Disease Transmission Research Articles

Classification of risk for transmission of vaccine-preventable diseases in Brazilian municipalities: comparative analysis before and after the national movement for vaccination and multivaccination proposed by the Ministry of Health as of 2023

ObjectiveTo analyze the classification of the risk of transmission of vaccine-preventable diseases in Brazilian municipalities before and after the National Movement for Vaccination and Multivaccination proposed by the Ministry of Health.MethodsThis is an epidemiological, ecological study using secondary data on vaccination coverage, dropout rates, and homogeneity of vaccination coverage (HCV) for ten immunobiologicals recommended for children under 2 years of age. The study aims to compare the years 2022 and 2023 in Brazil. The vaccination coverage index (VCI), HCV, and dropout rate (DR) were evaluated in the municipalities of Brazil in the years 2022 and 2023. The municipalities were classified into risk strata for transmission of vaccine-preventable diseases before and after the strategy proposed by the Ministry of Health.ResultsThe study found an increase in median vaccination coverage (VC) for all vaccines evaluated, except for the varicella vaccine. Regarding HCV, in 2022, 27.99% of Brazilian municipalities were classified as adequate (≥ 70%), and 410 (7.36%) achieved 100% HCV for all vaccines. In 2023, 34.90% of municipalities were classified as adequate (≥ 70%), and among them, 582 (10.46%) achieved 100% HCV for all vaccines. In terms of the risk classification for the transmission of vaccine-preventable diseases, Brazil had 72.01% of municipalities classified as high or very high risk in 2022, which decreased to 65.13% in 2023. As for municipalities classified as low or very low risk, 11.27% fell into this category in 2022, increasing to 18.12% in 2023.ConclusionThe study concludes that VC surveillance, in conjunction with the Microplanning for High-Quality Vaccination Activities methodology developed by the Ministry of Health in 2023, played a crucial role in resuming immunization efforts that had been hindered by science denialism and the COVID-19 pandemic.

Distinct patterns of prion strain deposition and toxicity in a novel whole brain organotypic slice culture system

Prion diseases are fatal transmissible neurodegenerative diseases that affect many mammals, including humans, caused by the templated misfolding of the prion protein. Different conformations of misfolded prions can occur, leading to distinct disease phenotypes or strains and the accumulation of prions in distinct brain regions. How prion structure influences this brain tropism is not clear, but the transmissible nature of prion diseases has allowed for the development of ex vivo brain slice models of disease. To date, work has been done in cerebellar cultures, but prion diseases are known to differentially affect many other brain regions. We have adapted this approach to a coronally sliced whole brain organotypic culture and demonstrate distinct profiles of cytotoxicity and neuronal loss upon exposure to four mouse-adapted scrapie strains. We were able to induce infection both diffusely through submersion of slice cultures in infectious media and locally through contact with prion-coated stainless-steel wires. Moreover, we observed consistent strain-specific regional differences in prion deposition by 8 weeks of infection, recapitulating what is seen in vivo. We predict that coronal whole brain organotypic slice cultures can be a powerful tool for elucidating strain-specific mechanisms of prion spread and pathology.

Development of highly bioactive long-acting recombinant porcine FSH for batch production management of sows

To improve the economic benefits, exogenous hormones are used to control follicular development and synchronize ovulation in the batch flow management of gilts and weaned sows. Equine chorionic gonadotropin (eCG) is widely used to stimulate follicular development in both experimental and farm animals. Despite its effectiveness, several side effects have been found, including the occurrence of follicular cysts, follicular premature luteinization, and increased follicular atresia. As eCG is a heterologous protein, the generation of antibodies has been found in the superovulation of cattle. Moreover, the extraction of eCG from pregnant mare serum raises concerns regarding animal welfare, as well as potential risks for disease transmission. Follicle stimulating hormone (FSH) controls the follicular growth and maturation in the porcine ovary under physiological conditions. In the current study, we developed a novel long-acting recombinant porcine FSH (rpFSH-pFc) consisting of porcine FSH and porcine fragment crystallizable (Fc) via (G4S)3 linker by using the available protein fusion technology to control the follicular development and maturation. The results of pharmacokinetic studies indicated that rpFSH-pFc exhibited a prolonged half-life in both rats and sows. The efficacy of rpFSH-pFc was confirmed by cAMP level evaluation and germinal vesicle breakdown (GVBD) analysis in vitro. Through ovarian weight gain, superovulation and fertility testing assays, our results revealed that a single rpFSH-pFc treatment could effectively promote follicular development and maturation in vivo. Meanwhile, the mRNA expression levels of the target genes associated with follicular development, maturation and ovulation were significantly up-regulated after rpFSH-pFc treatment. Taken together, our results revealed that rpFSH-pFc could bind to the FSH receptor, stimulate follicular growth and development in female mice, and possess a prolonged half-life in both rats and sows. These characteristics suggest that rpFSH-pFc may be an ideal candidate for promoting follicular growth and development in livestock production.

Environmental, socioeconomic, and sociocultural drivers of monkeypox transmission in the Democratic Republic of the Congo: a One Health perspective

BackgroundMonkeypox (mpox) is an emerging zoonotic disease that has persistently impacted public health in endemic regions of West and Central Africa for over half a century. The Democratic Republic of the Congo (DRC) remains one of the countries most affected. Understanding the risk factors for disease transmission from a One Health perspective is of great importance in the risk assessment, prevention, and control of zoonotic diseases. Therefore, this study aimed to investigate the risk factors for human mpox transmission at the human–animal–environment interface in the DRC.MethodsEpidemiological, environmental, socioeconomic, and sociocultural data from the DRC from 2000 to 2015 were obtained from publicly available dataset. Using these data, we applied negative binomial regression model, least absolute shrinkage and selection operator regression model, and principal component analysis (PCA) to identify key environmental, socioeconomic, and sociocultural factors contributing to mpox transmission. Moreover, a grey prediction model GM (1, n) was constructed to predict the epidemic trend of mpox post-2015 and validated using suspected mpox case data in the DRC from 2016 to 2021, sourced from the United States Centers for Disease Control and Prevention.ResultsBetween 2000 and 2021, a total of 43,628 suspected mpox cases were reported in the DRC, with a peak of 6216 cases in 2020. From 2016 to 2021, suspected cases accounted for over half (24,379/43,628, 55.9%) of the total reported during the 2000–2021 period. The proportion of primary forest [incidence rate ratio (IRR): 1.023, 95% confidence interval (CI): 1.018–1.027], index of economic well-being (IRR: 1.046, 95% CI: 1.039–1.052), and mean annual precipitation (IRR 1.040, 95% CI: 1.031–1.049) were positively associated with mpox incidence. PCA identified five principal components, explaining 69% of the variance in the environmental, socioeconomic, and sociocultural variables. The first component was characterized by socioeconomic factors. The GM (1, n) model, based on the proportion of primary forest, index of economic well-being, and mean annual precipitation, predicted the epidemic trend (revealed relative error: 2.69).ConclusionsBoth socioeconomic and environmental factors play important roles in mpox transmission. Our study further highlighted the importance of considering the interconnectedness among humans, animals, and the environment, and treating these factors as a whole to explain the transmission and emergence of mpox outbreaks in the DRC according to the One Health concept.

An observational, multigenerational platform for health systems and population health interventions to minimise intergenerational transmission of non-communicable diseases in India: the YUVAAN cohort study protocol

IntroductionNon-communicable diseases (NCDs) pose a significant health burden in India, with preventable risk factors contributing to their prevalence. In rural populations, inequalities may be reinforced by health risks passed down...

Geospatial modeling of geographical spread of Aedes species, in relation to climatic and topographical factors in Lagos State, Nigeria.

The ecology and biology of mosquito disease vectors of the genus Aedes are highly dynamic, adapting to various climatic and topographic factors which makes their control challenging. Evidence-based control of Aedes mosquitoes requires a detailed understanding of this adaptability, which is greatly influenced by environmental dynamics. Understanding the drivers of their distribution is hence pertinent to predict disease risk. To better understand drivers and dynamics, we studied the distribution of Aedes mosquitoes in Lagos State, Nigeria, and its connection to climatic and human factors. Aedes larvae and adults were collected from eight Local Government Areas (LGAs, four urban and four rural) in Lagos State, resulting in 98 occurrence points. Using 23 environmental variables, we modeled the geographic distribution of Aedes spp. under current climatic conditions. Human population density was overlaid to estimate the risk of arboviral diseases. Although Aedes mosquitoes were found in all the eight LGAs in different proportions, species distribution varied considerably. Both Aedes aegypti and Aedes albopictus were found across the LGAs with evidence of species partitioning. Virtually all the LGAs were predicted to be highly suitable environments for Aedes mosquitoes, with only two LGAs being moderately suitable. Anthropogenic factors including the extensive accumulation of tires contribute to larval habitat availability for both Aedes aegypti and Aedes albopictus. Urban areas with high population density were also associated with increased larval habitat availability when compared with rural areas. Furthermore, the model suggests that LGAs sharing border with Ogun State are highly suitable environments for Aedes spp. Our study highlights that the main contributing factors to Aedes distribution were precipitation and temperature in the coldest quarter. This paper aims to understand how human and climatic factors affect Aedes mosquitoes distribution in Lagos State, which is crucial to prevent disease transmission.

A comprehensive method on black-legged tick larvae and nymph feeding on mice to study Lyme disease transmission and acquisition

Tick-borne diseases are a growing public health concern in the United States, with cases rising steadily each year. Lyme borreliosis, or Lyme disease, remains the most prevalent, affecting approximately 476,000 individuals annually. Human-driven changes in climate and ecosystems have expanded the habitat of pathogen-carrying ticks, facilitating the spread of these infections. Additionally, increased instances of tick-borne diseases transmission through human tissues have been reported. Despite ongoing efforts to manage these infections, their incidence continues to rise. To develop effective control measures against these diseases and prevent the transmission of tick-borne infections through human and animal tissues, it is very important to develop detection assays and understand the transmission mechanisms of tick-borne infections. In this study, we provide detailed descriptions and visual references for larval and nymphal tick feeding on mice, focusing on the transmission and acquisition of Borrelia burgdorferi (sensu stricto). These methodologies can be applied to study other tick-borne diseases, tick vectorial capacity, and tick biology, aiding in the development of detection strategies to combat these infections.

Abundance of adult Aedes aegypti and Ae. albopictus (Diptera: Culicidae) across six settlements in South Sulawesi, Indonesia

Abstract. Saputra FR, Wahid I, Supriyono, Hadi UK. 2025. Abundance of adult Aedes aegypti and Aedes albopictus (Diptera: Culicidae) across six settlements in South Sulawesi, Indonesia. Biodiversitas 26: 509-519. Aedes aegypti and Ae. albopictus are major vectors of dengue, chikungunya, and Zika. These diseases impose a significant global health burden, particularly in tropical and subtropical regions where environmental conditions favor mosquito population growth and disease transmission. This study aimed to analyze the abundance of adult Ae. aegypti and Ae. albopictus across six settlements in South Sulawesi Province, Indonesia. Mosquito collections were conducted from January to October 2023. The selected settlements were Manuju, Pangembang, Tamala’lang, Adatongeng, Lae-Lae, and Panaikang. The findings indicated that Ae. aegypti was predominantly found indoors in Lae-Lae, with a total of 696 individuals (58.7%) from 100 surveyed houses, while Ae. albopictus was mostly found indoors in Pangembang, with 31 individuals (55.4%). Outdoors, Ae. aegypti was most abundant in Lae-Lae, where 32 individuals (80.0%) were captured in vegetated areas around 100 surveyed houses, such as near bamboo trees and other vegetation surrounding the settlements Similarly, Ae. albopictus was more frequently found outdoors in the same area, with 177 individuals (33.1%) captured under similar conditions. In total, Ae. aegypti was primarily found indoors, with 1186 individuals (p<0.01), while Ae. albopictus was mainly found outdoors, with 535 individuals (p<0.001). These findings reveal significant differences in the abundance of these mosquito species between indoors and outdoors, highlighting the influence of local environmental factors on their distribution in South Sulawesi Province, Indonesia.

Social network analysis of key stakeholders in Brucellosis prevention in Western Iran

BackgroundBrucellosis remains a persistent public health challenge in Iran, particularly in rural regions such as Lorestan province, due to systemic, economic, and cultural barriers. Effective disease control requires multisectoral collaboration among stakeholders. This study aimed to map the stakeholder network involved in brucellosis prevention in Lorestan province, identify gaps in coordination, and provide actionable recommendations for improving control strategies.MethodsThis cross-sectional study employed social network analysis (SNA) to explore the relationships among key stakeholders in brucellosis prevention. Data were collected through a structured questionnaire administered to 75 experts from various sectors, including health, veterinary, agriculture, and non-governmental organizations. The SNA evaluated network density, clustering coefficient, and centrality metrics to determine the levels of collaboration and influence among stakeholders.ResultsThe analysis revealed a moderately dense network (density: 0.2745; clustering coefficient: 0.2839) with central roles played by the Veterinary Organization of Lorestan Province, Lorestan University of Medical Sciences, and the Ministry of Agriculture. These organizations exhibited high levels of influence, support, and interest in brucellosis prevention. However, limited involvement of community-based organizations and environmental agencies was identified, highlighting a critical gap in grassroots engagement. Fragmented coordination was particularly evident in rural areas, where traditional livestock practices, inadequate veterinary services, and the consumption of unpasteurized dairy products perpetuate disease transmission. Economic constraints, such as the high cost of vaccines, along with limited public awareness, further hinder effective control efforts.ConclusionsBrucellosis prevention in Lorestan province requires a comprehensive, multisectoral approach. The adoption of a One Health framework can improve collaboration among stakeholders, enhance resource allocation, and address systemic barriers. Community engagement and intersectoral coordination are essential for improving public awareness and compliance with preventive measures. These findings provide a foundation for developing a National Brucellosis Control Program and inform strategies to mitigate zoonotic diseases in similar high-risk regions.

Dengue and Dengue Virus in Florida

This publication provides an overview of dengue fever, focusing on its epidemiological landscape in Florida. Dengue, caused by dengue virus and transmitted through the bites of infected Aedes mosquitoes, is a major global health concern. Florida has experienced local dengue transmissions, and the incidence of dengue is increasing in the state. The biology and ecology of the primary vectors, Aedes aegypti and Aedes albopictus, play important roles in the disease's transmission cycle. No vaccine and no specific antiviral treatments are yet available, and diagnosis is difficult because dengue symptoms overlap with those of other, similar febrile illnesses. Prevention and control strategies, such as mosquito management, are therefore crucial to mitigate disease risks. Alongside urbanization, climate change, and globalization, incidence of dengue is increasing in Florida. Continued vigilance and research will help to combat this public health threat.

Is Parasitic Contamination of Soil in the Southern United States Related to Poverty and Does It Represent a Human Health Threat? A Perspective.

In recent years, multiple reports have emerged describing real-time quantitative polymerase chain reaction (qPCR) detection of DNA derived from human parasite species in environmental soil samples. In one such report, sampling was focused in impoverished areas of the southeastern United States, and a link between poverty and the presence of parasite DNA in soil was proposed. Whether transmission of certain parasitic diseases persists in the United States in association with poverty remains an important question. However, we emphasize caution when reviewing interpretations drawn solely from qPCR detection of parasite-derived environmental DNA without further verification. We discuss here the limitations of using qPCR to test environmental DNA samples, the need for sampling strategies that are unbiased and repeatable, and the importance of selecting appropriate control areas and statistical tests to draw meaningful conclusions.

Bone fusion materials: past, present, and future.

Bone fusion is one of the mainstay managements for degenerative spinal diseases and critical-sized bone defects resulting from trauma, tumors, infection, and nonunion. Bone graft materials are required for promoting bone healing, with autografts historically considered the gold standard due to their osteogenic, osteoinductive, and osteoconductive properties. However, donor site morbidities have led to the development of alternative bone graft substitutes. Currently available alternative options for bone fusion include allografts, ceramics, demineralized bone matrix (DBM), and bone morphogenetic proteins (BMPs). Each material has its advantages and disadvantages. Allografts avoid donor site morbidities but lack osteogenic properties and pose disease transmission risks. DBMs are acid-extracted allografts that have osteoconductive and osteoinductive properties but require combination with autografts because of the lack of evidence for their stand-alone use. BMP-2 has potent osteoinductive properties and is considered an ideal fusion material, but faces unresolved challenges related to optimal dosage and carrier. Synthetic peptides, mimicking the cell-binding domain of type I collagen, facilitate the attachment of osteogenic cells (such as osteoblasts) to the graft material and the production of extracellular matrix, leading to improved bone growth at the fusion site. The development of materials with ideal properties is a research hotspot. Recent advancements in biomaterials, such as hydrogels, nanomaterials, and three-dimensional-printed biomaterials, offer promising future options for bone fusion. This review provides an overview of available bone fusion materials, their advantages and disadvantages, and introduces emerging candidate options for bone fusion.

Induced mesenchymal stem cells generated from periodontal ligament fibroblast for regenerative therapy

Bone fractures and bone loss represent significant global health challenges, with their incidence rising due to an aging population. Despite autologous bone grafts remain the gold standard for treatment, challenges such as limited bone availability, immune reactions, and the risk of infectious disease transmission have driven the search for alternative cell-based therapies for bone regeneration. Stem cells derived from oral tissues and umbilical cord mesenchymal stem cells (MSCs) have shown potential in both preclinical and clinical studies for bone tissue regeneration. However, their limited differentiation capacity and wound healing abilities necessitate the exploration of alternative cell sources. In this study, we generated induced pluripotent stem cells (iPSCs) using a safe, nonviral and mRNA-based approach from human periodontal ligament fibroblasts (PDLF), an easily accessible cell source. These iPSCs were subsequently differentiated into MSCs, referred to as induced MSCs (iMSCs). The resulting iMSCs were homogeneous, highly proliferative, and possessed anti-inflammatory properties, suggesting their potential as a superior alternative to traditional MSCs for regenerative therapy. These iMSCs demonstrated trilineage differentiation potential, giving rise to osteocytes, chondrocytes, and adipocytes. The iMSC-derived osteocytes (iOSTs) were homogeneous, patient-specific and showed excellent attachment and growth on commercial collagen-based membranes, highlighting their suitability for bone tissue regeneration applications. Given their promising characteristics compared to traditional MSCs, PDLF-derived iMSCs are strong candidates for future clinical studies in bone regeneration and other regenerative dental therapies.

Assessment of pathogenic yeast species in the oral cavity of dogs: Antifungal susceptibility and implications for human health.

Companions' animals can present a risk for the transmission of opportunistic diseases to their owners, including those caused by yeasts of the Candida genus residing in their oral microbiota. This study aimed to isolate and identify yeasts from the oral cavity of dogs and assess their susceptibility to antifungals. Yeast species were identified using automated methods MALDI-TOF-MS and VITEK 2 from 50 dogs (aged 2-4years, various breeds). Among the evaluated animals Candida albicans (37.5%) and Candida parapsilosis (25%) were predominant, followed by other species including C. haemuloni, C. tropicalis, C. krusei, and Trichosporon asahii (12.5% each). In this study, antifungal susceptibility testing revealed a general susceptibility with limited resistance. Although most antifungals exhibited good efficacy, some Candida strains demonstrated resistance to fluconazole (FLC), caspofungin (CAS), and amphotericin B (AMPB). These findings highlight the importance of conducting fungal cultures and antifungigram testing for the effective management of fungal infections in humans and animals. Therefore, vigilant monitoring and control measures are essential to reduce the transmission of opportunistic diseases from pets to humans.

Genetic characterization of infectious bursal disease virus strains with distinct VP2 amino acid profiles emerging in Pakistan.

Infectious bursal disease (IBDV) poses a significant threat to the global poultry industry and causes major economic losses. This study presents the genetic profile of IBDV strains emerging in Pakistan, focusing on the VP2 amino acid profile. The effects of these changes on disease transmission, vaccine effectiveness, and overall chicken health are concerning. A meticulous analysis was carried out by isolating and clustering IBDV strains collected from Faisalabad district of Pakistan. The genetics of these viruses were evaluated by analyzing the VP2 gene, the main component of the virus. Importantly, our results reveal the existence of IBDV strains with unprecedented VP2 amino acid profiles, indicating genetic changes that may affect virulence and immunity. This study highlighted the changing IBDV landscape in Pakistan and underscores the importance of continued research and surveillance efforts. Understanding the genetic structure of these emerging diseases is essential for developing effective control strategies, including vaccine development and control. This also emphasized the need for international cooperation to reduce the spread of the new IBDV strains, which could significantly impact the poultry industry outside Pakistan.

Distinguishing abiotic corrosion from two types of microbiologically influenced corrosion (MIC) using a new electrochemical biofilm/MIC test kit.

Biofilms can cause biofouling, water quality deterioration, and transmission of infectious diseases. They are also responsible for microbiologically influenced corrosion (MIC) which can cause leaks, resulting in environmental disasters. A new disposable biofilm/MIC test kit was demonstrated to distinguish abiotic corrosion of carbon steel from MIC. It used two solid-state electrodes inside a standard 10mL serum vial to form a miniature electrochemical cell. In this work, abiotic corrosion was exemplified using CO2 corrosion and acetic acid corrosion. Sulfate reducing Desulfovibrio ferrophilus IS5, nitrate reducing Pseudomonas aeruginosa, and an oilfield biofilm consortium were grown anaerobically as examples of MIC systems. Tafel curves from dual-half scans and continuous upward scans did not differ significantly in each of the two abiotic corrosion systems. However, obvious distortions in Tafel curve shapes with corrosion potentials (Ecorr) shifts and corrosion current density (icorr) deviations (Tafel skews) were observed in each of the three MIC systems. The polarization resistance (Rp) trend from linear polarization resistance (LPR) for an MIC system decreased in several days due to biofilm buildup while an abiotic system did not have this delay. The abiotic corrosion systems did not respond to electron mediators or biocide injections with negligible Rp changes, while electron mediators accelerated extracellular electron transfer-MIC but not metabolite-MIC, and biocide injection reduced MIC rates as reflected by Rp changes. The results in this work demonstrated that the new kit is a useful tool in MIC diagnosis, biofilm/MIC monitoring and assessment of biocide efficacy.

Analyzing disease control through testing game approach embedded with treatment and vaccination strategies.

This research introduces an expanded SEIR (Susceptible-Exposed-Infected-Recovered) model that incorporates the components of testing, treatment, and vaccination. The study utilizes an evolutionary game theory (EGT) framework to investigate the impact of human behavior on the acceptance and implementation of these interventions. The choice to undergo testing and vaccination is considered a strategic decision influenced by perceived risks and benefits. Regarding disease dynamics, adherence to vaccination and testing protocols is seen as a behavioral factor. The present study employs a finite difference method to numerically examine the impact of proactive vaccination and retroactive treatment policies on human behavior. The investigation focuses on these policies' individual and combined effects, considering various factors, including vaccination and testing costs, vaccine efficacy, awareness level, and infection rates. The findings indicate that the integration of heightened awareness and enhanced vaccination efficacy can successfully alleviate the transmission of diseases, even in situations where the expenses associated with testing and vaccination are substantial. Reducing infections in situations characterized by low or moderate awareness or vaccination effectiveness is contingent upon low testing costs. The final epidemic size (FES) negatively correlates with testing and vaccine costs, indicating that lower costs are linked to a lower FES. Optimal vaccine coverage (VC) occurs when vaccine costs are minimal and vaccine efficiency is efficient, whereas treatment coverage (TC) reaches its peak when testing costs are minimal. This research underscores the significance of considering human behavior and the intricate relationship between vaccination, testing, and treatment approaches in managing the transmission of contagious illnesses. It offers valuable perspectives for policymakers to mitigate the consequences of epidemics.

Taste adaptations in blood-feeding arthropods: mechanisms and ecological implications.

Hematophagous arthropods rely on taste mechanisms to navigate host selection, feeding, mating, and oviposition. These behaviors are driven by environmental taste cues, which shape acceptance or aversion depending on their valence. Positive stimuli, like low concentrations of salts, sugars, amino acids, and nucleotides, promote feeding and oviposition, while negative stimuli, including high salt, bitter compounds, and nociceptive chemicals, trigger avoidance to prevent hazards. Species-specific adaptations enable blood feeders to overcome ecological challenges. Understanding their behavioral, neuronal, and molecular taste mechanisms aids in developing targeted vector control strategies, such as repellents, toxic baits, and oviposition deterrents, to disrupt disease transmission.

Use of a hidden Markov model for interpretation of serial cow milk paratuberculosis antibody enzyme-linked immunosorbent assay results adjusted for milk yield and quality.

Paratuberculosis (Johne's disease), caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a common, economically-important and potentially zoonotic contagious disease of cattle, with worldwide distribution. Disease management relies on identification of animals which are at high-risk of being infected or infectious. The disease is chronic in nature, and infected animals may be infectious in the absence of overt clinical signs. Coupled with limited sensitivity of available diagnostic tests, this creates difficulties in identifying high-risk animals. In some disease-control programmes, dairy cows are classified with regards to risk according to the results of serial tests which quantify MAP antibodies in milk samples. Such classification systems are limited by the influence of non-disease factors on test results, dichotomisation of continuous results into "positive" or "negative" according to an imperfect threshold, and subjectivity in defining which patterns of serial test results indicate different risk-categories. An unsupervised learning (clustering) approach was applied to paratuberculosis test results and milk-recording data collated from 47 farms over an approximately ten-year period between 2010 and 2021. Paratuberculosis test results were first adjusted according to influential non-disease factors using linear models. Continuous-time hidden Markov models were fit to the adjusted test results. The final model revealed four distinct latent states (clusters). Examination of the distribution of adjusted test results associated with each latent state suggested that states were ordinal and aligned with disease progression. Model transition probabilities demonstrated that the probability of an animal progressing to the highest state was dependent on its current state. Of particular note was the existence of a latent state, characterised by paratuberculosis test results below the conventional test-positive threshold, which was associated with a relatively high probability of progression to the highest cluster. This research has led to objective classification of animals according to serial test results, and furthermore suggests the presence of groups of different disease risk amongst animals whose test results fall below the routinely used test-positive threshold. Identification of such groups could be used to better manage disease on farms, through implementation of management practices which limit disease transmission from high-risk animals.

A miniaturized RPA-CRISPR/Cas12a-based nucleic acid diagnostic platform for rapid and simple self-testing of SARS-CoV-2.

Nucleic acid testing is the most effective detection method currently available for the diagnosis of respiratory infectious diseases. However, the conventional real-time fluorescent quantitative PCR technique, which is regarded as the gold standard method for nucleic acid detection, presents significant challenges for implementation in home self-testing and popularization in underdeveloped regions due to its rigorous experimental standards. It is therefore clear that an easy-to-use, miniaturized nucleic acid testing technology and products for nonprofessionals are of great necessity to define the pathogens and assist in controlling disease transmission. (87) RESULTS: In this study, we propose a strategy for self-testing of respiratory pathogen nucleic acid that is oriented towards the public and user-friendly. The proposed system integrates the processes of extraction-free nucleic acid release, RPA isothermal amplification, and CRISPR fluorescence detection into a compact configuration. A microfluidic testing chip actuated by air pouches and a battery/USB-powered reusable device has been developed to enable simultaneous detection of internal reference genes and viral targets in a fully enclosed condition. The system allows for sample-in, and result-out testing in less than 30min with a detection limit of 2 copies/μL. Additionally, a straightforward signal-light-based result display method has been developed to make it easy and intuitive for users to access the results. Furthermore, freeze-drying reagent is introduced to guarantee the storage and transportation of testing chips in ambient conditions. (135) SIGNIFICANCE: This work presents a miniaturized, portable, and highly sensitive nucleic acid detection system, where simple operating procedures have been designed for unskilled users. It is our belief that the testing system developed in this work is well suited for home-based self-testing and infection diagnosis in resource-limited areas, due to the above-mentioned advantages. (52).