牛传染性角膜结膜炎科学防治措施

随着近些年来我国经济的快速发展,人们对于家畜产品的需求量不断提升,同时相关要求也在不断升高。这种情况的出现在很大程度上促进了我国家畜养殖业的发展。其中,牛作为我国传统的家畜养殖种类,在近些年的养殖过程中为广大养殖者带来了较大的经济效益。但是,在实际养殖过程中不可避免的会出现各种疾病,影响养殖效果。本文将就牛传染性角膜芥末炎的防治工作进行研究。

Epidemic Spreading Model Based on Social Active Degree in Social Networks

In this paper,an improved Susceptible-Infected-Susceptible(SIS) epidemic spreading model is proposed in order to provide a theoretical method to analyze and predict the spreading of diseases.This model is based on the following ideas:in social networks,the contact probability between nodes is decided by their social distances and their active degrees.The contact probability of two indirectly connected nodes is decided by the shortest path between them.Theoretical analysis and simulation experiment were conducted to evaluate the performance of this improved model.Because the proposed model is independent of the network structure,simulation experiments were done in several kinds of networks,namely the ER network,the random regular network,the WS small world network,and the BA scale-free network,in order to study the influences of certain factors have on the epidemic spreading,such as the social contact active degree,the network structure,the average degree,etc.This improved model provides an idea for studying the spreading rule of computer virus,attitudes,fashion styles and public opinions in social networks.

Hepatitis B and C virus co-infections in human immunodeficiency virus positive North Indian patients

AIM： To determine the prevalence of hepatitis B and C virus infections in human immunodeficiency virus （HIV） -positive patients at a tertiary care hospital in New Delhi, India. METHODS： Serum samples from 451 HIV positive patients were analyzed for HBsAg and HCV antibodies during three years （Jan 2003-Dec 2005）. The control group comprised of apparently healthy bone-marrow and renal donors. RESULTS： The study population comprised essentially of heterosexually transmitted HIV infection. The prevalence Fate of HBsAg in this population was 5.3% as compared to 1.4% in apparently healthy donors （P 〈 0.001）. Though prevalence of HCV co-infection （2.43%） was lower than HBV in this group of HIV positive patients, the prevalence was significantly higher （P 〈 0.05） than controls （0.7%）. Triple infection of HIV, HBV and HCV was not detected in any patient. CONCLUSION： Our study shows a significantly high prevalence of hepatitis virus infections in HIV infected patients. Hepatitis viruses in HIV may lead to faster progression to liver cirrhosis and a higher risk of antiretroviral therapy induced hepatotoxicity. Therefore, it would be advisable to detect hepatitis virus coinfections in these patients at the earliest.

Detection of HBsAg, HBcAg, and HBV DNA in ovarian tissues from patients with HBV infection

AIM: To investigate the presence of HBsAg, HBcAg, and HBV DNA in ovarian tissues from patients with HBV infection.METHODS: HBsAg and HBcAg were examined in ovarian biopsy tissues from 26 patients with HBV infection by immunocytochemistry, and HBV DNA was detected in ovarian tissues by PCR.RESULTS: HBsAg and HBcAg were present with the same positive rate of 34.6% (9/26). The total positive rate was 46.2% (12/26). HBsAg and HBcAg were positive in 6 (23.1%) of the 26 patients. Brown positive particles were diffusely distributed in ovarian cells. The positive rate of HBV DNA was 58.3% (7/12).CONCLUSION: HBsAg, HBcAg, and HBV DNA can be detected in ovarian tissues from patients with HBV infection. The presence of HBsAg and HBcAg in ovarian tissues does not correlate with the HBV markers in serum.

Risk factors for the recurrence of hepatocellular carcinoma after radiofrequency ablation of hepatocellular carcinoma in patients with hepatitis C

AIM: To analyze the risk factors of hepatocellular carcinoma (HCC) recurrence after radiofrequency ablation (RFA) treatment with HCV-associated hepatitis. METHODS: Twenty-six patients with HCV-associated HCC who were followed-up for more than 12 mo were selected for this study. Risk factors for distant intrahepatic recurrences of HCC were evaluated for patients in whom complete coagulation was achieved without recurrence in the same subsegment as the primary nodule. Twelve clinical and tumoral factors were examined: Age, gender, nodule diameter, number of primary HCC nodule, Child-Pugh classification, serum platelet, serum albumin, serum AST, post RFA AST, serum ALT, post RFA ALT, post RFA treatment.RESULTS: Distant recurrences of HCC in remnant liver after RFA were observed in 14 cases and in the number of primary HCC nodules (P = 0.047), and the serum platelets (P = 0.030), the clear difference came out by the recurrence group and the non-recurrence group. The cumulative recurrence rates after 1 and 2 years were30.8% and 86.8%, respectively for primary multinodular HCC, and 15.4% and 29.5% respectively, for primary uninodular HCC. In addition the 1-year recurrence rates for patients with serum albumin more than 3.4 g/dL and less than 3.4 g/dL were 23.1% for both, but the 2-years recurrence rates were 89.0% and 23.1%, respectively. The number of primary HCC nodules (relative risk, 6.970; P = 0.016) were found to be a statistically significant predictor for poor distant intrahepatic recurrence by univariate analysis.CONCLUSION: Patients who have multiple HCC nodules, low serum platelets and low serum albumin accompanied by HCV infection, should be carefully followed because of the high incidence of new HCC lesions in the remnant liver, even if coagulation RFA is complete.

A META-analysis of the association between breastfeeding and risk of infant hepatitis C virus infection

Objective: To investigate the association between breastfeeding and infant acquired infection of Hepatitis C Virus(HCV). Methods: To obtain studies eligible for META-analysis, China biological medicine discs(CBMD) and MEDLINE citations were surveyed. Criteria for enrollment of published studies for META-analysis were based on principle by Abdolmaleky HM[1]. Odd ratio(OR) was calculated and summarized by fixed effect model or random effects using RevMan software. The heterogeneity of ORs was assessed using an χ2 test of goodness of fit. The significance of the pooled OR was determined by the z-test. The strength of association was summarized usingOR. An OR>1.0 indicated a positive association between the risk factor and infants HCV infection. Results:After searching in Medline and CBMD, 120 articles were enrolled for further identification. Thirty-seven were of review on relative fields and were excluded. Abstracts of remaining articles were carefully read, and finally, only 6 articles met, the standards for enrollment criteria. After analysis of the factor concerned, no significant association was found between breastfeeding and infant HCV infection, with a pooled OR equal to 0.60(95%CI = 0.22-1.60), and proved not to be of risk factors on infant acquired infection of HCV. Conclusion: Breastfeeding dose not increase the risk of infant acquired infection of HCV.

Targeting mitochondrial phenotypes for non-communicable diseases

The concept that ＂Exercise is Medicine＂ has been challenged by the rising prevalence of non-communicable chronic diseases （NCDs）. This is partly due to the fact that the underlying mechanisms of how exercise influences energy homeostasis and counteracts high-fat diets and physical inactivity is complex and remains relatively poorly understood on a molecular level. In addition to genetic polymorphisms in humans that lead to gross variations in responsiveness to exercise, adaptation in mitochondrial networks is central to physical activity, inactivity, and diet. To harness the benefits of exercise for NCDs, much work still needs to be done to improve health effectively on a societal level such as developing personalized exercise interventions aided by advances in high-throughput genomics, proteomics, and metabolomics. We propose that understanding the mitochondrial phenotype according to the molecular information of genotypes, lifestyles, and exercise responsiveness in individuals will optimize exercise effects for prevention of NCDs.

Global asymptotic stability for a SEI reaction-diffusion model of infectious diseases with immigration

This paper studies the local and global stability of solutions for a spatially spread SEI epidemic model with immigration of individuals using a Lyapunov functional. It is shown that in the presence of diffusion, the unique steady state remains globally stable. Numerical results obtained through Matlab simulations are presented to confirm the findings of this study.

A MULTI-GROUP SVEIR EPIDEMIC MODEL WITH DISTRIBUTED DELAY AND VACCINATION

In this paper, based on a class of multi-group epidemic models of SEIR type with bilinear incidences, we introduce a vaccination compartment, leading to multi-group SVEIR model. We establish that the global dynamics are completely determined by the basic reproduction number R0V which is defined by the spectral radius of the next generation matrix. Our proofs of global stability of the equilibria utilize a graph-theoretical approach to the method of Lyapunov functionals. Mathematical results suggest that vaccination is helpful for disease control by decreasing the basic reproduction number. However, there is a necessary condition for successful elimination of disease. If the time for the vaccines to obtain immunity or the possibility for them to be infected before acquiring immunity is neglected in each group, this condition will be satisfied and the disease can always be eradicated by suitable vaccination strategies. This may lead to over evaluation for the effect of vaccination.

Permanence and extinction for a nonautonomous schistosomiasis model with saturation incidence rate

In the real world, quite a few infectious diseases like schistosomiasis spread seasonally. In this paper, a nonautonomous schistosomiasis system is established, in which the saturation incidence rate and the coefficients varying with time are taken into account. The long-time behavior of the model is studied. Under quite weak assumptions, sufficient conditions for the permanence and extinction of infectious population of disease are obtained. Finally, numerical simulations illustrate the validity of our results.

TWO TYPES OF CONDITION FOR THE GLOBAL STABILITY OF DELAYED SIS EPIDEMIC MODELS WITH NONLINEAR BIRTH RATE AND DISEASE INDUCED DEATH RATE

We study global asymptotic stability for an SIS epidemic model with maturation delay proposed by K. Cooke, P. van den Driessche and X. Zou, Interaction of maturation delay and nonlinear birth in population and epidemic models, J. Math. Biol. 39（4） （1999） 332-352. It is assumed that the population has a nonlinear birth term and disease causes death of infective individuals. By using a monotone iterative method, we establish sufficient conditions for the global stability of an endemic equilibrium when it exists dependently on the monotone property of the birth rate function. Based on the analysis, we further study the model with two specific birth rate functions BI（N） = be-aN and B3（N） = A/N ＋ c, where N denotes the total population. For each model, we obtain the disease induced death rate which guarantees the global stability of the endemic equilibrium and this gives a positive answer for an open problem by X. Q. Zhao and X. Zou, Threshold dynamics in a delayed SIS epidemic model, J. Math. Anal. Appl. 257（2） （2001） 282-291.