cells across all groups. The inverse correlation between total IgE levels and DENV neutralization in SLE sera suggests that IgE may facilitate virus replication. Further comprehensive exploration is needed to fully understand the role of IgE in dengue pathogenesis.

Anaplasma species are obligate rickettsial intraerythrocytic pathogens that cause an important tick-borne disease of economic importance in livestock production in many countries. Anaplasma species have been detected from farm animals worldwide, there is a paucity of information on Anaplasma infections in goats from Malaysia. Thus, this study aimed to assess the infection rate and identify Anaplasma species and some selected risk factors in goats across selected districts in Kelantan, Malaysia. A total of 411 blood samples were collected from goats and analysed for Anaplasma species targeting the msp4 gene using conventional PCR and sequencing. The infection risk was determined by breed, age, management system and location. Our results indicate an overall infection rate of 30.9% for Anaplasma species detected. Interestingly, sequencing of selected amplicons revealed the presence of Anaplasma ovis and A. marginale. Data analysis revealed a marked statistically significant association between Anaplasma infection and some variables such as location (district), farm management system, breed, and age (P < 0.05). Specifically, goats raised on intensive management had the highest prevalence of 46.25% (37/80) compared to other management types. Also, with regards to district, goats raised in the coastal region had a higher prevalence of 39.23% (71/181) compared to those raised in inland region 24.35% (56/230). Regarding breed, goats that were of the pure breed had a higher prevalence of Anaplasma species infection 38.19% (97/254) compared to crossbreeds with a prevalence of 19.11% (30/157). Lastly, goats 3 years had the least prevalence 18.99% (34/179). To the best of our knowledge, this is the first report of A. marginale and A. ovis in goats from northeastern Peninsular Malaysia. The infected goats were clinically healthy; this revealed the role of goats as a potential reservoir for A. marginale and the presence of A. ovis in goats in Malaysia. Continuous efforts towards tick control must be sustained to ensure high productive yield and reduced disease burden associated with TBPs of goats in the study area.

Numerous human diseases, including those caused by viruses like Nipah virus and SARS-CoV, can be traced back to bats as their origin. Malaysia, notably Sabah and Sarawak in Borneo Island, is home to a rich diversity of bats that serve as hosts for various viruses. This comprehensive review represents the inaugural exploration of viruses found in Malaysian bats, as documented in scientific journals. It also encompasses documented instances of bat virus-related disease outbreaks in Malaysia up to the present day, along with an analysis of the risk factors associated with virus spillover events. Furthermore, this review offers insights into prospective research areas of significance and suggests potential mitigation strategies.

This study explored the transcriptome differences in Fasciola hepatica at different developmental stages and identified functional genes related to growth and development during juvenile stages. DNBSEQ eukaryotic strand-specific transcriptome resequencing technology was used to sequence the transcriptomes of Fasciola hepatica eggs, juveniles, and adults. Additionally, the genes that were highly expressed during the juvenile stage were validated using qRT-PCR. The Q20 values of all three phases of sequencing were above 98%, and the Q30 values were above 94%. The differentially expressed genes (DEGs) in pairwise comparisons were analyzed by GO functional classification and the KEGG pathway database. Many immune-, growth-, and development-related pathways were found, which might be related to cell proliferation, development, and host immune evasion by Fasciola hepatica. In addition, five DEGs with high expression levels during the juvenile stage were identified: Cathepsin B, Glutathione S-transferase mu, heat shock protein 67B2, Kunitz-CH, and Legumain. Validation analyses revealed that these genes play key roles in maintaining normal growth, development, and immunological processes in liver Fasciola hepatica. RNA-seq was used to analyze the biological characteristics of the DEGs at different developmental stages concerning GO functional classification and KEGG metabolic pathways. Five DEGs with high expression during the juvenile stage were identified. These genes are related to the growth, development, and immune function of Fasciola hepatica, which provides a theoretical basis for subsequent research on the proteomics of Fasciola hepatica and the screening of candidate genes for early diagnosis.

Blastocystis a single-celled eukaryotic protist, is known to inhabit the intestines of various hosts, including humans, and has been implicated in a wide spectrum of symptoms, ranging from gastrointestinal issues to skin disorders, thereby establishing its status as an emerging infectious agent. In this study, the prevalence of Blastocystis infection was investigated in insects, including cockroaches, houseflies, and crickets, as well as sea turtles. Additionally, the genotypic characteristics of the isolated Blastocystis strains were examined, and the evolutionary relationships between Blastocystis species found in sea turtles, and animals/humans were determined. Microscopic techniques and molecular methods were utilized in this study. The results showed that four out of 90 insects (4.44%) and one out of 13 sea turtles (7.7%) were infected by Blastocystis. Furthermore, detailed observations revealed the presence of characteristic morphological features, such as vacuolar forms in the cockroach, cricket and sea turtle samples and binary fission from cockroach samples, indicative of Blastocystis' mode of reproduction. While the ST8 of Blastocystis in sea turtles were successfully identified, no subtyping was achieved for the infected insects. This study not only establishes the occurrence of Blastocystis infection in sea turtles but also uncovers its ability to infect insects, suggesting a potential reservoir role for these organisms. Overall, this research emphasizes the significance of comprehending the prevalence, genotypic diversity, and evolutionary relationships of Blastocystis across various hosts. Such insights are instrumental in developing effective control measures and public health interventions to mitigate the associated symptoms and prevent future outbreaks.

Rice is often associated with Bacillus cereus (B. cereus) food poisoning. This review aims to explore the food poisoning activity, antimicrobial resistance, and control measures of B. cereus in rice from 1974 to October 2023. We searched for eligible studies from the PubMed database based on explicit criteria following the PRISMA checklist. A total of 117 articles were collected, and the final analysis included 29 studies. Quality appraisal was performed using AMSTAR 2, SANRA 2, and Critical Appraisal Tool standards. B. cereus can grow and multiply in food to cause emetic vomiting or diarrheal syndrome. The primary etiology of B. cereus contamination is improper food handling and storage temperature during the cooking, cooling, and reheating stages of rice. The alarming rise of antimicrobial resistance in B. cereus to beta-lactam antibiotics necessitates alternatives from natural antimicrobial preservatives such as carvacrol, chitosan, or trans-cinnamaldehyde to prevent microbial infestation and toxin production. Implementing food safety strategies tailored to specific food settings, such as restaurants and factorymanufactured ready-to-eat rice, is critical for preventing food contamination by B. cereus. Given the heat-resistant spores and intoxication properties of B. cereus, it is important to develop effective interventions and hygienic protocols from farm to fork.

Liver fluke infection, particularly Opisthorchis viverrini, poses a significant public health risk in Thailand, where it is closely associated with cholangiocarcinoma and contributes to substantial mortality in the northeastern region. Diagnosis of this condition employs various parasitological approaches. This research aims to compare the diagnostic accuracy of three parasitological techniques: the Kato Katz technique (KKT), the formalin-ethyl acetate concentration technique (FECT), and the Fully Automatic Feces Analyzer (FAFA) for O. viverrini identification. A total of 455 fecal specimens were collected from rural areas across five provinces in northeastern Thailand. The specimens were processed according to each method and examined through microscopy for KKT and FECT, and by utilizing an artificial intelligence-based machine for FAFA. Data analysis was conducted to assess parasitic infection rates and observe diagnostic accuracy. The results revealed a parasitic infection rate of 19.34%, with the majority of infections attributed to O. viverrini (18.02%), followed by Strongyloides stercoralis (0.88%). FECT exhibited the highest positive detection of O. viverrini eggs (16.48%), followed by FAFA (10.55%), and KKT (8.57%), respectively. Statistical analysis indicated sensitivity and specificity values for O. viverrini detection by KKT (100% and 89.21%), FECT (98.67% and 97.63%), and FAFA (97.92% and 91.15%). The positive predictive value, negative predictive value, and kappa were reported for FECT (89.16%, 99.73%, 0.92), FAFA (56.63%, 99.73%, 0.67), and KKT (45.78%, 100%, 0.58). Additionally, the preparation time for KKT, FECT, and FAFA was 30, 15, and 10 min, respectively. In conclusion, this study highlights FECT, KKT, and FAFA as comparably sensitive in diagnosing O. viverrini. The FAFA machine emerges as a potentially valuable tool for detecting O. viverrini and other parasitic infections, showcasing promise for clinical use. The findings provide valuable insights into the diagnostic landscape and underscore the potential of FAFA in enhancing efficiency and accuracy in parasitological assessments.

Blastocystis is a ubiquitous waterborne parasite that has been implicated in some disease conditions including colorectal cancer and irritable bowel syndrome, and its surface coat characteristics have been associated with its pathogenicity. Although the morphology of Blastocystis isolates from human and animal sources have been studied, there is a paucity of data on the surface ultrastructure of Blastocystis isolated from water sources. Therefore, this study aimed to determine the occurrence and the ultrastructural surface of Blastocystis isolates from several water sources in Kedah and Penang, Malaysia. A total of 12 water samples were collected, namely, Pinang River and USM Harapan Lake all in Penang, whereas Lata Bayu Waterfall in Baling and UniSHAMS Lake, Kuala Ketil in Kedah. These were examined for Blastocystis by centrifugation and in vitro cultivation. Scanning electron microscopy (SEM) and light microscopy were employed to study the morphological characteristics and the surface ultrastructure of the parasite. Polymerase chain reaction (PCR) was carried out to obtain the subtypes (ST) of the positive Blastocystis isolates. The result revealed 25.0% (3/12) contamination with Blastocystis in which ST1, ST2, and an unknown ST (with a high similarity to ST1) were detected in water samples from the upstream, downstream, and midstream, respectively of Pinang River. Our study also revealed similarities in the sizes of the isolates from different river points, which were notably more diminutive compared to the sizes of the parasites observed in existing data from human and animal isolates. The surface characteristics showed a collection of single and dividing cells with smooth, folded surfaces enclosed in a film-like layer. Additionally, there were roundish, irregularly shaped cells with rough surfaces, and a woolly appearance. This study has added to our knowledge of the surface ultrastructure of Blastocystis and its possible contribution to the pathogenicity of the parasite.

Vector-borne diseases have been a growing health concern in recent decades due to the global warming, globalization, and increased international travel. With the typical Mediterranean climate and geographical features, Cyprus provides favorable conditions for the growth and survival of arthropod species. For the purpose of this review article, the terms "Cyprus", "vectors" and "vectorborne diseases" were searched in the National Library of Medicine ('PubMed') and the Google Scholar databases. Published articles in the literature have documented mosquito (including Anopheles, Aedes, Culex, and Culiseta), sandfly (Phlebotomus, Sergentomyia), flea (including Ctenocephalides, Xenopsylla, Leptopsylla), and tick (including Rhipicephalus, Ixodes, Hyalomma, Haemaphysalis) species in the island. The presence of these arthropods poses a risk to public health as they can transmit a variety of diseases to both humans and animals. Research studies in Cyprus have identified infectious agents such as West Nile virus, Leishmania spp., sandfly viruses, Rickettsia spp., Coxiella burnetii, and Bartonella spp. in the local arthropods. More importantly, West Nile virus infection and imported malaria cases (mosquitoborne diseases); leishmaniasis and sandfly fever (sandfly-borne diseases); rickettsiosis, tularemia, Q fever, anaplasmosis, tick-borne relapsing fever, and Lyme disease (tick-borne diseases); and flea-borne rickettsiosis were reported in Cyprus. Taken together with the presence of arthropod vectors, published evidence in the literature suggests that Cyprus is an important region for VBDs. In addition to its climatic and geographical conditions, international travels particularly from endemic countries pose a risk for the circulation of VBDs on the island. Therefore, vector control programs should be continuously implemented, and public awareness must be raised in the region. This review, which to the best of our knowledge is the first comprehensive report on VBDs from Cyprus, will provide insight into future islandwide studies and also will be an important contribution to the elimination of VBDs in the region.