Vector borne and zoonotic diseases最新文献

Background: Cutaneous leishmaniasis (CL) is one of the most common vector-borne diseases worldwide and is prevalent in many parts of Iran. Phlebotomine sand flies act as vectors, transmitting the parasite through blood feeding on infected hosts. This study aimed to identify the fauna and seasonal activity of sand flies and to detect Leishmania DNA in vectors and human samples in rural areas of Bastak County, southern Iran, in 2021. Materials and Methods: A cross-sectional survey was conducted from March 2020 to February 2021. Sand flies were collected indoors and outdoors every 15 days using sticky traps. After morphological identification and activity assessment, DNA was extracted from a subset of sand flies and from human lesion samples. PCR was applied to detect the presence of Leishmania parasites. Results: A total of 2,747 sand flies were collected and identified. Activity showed two peaks, one in early March and another in early October. Eleven species were recorded, including four Phlebotomus and seven Sergentomyia species. Phlebotomus alexandri was the most abundant (49.1%). No Leishmania DNA was detected in captured sand flies, whereas human samples revealed PCR bands (650 bp) consistent with L. major. Conclusion: The presence of P. alexandri and P. papatasi as dominant species highlights their potential epidemiological importance in Bastak County. These findings provide baseline information on sand fly fauna and activity, emphasizing the need for continued entomological surveillance and molecular monitoring to better understand leishmaniasis transmission in the region.

Background: The USA-Mexico transboundary region has environmental conditions that may favor the occurrence and abundance of ticks and tick-borne diseases (TBDs). About 40 cases of Rickettsial infections have been reported in recent years in this region, mainly in Tamaulipas, Mexico (28 cases) and in the Lower Rio Grande Valley (Cameron, Hidalgo, Starr, and Willacy Counties, Texas, USA; 12 cases). A low level of knowledge about TBD, along with inappropriate protection practices to prevent tick bites, could severely affect human health in this region. Methods: We assessed the purported understanding of ticks and TBDs among residents in cities of the transboundary region of USA-Mexico, creating awareness on how to prevent TBD. We developed and validated an online bilingual (English and Spanish) survey and distributed it using the University of Texas Rio Grande Valley Qualtrics platform from October to December 2020. Results: In total, 543 people, aged from 18 to 67 years old, answered the survey. We found that 54.80% of the people reported knowledge of ticks and TBD, whereas 45.20% reported no knowledge, contradicting our prediction. Nonetheless, residents lack protection practices to prevent tick bites. Conclusion: Our findings can help develop educational tools in English and Spanish (e.g., videos and flyers) to prevent TBD in the transboundary region of USA-Mexico.

Introduction: Orientia tsutsugamushi, the causative agent of scrub typhus, is endemic to South Korea. While diagnostics such as PCR and immunochromatographic tests (ICT) are widely used, pathogen isolation remains essential for antimicrobial resistance and genetic studies. Methods: In this study, 444 blood samples were collected from febrile patients across 13 hospitals. Among 263 samples identified as scrub typhus-positive by at least one diagnostic method, 99 isolates were successfully cultured. Fisher's exact test and the Wilcoxon rank-sum test were used to estimate odds ratios. Results: A positive nested PCR result (odds ratio [OR] = 28.85), clinician's diagnosis (OR = 16.33), and presence of eschar (OR = 10.95) were strongly associated with successful isolation. Furthermore, delays from blood collection to inoculation significantly impacted outcomes: Isolation success was 41.4% when inoculated within 2 days, but declined to 15.0% after ≥8 days. Conclusions: These findings underscore the importance of prompt sample handling and key clinical indicators in improving O. tsutsugamushi isolation efficiency for downstream research applications.

Background: Understanding the composition, structure, and function of mosquito gut microbiota is critical for developing microbial-based strategies to control mosquito-borne diseases. Regional variations in gut microbial diversity and abundance may influence pathogen transmission and facilitate the dissemination of antimicrobial resistance (AMR). Methods: Adult Culex pipiens pallens and Culex tritaeniorhynchus mosquitoes were collected from four provinces in China. The gut microbiota was analyzed using 16S rRNA gene amplicon sequencing targeting the V3-V4 hypervariable region. Taxonomic profiles were determined at the phylum and genus levels, and functional characteristics of the gut bacterial community were inferred from 16S rRNA gene data using predictive functional profiling tools. In addition, whole-genome sequencing (WGS) was performed on 49 cultured bacterial isolates to identify antibiotic and insecticide resistance genes. Results: At the phylum level, Proteobacteria (49.87-99.69%) and Firmicutes (3.43-49.81%) dominated the mosquito gut microbiota. At the genus level, Wolbachia (13.67-61.96%), Acinetobacter (1.46-29.57%), Staphylococcus (0.53-37.80%), and Providencia (13.64-19.20%) were predominant. Functional profiling revealed regional variation in microbial communities, particularly in genes associated with metabolic processes. WGS analysis of bacterial isolates demonstrated a high prevalence of antibiotic resistance genes, especially those conferring multiclass resistance, whereas insecticide resistance genes were detected at lower frequencies. Conclusion: This study reveals significant regional differences in the composition and functional potential of mosquito gut microbiota, accompanied by widespread antimicrobial resistance among cultured isolates. These findings provide critical insights for identifying microbial targets and developing region-specific microbial or genetic control strategies for mosquito-borne diseases.

Babesia microti, a causative agent of human babesiosis, a tick-borne zoonotic disease, has been detected in Ixodes persulcatus ticks in Mongolia. Large-scale surveys of B. microti in ticks and its infectivity in rodents are essential. Of 458 I. persulcatus ticks, 94 females and 176 males were screened for B. microti infection, while 111 female and 77 male ticks were used to investigate B. microti transmission to BALB/c mice and hamsters. The prevalence of B. microti was higher in female ticks (26.6%) than in males (13.1%), with nearly one-sixth (17.8%) of ticks carrying the parasite. The infectivity of Mongolian isolates, as a sister clade to the U.S. lineage, remains unclear, as they failed to infect rodents. Our study suggests that the risk of B. microti transmission is approximately of one-sixth of I. persulcatus ticks, with a higher risk observed in females than in males.

Background: Leishmania mexicana was identified as the causal agent of localized as well as diffuse cutaneous leishmaniasis (DCL) in Mexico. Methods: To clarify the roles of the inoculum size and host sex, three different doses of the L. mexicana reference strain MNYC/BZ/62/M379 were inoculated into susceptible BALB/c mice. Results: A low dose (25 × 10⁰) did not produce lesions, a medium dose (25 × 10³) produced localized lesions, and a high dose (25 × 10⁶) produced diffuse leishmaniasis. Male mice became infected with the reference strain M379 at a dose 1000 times lower than that required to produce the same type of infection in female mice. Male mice developed lesions 2 or 3 months earlier than female. The dose-dependent severity of lesions was confirmed in 22 previously frozen L. mexicana isolates obtained from patients with either localized or diffuse forms of the disease. Conclusion: We concluded that DCL caused by L. mexicana is a severe form of tegumentary leishmaniasis caused by a high parasite inoculum dose in susceptible hosts, with increased susceptibility in males.

Background: Visceral leishmaniasis (VL) is a vector-borne zoonotic disease that remains endemic and poses an ongoing public health concern in western and central China. In recent years, several areas in Shaanxi Province have reported a resurgence of VL. This highlights the need for spatial risk assessments under current and future climatic conditions. Methods: This study employed the maximum entropy (MaxEnt) ecological niche modeling approach to predict the potential distribution of VL in Shaanxi Province. Historical VL case report data from 2005 to 2024 were integrated with environmental, climatic, and socioeconomic variables to identify key contributing factors and assess both current risk areas and projected future VL distributions under four Shared Socioeconomic Pathways (SSPs) across four future periods in the model. Results: The MaxEnt model showed good performance, with the area under the receiver operating characteristic curve values of 0.902 for the training data and 0.862 for the testing data. The most important contributing factors were annual mean temperature, mean temperature of the warmest quarter, and gross domestic product to VL suitability distribution. Under the current climatic conditions, the potential risk area accounted for approximately 25.28% of Shaanxi Province, with 0.97% classified as high-risk regions. These risk areas were primarily located in Hancheng, Weinan, and Shangluo City, Shaanxi Province. Under future climate scenarios, especially the high-emission pathway, high-risk regions are projected to expand significantly, particularly in northern Shaanxi. Conclusions: This study identified the influence of climatic, environmental, and socioeconomic factors on the distribution of VL in Shaanxi Province and revealed the substantial expansion of ecologically suitable areas under future climate change. The risk maps and ecological insights generated in the study can assist public health authorities in optimizing vector surveillance, region-specific surveillance, early warning, and targeted control efforts, particularly in the context of climate change.

Background: In view of Corona pandemic, scientists have taken significant efforts to study and recognize the peculiarities of the SARS-CoV-2 outbreak in order to prevent it from spreading. It was discovered that the virus is spreading in many places and nations that have made significant progress in addressing environmental pollution or are not subject to dusty storms. Infections are growing again in the same country, with varied densities of sick persons depending on the weather and windy season. Methods: Sun and dust are safe techniques for the deactivation and disinfection of SARS-CoV-2. Here, we used metal oxide discs (Fe₂O₃ 9%, SiO₂ 60%, CaO 6%, MgO 8%, and Al₂O₃ 17%) to safely disinfect SARS-CoV-2 after being subjected to the sun for 30 min. As a result, all SARS-CoV-2 were destroyed completely by transmission electron microscope (TEM) after sun exposure. Three major countries have been chosen as case studies: Italy, China, and Iran. Conclusion: It was discovered that places subjected to dust currents have a lower spread of the coronavirus. This is owing to the fact that the dust contains about 90% metal oxide, which functions as a natural photocatalyst for the synthesis of oxygen and hydrogen. These oxidizing spices can kill SARS-CoV-2.

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).