Vector borne and zoonotic diseases最新文献

Purpose: Dengue is a systemic vector-borne viral disease caused by infection of any one (monoinfection) or more than one serotype (coinfection) of the Dengue virus (DENV). Till date, there have been few studies, which have focused on assessing the cytokine and hematological parameters during DENV mono and coinfection giving emphasis to specific serotype combinations. This is important because all four DENV serotypes do not induce the same disease severity. Taking this into account, the current study was conducted to analyze the hematological parameters, inflammatory cytokine responses, and symptomatic variations in dengue patients of similar age who were admitted and were infected with either DENV-1 serotype or coinfected with DENV-1 and DENV-4 serotypes.

Methods: In this cross-sectional study, samples of dengue-suspected patients were subjected to serological tests. Serologically positive or acute samples of suspected dengue were further subjected to RT-PCR serotyping, hematological, and cytokine profiling studies. The sample size for cytokine hematological and cytokine profiling studies has been estimated using G* Power 3.1.9.7 software.

Results: Of the 1068 samples tested for dengue, 194 serologically positive or acute samples were further serotyped, of these, 87 samples (44.84%) tested positive in RT-PCR; 78.2% (68/87) had monoinfection, and 19 (21.8%) had coinfections. White blood cells, platelets, and neutrophil counts were significantly elevated in patients with monoinfections, and lymphocyte count was high in coinfection. Interleukin 8 (IL-8) and IL-6 were high in monoinfections, and IL-10 and interferon γ were higher in coinfections.

Conclusion: Findings of the present study indicate that there was a better antiviral immune response during coinfections in comparison to monoinfection cases. However, further research with a larger number of coinfections is needed to make a reliable comparison between each combination of mixed serotypes, which will help understand the disease kinetics in DENV coinfections.

During a faunal survey in Great Nicobar Island, we collected four Amblyomma helvolum ticks infesting the snake Xenochrophis trianguligerus and processed for gut-metagenomic analysis using Illumina paired-end sequencing. A total of 8.7 million high-quality reads were generated, revealing that the gut microbiome was dominated by Bacteria (∼99.9%), primarily represented by Proteobacteria (∼95.7%), followed by minor fractions of Firmicutes, Actinobacteria, and Bacteroidetes. The predominant bacterial families were Alcaligenaceae, Bradyrhizobiaceae, Boseaceae, and Rickettsiaceae, with Achromobacter xylosoxidans emerging as the most abundant species (∼30% of total reads). Species-level analyses revealed a complex microbial community dominated by Achromobacter, Brevibacillus, Stutzerimonas, and Aeromicrobium. Several putative opportunistic pathogens were detected, including Myroides sp., Sphingobacterium sp., Stutzerimonas stutzeri, Cutibacterium acnes, Mycobacterium abscessus, Staphylococcus hominis, Achromobacter xylosoxidans, and Pseudomonas otitidis. This study represents the first metagenomic characterization of A. helvolum from India and provides baseline data on reptile-tick-associated microbial diversity from Great Nicobar Island. The findings underscore the importance of molecular surveillance in remote ecosystems and highlight the potential of reptile ticks as reservoirs of opportunistic and zoonotic bacteria.

Introduction: Crimean-Congo hemorrhagic fever (CCHF) is a life-threatening viral infection with multiorgan involvement. While laboratory markers are well-established, the prognostic value of ultrasonography (US) remains underexplored. This prospective study aimed to characterize abdominal US findings in patients with suspected CCHF and to assess their correlation with clinical parameters and disease severity.

Materials and methods: A total of 122 patients hospitalized with suspected CCHF were included and classified as RT-PCR positive (n = 70) and RT-PCR negative control (n = 52) groups. Serial abdominal US was performed on days 1, 3, and 5 of hospitalization. Sonographic findings, clinical data, and Severity Scoring Index (SSI) values were recorded and analyzed.

Results: The most frequent sonographic findings in RT-PCR-positive patients were hepatomegaly (30%), gallbladder wall thickening (26%), periportal echogenicity (19%) and intra-abdominal free fluid (19%). Notably, gallbladder wall thickening was significantly more common in the patient group compared with controls (p = 0.034), while splenomegaly was significantly more frequent in the RT-PCR-negative group (p = 0.003). US findings showed significant regression by day 5, paralleling SSI improvement (p < 0.001).

Conclusion: Abdominal US serves as a complementary, non-invasive modality in the clinical evaluation and follow-up of patients with suspected CCHF. The correlation between US findings and SSI scores, together with the temporal evolution of sonographic changes, highlights its potential to be incorporated into future disease severity scoring systems as a non-invasive prognostic indicator. Routine use of abdominal US, particularly in endemic regions, may provide meaningful support in the early detection of complications, dynamic assessment of disease severity, and objective monitoring of treatment response, thereby enhancing clinical decision-making.

Background: Canine visceral leishmaniasis (CVL), also known as kala-azar, is a significant vector-borne and largely zoonotic disease caused by Leishmania spp. The disease is naturally transmitted by sandflies as vectors and affects dogs and wild dogs in many countries worldwide. A literature review and meta-analysis were conducted to estimate the prevalence of CVL in Mainland China from 2013 to 2023.

Results: A total of 17 publications on CVL investigation in Mainland China were screened from the Chinese National Knowledge Infrastructure, Wan Fang Database, Chinese Science and Technology Periodical Database (VIP), Medline database via PubMed interface, and ScienceDirect. The study utilized a random-effect model to determine the pooled prevalence of CVL. The analyzed data were selected, and the estimated prevalence of CVL in Mainland China was 21.3% (95% confidence interval [CI]: 14.0-29.6). The prevalence of CVL in Northwestern China (39.4%, 95% CI: 33.9-45.0) was significantly higher than in other regions. The main cases of CVL are located mainly in Northwest and Southwest China. In nonendemic areas, the infection occurred in samples collected, but the prevalence was lower, only 3.5% (95% CI: 1.7-5.7). Conversely, it was much higher in endemic areas (33.0%, 95% CI: 23.66-443.1). Additionally, we presented potential factors, such as detection methods, age, and sex.

Conclusion: Our data showed that CVL infection still exists in some parts of China.

Background: Zika virus (ZIKV) is primarily transmitted by Aedes mosquitoes, which thrive in tropical regions. However, reports indicate that asymptomatic carriers can inadvertently transmit ZIKV through blood and blood components.

Methods: To evaluate the risk of ZIKV transmission via blood donation, we investigated the prevalence of ZIKV RNA among healthy Thai blood donors over two consecutive rainy seasons. From January 2020 to September 2021, a total of 64,705 blood donations from 56,145 individual donors were screened for ZIKV RNA at Thailand's National and Regional Blood Centers. Testing was performed using the cobas Zika test, with initially reactive samples subjected to further confirmation via in-house real-time RT-PCR. Donors with confirmed positive results were recalled for follow-up testing. The complete coding genome was sequenced and analyzed phylogenetically to determine the ZIKV strain lineage.

Results: ZIKV RNA was detected in four confirmed-reactive blood donations, equating to a prevalence of 0.006% (95% CI: 0.0000, 0.0002) or approximately 1 in 16,176 donations. These cases originated from four individual donors who were asymptomatic at the time of donation but subsequently developed mild symptoms, which were resolved within a week. Genetic analysis revealed that the identified ZIKV strains belonged to the Asian lineage.

Conclusions: The very low prevalence of ZIKV RNA in blood donations from healthy Thai donors over the 20-month study period suggests that routine ZIKV nucleic acid screening for blood donations is not currently warranted.

Background: Vector-borne diseases, especially those carried by ticks, are one of the major public health challenges worldwide, especially in tropical and subtropical regions. Ticks, as vectors and reservoirs of dangerous pathogens, play an important role in the transmission of common diseases between humans and animals. Relapsing fever caused by Borrelia spp. is one of these diseases that has become endemic in many regions of the world, as well as in Iran.

Method: Blood samples and ticks were collected from small ruminants in eight counties of Kurdistan province, Western Iran. DNA from collected ticks and blood samples was extracted, and all were tested for the detection of the 16S rRNA gene of Borrelia spp. by quantitative polymerase chain reaction (qPCR). For the identification of Borrelia species, flaB and groEL genes were amplified by polymerase chain reaction (PCR) and then sequenced.

Result: In this study, 416 blood samples from sheep and goats and 520 collected ticks from these animals were examined from eight counties in Kurdistan Province. Molecular analyses revealed that 3.1% of the blood samples and 1.74% of the tick samples were infected with Borrelia spp. The highest infection rates in both livestock and ticks were observed in Marivan County. The identified tick species were predominantly Rhipicephalus bursa (60.9%) and Rhipicephalus sanguineus (33.4%), and all positive tick samples belonged to these two species. Phylogenetic analysis of flaB and groEL gene sequences confirmed the presence of Borrelia lonestari and Borrelia theileri in blood samples.

Conclusion: This study provides the molecular evidence of Borrelia species in livestock and ticks from Kurdistan Province, Iran. However, the limited number of positive samples and the restriction of sampling to a single province should be considered when interpreting these results. Broader studies covering multiple regions and host species are needed to better understand the epidemiology of Borrelia infections in Iran.

Background: Vector-borne zoonotic diseases remain a major global public health concern, particularly at interfaces where humans, domestic animals, and wildlife interact closely. Conventional surveillance approaches often fail to detect early zoonotic spillover events, especially in farm and zoological settings. Blood-fed mosquitoes, which feed on diverse vertebrate hosts, offer a unique opportunity for non-invasive environmental surveillance through xenosurveillance. This study evaluates the feasibility of using blood-fed mosquitoes as biological samplers to assess zoonotic risk in managed animal settings in eastern India.

Methods: A total of 185 blood-fed female mosquitoes were collected from livestock farms and zoological enclosures in West Bengal, India, and grouped based on host association (cattle, buffalo, goat, poultry, zebra, and deer). Mosquito species were identified using mitochondrial cytochrome c oxidase I (COI) gene sequencing. Host-group-wise pooled DNA from mosquito heads and abdomens was subjected to shotgun metagenomic sequencing using Oxford Nanopore MinION technology. Taxonomic classification was performed using Kraken 2, and microbial diversity was analyzed through alpha and beta diversity metrics using phyloseq.

Results: Six mosquito species were identified, including Culex tritaeniorhynchus, Culex vishnui, and Mansonia uniformis, known vectors of zoonotic pathogens. Metagenomic analysis revealed diverse microbial communities dominated by Actinobacteria, Proteobacteria, and Firmicutes, with significant host-associated variation in microbial composition. Buffalo- and zebra-associated mosquitoes exhibited the highest microbial richness, while cattle-associated mosquitoes showed comparatively lower diversity. Genomic fragments corresponding to potential zoonotic and veterinary pathogens-including Plasmodium relictum, Babesia bigemina, and Clostridium botulinum-were detected across multiple host groups. Beta diversity analysis demonstrated clear host-driven clustering of mosquito-associated microbiomes.

Conclusion: This pilot study demonstrates that blood-fed mosquitoes can serve as effective non-invasive biological samplers for detecting environmental DNA signatures of potential zoonotic pathogens in managed animal settings. While the detection of pathogen-associated genomic fragments does not confirm active infection or transmission, the findings highlight the utility of mosquito-based metagenomic surveillance as an early warning and risk-detection tool within a One Health framework. Integrating such approaches with targeted diagnostics and epidemiological surveillance may strengthen preparedness for emerging vector-borne zoonotic threats.

Introduction: Lyme disease (LD), the most common vector-borne disease in the United States, is caused by the transmission of bacteria via the bite of infected Ixodes ticks including Ixodes scapularis. Deciduous forests are a highly suitable habitat for I. scapularis survival and development. This case-control study investigated how LD risk was impacted by residential proximity to deciduous forest land cover.

Materials and methods: Participants were selected from the Optum Research Database and mailed a one-time survey regarding LD history, outdoor activities, residential characteristics, and demographics. Cases were identified through the combination of LD diagnosis codes and antibiotic treatment in claims data during January 2020-January 2022; controls were matched based on residential county and census block group housing density. The National Land Cover Database was used to identify the presence and proportion of deciduous land cover within a 50 m and 500 m radius of participants' residential addresses.

Results: LD was associated with deciduous land cover when present at both a 50 and 500 m radius (odds ratio [OR] = 1.80, 95% confidence interval [CI]: 1.33-2.44) and when present at the 500 m radius only (OR = 1.40, 95% CI: 1.04-1.88). Odds of LD also significantly increased with increasing deciduous cover. Independent of residential proximity to deciduous land cover, spending time in yards or hiking/walking/running in wooded/grassy areas was associated with LD. Stratified stepwise models showed that for individuals with deciduous land cover within both 50 and 500 m, risk was uniformly elevated regardless of activity, whereas outdoor activities were significant predictors in individuals with deciduous land cover within the 500 m radius only or within neither radius.

Conclusion: This study identified the presence of deciduous land cover as a key indicator associated with increased LD risk, though outdoor activities conferred increased risk independent of residential land cover. Furthermore, individual behaviors were found to modulate LD risk differently across residential contexts.

Background: The cat flea (Ctenocephalides felis) is the primary arthropod vector responsible for the transmission of Bartonella henselae, the etiologic agent of cat scratch disease. Although domestic cats serve as the principal reservoir host, maintaining long-term intraerythrocytic bacteremia, the spread of B. henselae within feline populations relies entirely on flea-mediated acquisition and transmission. Early work demonstrated that fleas readily acquire the bacterium while feeding on bacteremic cats and can subsequently infect naïve hosts; however, the underlying biological mechanisms remain only partially understood.

Methods: This review synthesizes current knowledge of how B. henselae interacts with its flea vector, tracing the process from acquisition through midgut colonization, persistence, and transmission via contaminated feces.

Conclusions: By integrating findings from artificial feeding systems, natural infection models, and recent advances in bacterial and vector biology, this review provides an updated assessment of the field and identifies key knowledge gaps that must be addressed to fully elucidate this vector-pathogen relationship.

Introduction: Lyme disease is a growing public health concern in the United States. Despite higher rates of infection among children and disseminated disease among racial minorities, few studies have investigated the role of health care inequities on tick-borne disease knowledge among parents.

Methods: We conducted a single-center, cross-sectional, anonymous survey of tick-borne disease recognition and prevention strategies among English- and Spanish-speaking parents/caregivers in a region of high Lyme disease incidence (Long Island, New York). Survey questions consisted of demographics, knowledge assessment, and tick bite prevention practices. Survey responses were analyzed with descriptive statistics and a multivariable logistic regression model to identify associations between participant characteristics and a calculated knowledge score.

Results: In total, 120 participants completed the survey, including 95 (79.2%) English speakers and 25 (20.8%) Spanish speakers. Of these, 72 participants (60%) answered all 4 knowledge questions correctly, and 94 (78.3%) answered 75% of the knowledge questions correctly. English language preference was associated with higher knowledge scores on univariate but not multivariable analysis. Multivariable analysis identified Hispanic or Latino race/ethnicity, lower household income, and fewer years of residence on Long Island as predictors of lower Lyme disease knowledge scores.

Discussion: Our findings highlight the role of adverse social determinants of health on Lyme disease risk, underscoring the need for focused educational interventions on high-risk populations.