Control Disease Transmission Research Articles

Global Dynamics of SIRS Model with No Full Immunity on Semidirected Networks

In this paper, an epidemic model with no full immunity is analyzed on semidirected networks. Directed networks led into previous scale-free networks, and we consider that some infectious diseases do not have full immunity. So we use strong self-protection instead of immunity and establish a semidirected network infectious disease model without full immunity. The basic reproduction number R0 is calculated. If R0<1, the disease-free equilibrium E0 is locally and globally asymptotically stable. And the endemic equilibrium E∗ is globally asymptotically stable in some condition. A large number of simulation results in this paper verify the correctness of the above conclusions and provide a solution for controlling disease transmission in the future.

Prevalence and associated factors for needlestick and sharp injuries (NSIs) among dental assistants in Jeddah, Saudi Arabia

BackgroundDental personnel are subject to exposure to a number of occupational factors including needlestick and sharp injuries (NSIs). Our study aims to address knowledge gaps on prevalence and associated factors for needlestick and sharp injuries (NSIs) for the first time in Saudi Arabia.MethodsThis cross-sectional study was conducted on a sample of 450 dental assistants recruited from 40 randomly selected private clinics in Jeddah, Saudi Arabia. Data on demographic characteristics, history of NSIs, nature of work, compliance with infection control protocols, and knowledge of infection control procedures and disease transmission were collected using a self-administered questionnaire. Logistic regression analysis was used to assess factors associated with NSIs; unadjusted and adjusted odds ratios (aORs) and their respective 95% confidence intervals (CIs) were computed.ResultsAbout three in ten dental assistants experienced at least one NSI (29.8%, 95% CI 25.6–34.2%) in private dental clinics. Lack of adequate knowledge of infection control procedures and disease transmission, non-compliance with infection control protocol of vaccination against hepatitis B virus, and attending 12 or less number of patients daily were significantly associated with increased risk of NSIs (p ≤ 0.05); adjusted odds ratios (95% CI) were 1.87 (1.18–2.97), 1.89 (1.05–3.41), and 1.63 (1.03–2.56), respectively. In addition, dental assistants working in 45.8% of dental clinics that had no infection control unit were positively associated with higher NSI risk (aOR = 2.28, 95% CI 1.45–3.57).ConclusionOur study reported the prevalent nature of NSIs among dental assistants in Saudi Arabia and identified key factors that could be targeted to mitigate this preventable condition. Dental assistants would benefit from proper training on infection control protocols and procedures.

Rising threat of H1N1 Cases in Dakshina Kannada, India: An Epidemiological Assessment from January 2011 To August 2017

Background: H1N1 or swine flu is a disease caused my influenza virus of family Orthomyxoviridae. Initial cases in India were seen in 2009 and ever since then it has been adding to the mortality rate over the years across various parts of the country. Dakshina Kannada district of Karnataka, India, had several cases of H1N1. But despite the efforts, the magnitude is rising inconspicuously. Aim & Objective: Assessment of H1N1 cases throughout Dakshina Kannada district from Jan 2011 to August 2017. Objectives: To observe the disease trend, its factors and provide certain recommendations to control the disease and promote Health. Material & Methods:H1N1 cases notified to District surveillance unit from all the Health collaborated settings over a period of six years from January 2011 to August 2017 were assessed to measure the burden of the disease across different age groups and Gender. Result: The study revealed a considerable increase in H1N1 cases compared to previous years with peak during monsoon and difference in risk among the gender. Conclusion: Vaccination of Health professionals, High alert for travelers, Pregnant women and individuals with co-morbid conditions is essential. Control of disease transmission with early diagnosis, isolation and treatment, effective vaccination to high risk individuals will be helpful to reduce disease burden

Factors Affecting Indonesian Nurse Behavior in Applying Universal Precaution

Professional nurses in carrying out their roles and functions on a daily basis, are always at risk of contacting various diseases. Transmission of the disease can occur via direct or indirect contact, transmission can be through droplet transmission, and airborne transmission (CDC). Universal precautions are one of the strategies that have been recommended by the Centers for Disease Control and Prevention (CDC) in efforts to control infection and disease transmission in health facilities, such as hospitals, doctors' practices, and other health care centers. The purpose of the study was to determine the factors that influence the behavior of Indonesian nurses in implementing universal precaution in the Center for Health Services in Qatar. The research process was carried out in October 2011 in Qatar with a total sampling method, a total sample of 52 respondents. The results showed that most Indonesian nurses in Qatar with a Diploma in Nursing, had work experience of more than 6 years. Placed in various locations such as; ambulance services, company clinics and hospitals. There was no significant relationship between knowledge and nurses behavior in applying Universal Precaution (p <0.05). There was no significant relationship between attitude and behavior of Indonesian nurses in implementing Universal Precaution (p <0.05). There was no significant relationship between motivation and the behavior of Indonesian nurses in implementing Universal Precaution (p <0.05). There was a significant relationship (p <0.05) between the means and the behavior of Indonesian nurses in implementing Universal Precaution. Based on these results it is necessary to maintain the consistency of nurses to always apply universal precaution appropriately according to the patient's condition at hand

An association of Orf virus infection among sheep and goats with herd health programme in Terengganu state, eastern region of the peninsular Malaysia

BackgroundOrf virus causes a scabby skin lesions which decreases productivity in small ruminants. The unknown status of this disease in the eastern region of Peninsular Malaysia warrants a study to determine sero-prevalence of orf with regards to farmers’ compliance level towards the Herd Health Program (HHP) programme.ResultsOut of 504 animals, 115 were positive for Orf-virus antibodies. An overall prevalence rate of 22.8% indicated a high prevalence of orf disease in this region. It was observed that 25.1% (92/367) of goats were positive and 16.8% (23/137) of sheep sero-converted for Orf virus antibody. Several factors were measured for their possible association with prevalence of Orf virus infection. The prevalence was higher in LY farm, JC breed, kid and female animals, and in the presence of disease lesion. Chi-square analysis showed a significant association of three risk factors which are species, age and sex of the animals (P < 0.05). Notwithstanding, all other variables showed no significant difference (P > 0.05). Farms surveyed usually practised intensive management system, keeping animals in the shade at all time, due to limited availability of suitable land as a free-range grazing area. An interview with small holder farmers revealed a lack of awareness of the main goals of herd health programme. An overall compliance level of 42.7% was observed for all HHP parameters. Among the 14 main components of HHP modules, animal identification had recorded highest compliance level (84.62%) while milking management recorded the least compliance (− 82.69%). That explained why there was a high sporadic prevalence of Orf infection in this region.ConclusionGood herd health supervision is a rehearsal target to prevent an outbreak and the spread of diseases thus reduces economic losses among farmers. Therefore, a good herd health programme should be in place, in order to prevent and control disease transmission as well as to improve herd immunity.

Bacteria detected in the genital tract, semen or pre-ejaculatory fluid of Swedish stallions from 2007 to 2017

BackgroundAlthough artificial insemination (AI) was developed as a means of controlling disease transmission, pathogens can still be transmitted to females in semen used for AI. In addition, bacteria can cause deterioration in sperm quality during storage. Semen becomes contaminated by the male’s normal bacterial flora as it passes out of the reproductive tract but potential pathogens may also contaminate the semen. Therefore, semen samples from stallions to be used for AI are tested before the breeding season to minimize transmission of pathogens to inseminated mares. In Sweden, semen samples are tested at the National Veterinary Institute, Uppsala (SVA). For the present study, a retrospective analysis was made of potentially pathogenic bacteria isolated from samples submitted to the SVA from 2007 to 2017.ResultsIn our study, Taylorella equigenitalis was found infrequently (53 out of 25,512 samples), representing 11 out of 2308 stallions. If T. equigenitalis was detected, the stallions were treated with antibiotics and re-tested later in the same year. Klebsiella pneumoniae and beta haemolytic streptococci were the most commonly found potential pathogens, whereas Pseudomonas aeruginosa was also isolated occasionally. There were considerable differences in the number of species isolated each year.ConclusionsPotential pathogens were identified in relatively few of the samples submitted to SVA during this period, with T. equigenitalis not being identified since 2015. Of the other potential pathogens, K. pneumoniae and beta haemolytic streptococci were the most common. The information is relevant for determining guidelines on the testing and treatment of stallions before breeding.

Identification through Culture and Molecular Methods of Campylobacter jejuni, Campylobacter coli and Campylobacter fetus in Surface Waters in Rasht

Backgrounds: As zoonotic infectious agents, Campylobacter spp. are important factors causing gastroenteritis in humans. Surveys show that the three strains; Campylobacter jejuni, Campylobacter coli and Campylobacter fetus play a major role in human infections. Identification of these infectious agents is valuable for sanitary control of disease transmission through water resources.&#x0D; Objectives: The aim of this study was identification and molecular diagnosis of Campylobacter jejuni, Campylobacter coli and Campylobacter fetus in surface waters in Rasht.&#x0D; Materials and Methods: This cross-sectional study was conducted on 45 samples of surface water in Rasht collected according to water health guidelines. After culture and biochemical tests on collected samples, detection and identification of Campylobacter jejuni, Campylobacter coli and Campylobacter fetus was done using sequence-specific amplification by Multiplex PCR. The results were subjected to statistical analysis using SPSS software.&#x0D; Results: Out of 45 samples tested, 6 were positive in culture, four of which were identified as Campylobacter jejuni after biochemical tests. Using Multiplex PCR, 8 samples were positive, from which 3 were Campylobacter jejuni, 1 Campylobacter coli and 4 were positive for both Campylobacter jejuni and Campylobacter coli. All the samples did not yield C. fetus.&#x0D; Conclusions: Multiplex PCR is regarded a diagnostic method with higher sensitivity and specificity than compared to methods for Campylobacter. The prevalence of Campylobacter jejuni and Campylobacter coli in surface waters in Rasht is considerable. Therefore, public health measures for the control of these organisms are recommended.

Contrasting Patterns of Virus Protection and Functional Incompatibility Genes in Two Conspecific Wolbachia Strains from Drosophila pandora.

Wolbachia infections can present different phenotypes in hosts, including different forms of reproductive manipulation and antiviral protection, which may influence infection dynamics within host populations. In populations of Drosophila pandora two distinct Wolbachia strains coexist, each manipulating host reproduction: strain wPanCI causes cytoplasmic incompatibility (CI), whereas strain wPanMK causes male killing (MK). CI occurs when a Wolbachia-infected male mates with a female not infected with a compatible type of Wolbachia, leading to nonviable offspring. wPanMK can rescue wPanCI-induced CI but is unable to induce CI. The antiviral protection phenotypes provided by the wPanCI and wPanMK infections were characterized; the strains showed differential protection phenotypes, whereby cricket paralysis virus (CrPV)-induced mortality was delayed in flies infected with wPanMK but enhanced in flies infected with wPanCI compared to their respective Wolbachia-cured counterparts. Homologs of the cifA and cifB genes involved in CI identified in wPanMK and wPanCI showed a high degree of conservation; however, the CifB protein in wPanMK is truncated and is likely nonfunctional. The presence of a likely functional CifA in wPanMK and wPanMK's ability to rescue wPanCI-induced CI are consistent with the recent confirmation of CifA's involvement in CI rescue, and the absence of a functional CifB protein further supports its involvement as a CI modification factor. Taken together, these findings indicate that wPanCI and wPanMK have different relationships with their hosts in terms of their protective and CI phenotypes. It is therefore likely that different factors influence the prevalence and dynamics of these coinfections in natural Drosophila pandora hosts.IMPORTANCEWolbachia strains are common endosymbionts in insects, with multiple strains often coexisting in the same species. The coexistence of multiple strains is poorly understood but may rely on Wolbachia organisms having diverse phenotypic effects on their hosts. As Wolbachia is increasingly being developed as a tool to control disease transmission and suppress pest populations, it is important to understand the ways in which multiple Wolbachia strains persist in natural populations and how these might then be manipulated. We have therefore investigated viral protection and the molecular basis of cytoplasmic incompatibility in two coexisting Wolbachia strains with contrasting effects on host reproduction.

Uncovering mechanisms behind mosquito seasonality by integrating mathematical models and daily empirical population data: Culex pipiens in the UK

BackgroundMany mosquito-borne diseases exhibit substantial seasonality, due to strong links between environmental variables and vector and pathogen life-cycles. Further, a range of density-dependent and density-independent biotic and abiotic processes affect the phenology of mosquito populations, with potentially large knock-on effects for vector dynamics and disease transmission. Whilst it is understood that density-independent and density-dependent processes affect seasonal population levels, it is not clear how these interact temporally to shape the population peaks and troughs. Due to this, the paucity of high-resolution data for validation, and the difficulty of parameterizing density-dependent processes, models of vector dynamics may poorly estimate abundances, which has knock-on effects for our ability predict vector-borne disease outbreaks.ResultsWe present a rich dataset describing seasonal abundance patterns of each life stage of Culex pipiens, a widespread vector of West Nile virus, at a field site in southern England in 2015. Abundance of immature stages was measured three times per week, whilst adult traps were run four nights each week. This dataset is integrated with an existing delay-differential equation model predicting Cx. pipiens seasonal abundance to improve understanding of observed seasonal abundance patterns. At our field site, the outcome of our model fitting suggests interspecific predation on mosquito larvae and temperature-dependent larval mortality combine to act as the main sources of population regulation throughout the active season, whilst competition for resources is a relatively small source of larval mortality.ConclusionsThe model suggests that density-independent mortality and interspecific predation interact to shape patterns of mosquito seasonal abundance in a permanent aquatic habitat and we propose that competition for resources is likely to be important where periods of high rainfall create transient habitats. Further, we highlight the importance of challenging population abundance models with data from across all life stages of the species of interest if reliable inferences are to be drawn from these models, particularly when considering mosquito control and vector-borne disease transmission.

A periodic SEIRS epidemic model with a time-dependent latent period.

Many infectious diseases have seasonal trends and exhibit variable periods of peak seasonality. Understanding the population dynamics due to seasonal changes becomes very important for predicting and controlling disease transmission risks. In order to investigate the impact of time-dependent delays on disease control, we propose an SEIRS epidemic model with a periodic latent period. We introduce the basic reproduction ratio [Formula: see text] for this model and establish a threshold type result on its global dynamics in terms of [Formula: see text]. More precisely, we show that the disease-free periodic solution is globally attractive if [Formula: see text]; while the system admits a positive periodic solution and the disease is uniformly persistent if [Formula: see text]. Numerical simulations are also carried out to illustrate the analytic results. In addition, we find that the use of the temporal average of the periodic delay may underestimate or overestimate the real value of [Formula: see text].

Enabling rapid intervention and isolation for patients with highly infectious diseases at points of need

The 2014–2015 Ebola virus disease (EVD) epidemic in West Africa proved unequivocally the need for immediate intervention to control disease transmission. The efforts of the World Health Organization (WHO), Center for Disease Control and Prevention (CDC), United Nations (UN), UNISEF, United States Agency for International Development (USAID) and Liberian Ministry of Health and Social Welfare (MOHSW), while initially slow to respond, helped quell the EVD epidemic.

PubMLST for Antigen Allele Mining to Inform Development of Gonorrhea Protein-Based Vaccines.

Neisseria gonorrhoeae (Ng) is a human-specific pathogen and the etiological agent of gonorrhea, a sexually transmitted infection with a significant global health burden. While often asymptomatic, untreated gonorrhea can lead to pelvic inflammatory disease, ectopic pregnancy, infertility, and increased transmission/acquisition of HIV. A protective gonorrhea vaccine may be the only way to control disease transmission in the future due to the inexorable development of antibiotic resistance. Subunit antigens are proven candidates for vaccine development due to their safety, cost-effectiveness, and rapid preparation. To inform protein-based gonorrhea vaccine design by including different antigen variants, herein we present bioinformatics mining of alleles and single nucleotide/amino acid polymorphisms using DNA/protein sequences of all Ng isolates deposited into the PubMLST database and MtrE and BamA as model antigens. We also present phylogenetic analyses that can be performed using sequence data to gain insights into the evolutionary relationships between the polymorphisms found among the population of isolates using a convenient tool: Molecular Evolutionary Genetics Analysis (MEGA) software. Finally, we perform antigen polymorphism mapping onto the MtrE and BamA structures. This methodology can be applied for rational vaccine design to increase vaccine coverage and cross-protection by heteroligand presentation achieved via inclusion of diverse antigen variants and is relevant to over 100 different species and genera deposited into the PubMLST family of databases.

The epidemic spreading on the multi-relationships network

Different from traditional multi-community, the paper proposes a new multi-relationship network which is constructed to assess the effect of interlaced complex interpersonal relationships on the epidemic spreading process. Besides, an innovative MR-SIS epidemic model is proposed and analyzed in this paper. Empirically, we simulate MR-SIS spreading process on a multi-relationship network. The experiment results show that immunizing the nodes in overlapping sub-networks inhibits the epidemic spreading. Moreover, when considering the multi-relationship network structure and the above conclusion, this paper proposes a novel immunization to overcome the limitations of traditional immunization strategy, which has been proven a satisfying desirable performance on controlling disease transmission.

Prevalence and risk factors associated with leishmania infection in Trang Province, Southern Thailand

Background Autochthonous cutaneous and visceral leishmaniasis caused by Leishmania martiniquensis and Leishmania siamensis have been considered emerging infectious diseases in Thailand. The disease burden is significantly underestimated, especially the prevalence of Leishmania infection among HIV-positive patients. Methods A cross-sectional study was conducted to determine the prevalence and risk factors associated with Leishmania infection among patients with HIV/AIDS living in Trang Province, southern Thailand between 2015 and 2016. Antibodies against Leishmania infection were assayed using the direct agglutination test (DAT). DNA of Leishmania was detected by ITS1-PCR using the buffy coat. Species of Leishmania were also identified. Results Of 724 participants, the prevalence of Leishmania infection was 25.1% (182/724) using either DAT and/or PCR assays. Seroprevalence of Leishmania infection was 18.5% (134/724), while Leishmania DNA detected by PCR method was 8.4% (61/724). Of these, 24.9% (180/724) were asymptomatic, whereas 0.3% (2/724) were symptomatic VL and VL/CL. At least five species were identified, that is, L siamensis, L. martiniquensis, L. donovani complex, L. lainsoni, and L. major. Multivariate analysis showed that CD4+ levels Conclusions A magnitude of prevalence of underreporting Leishmania infection among Thai patients with HIV was revealed in this study. Effective public health policy to prevent and control disease transmission is urgently needed.

Survival of the Enveloped Virus Phi6 in Droplets as a Function of Relative Humidity, Absolute Humidity, and Temperature.

ABSTRACTInfectious diseases caused by enveloped viruses, such as influenza, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS), cause thousands of deaths and billions of dollars of economic losses per year. Studies have found a relationship among temperature, humidity, and influenza virus incidence, transmission, or survival; however, there are contradictory claims about whether absolute humidity (AH) or relative humidity (RH) is most important in mediating virus infectivity. Using the enveloped bacteriophage Phi6, which has been suggested as a surrogate for influenza viruses and coronaviruses, we designed a study to discern whether AH, RH, or temperature is a better predictor of virus survival in droplets. Our results show that Phi6 survived best at high (>85%) and low (<60%) RHs, with a significant decrease in infectivity at mid-range RHs (∼60 to 85%). At an AH of less than 22 g · m−3, the loss in infectivity was less than 2 orders of magnitude; however, when the AH was greater than 22 g · m−3, the loss in infectivity was typically greater than 6 orders of magnitude. At a fixed RH of 75%, infectivity was very sensitive to temperature, decreasing two orders of magnitude between 19°C and 25°C. We used random forest modeling to identify the best environmental predictors for modulating virus infectivity. The model explained 83% of variation in Phi6 infectivity and suggested that RH is the most important factor in controlling virus infectivity in droplets. This research provides novel information about the complex interplay between temperature, humidity, and the survival of viruses in droplets.IMPORTANCE Enveloped viruses are responsible for a number of infectious diseases resulting in thousands of deaths and billions of dollars of economic losses per year in the United States. There has been a lively debate in the literature over whether absolute humidity (AH) or relative humidity (RH) modulates virus infectivity. We designed a controlled study and used advanced statistical modeling techniques specifically to address this question. By providing an improved understanding of the relationship between environmental conditions and virus infectivity, our work will ultimately lead to improved strategies for predicting and controlling disease transmission.

Assessing Biosecurity Risks for the Introduction and Spread of Diseases Among Commercial Sheep Properties in New South Wales, Australia, Using Foot-and-Mouth Disease as a Case Study.

Sheep production systems are a major industry in Australia, with a gross value of roughly $4.66 billion; 87.3% of which is attributable to export markets. Exotic diseases such as foot-and-mouth disease (FMD) are a potential threat to the viability of Australia’s export market. Previous outbreaks of FMD in developed countries, and challenges in the management of onshore biosecurity, signify the importance of on-farm biosecurity in controlling disease transmission. This study aims to investigate the risk of disease introduction and spread among New South Wales (NSW) sheep properties using FMD as a case study and draw recommendation for the industry. Exposure and partial consequence assessments, using scenario trees and Monte Carlo stochastic modeling, were conducted to identify pathways of introduction and spread and calculate the probabilities of these pathways occurring. Input parameters were estimated from the data obtained during qualitative interviews with producers and scientific literature. According to the reported practices of sheep producers and assuming each pathway was carrying the FMD virus, the exposure assessment estimates the median (5–95%) probability of FMD exposure of sheep on a naive property to be 0.619 (0.541–0.698), 0.151 (0.085–0.239), 0.235 (0.153–0.324), and 0.710 (0.619–0.791) for introduction through new stock, wildlife, carriers (humans, dogs, and vehicles), and neighbors, respectively. The spread assessment estimated the median probability of FMD spreading from an infected sheep property to neighboring enterprises to be 0.603 (0.504–0.698). A similar probability was estimated for spread via wildlife (0.523; 0.404–0.638); and a lower spread probability was estimated for carriers (0.315; 0.171–0.527), sheep movement (0.285; 0.161–0.462), and dead stock (0.168; 0.070–0.312). The sensitivity analysis revealed that the introduction of an FMD-infected sheep was more influential for exposure via new stock than isolation practices. Sharing adjacent boundaries was found to be the most influential factor for exposure and spread between neighboring enterprises, and to a lesser extent, hygiene practices were found to have the most influence on exposure and spread through carriers. To minimize the potential risk of FMD introduction and spread between sheep properties, maintenance of boundary fences, identification of infected animals before introduction to the property, and hygiene and disinfection practices should be improved.

Out of Asia: the independent rise and global spread of fluoroquinolone-resistant Shigella.

Shigella are ranked among the most prevalent aetiologies of diarrhoeal disease worldwide, disproportionately affecting young children in developing countries and high-risk communities in developed settings. Antimicrobial treatment, most commonly with fluoroquinolones, is currently recommended for Shigella infections to alleviate symptoms and control disease transmission. Resistance to fluoroquinolones has emerged in differing Shigella species (S. dysenteriae, flexneri and sonnei) since the turn of the 21st century, originating in endemic areas, and latterly spreading into non-endemic regions. Despite occurring independently, the emergence of fluoroquinolone resistance in these different Shigella species shares striking similarities regarding their epidemiology and resistance mechanisms. Here, we review and discuss the current epidemiology of fluoroquinolone-resistant Shigella species, particularly in the light of recent genomic insights.

Detailed ecological associations of triatomines revealed by metabarcoding and next-generation sequencing: implications for triatomine behavior and Trypanosoma cruzi transmission cycles

Trypanosoma cruzi is the agent of Chagas disease, transmitted by hematophagous triatomine vectors. Establishing transmission cycles is key to understand the epidemiology of the disease, but integrative assessments of ecological interactions shaping parasite transmission are still limited. Current approaches also lack sensitivity to assess the full extent of this ecological diversity. Here we developed a metabarcoding approach based on next-generation sequencing to identify triatomine gut microbiome, vertebrate feeding hosts, and parasite diversity and their potential interactions. We detected a dynamic microbiome in Triatoma dimidiata, including 23 bacterial orders, which differed according to blood sources. Fourteen vertebrate species served as blood sources, corresponding to domestic, synantropic and sylvatic species, although four (human, dog, cow and mice) accounted for over 50% of blood sources. Importantly, bugs fed on multiple hosts, with up to 11 hosts identified per bug, indicating very frequent host-switching. A high clonal diversity of T. cruzi was detected, with up to 20 haplotypes per bug. This analysis provided much greater sensitivity to detect multiple blood meals and multiclonal infections with T. cruzi, which should be taken into account to develop transmission networks, and characterize the risk for human infection, eventually leading to a better control of disease transmission.

Cytokine and Chemokine Profiling in Patients with Hand, Foot and Mouth Disease in Singapore and Malaysia

Hand, foot and mouth disease (HFMD) is a prevalent contagious childhood disease typically associated with fever, oral lesions and limb exanthema. While HFMD is caused by a plethora of serotypes of viruses under the genus Enterovirus within the Picornaviridae family, Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-A71) are considered the main etiological agents. In recent years however, other viruses have also been isolated in considerable numbers from infected individuals in many regions, joining the legion commonly associated with HFMD. The present study investigated the cytokine and chemokine profiles of HFMD patients from Singapore and Malaysia for the first time. Comparative cohort studies of EV-A71-associated HFMD cases revealed that the Malaysia cohort had a distinct profile from the Singapore cohort, and this could be partly attributed by different EV-A71 genotypes. As the isolation of CV-A6, instead of CV-A16, had become prevalent in the Singapore cohort, it was also of particular interest to study the differential cytokine and chemokine profiles. Our data revealed that overlapping as well as unique profiles exist between the two major causative clinical isolates in the Singapore cohort. Having a better understanding of the respective immunological profiles could be useful for more accurate HFMD diagnosis, which is imperative for disease transmission control until multi-valent vaccines and/or broad-spectrum anti-viral drugs become available.

Global Dynamic Analysis of a Vector-Borne Plant Disease Model with Discontinuous Treatment

This paper proposes a vector-borne plant disease model with discontinuous treatment strategies. Constructing Lyapunov function and applying non-smooth theory to analyze discontinuous differential equations, the basic reproductive number R0 is proved, which determines whether the plant disease will be extinct or not. If R0 R0 > 1 , there exists a unique endemic equilibrium which is globally stable. The numerical simulations are provided to verify our theoretical results, which indicate that after infective individuals reach some level, strengthening treatment measures is proved to be beneficial in controlling disease transmission.