Vector borne and zoonotic diseases最新文献

Background: In the Netherlands, Usutu virus (USUV) is endemic in birds, and recently West Nile virus (WNV) was also detected in birds, mosquitoes and humans. Here we investigated the possible role of rodents in the viruses' transmission ecology. Materials and Methods: We sampled rodents at six locations including sites where WNV had been previously detected. Brains (n = 668), oral swabs (n = 282), and ticks (n = 91) collected from rodents were tested for arboviruses via Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Also, sera from 118 rodents were tested for WNV- and USUV-antibodies. Results and Conclusion: Brain samples, swabs, and ticks tested negative for viral RNA. However, 2.5% (3/118; two wood mice, one field vole) of rodents had WNV-neutralizing antibodies (WNV-NAbs). USUV-NAbs were detected in a wood mouse. Two bank voles had NAbs against both viruses. The WNV and USUV antibody-positive rodents were found at locations with previous WNV and USUV circulations, suggesting that rodents may be involved in the ecology of WNV and USUV.

Background and Methods: This Lyme borreliosis (LB) and Borrelia burgdorferi sensu lato (Bbsl)-infected Ixodes ticks surveillance review-from the WHO regions of the Americas, Eastern Mediterranean, Europe, South-East Asia, and Western Pacific-is informed by LB cases or incidence, Bbsl antibody seroprevalence, and Ixodes (I.) tick surveillance results from publications (2005-2022) and recent government websites. Results: LB cases, by the WHO region-country, were documented in the following: the Americas-Brazil and México; Europe-Russian Federation and Türkiye; South-East Asia-India; and Western Pacific-Japan, Mongolia, and South Korea. Mean incidence, cases/100,000 population per year (country, period), was as follows: Europe, 4.8 (Russian Federation, 2009-2021); Western Pacific, 0.01 (Japan, 2005-2021) and 0.03 (South Korea, 2012-2021). Two-tier testing Bbsl antibody seroprevalence estimate ranges were as follows: the Americas, 1.0-6.2% (Brazil), 4.6% (Colombia), and 23.1% (México); Europe, 0-15.8% (Türkiye); South-East Asia, 0.4-3.0% (India); and Western Pacific, 0-14.0% (Mongolia). Ixodes tick surveillance was presented by species (nymph, adult, or not reported, NR, life stage and [Bbsl-infected proportion]): the Americas-México, I. scapularis (NR [34.2%]); Eastern Mediterranean-Iran, I. ricinus (adult [0.9% Borrelia]); Europe-Russian Federation, I. ricinus (nymph [27.3%], nymph/adult [33.4%], adult/NR [9.8-80.4%]) and I. persulcatus (adult/NR [12.0-75.3%]) and Türkiye, I. ricinus (adult/NR [19.9%]); and Western Pacific-Japan, I. persulcatus (nymph [0-10.0%], nymph/adult [1.8-23.6%], adult/NR [detected-up to 25.5%]) and Mongolia, I. persulcatus (nymph [detected], nymph/adult [49.4%], adult [7.0-49.7%]). Conclusions: LB burden might be underrecognized in certain countries of the Americas, Eastern Mediterranean, and South-East Asia, whereas LB cases or incidence, Bbsl antibody seroprevalence, and Bbsl-infected tick presence is established in certain countries of WHO Europe (Russian Federation and Türkiye) and Western Pacific (Japan, Korea, and Mongolia), and LB could be present in neighboring countries within these WHO regions (PROSPERO: CRD42021236906).

Background: Coxiella spp. are widespread in ticks. Coxiella burnetii, the agents of Q fever, is vectored by ticks and is well known for its veterinary and medical importance. However, reports on C. burnetii in ticks from China have been quite few compared with other tick-borne pathogens. In addition to C. burnetii, more and more Coxiella endosymbionts of ticks have been described in China. Materials, Methods, and Results: In this study, ticks were collected from domestic animals in two provinces (Chongqing and Xinjiang) in western China, and the Coxiella spp. in them were molecularly studied. In the 168 ticks (all Hyalomma asiaticum) from Xinjiang, C. burnetii was detected with an overall positive rate of 76.19%. In contrast, in 96 ticks (all Rhipicephalus microplus) from Chongqing, only Coxiella endosymbiont was identified with an extremely high prevalence (97.92%). Conclusions: We propose that there may have been a tick-animal-tick circulation of C. burnetii in Xinjiang. The high positive rate of C. burnetii suggests a high risk to public health.

Background: The zoonotic infectious disease, severe fever with thrombocytopenia syndrome (SFTS), caused by the SFTS virus (SFTSV), Bandavirus dabieense, was first identified in China in 2009 and reported in the Republic of Korea in 2013. The primary vector is the tick Haemaphysalis (H.) longicornis, which is endemic to the Asia-Pacific region and has a wide range of hosts. While SFTSV has been studied in various wildlife species, no investigation has focused explicitly on bats, which are ecologically significant in the transmission of zoonotic viruses. Materials and Methods: To investigate the relationship between bats and SFTSV, 1,200 ticks were collected from 12 sites in 6 provinces within 1 km of bat habitats using flagging, and 147 bat sera were collected via cardiac puncture after ether anesthesia between November 2021 and September 2022. Total RNA was extracted from the ticks and bat sera, and nested reverse transcription polymerase chain reaction was performed to amplify the S segment of SFTSV. Bat sera were analyzed for IgG antibodies against SFTSV by enzyme-linked immunosorbent assay (ELISA). Results: Within 1 km of bat habitats, 881 H. longicornis, 209 H. flava, 96 Haemaphysalis spp., and 14 Ixodes (I.) nipponensis were identified. SFTSV was detected in 12.3% (147/1,200) of the ticks. Although no SFTSV RNA was detected in bat sera by nested PCR, 3.4% (5/147) were seropositive by ELISA. Conclusion: While molecular evidence of SFTSV infection was not observed in bats, a few serological positives suggest possible past exposure. The detection of SFTSV in ticks collected from bat habitats suggests potential ecological interactions involving bats, ticks, and other wildlife species. These findings highlight the importance of considering both wildlife reservoirs and the indirect role of bats in the geographical spread of SFTSV.

Background: Mosquitoes harbor diverse insect-specific viruses (ISVs) frequently overlooked in arbovirus surveillance. Comprehensive characterization of ISVs is crucial for understanding their impact on host ecology and potential roles in arbovirus transmission. Methods: Using metagenomic sequencing on Armigeres subalbatus from Yunnan, China, we identified two novel picorna-like viruses, assembled their genomes, and conducted phylogenetic analysis. Detection was confirmed via RT-PCR and Sanger sequencing. Results: Both viruses are closely related to Hubei picorna-like virus 59, previously reported in spiders but unconfirmed. This work provides the first genomic evidence of this lineage in mosquitoes. Conclusion: This study characterizes two novel ISVs, expanding known picorna-like virus diversity and offering insights into cross-species virus evolution and arbovirus ecology.

Background: Arboviruses, transmitted to humans and animals by blood-feeding arthropods, pose significant public health risks. This study investigates the types, distribution, and epidemiology of arboviruses in the central Yuxi region of Yunnan Province, providing crucial data for the prevention and control of mosquito-borne diseases. Methods: In 2015, mosquitoes were collected from Tonghai County, Huaning County, Jiangchuan District, and Chengjiang County in Yuxi using light traps. The mosquitoes were homogenized, and virus isolation was performed by inoculating the homogenates onto BHK-21 (baby hamster kidney) and C6/36 (Aedes albopictus) cell lines. Reverse Transcription Polymerase Chain Reaction (RT-PCR) amplification was performed with universal and virus-specific primers, followed by sequencing of positive products using bioinformatics tools (DNAstar, MEGA X). Results: A total of 13,050 mosquitoes from four counties were collected, with 261 pools processed for virus detection. The mosquitoes belonged to three genera: Culex Anopheles and Aedes, with Culex tritaeniorhynchus as the predominant species. Cytopathic effects were observed in 95 pools. Nine viruses were identified: Japanese Encephalitis Virus (JEV), Bannavirus, Getah Virus, Tibet Orbivirus (TIBOV), Nam Dinh Virus, Akabane Virus (AKAV), Ngewotan Virus (NWTV), Quang Binh Virus (QBV), and Culex pipiens pallens densovirus. The distribution of viruses varied: six viruses with 35 isolates in Tonghai County; six viruses with 88 isolates in Huaning County; two viruses with five isolates in Chengjiang County; and no viruses were found in Jiangchuan District. TIBOV and NWTV were present in all three counties, while JEV, AKAV, and QBV were found only in Tonghai County. Conclusion: Nine arboviruses were isolated across four counties in Yuxi, with varying distributions. This highlights the epidemiological diversity of mosquito-borne viruses in the region, emphasizing the need for targeted control measures.

Introduction: Herbs and their products are a source for drug discovery, and most of all synthetic drugs originate from them. The present study was designed to evaluate the in vitro and in vivo efficacy, as well as the potential mechanisms, of Rhanterium epapposum essential oil (REE), β-myrcene (MC), camphene (CP), and limonene (LN) alone and in combination with pyrimethamine (PYM) against Toxoplasma gondii. Materials and Methods: In vitro, the effectiveness of REE and its components on tachyzoites, the infectivity rate, caspase-3 activity, and nitric oxide (NO) and expression levels of inducible NO synthase and gamma interferon (IFN-γ) genes were evaluated. In the in vivo assays, infected mice received REE, MC, CP, and LN either alone or in combination with PYM for 2 weeks. Subsequently, the number and diameter of tissue cysts, oxidant/antioxidant enzyme levels, inflammatory cytokines, and bradyzoite surface antigen 1 (BAG1) gene expression were examined. Results: The best 50% inhibitory concentration values were reported for MC + LN, PYM + MC, and MC + CP, with values of 12.1, 15.4, and 16.6 µg/mL, respectively. REE and its primary compounds significantly increased (p < 0.001) NO release (6.6-14.1 nM), caspase-3 activity, and the expression levels of inducible NO synthase and IFN-γ genes in cells. In addition, significantly decreased (p < 0.001) the number (0.0-115.3 cysts) and size (0.0-83.1 nm) of tissue cysts, oxidative stress markers, decreased the expression levels of IL-1β and TNF-α, and BAG1 (0.48-5.10 fold change), while, significantly increased (p < 0.001) glutathione peroxidase (1.65-5.12 U/mg) and superoxide dismutase (31.9-74.1 U/mg) levels in the infected mice. Conclusions: We demonstrated the high in vitro and in vivo efficacy of REE and its principal compounds against chronic toxoplasmosis. The highest efficacy was observed following combination therapy of T. gondii-infected mice with PYM and these compounds, with a significant difference noted compared with PYM alone. However, further trials must validate these findings and clarify the underlying mechanisms.

Background: Q fever, caused by Coxiella burnetii, is an underdiagnosed zoonotic disease with significant public health implications. Serological tests remain the diagnostic cornerstone but often fail in early infection. This study investigates the utility of polymerase chain reaction (PCR) targeting the IS1111 gene for molecular detection of C. burnetii in human clinical samples from a resource-limited setting. Methods: A retrospective PCR-based study was conducted on 243 archived clinical specimens collected from febrile patients across 11 districts of North India. DNA was extracted and subjected to conventional PCR targeting the IS1111 insertion sequence. Samples positive for C. burnetii were further evaluated for coinfection with rickettsial pathogens using real-time and nested PCRs. Sequencing and phylogenetic analysis were performed on positive samples to determine genetic relationships. Results: C. burnetii DNA was detected in 4 of 243 samples (1.64%). Half the positive cases belonged to the patients in 1-15 year age group, and two had coinfections with Orientia tsutsugamushi. One case showed coinfection with spotted fever group rickettsia. Clinical features included fever (100%), myalgia (75%), and rash (25%). Phylogenetic analysis revealed that the isolates clustered with the Z3055 reference strain, indicating a close genetic relationship to known zoonotic strains. Conclusion: PCR targeting IS1111 is a valuable diagnostic tool for early detection of C. burnetii, particularly in settings where serological testing is delayed or unavailable. Detection in pediatric patients and coinfection with other rickettsiae underscore the need for broader diagnostic consideration of Q fever in endemic febrile illnesses.

Background: Brucellosis is a zoonotic bacterial disease that can affect humans and animals. It is often transmitted to humans through the consumption of contaminated animal products or by direct contact with infected animals. In Kenya, data on human and animal brucellosis are limited. Methods: To investigate the seroprevalence and molecular prevalence of human brucellosis in Kenya, we randomly selected from the healthy participants with possible exposure to animals and animal products and randomly selected 348 out of 2,779 human blood samples, that were obtained from a larger longitudinal cohort study that investigated of dengue, chikungunya and Rift Valley Disease exposure in western (Kisumu) and coastal (Ukunda) Kenya. Results: Our study included 126 males (36%), 222 females (64%) in different age categories, and 61 children aged 16 years and younger (18%), with an overall median age of 29.5 years (2- to 75-year age range). Samples were tested by Abnova Brucella IgG enzyme-linked immunosorbent assay (ELISA) Kit (KA0954). Of the tested individuals, anti-Brucella IgG antibodies were detected in 96 (28%) of 348 randomly selected participants. All samples yielded negative results in quantitative polymerase chain reaction (qPCR) analysis. There was no statistically significant correlation between Brucella exposure and study site, gender, age, socioeconomic status, ownership of particular livestock (sheep, goats, and cattle), or consumption of raw animal products. However, highly educated individuals were more likely to have Brucella exposure (odds ratio = 2.02, 1.20-3.41, p = 0.01). Conclusion: In comparison to previous seroprevalence-based studies conducted in nonpastoral Kenyan communities, our study revealed relatively higher seropositivity. This article emphasizes the importance of conducting surveillance for brucellosis in urban areas. Urban brucellosis surveillance within the framework of One Health could serve as a baseline to guide future research on brucellosis in humans.

Background: Throughout Armenia, a range of climate conditions exist, from dry subtropical to cold alpine, with a topographic diversity from 400 to 4,100 meters above sea level. Climate analysis has suggested what the territory of Armenia may experience in response to climate change. The persistence of tularemia in Armenia, in conjunction with observed ecological trends, indicates that host reservoir distributions are likely to shift, consequently altering the geographic regions at risk of transmission. This study endeavors to evaluate the potential effects of climate change on the habitat suitability and population dynamics of the common vole, the principal reservoir of Francisella tularensis in Armenia. The objectives aim to elucidate prospective changes in disease-endemic areas, thereby informing targeted control strategies to mitigate pathogen dissemination and reduce public health risks associated with tularemia. Methods: Field and laboratory data from 2000 to 2023 on the common vole and presence of tularemia were compiled from the National Center for Disease Control and Prevention archived records. For spatial and geostatistical analyses, data were compiled from monthly historical temperature and precipitation records from 2000 to 2021 and forecasted data from the WorldClim database. Data were analyzed using a geographic information system. Results: The comparison of current climate data with predictive models indicates a likely shift in regions with favorable habitats for the common vole. By 2100, areas below 2,000 meters are projected to partially lose suitability, the conditions there could be less suitable for particular animal species. Currently, the common vole's habitat area is above an altitude of 1,400 meters above sea level but by 2100, changes in climate suggest the habitat will shift above an altitude of 2,000 meters above sea level. Conclusion: The vole distribution shrinks because of the change in habitats attributed to climate change. This dynamic underscores the critical need for more targeted surveillance and integrated collaboration between human and animal health agencies to effectively monitor alterations in the ecology of zoonotic diseases. Such proactive measures are essential to anticipate and prevent future cases of human tularemia, ensuring a coordinated response to emerging public health threats.