Journal of Vector Borne Diseases最新文献

Background objectives: Compressive mapping and in-depth analysis of malaria vulnerability risk foci are important tools for strategic planning, vector surveillance, implementing necessary interventions, and managing scarce resources to combat the daunting challenges of malaria infections in Nigeria.

Methods: The study utilized environmental risk factors and spatial multi-criteria decision analysis techniques to analyze and map the spatial variations in malaria-endemic prone areas within the Northern Zone of Plateau State.

Results: Analysis of the criteria's weights of environmental risk factors and the stratification of the malaria risk vulnerability revealed that high-risk areas covered a total of 4017.25 Km2, while low-risk areas covered 1294.83Km2, having a close resemblance to the corresponding ground conditions. The results showed that a significant 60% of the study areas were characterized by high risk of malaria transmission, particularly in most settlements around the Jos North, Jos South and Barkin Ladi Local Government Areas. The malaria risk map's predictive abilities demonstrated a high level of accuracy, as indicated by the area under the curve score of 0.989. Furthermore, the risk map demonstrates a high-performance rate in identifying malaria hotspots, with a sensitivity of 98%, a proficiency rate of 54%, and a statistical significance confidence level ranging from 90% to 99% for identifying malaria hotspots and coldspots.

Interpretation conclusion: The malaria risk analysis and mapping within the endemic prone areas of the Northern Zone of Plateau State not only equips policymakers with effective tools for identifying malaria foci but also offers a deeper comprehension of the appropriate intervention measures to be implemented.

Background objectives: Scrub typhus is an acute febrile zoonotic disease caused by the obligate intracellular gram-negative bacteria Orientia tsutsugamushi. Growing data over the last few years on the Indian subcontinent suggest that it is one of the most widespread but under-reported diseases. The study aimed to document the clinical and paraclinical profile and evaluate complications of scrub typhus in severe and nonsevere pediatric age groups.

Methods: A prospective observational study was conducted in pediatric patients. Frequency, mean, percentage and standard deviation were all included in the descriptive statistical analysis calculation. Multivariate analysis was conducted to predict the severity factor.

Results: A total of 189 patients met the eligibility criteria and were included in the final analysis. The mean and standard deviation (mean ± SD) age of the cohort was 5.54 ± 3.9 years, with a male predominance of 68.2%. The mean ± SD duration of fever was 6.64 ± 1.43 days. Patients with severe scrub typhus experienced complications including hepatic involvement (42, 64.6%), respiratory distress (23, 46.1%), neurological involvement (14, 24.6%), acute kidney injury (10, 15.4%), myocarditis (9, 13.8%), and (16, 24.6%) have multi-organ dysfunction. patients with raised transaminases (> 180 IU/L) have a 3.7 to 4.1 times greater chance of developing severity. Thrombocytopenia is found to be another independent predictor of severe scrub typhus in our study.

Interpretation conclusion: Clinical signs of hepatomegaly, skin rash, and lymphadenopathy were significant predictors of severity. Delays in treatment are a key contributor to the severity of pediatric scrub typhus.

Background objectives: Malaria, a vector-borne disease, is caused by Plasmodium species and transmitted by Anopheles species. Among these vectors, Anopheles subpictus has emerged as a potent malarial vector in coastal areas of India. Numerous studies have highlighted that bacterial communities within mosquito influence vector competence. The present study was designed to isolate and characterize bacterial microbiota from An. subpictus larvae.

Methods: Isolation and purification of the predominant bacterial strain (ALl) was carried out. Morphological, biochemical, antibiotic susceptibility and molecular characterization of the isolated bacteria was performed.

Results: Bacterial isolate (AL1) was found to be rod, gram negative, catalase positive and oxidase negative. AL1 was identified as Leclercia adecarboxylata (Accession number: OR649235) through 16S rRNA ribotyping. Further, the leaf extract of Nyctanthes arbortristis showed inhibitory effect against ALl.

Interpretation conclusion: The study provided the first report on the isolation of symbiotic bacteria (L. adecarboxylata) from An. subpictus and its control by leaf extract of Nyctanthes arbortristis. Isolated gram-negative bacterial strain might inhibit the development of mosquito vectors and can be implemented for various biological control strategies to combat malaria transmission.

Background objectives: Anopheles funestus is playing an increasingly important role in malaria transmission in sub-Saharan Africa. Trehalase, an enzyme required for trehalose breakdown, is important for mosquito flight and stress adaptation. Hence, its inhibition has emerged as a promising malaria management strategy.

Methods: A collection of 1900 natural compounds from the ZINC database were screened against the 3D modeled structure of An. funestus trehalase protein using in silico tools. ADMET-AI, a web-based platform, was used to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the selected compounds.

Results: We report 5 natural compounds namely, ZINC00488388, ZINC00488525, ZINC00488566, ZINC00488304, and ZINC00488456 that demonstrated strong binding affinity to the trehalase protein. These compounds interacted with critical residues of the trehalase protein and exhibited good drug-like characteristics.

Interpretation conclusion: These compounds show promise as trehalase protein inhibitors for malaria management. Nonetheless, additional experimental studies are required to optimize these compounds as potential trehalase inhibitors.

Background objectives: Mosquito-bome diseases are a major health issue among communities in Asia, and dengue has become a serious public health concern in Sri Lanka with varying magnitude since 1960. With the realization of the failures and limitations of current vector control strategies, the authorities are moving towards simple, low- cost, and eco-friendly vector management methods. Thus, the present study was devised to evaluate the potential densities of mosquito natural enemies in natural water habitats in Galle district, Sri Lanka, and to investigate the feeding efficacy of prominent mosquito natural enemies on main dengue vectors (Aedes sp.) in a laboratory setting.

Methods: The survey was carried out using eight sentinel sites in Galle district, and samples of mosquito natural enemies and mosquito larvae were collected, and identified using taxonomic keys.

Results: Study records, the aquatic insects of family Hydrometridae, Belostomatidae, Notonectidae, Nepidae, Ranat- ridae, and Corixidae as dominant mosquito natural enemies, and Libellulidae and Dytiscidae insects as sub-dominant families. The highest density of the family Hydrometridae was recorded in rural, natural inland, and rocky study sites. The order Hemiptera was recorded as the key order of the mosquitos' natural enemies in Galle district. The family Hydrometridae had the highest density of recorded mosquito natural enemies.

Interpretation conclusion: Aedes aegypti and Ae. albopictus were recorded as abundant vector mosquitoes. Family Nepidae is the most effective natural mosquito predator on Ae. aegypti and Ae. albopictus, and this knowledge will be vital for implementing future biological control strategies for Aedes vectors in Sri Lanka.

Background objectives: Mass Drug Administration (MDA) of Di-Ethyl Carbamazine and Albendazole is an effective strategy recommended by the World Health Organization to prevent transmission and eliminate lymphatic filariasis. Under the National Vector Borne Disease Control Programme (NVBDCP) in India, MDA is carried out as a yearly activity in endemic areas to accelerate the progress towards elimination of lymphatic filariasis. The study was carried with the objective to determine the coverage of MDA against lymphatic filariasis among the eligible population in Kalaburagi district, Karnataka and delineate the common reasons for non-acceptance of MDA.

Methods: Field-based cross-sectional survey was carried out. Cluster sampling of 4 clusters (3 rural and 1 urban) from four different taluks (one cluster from each taluk) of the district reporting high, medium and low coverage of MDA (as reported by District Malaria Office) Members from selected households in all clusters were interviewed regarding MDA administration, directly observed treatment, side effects and any co morbidities which ruled out MDA administration. Responses documented as tally marks in assessment sheets shared by NVBDCP office. Proportions, frequencies, and mean were calculated and inferential statistics were used.

Results: A total of 1263 individuals were assessed for MDA from a total 240 households (60 households in each cluster). The coverage of MDA varied from 90.33% in Heerapur in Kalaburagi Urban to 97.87% in Mogala thanda (Chittapur Taluk).

Interpretation conclusion: MDA Coverage against lymphatic filariasis has improved when compared to previous studies and it has also exceeded the coverage threshold as determined by programme for elimination of lymphatic filariasis.

Background objectives: Mosquito vectors are a significant cause of pathogen transmission to both animals and humans. Mosquitoes are responsible for transmitting various diseases, including chikungunya, filariasis, West Nile fever, dengue, malaria, and Zika fever, placing approximately 80% of the world's population at risk of infection at any given time. Controlling mosquitoes has become a multifaceted challenge, influenced by diverse environmental factors such as deforestation, urbanization, and climate change on a global scale. For centuries, medicinal plants have been utilized as bioinsecticides to control insect pests. Ziziphus mauritiana, also known as Chinese apple or Indian jujube is a deciduous thorny tree or shrub. Different parts of the Z. mauritiana plant have been traditionally used to treat various common diseases, a practice still prevalent in India and China.

Methods: In the current investigation, the chemical properties of Z. mauritiana leaf extract were examined through UV-Vis Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), and GC-MS Analysis. Second and fourth instar larvae, as well as pupae, of Aedes aegypti and Culex quinquefasciatus were subjected to different concentrations of the methanolic extract of Z. mauritiana for 24 h and 48 h to assess larvicidal and pupicidal activity.

Results: The FT-IR spectrum analysis revealed the presence of various functional groups in the chemical compounds extracted from Z. mauritiana , including amines, aromatics, alkanes, alkyls, carbonyls, and carboxylic acids. Additionally, GC-MS analysis identified Isoborneol (25.37%), 4-Acetylbutyric Acid (26.82%), and 2-Vinyl- 9-[Beta-D-Ribofuranosyl] Hypoxanthine (24.24%) as the three major phytoconstitutents in the methanol extracts of Z. mauritiana. Regarding the larvicidal activity, the methanolic extract of Z. mauritiana exhibited LC 50 values of 155.67 mg/L and 208.57 mg/L for second instar larvae, and 177.68 mg/L and 252.13 mg/L for fourth instar larvae of Cx. quinquefasciatus and Ae. aegypti, respectively, after 24 h of exposure. For pupicidal activity, the LC 50 values were 502.02 mg/L and 514.99 mg/L on pupae of Cx. quinquefasciatus and Ae. aegypti, respectively, within 24 h.

Interpretation conclusion: Overall, the GC-MS analysis provides valuable insights into the chemical composition of the Z. mauritiana extract, highlighting its potential as a natural and eco-friendly alternative for combating insect vectors and contributing to integrated mosquito management programs.

Background objectives: Aedes aegypti (Linnaeus) is the vector of multiple arboviruses, the most important being dengue viruses (DENV) that causes more than 90 million cases per year. The expanded range of Ae.aegypti into temperate climates has contributed to the increasing risk of DENV to new human populations. As an effort to better understand the ecology of Ae. aegypti in a temperate climate, larval surveillance was conducted to identify oviposition locations of this species from 2016-2018 in two nonincorporated communities located in El Paso, Texas and Ciudad Juarez, Chihuahua, Mexico.

Methods: This survey was conducted inside and outside private residences examining any possible water holding containers to collect with a dipper, turkey baster, or Pasteur pipette. Larvae and pupae were transported to the laboratory and reared to adults for morphological identification. A total of 601 Ae. aegypti larvae were collected and reared to adults from 24 containers in the Sparks community. In contrast, a total of 68 Ae. aegypti were collected and reared to adults from seven containers in the Anapra community.

Results: In both locations, the predominant container type that yielded immature mosquitoes were plastic buckets. Although the results were based on a small sample size, the finding provided a preliminary understanding of the oviposition sites of Ae. aegypti in two urban communities in a temperate climate region.

Interpretation conclusion: The identification of oviposition sites can be used to develop and implement vector control strategies.

Background objectives: Mosquitoes vectors are the key threat that spread viruses, bacteria, nematodes, protozoans, and other infections responsible for the transmission of serious public health ailments including dengue, yellow fever, malaria, and chikungunya.

Methods: To rear and cultivate mosquitoes at multiple stages of development (egg, larva, pupa, and adult) to be employed in various biomedical research, an innovative tool mosquito larva adult 2-in-1 rearing jar was designed and developed. The eggs/larvae or adults collected from the field or laboratory cultures can be released into the lower larvae or upper adult-rearing chamber so that they can find a suitable breeding place to oviposit or metamorphose into wrigglers and tumblers attaining the adult stage. Aedes, Anopheles, and Culex are three significant genera (Diptera: Culicidae) that were reared in experiments using this jar (Method I) in contrast to other conventional instruments available (Method II).

Results: Results of one-way ANOVA showed that the prototype was compatible and competitive for rearing, as the data was non-significant when compared in both groups. However, throughout the trials, it was discovered that the prototype had a greater record of mean percentage of adult emergence (98.33), which supports the novelty of the instrument.

Interpretation conclusion: This unique device eliminates the need for multiple tools, causes minimum bodily damage to stages during handling, can be used in both the lab and the field, is inexpensive, lightweight, portable, and requires single manpower to operate.