Vector borne and zoonotic diseases最新文献

Background: Rickettsial diseases were reported from Kashmir, India, in the early 20th century. Since then, limited research was carried that has resulted in a significant gap in understanding these diseases. This study was conducted to find out the prevalence and diversity of rickettsial diseases in this region. Methods: Blood sample from 476 patients were collected. Enzyme-linked immunosorbent assay was done for the detection of IgM and IgG, and immunofluorescence assay was done for endpoint titer determination. Nested polymerase chain reaction was performed for detection of spotted fever group (gltA, sca0, sca5 genes), typhus group (17 kDa gene) scrub typhus group (47 and 56 kDa gene), followed by sequencing and phylogenetic analysis. Results: The seropositivity of scrub typhus, spotted fever group, typhus group was 74 (15.54%), 71 (14.91%), and 60 (12.60%), respectively. Scrub typhus was significantly associated with the urban population (odds ratio = 1.812, 95% confidence interval 1.099-3.0, p = 0.02). Bimodal seasonal variation was observed in all the three groups. In spotted fever group, out of 48 samples 81.25%, 45.83%, and 38.09% were positive for gltA, sca0, and sca5 genes, respectively, and in typhus group 20.83% were positive for 17 kDa. In the scrub typhus group, out of 62 samples, the 56 kDa gene was positive in 56.45%, while the 47 kDa gene was positive in 35.48%. Phylogenetic analysis revealed Rickettsia conorii, Rickettsia parkeri, Rickettsia typhi, and Orientia tsutsugamushi. Conclusions: This study confirms the presence of human rickettsial infections in Kashmir, highlighting the need for including rickettsial diseases in diagnostic algorithm for acute febrile illness.

Background: Triatomines (Hemiptera: Reduviidae: Triatominae), which are the vectors of Chagas disease in Brazil, are associated with forested areas. This study analyzed triatomines and their natural infection by Trypanosoma cruzi in an Atlantic Forest remnant in the state of São Paulo, Brazil. Materials and Methods: Thirty-five triatomines were captured and identified as Triatoma tibiamaculata and Panstrongylus megistus. The study included direct trypanosome research and isolation in Balb/c mice. Results: Fifteen isolates were obtained from seven triatomines representing both species. Protein sequences from the V7-V8 SSUrDNA region were obtained from the isolates and positive triatomines and were analyzed using maximum parsimony and Bayesian methods for phylogenetic positioning. All sequences obtained were identified as T. cruzi; the isolates were classified as TcII, whereas a direct sample was typed as TcIV. Conclusion: The results demonstrated the occurrence of active transmission cycles and the risk of vector transmission to the population in these regions.

Background: Visceral leishmaniasis is a zoonosis distributed throughout Brazil and caused by the protozoan Leishmania infantum. The disease manifests in its visceral form, with dogs being the primary reservoir. Manaus is the largest city in the Brazilian Amazon region, and despite its significance, there are only documented cases of cutaneous leishmaniasis in humans. The aim of this study was to assess the occurrence of Leishmania infantum in horses in Manaus, Amazonas, Brazil. Materials and Methods: A total of 178 horses from 16 different properties within the city were sampled, and the specific molecular diagnosis was based on the L-like cathepsin gene. Results: Of the 178 horse samples, 82% were positive for L. infantum in the molecular diagnosis based on the L-like cathepsin gene, and of the 16 different properties sampled, only one did not have any positive animals. Conclusion: The role of horses in the transmission cycle of visceral leishmaniasis remains controversial, but the presence of infected horses before the appearance of human cases suggests that this host group could be considered sentinel, and their monitoring may serve as an early warning for the emergence of leishmaniasis in a given area.

Background: In the United States, West Nile virus (WNV) was first identified in 1999 in New York City and in Kansas in 2002. How the virus was introduced remains uncertain, although several potential methods have been hypothesized. This review presents an overview of what has occurred with WNV since 1999 and the potential for establishment of related viruses, such as Japanese encephalitis virus, if they were to be introduced in the United States. Materials and Methods: We have compiled human West Nile case data from Kansas over time with the purpose of illustrating how this virus has become endemic in the center of North America in a representative Midwestern state that is seasonal and does not have year-round mosquito vector activity. Case data were compiled from multiple sources including the U.S. Center for Disease Control and Prevention, the U.S. Department of Agriculture, and the Kansas Department of Health and Environment. Results: The annual reported numbers of human WNV infections have fluctuated widely in Kansas since the introduction in 2002. Between 2002 and 2022, there were a total of 715 reported cases in Kansas, with an average of 34 cases per year. Among the 715 cases, 73% were from 23 counties, but 4 counties accounted for 32% of this total with clusters of cases. Sedgwick County, which is the second most populous county in Kansas, represented 15% of the 715 total cases. Conclusion: The reasons for fluctuations in the number of cases reported each year and the distribution of these cases is uncertain, but they are most likely due to changes in the mosquito vector populations, which are influenced by environmental factors, such as seasonal rainfall, temperature, and humidity. With regards to the future, WNV is here to stay with annual fluctuations that are difficult to predict. The establishment of WNV in the U.S. and Kansas should serve as a warning for the possibility of establishment of other mosquito-vectored diseases, including Japanese Encephalitis virus.

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.