Vector borne and zoonotic diseases最新文献

Background: Tick-borne diseases are an endemic and emerging public health concern in the United States. Ongoing tick range expansion, invasive species, and newly identified pathogens are rapidly altering disease epidemiology. Surveillance is critical to understanding vector ecology and disease risk. Harris County, Texas, with nearly five million residents and diverse ecological zones, offers a unique setting to study local tick dynamics. Methods: From January 2021 to December 2022, we conducted weekly tick surveillance across 63 sites in Harris County (City of Houston), Texas. Ticks were morphologically identified and tested for Rickettsia, Borrelia, Ehrlichia, and Anaplasma via real-time PCR. Samples positive by initial screening were confirmed to the species level using endpoint PCR and sequencing. Results: We collected 1,219 ticks-primarily Ixodes scapularis and Amblyomma maculatum-with distinct seasonal and spatial patterns. Of 1,195 tested ticks, 61% were positive for Rickettsia, with multiple species identified. Notably, Rickettsia parkeri was detected in 23.1% of Rickettsia-positive A. maculatum ticks. Conclusion: Our findings reveal significant tick-borne pathogen activity in Harris County, highlighting the need for continued surveillance and public health efforts in urban and peri-urban Texas.

Background: Monkeypox (Mpox) virus is a virulent zoonotic agent and a member of Poxviridae family. Owing to environmental, social and behavioral factors, and lack of approved vaccines or antiviral agents, the eradication of Mpox has not been successful until today. Material and methods: This study overviewed published data to assess predisposing factors, control strategies and antiviral therapy of mpox virus. Results: The recent Mpox outbreak occurred due to human behavioral factors with a cumulative total of 91,123 laboratory-confirmed cases, including 157 deaths during March 2022-September 2023. Viral immunoregulatory proteins, such as vaccinia complement control protein, inflammation modulatory protein, smallpox inhibitor of complement enzymes, chemokine binding protein, and vaccinia virus growth factor, suppress efficient responses. Host genetic variations in IL1RN (interleukin 1 Receptor Antagonist, rs452204) and IL12RB2 (rs3790567) genes and interferon-α deficiency predispose the host to more severe Mpox infection. Conclusion: Combination therapy and drug repositioning include promising approaches for the efficient antiviral therapy. The worldwide collaboration is required to enhance outbreak preparedness and infection control.

Background: Understanding enzootic cycles is key to arbovirus control. Rodents are primary reservoirs of Venezuelan equine encephalitis virus (VEEV), whereas the vertebrate host of Madariaga virus (MADV) remains unknown. Culex (Melanoconion) mosquitoes are considered primary vectors. We studied small mammals and mosquito ecology in the Darién province and Panamá Oeste province, two enzootic regions of Panama. Additional alphavirus seroprevalence was assessed in small mammals. Methods: Small mammals were trapped using Sherman and Tomahawk traps, and blood samples were tested for MADV and VEEV neutralizing antibodies using plaque reduction neutralization test and attempt viral isolation and generic alphavirus RT-PCR from small mammal tissues. Mosquitoes were collected concurrently using Centers for Disease Control and Prevention (CDC) light, Trinidad, and resting traps. Diversity and similarity were analyzed using standard ecological indices. Results: We sampled 599 small mammals (16 species). MADV seroprevalence was highest in Los Pavitos (9.0%) and restricted to Darién; VEEV was more widespread, peaking in El Cacao (27.3%) and El Real (20.4%). Oryzomys couesi and Transandinomys bolivaris showed elevated MADV seroprevalence; T. bolivaris and Proechimys semispinosus had higher VEEV seroprevalence. Among 4118 mosquitoes, Coquillettidia venezuelensis was most abundant. El Real had the highest species richness and diversity. Geographic proximity influenced community similarity. Conclusions: Spatial differences in host and vector communities may reflect distinct transmission patterns of MADV and VEE. These findings could contribute to better understanding of alphavirus ecology and potentially inform public health strategies in endemic regions.

From 2006 through 2008, 543 synanthropic Rattus norvegicus were sampled from 20 alleys clustered in five high-density human neighborhoods throughout Baltimore, Maryland, USA. Results indicated that rat coronaviruses (RCV) circulated endemically and infected most rats in the region. Collected animals were tested by serology and RT-PCR for evidence of exposure to RCV and the results were used to characterize the epizootiology of natural infection. Serology showed that 71.8% of rats had IgG antibodies to RCV, indicating previous exposure, while only 3.0% showed evidence of recent infection based on positive PCR results. Incidence was estimated at 16% per month. Antibody and PCR results were uniformly distributed throughout the city. Consistent with historical laboratory studies, RCV appeared to be horizontally transmitted and generated an acute infection with a short period of infectiousness. Evidence of past infection increased with rat age but did not differ significantly between males and females. The low incidence (6/1000) of infectious rats (PCR positive/IgG negative) limits the risk of spillover to nearby species, including humans. These results encourage surveys for other wildlife agents to collect sufficient samples to estimate the power to detect the agents and use serological surveys as a screening tool if active infection is of short duration. Otherwise, substantial efforts may be expended with a low likelihood of detection.

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.