Probability Of Infection Research Articles

Clinical prediction rules for surgical site infection after minor surgery in general practice.

Surgical site infection (SSI) after dermatological surgery is associated with poor outcomes. Developing clinical prediction rules based on the predicted probability of infection might encourage guided prophylaxis and judicious prescribing. The purpose of this study was to develop a clinical prediction rule based on identified risk factors for SSI in a large general practice patient cohort. We examined a large, pooled dataset from four randomised controlled trials performed in a regional centre of North Queensland, Australia. Multivariable logistic regression identified a prediction model. Bootstrapping was used for internal validation. A scoring system was based on predicted probabilities of infection. The final prediction rule included age >55years and the anatomical site, histology and complexity of the excision. The area under the curve was 0.704. Our prediction rule encourages judicious use of prophylaxis in clinical practice.

Comparative Chemical Analysis and Bioactive Properties of Aqueous and Glucan-Rich Extracts of Three Widely Appreciated Mushrooms: Agaricus bisporus (J.E.Lange) Imbach, Laetiporus sulphureus (Bull.) Murill and Agrocybe aegerita (V. Brig.) Vizzini.

Herein we describe the antioxidant, antimicrobial, antibiofilm, anti-inflammatory and wound-healing potential of aqueous and polysaccharide extracts from three widely appreciated mushrooms: Agrocybe aegerita, Laetiporus sulphureus and Agaricus bisporus. Moreover, we present their detailed phenolic, polysaccharide and protein profiles and ATR-FTIR spectra. The study found that polysaccharide extracts (PEs) from mushrooms had higher total and β-glucan levels than aqueous extracts (AEs), with A. aegerita showing the highest content. L. sulphureus had a higher total protein content, and A. aegerita AE had the highest phenolic content. Our results indicate that all the tested extracts have high potential regarding their bioactive properties, with A. aegerita being the most promising one. Namely, the antibacterial activity assay showed that the development of the skin-infection-causing agent, Staphylococcus aureus, was inhibited with a minimal inhibitory concentration of 4.00 mg/mL and minimal bactericidal concentration of 8.00 mg/mL, while the results regarding wound healing showed that, over the course of 24 h, the A. aegerita extract actively promoted wound closure in the HaCaT keratinocyte cell line model. The anti-inflammatory activity results clearly showed that when we used S. aureus as an inflammation-inducing agent and the A. aegerita aqueous extract in treatment, IL-6 levels reduced to the level of 4.56 pg/mL. The obtained data suggest that the tested mushroom extracts may serve as a source of bioactive compounds, with potential applications in the cosmeceutical, pharmaceutical and food industries. Furthermore, potential skin preparations carefully crafted with mushroom extract may help restore the skin's barrier function, decrease the probability of staph infections and minimize skin irritation.

About the global strategy for the prevention of influenza in 2019–2030

The development of modern methods of epidemiological control, on the one hand, and the creation of modern methods of diagnosis, prevention, and treatment, which will be available to all strata of society, on the other hand, is the key to preventing the pandemic spread of influenza in the world. Today, influenza is a serious threat to human health globally, which covers all countries of the world. Thus, according to the World Health Organization estimates, about 1 billion cases of influenza are registered annually worldwide, of which 3–5 million are severe cases and 290,000–650,000 are cases of death due to severe complications of respiratory dysfunction caused by influenza. Children are more susceptible to acute respiratory viral infections and influenza in the general population due to the physiological instability of the immune system, being mostly in crowded places and in large social groups (kindergartens, schools, entertainment centers), which increases the probability of infection. The risk group consists of patients with chronic pathology, particularly affecting the heart and lungs, who have problems with the immune system.

The significance of serum lysozyme in predicting bacterial complications in patients after kidney transplantation

The aim of the study was to conduct a comparative analysis of serum lysozyme activity and study its innovativeness in predicting bacterial complications after kidney transplantation. Material and methods. Lysozyme activity was studied in 99 patients after kidney transplantation and 81 practically healthy volunteers. Patients depending on period after surgery were divided into five groups: group 1 – 1st day after kidney transplantation (n = 6); group 2 – 1–5 months (n = 10); group 3 – 6–12 months (n = 21); group 4 – 2–5 years (n = 30); group 5 – 6–10 years (n = 32). An analysis of the correlation between serum lysozyme level, absolute leukocyte count and creatinine content was performed. Lysozyme activity was assessed in bacterial complications, transplant dysfunction and organ rejection. Results and discussion. On the 1st day after kidney transplantation lysozyme activity was minimal – 117.95 [60.80–133.51] µg/ ml (median [lower quartile – upper quartile]) (in healthy volunteers it was 243.80 [190.76–305.69] µg/ml, p < 0,001). One month after surgery, it returned to normal (292.08 [311.66–218.48] μg/ml) and did not differ from the value of the group of practically healthy volunteers for 5 months (p = 0,17). Lysozyme activity in serum of patients after kidney transplantation had inverse moderate correlation with creatinine content (r = –0,32, p < 0,05). The threshold value for the probability of bacterial infections for serum lysozyme was > 321,4 μg/ml (p = 0,003). Creatinine level > 0,11 mmol/l predicts graft dysfunction. Conclusions. On the first day after transplantation a low level of lysozyme indicates high risk of bacterial infection. One month after surgery lysozyme returned to normal which indicates restoration of humoral component of nonspecific immune resistance. Relationship between creatinine content and lysozyme activity as well as an increase in the latter in comparison with healthy group allows to use lysozyme as an additional diagnostic criterion for acute bacterial infection and creatinine – for prognosis of graft dysfunction.

Use of wearable ventilation for reducing the infection risk of healthcare workers in isolation wards: A numerical study

This study investigates the protective effectiveness of a novel head-mounted air supply (HAS) system on healthcare workers (HCWs) in COVID-19 isolation wards. The study employs computational fluid dynamics (CFD) to explore the effectiveness of the HAS and the infection probability for HCWs during constant exhaling and coughing of patients. It also studies the effect of air changes per hour (ACH) and exhaust outlet locations in the isolation ward on the infection probability of the HCW. Additionally, the effectiveness between the HAS and various types of common masks is compared. Results indicate that when the flow rate of the HAS reaches 10 L/s with supplying clean air, the infection probability of the HCW can be reduced from approximately 30 % without protection to below 0.18 %. Patients' coughing increases the infection probability of the HCW by approximately tenfold within a short period, and wearing the HAS can effectively reduce the effect of patients’ coughing on the HCW. When ACH increases, the infection probability of the HCW decreases. Wearing the HAS can mitigate the effects of changes in ACH, with an infection probability below 0.18 % at 9 ACH or above. Ceiling-level exhausts are more effective than floor-level exhausts in removing pollutants from the ward. Under experimental settings, HAS with suitable parameters may be more effective than commonly used masks in terms of reducing the infection probability of the wearer. These findings provide valuable references for the application of wearable ventilations in hospital environments.

Microsporidian coinfection reduces fitness of a fungal pathogen due to rapid host mortality.

Infection outcomes can be strongly context dependent, shifting a host-symbiont relationship along a parasitism-mutualism continuum. Numerous studies show that under stressful conditions, symbionts that are typically mutualistic can become parasitic. The reverse possibility, a parasite becoming mutualistic, has received much less study. We investigated whether the parasitic microsporidium Ordospora pajunii can become beneficial for its host Daphnia dentifera in the presence of the more virulent fungal pathogen Metschnikowia bicuspidata. We found that, even though infection with O. pajunii reduces the frequency of penetration of M. bicuspidata spores into the host body cavity, it does not improve the survival or reproduction of the host; conversely, coinfection increased the mortality of Daphnia. This shorter lifespan of coinfected hosts disrupted the life cycle of M. bicuspidata, greatly reducing its fitness. Thus, coinfection with both pathogens was detrimental to the host at the individual level but might be beneficial for the host population as a result of greatly reduced production of M. bicuspidata spores. If so, this would mean that O. pajunii outbreaks should delay or prevent M. bicuspidata outbreaks. In support of this, in an analysis of dynamics of naturally occurring outbreaks in two lakes where these pathogens co-occur, we found a time lag in occurrence between O. pajunii and M. bicuspidata, with M. bicuspidata epidemics only occurring after the collapse of O. pajunii epidemics. Thus, these results suggest that the interaction between co-occurring symbionts, and the net impact of a symbiont on a host, might be qualitatively different at different scales.IMPORTANCEUnderstanding the factors that modify infection probability and virulence is crucial for identifying the drivers of infection outbreaks and modeling disease epidemic progression, and increases our ability to control diseases and reduce the harm they cause. One factor that can strongly influence infection probability and virulence is the presence of other pathogens. However, while coexposures and coinfections are incredibly common, we still have only a limited understanding of how pathogen interactions alter infection outcomes or whether their impacts are scale dependent. We used a system of one host and two pathogens to show that sequential coinfection can have a tremendous impact on the host and the infecting pathogens and that the outcome of (co-)infection can be negative or positive depending on the focal organization level.

Type 2 diabetes mellitus as an independent risk factor of pulmonary tuberculosis: A hospital based cross-sectional study

Background: The growing frequency of infectious and non-communicable illnesses on a global scale is primarily associated with the changing patterns observed in epidemiology. Diabetes mellitus (DM) significantly leads to the development of tuberculosis (TB) and less effective treatment outcomes if not identified early. Objective: This study aims to investigate type 2 DM as a risk factor for TB infection.Methods: Participants in this cross-sectional research study comprised DM patients who reported cough complaints at the TB treatment center and the internal medicine department of Zainoel Abidin Hospital. Random blood glucose and glycated hemoglobin (HbA1c) levels were measured in all respondents. The Chi-Square test assesses the association between DM and Pulmonary TB.Results: There are 48 DM patients with new pulmonary TB, an averageage of 53 years (SD 9.1). Most of them have symptoms of cough for more than 2 weeks (85.4%), loss of body weight (77.1%), chest pain (58.3%), and loss of appetite (72.9%). The high HbA1c levels were associated with TB, as detected by Xpert MTB/RIF assay and typical radiographic signs (p<0.05). DM patients with increased HbA1c were found to have a two times chance of showing results from a chest x-ray typical of TB and probability of TB infection (PR: 2.850, 95% CI (1.152-7.053); 2.745, 95% CI (0.969-7.780)) respectively.Conclusion: DM patients had two times the risk of lung damage based on chest X-rays and having TB. DM may seriously compromise the efficacy of TB control programs and impede a nation's progress toward TB elimination.

Exploring the limits of the law of mass action in the mean field description of epidemics on Erdös-Rényi networks

The manner epidemics occurs in a social network depends on various elements, with two of the most influential being the relationships among individuals in the population and the mechanism of transmission. In this paper, we assume that the social network has a homogeneous random topology of Erdös-Rényi type. Regarding the contagion process, we assume that the probability of infection is proportional to the proportion of infected neighbours.We consider a constant population, whose individuals are the nodes of the social network, formed by two variable subpopulations: Susceptible and Infected (SI model). We simulate the epidemics on this random network and study whether the average dynamics can be described using a mean field approach in terms of Differential Equations, employing the law of mass action. We show that a macroscopic description could be applied for low average connectivity, adjusting the value of the contagion rate in a precise function. This dependence is illustrated by calculating the transient times for each connectivity.This study contributes valuable insights into the interplay between network connectivity, contagion dynamics, and the applicability of mean-field approximations. The delineation of critical thresholds and the distinctive behaviour at lower connectivity enable a deeper understanding of epidemic dynamics.

Nematodes of concern to public and animal health associated with the invasive snail Achatina fulica, in Sergipe, Northeastern Brazil

The giant African land snail Achatina fulica is known to be the intermediate host of a number of nematode species that are prejudicial to human and veterinary health, being also an agricultural and urban pest. The present study investigated the presence of nematodes in A. fulica and other terrestrial mollusks in 24 municipalities of Sergipe State, northeastern of Brazil, in the dry and rainy seasons. In 2019 and 2020, the specimens were collected in standard 20 m × 10 m plots (10 min/01 collector), while in 2021, they were collected by convenience sampling. The nematode species were identified based on sequencing of the mitochondrial Cytochrome C Oxidase Subunit I (COI) gene and the ribosomal nuclear Internal Transcribed Spacer (ITS 2). Specimens of A. fulica infected with Angiostrongylus cantonensis, a nematode that causes eosinophilic meningitis (EM) in humans and animals, were collected in four municipalities. Two nematodes of veterinary importance were also identified, Aelurostrongylus abstrusus and Cruzia tentaculata in seven municipalities. This is the first record of Cruzia tentaculata in Sergipe. Free-living nematodes were also found in 18 municipalities. One of these species – Caenorhabditis briggsae – was identified in the municipality of Itabaiana. Specimens of other mollusks species were also collected. Only one of these mollusks, C. fasciata from Japaratuba, was found infected with free-living nematodes. A. fulica showed greater positivity for nematodes in the dry season, especially in the regions of Lower São Francisco River, Greater Aracaju and South Central Sergipe. The probability of infection increased when mollusks were larger and more recurrent in plots. Given that A. cantonensis is the etiological agent of EM and was found associated to A. fulica in four municipalities, it will be important to implement programs of continuous monitoring of the mollusk's fauna, combined with educational programs that provide information necessary to control A. fulica.

Influence of Weather Conditions and the Aphid Population on the Potato Virus Y Infection of Tobacco in the Field

Potato virus Y (PVY) is a major tobacco (Nicotiana tabacum L.) pathogen that causes severe crop losses. We studied the influence of meteorological factors and a population of twelve aphid species on the development of PVY in field-grown tobacco from 1996 to 2010 in Poland. Three PVY-susceptible tobacco varieties were used in the study. The mean virus incidence ranged from 18% in 2010 to almost 99% in 1996, 2004, and 2009. For determining the relationship between tobacco plant infection and meteorological conditions and aphid populations, logistic regression analysis was used. It was found that the probability of PVY infection is significantly dependent on the average air temperature, relative humidity, number of days with an average temperature of at least 25 °C, and the abundance of Aphis fabae and Brachycaudus helichrysi. The probability of infection of tobacco plants with potato virus Y decreased with increasing air temperature and relative humidity. In addition, with each subsequent day with a temperature of at least 25 °C, the risk of infection decreased by 24%. Furthermore, it was often observed that high populations of Aphis fabae and Brachycaudus helichrysi were associated with a high incidence of virus infection in tobacco plants.

Risk assessment of infection of COVID-19 contacts based on scenario simulation.

We constructed a rapid infection risk assessment model for contacts of COVID-19. The improved Wells-Riley model was used to estimate the probability of infection for contacts of COVID-19 in the same place and evaluate their risk grades. We used COVID-19 outbreaks that were documented to validate the accuracy of the model. We analyzed the relationship between controllable factors and infection probability and constructed common scenarios to analyze the infection risk of contacts in different scenarios. The model showed the robustness of the fitting (mean relative error = 5.89%, mean absolute error = 2.03%, root mean squared error = 2.03%, R2 = 0.991). We found that improving ventilation from poorly ventilated to naturally ventilated and wearing masks can reduce the probability of infection by about two times. Contacts in places of light activity, loud talking or singing, and heavy exercise, oral breathing (e.g., gyms, KTV, choirs) were at higher risk of infection. The model constructed in this study can quickly and accurately assess the infection risk grades of COVID-19 contacts. Simply opening doors and windows for ventilation can significantly reduce the risk of infection in certain places. The places of light activity, loud talking or singing, and heavy exercise, oral breathing, should pay more attention to prevent and control transmission of the epidemic.

Alcohol in Baijiu Contributes to the Increased Probability of Host Infection by Clostridioides difficile Spores.

Clostridioides difficile and its endospores possess the characteristics of a foodborne pathogen and have been detected at several stages in the food chain. In the presence of an imbalance in host intestinal ecology, C. difficile can proliferate and cause intestinal infections. Multiple food source factors can substantially alter the host's gut ecosystem, including the consumption of baijiu. However, it remains to be known whether the gut ecological changes induced by the consumption of baijiu increase the risk of C. difficile invasion and infection. In this study, C. difficile cells were exposed to two commercially available baijiu to evaluate the effect of baijiu on C. difficile cells and to verify through a mouse model. The results showed that baijiu effectively inhibited the growth and biofilm production of C. difficile, downregulated the expression levels of tcdA and tcdB virulence genes but upregulated the expression level of spore-producing genes Spo0A, enhanced the spore production, as well as increased C. difficile cell adhesion to Caco-2 cells. The mouse model showed that the intake of baijiu promoted the invasion and infection of C. difficile spores, causing damage to the cecum tissue, accompanied by an increase in the gut lipid carrier protein-2 (Lcn-2) and TcdA toxin protein levels. Simultaneously, cholic acid was elevated, whereas deoxycholic acid was decreased. This study is the first to find a possible link between baijiu intake and C. difficile spore invasion and infection.

ВЕРОЯТНОСТЬ ИНФЕКЦИОННОГО ПРОЦЕССА RABIES У ЛЮДЕЙ В РЕГИОНЕ СО СЛОЖНОЙ ЭПИЗООТИЧЕСКОЙ ОБСТАНОВКОЙ ПО БЕШЕНСТВУ

The aim of the study was to establish the relationship between cases of animal rabies and cases of people seeking medical help after bites of synanthropic and wild animals in various geographical areas of the Saratov Region. An analysis of the number of people who sought medical help for animal bites in the right-bank Districts of the Saratov Region in 2022 showed that the largest number of people sought medical help after traumatic contacts with animals in Balashovsky (272 people), Volsky (213 people), Rtishchevsky Districts (126 people), and in the left-bank Districts of the Region, the largest number of people sought medical help after traumatic contacts with animals in Balakovsky, Pugachevsky and Krasnokutsky Districts of the Region, which amounted to 580, 167 and 82 people, respectively. The lea-ding positions in the number of people injured by animal bites during the period under review are occupied by the city of Saratov – 2,342 people, as well as the city of Engels and the Engels District of the Region – 1,037 people. Having analyzed the number of people injured by animals with established rabies in the Saratov Region in 2022, it was found that the largest number of people were injured in Saratov (11 people). In Dergachevsky – 9 people, in Rtishchevsky and Sovetsky Districts – 8 people, respectively. An analysis of the number of cases of rabies in animals of different species in the region in 2022 showed that the lea-ding positions among the recorded cases of rabies were occupied by dogs (16 cases), cats (14 cases), and wild animals (9 cases). The probability of infection of the population with the rabies virus during traumatic contact with an animal is 0.066. In conditions of stationary trouble in the Region over a long period of time, the contagiousness index is 2.1, which indicates an extremely high danger and probability of rabies among the population of the Region.

Comparison of treatment trains for indirect potable reuse and use of quantitative microbial risk assessment (QMRA) to evaluate reliability of pathogen removal: Zoo Miami case study

Wastewater and reclaimed water contain various microorganisms such as bacteria, viruses, and protozoa that can cause waterborne diseases in humans and animals. Zoos and animal conservation parks utilize reclaimed water for various purposes which may contain pathogens harmful to human and animal health. The goal of this study was to assess the treatment performance of two treatment trains for indirect potable reuse (IPR) and perform quantitative microbial risk assessment (QMRA) to evaluate the reliability of pathogen removal at a proposed advanced water treatment facility at the Zoo Miami. A review of advanced treatment and disinfection technologies relevant for reclaimed water production and pathogen removal was conducted as a part of this study. DPRisk was used to perform QMRA for four reference pathogens selected as model organisms for two IPR treatment trains (TT1 and TT2). Public health risk estimates for pathogens including Adenovirus, Cryptosporidium, Giardia, and enteric viruses indicated that the risk of infection was below the EPA's target daily threshold of 2.7 × 10−7 and annual risk threshold of 10−4 without failure analysis. With failure analysis, both treatment trains met the daily risk goals for each of the reference pathogens approximately 99 % of the time. Adenovirus demonstrated the highest probability of infection with a mean annual risk of infection for TT1 of 6.65 × 10−9 in the absence of failures but reached a maximum of 7.34 × 10−2 with failure analysis. TT2 resulted in higher risk estimates compared to TT1 with a mean annual risk of infection of 2.10 × 10−8 without failure and a maximum of 8.37 × 10−2 with failure analysis. The results of the failure analysis demonstrate the benefit of treatment redundancy in potable reuse system design and highlight the importance of online process monitoring to rapidly identify off-spec or treatment failure events to protect public health. With this information, stakeholders can better understand treatment requirements and microbiological risks to inform potable reuse planning, design, and risk management.

Identifying highly connected sites for risk-based surveillance and control of cucurbit downy mildew in the eastern United States.

Surveillance is critical for the rapid implementation of control measures for diseases caused by aerially dispersed plant pathogens, but such programs can be resource-intensive, especially for epidemics caused by long-distance dispersed pathogens. The current cucurbit downy mildew platform for monitoring, predicting and communicating the risk of disease spread in the United States is expensive to maintain. In this study, we focused on identifying sites critical for surveillance and treatment in an attempt to reduce disease monitoring costs and determine where control may be applied to mitigate the risk of disease spread. Static networks were constructed based on the distance between fields, while dynamic networks were constructed based on the distance between fields and wind speed and direction, using disease data collected from 2008 to 2016. Three strategies were used to identify highly connected field sites. First, the probability of pathogen transmission between nodes and the probability of node infection were modeled over a discrete weekly time step within an epidemic year. Second, nodes identified as important were selectively removed from networks and the probability of node infection was recalculated in each epidemic year. Third, the recurring patterns of node infection were analyzed across epidemic years. Static networks exhibited scale-free properties where the node degree followed a power-law distribution. Betweenness centrality was the most useful metric for identifying important nodes within the networks that were associated with disease transmission and prediction. Based on betweenness centrality, field sites in Maryland, North Carolina, Ohio, South Carolina and Virginia were the most central in the disease network across epidemic years. Removing field sites identified as important limited the predicted risk of disease spread based on the dynamic network model. Combining the dynamic network model and centrality metrics facilitated the identification of highly connected fields in the southeastern United States and the mid-Atlantic region. These highly connected sites may be used to inform surveillance and strategies for controlling cucurbit downy mildew in the eastern United States.

Clinical characteristics and logistic regression analysis of macrolide-resistant Mycoplasma pneumoniae pneumonia in children.

To investigate macrolide-resistant Mycobacterium pneumoniae (MRMP) pneumonia in children and construct a logistic regression model for mutations in the Mycoplasma pneumoniae drug-resistant gene. Clinical data of 281 children were analyzed. Sequencing confirmed a mutation at the A2063G locus of the 23S rRNA gene in 227 children (A2063G group); 54 children showed no mutations (non-MRMP [NMRMP] group). We compared clinical features, laboratory tests, imaging, and bronchoscopy results and constructed a multifactorial logistic regression model to analyze risk and protective factors. The A2063G group had longer durations of fever and hospitalization before admission, a higher proportion of treatment with sodium methylprednisolone succinate (MPS)/dexamethasone, longer time to discontinue hormones, and higher probability of combined infections. Monocyte percentage was significantly higher in the A2063G group. Imaging suggested a higher incidence of infections in the right lung compared to both lungs. Univariate analysis revealed fever duration before admission, hormone dose and duration, monocyte percentage, and mixed infections as risk factors for Mycoplasma pneumoniae infection with the A2063G mutation. The logistic regression model showed that mixed infections were an independent risk factor for the A2063G locus mutation, whereas hormone dose was a protective factor. A prevalence of macrolide resistance of 80.8% among children was observed in the region. Logistic regression analysis revealed that co-infection with other respiratory pathogens is an independent risk factor for the development of resistance genes, while the use of hormone dosage acts as a protective factor.

Drivers of epidemic dynamics in real time from daily digital COVID-19 measurements.

Understanding the drivers of respiratory pathogen spread is challenging, particularly in a timely manner during an ongoing epidemic. Here we present insights obtained using daily data from the NHS COVID-19 app for England and Wales and shared with health authorities in almost real time. Our indicator of the reproduction number R(t) was available days earlier than other estimates, with a novel capability to decompose R(t) into contact rates and probabilities of infection. When Omicron arrived, the main epidemic driver switched from contacts to transmissibility. We separate contacts and transmissions by day of exposure and setting, finding pronounced variability over days of the week and during Christmas holidays and events. As an example, during the Euro football tournament in 2021, days with England matches showed sharp spikes in exposures and transmissibility. Digital contact tracing technologies can help control epidemics not only by directly preventing transmissions but also by enabling rapid analysis at scale and with unprecedented resolution.

Identification and validation of diagnostic cut-offs of the ELISpot assay for the diagnosis of invasive aspergillosis in high-risk patients.

We investigated the performance of enzyme linked immunospot (ELISpot) assay for the diagnosis of invasive aspergillosis (IA) in high-risk patients with hematologic malignancies. We prospectively enrolled two cohorts of patients undergoing intensive myelosuppressive or immunosuppressive treatments at high risk for IA. ELISpot was performed to detect Aspergillus-specific T cells producing Interleukin-10. In the discovery cohort, a derived cut-off of 40 spot forming cells (SFCs)/106 PBMCs has shown to correctly classify IA cases with a sensitivity and specificity of 89.5% and 88.6%, respectively. This cut-off is lowered to 25 SFC when considering the subset of possible IA patients, with sensitivity and specificity of 76% and 93%, respectively. The application of the 40 SFCs cut-off to the validation cohort resulted in a positivity rate of 83.3% in proven/probable cases and a negativity rate of 92.5% in possible/non-IA cases. Adopting the 25 SCFs cut-off, the assay resulted positive in 83.3% of proven/probable cases while it resulted negative in 66.7% of possible/non-IA cases. ELISpot shows promises in the diagnosis of IA and the possibility to use two distinct cut-offs with similar diagnostic performances according to patients' different pre-test probability of infection can widen its use in patients at risk.

Quantitative Risk Assessment of Wind-Supported Transmission of Highly Pathogenic Avian Influenza Virus to Dutch Poultry Farms via Fecal Particles from Infected Wild Birds in the Environment.

A quantitative microbial risk assessment model was developed to estimate the probability that the aerosolization of fecal droppings from wild birds in the vicinity of poultry farms would result in the infection of indoor-housed poultry with highly pathogenic avian influenza virus (HPAIv) in the Netherlands. Model input parameters were sourced from the scientific literature and experimental data. The availability of data was diverse across input parameters, and especially parameters on the aerosolization of fecal droppings, survival of HPAIv and dispersal of aerosols were uncertain. Model results indicated that the daily probability of infection of a single poultry farm is very low, with a median value of 7.5 × 10-9. Accounting for the total number of poultry farms and the length of the bird-flu season, the median overall probability of at least one HPAIv-infected poultry farm during the bird-flu season is 2.2 × 10-3 (approximately once every 455 years). This is an overall estimate, averaged over different farm types, virus strains and wild bird species, and results indicate that uncertainty is relatively high. Based on these model results, we conclude that it is unlikely that this introduction route plays an important role in the occurrence of HPAIv outbreaks in indoor-housed poultry.

Haemaphysalis longicornis (Acari: Ixodidae) does not transmit Babesia bovis, a causative agent of cattle fever

The Asian longhorned tick (Haemaphysalis longicornis) was first reported in the United States in 2017 and has since been detected in at least 17 states. This tick infests cattle and can produce large populations quickly due to its parthenogenetic nature, leading to significant livestock mortalities and economic losses. While H. longicornis has not been detected in Texas, species distribution models have identified southern Texas as a possible hospitable region for this tick. Southern Texas is currently home to the southern cattle tick (Rhipicephalus microplus), which can transmit the causative agent of cattle fever (Babesia bovis). With the potential for H. longicornis and B. bovis to overlap in southern Texas and their potential to negatively impact the national and global livestock industry, it is imperative to identify the role H. longicornis may play in the cattle fever disease system. A controlled acquisition and transmission experiment tested whether H. longicornis is a vector for B. bovis, with the R. microplus-B. bovis system used as a positive control. Transstadial (nymphs to adults) and transovarial (adults to larvae) transmission and subsequent transstadial maintenance (nymphs and adults) routes were tested in this study. Acquisition-fed, splenectomized animals were used to increase the probability of tick infection. Acquisition nymphs were macerated whole and acquisition adults were dissected to remove midguts and ovaries at five time points (4, 6, 8, 10, and 12 days post-repletion), with 40 ticks processed per time point and life stage. The greatest percentage of nymphs with detectable B. bovis DNA occurred six days post-repletion (20.0 %). For adults, the percentage of positive midguts and ovaries increased as days post-repletion progressed, with day 12 having the highest percentage of positive samples (67.5 % and 60.0 %, respectively). When egg batches were tested in triplicate, all H. longicornis egg batches were negative for B. bovis, while all R. microplus egg batches were positive for B. bovis. During the transmission phase, the subsequent life stages for transstadial (adults) and transovarial transmission/transstadial maintenance (larvae, nymphs, and adults) were fed on naïve, splenectomized calves. All life stages of H. longicornis ticks tested during transmission were negative for B. bovis. Furthermore, the transmission fed animals were also negative for B. bovis and did not show signs of bovine babesiosis during the 45-day post tick transmission period. Given the lack of successful transstadial or transovarial transmission, it is unlikely that H. longicornis is a vector for B. bovis.