Vector borne and zoonotic diseases最新文献

Background: Cystic echinococcosis (CE) caused by the parasite Echinococcus granulosus sensu lato is one of the most important zoonoses worldwide, causing a great impact on human and animal health. Despite its impact, control programs have not been able to eradicate the parasite; in part, because its transmission cycles, its phylogeny, and the host-parasite relationships are still not well known. In order to deepen knowledge about Echinococcus spp. populations in the endemic areas of southern Chile, the present study was carried out. Materials and Methods: Ten isolates of CE cysts were analyzed, mostly from cattle from southern Chile. A segment of the gene that codes for ribosomal RNA of the minor subunit of the ribosome (rrnS marker) was amplified by PCR using total DNA from this parasite as a sample. Then, they were sequenced, analyzed by molecular phylogeny, and their haplotype network was studied. Results: It was demonstrated that the rrnS marker allows the unambiguous identification of genotypes G1 and G3. Interestingly, it was found that some Chilean parasite isolates of genotype G1 could ancestrally originate from Spain; different to the majority of these isolates that would come from Turkey or Iran. However, further studies are required to confirm this hypothesis. In addition, an animal was detected that had been infected on at least two occasions by parasites with different haplotypes. Conclusion: The present results support the usefulness of the rrnS marker to identify the G1 and G3 genotypes, allowing a simple and low-cost tool for large-scale studies. More information is provided on the population structure of the populations of E. granulosus sensu stricto from Chile and the usefulness of distinguishing between different haplotypes is verified; increasing the resolution of the information that can be very useful to providing more information on the phylogenetic relationships and molecular history of this important parasite.

Background: Entomological surveillance indices are used to estimate the risk of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) transmission. To determine when and where to initiate mosquito control activities, integrated vector management programs establish action thresholds based on entomological surveillance indices. However, the application of entomological surveillance indices needs further investigation relative to the human risk of WNV infection. Herein, we examine the evidence from studies that investigated the quantitative relationship between entomological surveillance indices and human WNV cases using systematic review methods. Results: Across three databases, 5378 articles were identified. Using the selection criteria, 38 studies were included for study. Most articles explored entomological indices weekly and devised unique geographic scales to aggregate human and/or mosquito data. The most used models were logistic and negative binomial regression. Maximum likelihood estimates (MLEs) and vector index (VI) demonstrated the greatest ratio of number of positive results to number of times tested. Among all selected articles, 35 unique U.S. locations assessed MLE and/or VI. Human WNV infection had a significant association with MLE across 81.25% (13/16) of locations. VI showed successful performance across 80.00% (24/30) sites tested. Conclusions: This systematic review identifies methods for quantifying relationships between entomological and human WNV infection data. We found entomological surveillance indices applied to human WNV risk should include a measure of virus presence, such as MLE and VI. Model type and covariates were too variable to identify geographic or species-specific trends, though, when tested, including temperature, land cover, population density, and time improved the model. This study is meant to be informative and designed to assist public health agencies in seasonal WNV preparations but are not meant to be a panacea for all WNV surveillance challenges.

Background: In the study, we aimed to determine the prevalence rate of hyponatremia in patients with Crimean-Congo hemorrhagic fever (CCHF) and to investigate the relationship between hyponatremia and disease severity. Materials and Methods: Patients over 18 years of age who received a definitive diagnosis of CCHF between April 2018 and October 2023 were included in the study. The patients' sodium levels, symptoms, and findings at the time of admission to the hospital were recorded. In addition, the severity score index was calculated according to the laboratory values and findings at the time of admission. Results: The total number of patients included in the study was 219. Hyponatremia was detected at admission in 99 (45.2%) patients. The median serum sodium value in patients with hyponatremia was 133 (127-135) mEq/L. Spearman correlation analysis revealed a statistically significant inverse correlation between serum sodium level and severity score index (r = -0.522, p < 0.001). Conclusions: Mild hyponatremia was detected in almost half of the patients with CCHF, and this parameter may be useful in determining disease severity on admission.

Background: As a natural accelerator of highly pathogenic avian influenza in wild birds, the H9 subtype of avian influenza poses a substantial threat to both humans and the poultry industry. A comprehensive meta-analysis is necessary to assess the current status of the global H9 outbreak. In this research, a literature review and meta-analysis are presented on the surveillance studies of the H9 subtype of avian influenza in wild birds worldwide up to 2024. Methods: A comprehensive search strategy was employed, utilizing the China Science and Technology Journal Database, China National Knowledge Infrastructure, PubMed, Google Scholar, and Scientific Direct databases. The exclusion criteria for this study included duplicate studies, reviews, other host studies, as well as research with inconsistent or insufficient data. An analysis was conducted on data obtained from a total of 31 publications. The rate-conversion analyses were conducted using a random-effects model in the "meta" package of the "R" software, with the PFT method implemented. Results: In the meta-analysis, the prevalence of wild bird H9 avian influenza virus (AIV) was found to be 0.02% (193 out of 365,972). Statistically significant higher prevalences of wild bird influenza A virus were observed in Norway and South Africa (0.87%, 21/2417 and 0.44%, 10/1155, respectively) in comparison with other regions. Within the Anseriformes family, the prevalence rate was much greater (0.17%, 80 out of 90,014) compared with other species. In addition, we performed subgroup analyses that included geographical variables. These assessments showed a higher prevalence of H9 in wild birds in cold regions (0.08%, 30/100,691). Conclusion: In summary, our results suggest that the occurrence of H9 AIV in avian populations differs among different geographical areas and species. Therefore, it is necessary to conduct further surveillance on the prevalence of AIV in wild birds to guide the creation of strong and efficient regulatory strategies targeted at eradicating the transmission of AIV across different species.

Background: DNA extraction from ticks is essential for research on tick-borne diseases, yet the methodologies currently employed exhibit significant variability in terms of yield and purity. This systematic review aims to consolidate existing literature on DNA extraction from ticks, evaluate the various methodologies, challenges, and research gap. Methodology: A systematic review of existing literature was conducted to assess the efficacy, yield, and purity of DNA extracted from various tick species using the aforementioned methods. Comparative analyses focused on factors such as extraction efficiency, contamination issues, and the impact of tick exoskeleton resilience. Results: Phenol-chloroform extraction achieved high DNA yields (50-100 ng/µL) but posed safety risks and was time-consuming. Silica-based methods provided yields of 40-80 ng/µL, effective for many species but less so for those with high microbial loads. Magnetic bead-based extraction offered rapid results with yields ranging from 20 to 70 ng/µL, although it faced challenges such as bead carryover and equipment requirements. Variability in extraction efficiency was noted across different tick species, necessitating method optimization. Conclusion: The review identified several critical research gaps in DNA extraction methods for tick-borne disease diagnostics and research. Currently, methods such as mechanical disruption combined with chemical lysis and column-based methods have shown effectiveness in extracting DNA from ticks, but they come with limitations, including high cost, labor intensity, and reduced efficiency under certain conditions. Despite their utility, these methods often face challenges in resource-limited settings or in varying environmental conditions. To address these issues, there is a need for standardized protocols, cost-effective extraction techniques, and longitudinal studies to evaluate performance under diverse conditions. By addressing these gaps, we can improve diagnostic accuracy, enhance our understanding of tick-borne diseases, and advance both research and public health efforts.

Background: Bats act as reservoirs for a variety of zoonotic viruses, sometimes leading to spillover into humans and potential risks of global transmission. Viral shedding from bats is an essential prerequisite to bat-to-human viral transmission and understanding the timing and intensity of viral shedding from bats is critical to mitigate spillover risks. However, there are limited investigations on bats' seasonal viral shedding patterns and their related risk factors. We conducted a comprehensive review of longitudinal studies on bat viruses with spillover potential to synthesize patterns of seasonal viral shedding and explore associated risk factors. Methods: We extracted data from 60 reviewed articles and obtained 1085 longitudinal sampling events. We analyzed viral shedding events using entropy values to quantitatively assess whether they occur in a consistent, pulsed pattern in a given season. Results: We found that clear seasonal shedding patterns were common in bats. Eight out of seventeen species-level analyses presented clear seasonal patterns. Viral shedding pulses often coincide with bats' life cycles, especially in weaning and parturition seasons. Juvenile bats with waning maternal antibodies, pregnant bats undergoing immunity changes, and hibernation periods with decreased immune responses could be potential risk factors influencing seasonal shedding patterns. Conclusion: Based on our findings, we recommend future longitudinal studies on bat viruses that combine direct viral testing and serological testing, prioritize longitudinal research following young bats throughout their developmental stages, and broaden the geographical range of longitudinal studies on bat viruses based on current surveillance reports. Our review identified critical periods with heightened viral shedding for some viruses in bat species, which would help promote efforts to minimize spillovers and prevent outbreaks.

Arthropod-borne viruses (arboviruses) are a taxonomically varied group of viruses that affect the health of many avian species, including the ruffed grouse (Bonasa umbellus), a popular upland game bird whose numbers are in decline in portions of its range. Hunter-harvested ruffed grouse tissue samples were tested for arboviruses during the 2018-2022 hunting seasons in Michigan, Minnesota, and Wisconsin, USA. A low percentage of harvested ruffed grouse were infected with West Nile virus (8/1892; 0.4%), eastern equine encephalitis virus (18/1892; 1.0%), and Highlands J virus (4/1892; 0.2%), and approximately half (16/30) of those infected had histologic cardiac lesions consistent with arboviral infection. Some ruffed grouse may be adversely affected following infection with these viruses, highlighting the need for increased awareness and continued surveillance, particularly in the face of additional stressors such as climate change, which may alter virus-vector-host dynamics, host susceptibility to arbovirus infections, and geographical distributions.

Objective: Severe fever with thrombocytopenia syndrome (SFTS) poses a significant public health concern in China and has the potential for severe morbidity and mortality. Previous studies on SFTS have focused primarily on analyzing its incidence under existing climate conditions, often overlooking the impacts of future climate change on the disease's distribution. Moreover, the key factors influencing SFTS transmission identified in prior research are limited and lack a comprehensive consideration of multiple environmental and socioeconomic factors in specific regions. Methods: In this study, by utilizing SFTS case data from Chuzhou city alongside multisource environmental variables, the maximum entropy ecological niche (MaxEnt) model was employed to identify the key climatic factors influencing the distribution of SFTS. Risk areas were projected for the present and future climate scenarios, including shared socioeconomic pathway (SSP)126, SSP245, SSP370, and SSP585. Results: The results indicate that (1) precipitation in the driest quarter, elevation, and precipitation in the wettest month are the most critical variables; (2) potential risk areas are situated predominantly in the central hilly region, with the total area of medium- and high-risk zones measuring 5731.86 km², which accounts for 42.67% of the total area; (3) in future climate scenarios, the central-south and southwestern regions emerge as high-risk areas, with the maximum area of future high-risk zones reaching 6417.8398 km², projected for the 2030s under the SSP585 scenario; and (4) the current epicenter of the SFTS risk area is located in Zhang Baling town (118°12'23″E, 32°28'56″N). Under the SSP126 and SSP370 scenarios, the epicenter exhibits minimal movement, whereas significant shifts occur under the SSP245 and SSP585 scenarios. Conclusion: These findings provide essential insights for formulating scientifically grounded prevention and control strategies against SFTS in Chuzhou city.

Background: Black flies (Diptera: Simuliidae) are a notorious group of blood-sucking insects acting as vectors of various diseases in humans and other animals, most notable being Onchocerciasis. Due to its medical and veterinary significance, accurate and quick species identification is of utmost importance in the field of black fly research. DNA barcoding is one such taxonomic tool, aiding in quick and efficient species identification using molecular methods. Despite sporadic reports of ocular and cutaneous Onchocerciasis, especially from North-East India, Indian Simuliidae has been understudied due to lack of expertise on morphological taxonomy and lack of genetic library. Materials and Methods: Blackflies were collected from eight distinct locations in the Central Himalayan region that are part of the West Bengal, India, districts of Kalimpong and Darjeeling. Various traps were used to collect the specimens, and they were kept it in 70% ethyl alcohol. Following the morphological identification of each fly specimen, genomic DNA was extracted from its dissected legs using the QIAmp DNA extraction kit (QIAGEN, Germany). The voucher specimen slide was deposited in the National Zoological collection, ZSI, Kolkata, India. Results: This is the first comprehensive DNA barcoding study of black flies (Feuerborni and Multistriatum species group) using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences along with morphological identification from the Central Himalayan region of West Bengal involving four species: Simulium dentatum, Simulium digitatum, Simulium praelargum, and Simulium senile. DNA barcode approach through ML tree clearly distinguished all the species with supporting PTP, ASAP, and GMYC analysis. Interspecific genetic distances were also calculated where S. dentatum and S. digitatum showed minimum distances in the study area. Conclusion: Coupled with a robust morpho-taxonomic framework, the DNA barcodes generated here will help with accurate species identification, which will lead to better management and control strategies for these harmful vector species at the study site.