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61.
Giulio Caravagna Alberto d’Onofrio Paolo Milazzo 《Journal of theoretical biology》2010,265(3):336-345
The well-known Kirschner-Panetta model for tumour-immune System interplay [Kirschner, D., Panetta, J.C., 1998. Modelling immunotherapy of the tumour-immune interaction. J. Math. Biol. 37 (3), 235-252] reproduces a number of features of this essential interaction, but it excludes the possibility of tumour suppression by the immune system in the absence of therapy. Here we present a hybrid-stochastic version of that model. In this new framework, we show that in reality the model is also able to reproduce the suppression, through stochastic extinction after the first spike of an oscillation. 相似文献
62.
The diversion of disease carrying insect from humans to animals may reduce transmission of diseases such as malaria. The use of animals to mitigate mosquito bites on human is called ‘zooprophylaxis’. We introduce a mathematical model for Plasmodium vivax malaria transmission with two bloodmeal hosts (humans and domestic animals) to study the effect of zooprophylaxis. After computing the basic reproduction number from the proposed model, we explore how perturbations in the parameters, sensitive to the effects of control measures, affect its value. Zooprophylaxis is shown to determine whether a basic reproduction becomes bigger than an outbreak threshold value or not. Sensitivity analysis shows that increasing the relative animal population size works better in P. vivax malaria control than decreasing the mosquito population when the relative animal population size is larger than a threshold value. 相似文献
63.
Morgan D 《FEMS immunology and medical microbiology》2006,48(3):305-312
Although there is no recognized transmission of human arboviral infections in the UK, concerns about the possible spread of West Nile virus (WNV) have precipitated coordinated activities around both surveillance and response. The Department of Health has chaired a UK WNV task force since the end of 2000. This is a multidisciplinary group of senior representatives from Agencies and Government Departments involved in human and animal health, entomology and academic departments. Activities include surveillance for WNV infections in humans, and in dead birds, mosquitoes and horses. All have been negative for WNV. A WNV contingency plan was produced in 2004, and this could be used as a generic plan for an effective and coordinated response in the event of the emergence of a new vector-borne zoonotic infection. 相似文献
64.
R. Kambiré K. Lingué F. Courtin I. Sidibé D. Kiendrébéogo K.E. N’gouan L. blé D. Kaba M. Koffi P. Solano B. Bucheton V. Jamonneau 《Parasite (Paris, France)》2012,19(4):389-396
The objective of this paper was to describe recent data from Burkina Faso and Côte d’Ivoire on Human African Trypanosomosis medical monitoring in order to (i) update the disease situation in these two countries that have been sharing important migratory, economic and epidemiological links for more than a century and (ii) to define the future strategic plans to achieve the goal of a sustainable control/elimination process. Results of active and passive surveillance indicate that all sleeping sickness patients diagnosed these last years in Burkina Faso were imported cases from Côte d’Ivoire. Nevertheless the re-introduction of the parasite is effective and the risk of a resumption of transmission exists. In Côte d’Ivoire, few cases are still diagnosed in several historical foci and the fear exists that the disease could reemerge in these foci or spread to other areas. In order to achieve a sustainable elimination of sleeping sickness in these two countries, control entities have to adapt their strategy to the different epidemiological contexts. At the exception of specific cases, the current disease prevalence no longer justifies the use of expensive medical surveys by exhaustive screening of the population. New disease control strategies, based on the exchange of epidemiological information between the two countries and integrated to the regular national health systems are required to target priority intervention areas. Follow-up in time of both treated patients and serological suspects that are potential asymptomatic carriers of parasite is also important. In parallel, researchers need to better characterize the respective roles of the human and animal reservoir in the maintenance of transmission and evaluate the different control strategies taken by National Control Programs in term of cost/effectiveness to help optimize them. 相似文献
65.
66.
目的了解2011年河南省流行性腮腺炎发病水平及流行特点。方法对河南省2011年"疾病监测信息报告管理系统"的流行性腮腺炎病例资料进行分析。结果 2011年河南省共报告流行性腮腺炎20 572例,发病率为21.88/10万,发病率与2010年相比上升了35.33%,发病构成占2011年丙类传染病的16.57%,在河南省11种丙类传染病中居第3位。第一季度和第三季度发病数明显少于第二季度和第四季度,豫北豫西发病率高于豫南豫东,发病年龄以4~8岁儿童为主,发病性别男性高于女性,发病人群以学生和儿童为主。结论当前流行性腮腺炎仍然是严重危害河南省居民身体健康的重要公共卫生问题之一,建议当地政府及有关部门继续加强对流行性腮腺炎预防控制工作的投入和管理力度。 相似文献
67.
Brucellosis in India — a review 总被引:1,自引:0,他引:1
Brucellosis is an important re-emerging zoonosis with a worldwide distribution. It is still an uncontrolled serious public
health problem in many developing countries including India. Brucellosis in India is yet a very common but often neglected
disease. Currently, Brucella melitensis accounts for most recorded cases globally with cattle emerging as a important reservoir with the few cases of B. suis. Isolated cases of non-terrestrial brucellosis and continuing transmission from wild animals have raised important epidemiological
issues. Routine serological surveillance along with high clinical suspicion and screening of family members of index cases
would be essential in delineating the real magnitude of human brucellosis in endemic countries. Increased business and leisure
travel to endemic countries have led to diagnostic challenge in non-endemic areas. Laboratory testing is indispensable for
diagnosis. Advances in newer rapid, sensitive, and specific testing methodologies and alternate treatment strategies are urgently
needed. A safe and effective vaccine in human is not yet available. Prevention is dependent upon increasing public awareness
through health education programmes and safe livestock practices. Active co-operation between health and veterinary services
should be promoted. This review collates world literature and its impact to the discovery, isolation and diagnosis and epidemiology
along with the control measures adapted in the Indian scenario. 相似文献
68.
José Guilherme Chaui-Berlinck José Alexandre Marzagão Barbuto Luiz Henrique Alves Monteiro 《Theorie in den Biowissenschaften》2004,123(2):195-208
Summary A continuous harvest effort can lead a population to extinction. How an “unconscious” immune system would perpetrate such
an effort in order to eliminate a self-replicating antigen (a pathogen) becomes an intriguing problem if the system responses
are functions of the pathogen population: the responses cannot be a continuous effort as the pathogen vanishes. On theoretical
grounds, we show some qualities an immune response must have to support pathogen elimination. Then, three specific mechanisms
are addressed: a pathogen-independent positive feedback loop among the responding cells of the system (e.g., B-lymphocyte
and T-helper); the persistence of antigen bound to presenting cells; and the programmed expansion/contraction of a pool of
responding cells. The maintenance of responding cells due to these mechanisms is the essential feature to the effective clearance
of self-replicating agents. Thus, evolutionarily, the primary function of a helper lymphocyte would be to amplify a response
and the primary function of memory would be the very elimination of pathogens. 相似文献
69.
为了评价国产钩端螺旋体外膜疫苗的流行病学效果。于1998年6-10月,用队列研究和病例对照研究等方法在钩体病流行区5-60岁农业人口 ,观察比较接种组和对照组钩体发病情况。队列研究显示,钩体外膜疫苗对同血清群钩体的保护率为75.17%,效果指烽为4.03。1:2配对调查的疫苗保护率为81.25%,1:3配对结果为73.33%。用筛选法估计的疫苗效果为755。不同研究方法的结果相近,均一致说明,该疫苗的流行病学效果较理想。研究结果还显示,该疫苗对异血清群钩体也有一定的保护作用。 相似文献
70.
Valeria Ibáñez Henríquez Gloria Rojas Villegas Joan Maria Roure Nolla 《Aerobiologia》2001,17(2):137-142
Fungal airborne spores were studied from September 1996throughout August 1997 in Santiago, Chile. Total concentrationsfluctuated between 308 and 10,334 spores/m3/day withan annual mean of 2,154 per m3, the highest dispersion beingduring April and May. Forty-five percent of total fungal content wasfound in autumn. Thirteen genera and 3 other spore types wereidentified. Cladosporium, the most abundant genera in ouratmosphere, contributed with 70.9% of the total fungi counts andreached an annual mean of 1,527 spores/m3/day, itshighest frequency being in autumn. Alternaria appeared as thesecond most frequent genera, with an annual mean of 40spores/m3/day, representing a 1.9% of theannual fungal catch. Altogether, Stemphylium, Torula, Epicoccum,Ganoderma, Helminthosporium, Chaetomiun, Pleospora and othersreached relative frequencies of 0.5% or less. It is concludedthat fungi are present in Santiago's atmosphere all year round, some ofthem with a clear seasonality. 相似文献