Factors associated with the introduction of classical swine fever virus into pig herds in the central area of the 1997/98 epidemic in the Netherlands

A matched case-control study of 135 infected and 99 uninfected pig herds from the central area of the 1997 to 1998 epidemic of classical swine fever (CSF) in The Netherlands was undertaken to identify factors associated with the introduction of the virus. The herds were matched on the basis of herd type and the shortest geographical distance between pairs of herds. Data on management, hygienic measures, experiences during the depopulation of an infected nearest neighbour, and the frequency of contact with professionals and other agencies were collected by means of a questionnaire taken by personal interview. There were no significant differences between the infected and uninfected herds in the median total number of contacts per year with professionals and other agencies either with or without contact with the pigs. On the basis of a multivariable analysis, five variables were found to be significantly associated with an increased risk of infection: (1) the presence of commercial poultry on the premises; (2) visitors entering the pig units without wearing an overcoat or overalls and boots supplied by the farm; (3) the driver of the lorry transporting pigs for the Pig Welfare Disposal Scheme (PWDS) using his own boots instead of boots supplied by the farm; (4) herds of moderate size (500 to 1,000 animals) and very large herds (>7,000 animals) were at greater risk than small herds (<500 animals); and (5) an aerosol, produced during high-pressure cleaning of the electrocution equipment used to kill the pigs on a neighbouring infected herd less than 250 m away was carried by the wind on to the premises. Two variables were significantly associated with a decreased risk of CSFV-infection: (1) more than 30 years of experience in pig farming; and (2) additional cleaning of the lorries used to transport pigs for the PWDS before they were allowed on to the premises. In the opinion of the cooperating farmers, airborne transmission of the virus and its transmission during the depopulation of an infected neighbour were among the most important routes of infection

Rate of inter-herd transmission of classical swine fever virus by different types of contact during the 1997-8 epidemic in The Netherlands

In this study we quanti®ed the rate at which classical swine fever had been transmitted by several different types of inter-herd contact during the 1997±8 epidemic in The Netherlands. During that epidemic 428 CSFV-infected pig herds were detected, 403 of which were include in this study. The estimated rates of transmission were 0±065 per shipment of live pigs, 0±011 per contact by a pig transportation lorry, 0±0068 per person contact, 0±0007 per dose of semen, 0±0065 per contact with a potentially contaminated pig assembly point, 0±027 per week per infected herd within a radius of 500 metres and 0±0078 per week per infected herd at a distance between 500 and 1000 metres. These transmission rates can be used to optimize the strategy to stop future epidemics of CSF in The Netherlands. In addition, the analysis demonstrated in this paper, can be used to quantify CSFV transmission rates from other epidemics

Intra- and interspecies transmission of H7N7 highly pathogenic avian influenza virus during the avian influenza epidemic in the Netherlands in 2003

The poultry epidemic of H7N7 highly pathogenic avian influenza (HPAI) virus in the Netherlands in 2003 was probably the result of the introduction of an H7N7 low pathogenic avian influenza (LPAI) virus (by interspecies transmission from wild birds) and the subsequent intraspecies transmission of this virus in poultry. The intraspecies transmission of the ensuing H7N7 HPAI virus was very successful both within and between flocks. Consequently, in the two poultry-dense areas that were affected, the epidemic could only be stopped by eliminating all poultry in the region. According to the spatial models these are the only areas where this was the case in the Netherlands. There was also interspecies transmission to mammals, i.e. to pigs and to humans. For pigs it was shown that possible subsequent intraspecies transmission was negligible (R0 <1). With hindsight the same was probably also true for human

Transmission and quantification of verocytotoxin-producing Escherichia coli O157 in dairy cattle and calves

Data from a field study of 14 months duration in a naturally colonized dairy herd and data from an experiment with calves were used to quantify transmission of verocytotoxin-producing Escherichia coli (VTEC O157) in cattle. For the latter, two groups of 10 calves were randomly assigned and put out in one of two pastures. From each group, five animals were experimentally inoculated with 109 c.f.u. O157 VTEC and, considered infectious, put back in their group. Each of the susceptible contact calves became positive within 6 days of being reunited. The estimate of the basic reproduction ratio (R0) in the experiment was 7·3 (95% CI 3·92¿11·5), indicating that each infectious calf will infect seven other calves on average during an assumed infectious period of 28 days in a fully susceptible population. The R0 among dairy cows appeared to be about 10 times lower (0·70, 95% CI 0·48¿1·04). After the transmission experiment, six contact-infected animals that were shedding continuously during the experiment were housed in a tie stall during winter. After 40 days, all six tested negative for O157 VTEC. In June, after a period of 34 weeks in which the heifers remained negative, they were put out in a clean and isolated pasture to observe whether they started shedding again. On each pasture that was infected with O157 VTEC during the transmission experiment the previous summer, newly purchased susceptible calves were placed. None of the heifers or calves started shedding during 14 weeks, indicating that both the heifers and the previously contaminated pasture did not function as reservoir of O157 VTE

Оксид азота и нитритные ионы в энергетике нейронов мозжечка

Зниження вмісту АТФ в нейронах при гіпоксії мозку і гіперстимуляції глутаматних рецепторів здатне порушити систему внутри і міжклітинної сигналізації в нейронах мозку, зокрема іонний обмін, активність ферментів гліколізу і окислювального фосфорилірування, захоплення Са2+ мітохондріями і синтез білків. В даній роботі вивчали дію ендогенного глутамат індукованого NO і дію екзогенний доданих донорів NO – нітриту натрію (NaNO2) і нітрозоцистеїну (SNOC) на вміст АТФ в 7-8 денних культивованих нейронах мозочка.Decrease of content ATPA in neurones at a hypoxia of a brain and a hyperstimulation глутаматных receptors is capable to break system inside and the intercellular signal ystem in neurones of a brain, in particular an ion exchange, activity of enzymes of glycolysis and oxidative phosphorylation, seizure Са 2+ mitochondrions and synthesis of proteins. In the given work studied action endogenic glutamate inducted NO and action of exogenous padding donors NO diazotizing salt (NaNO2) and нитрозоцистеина (SNOC) on content ATPA in 7 8 diurnal cultivated{incubated} neurones of a cerebellum

Роль международной мобильности ученых на разных этапах истории науки Украины

В статье освещается эволюция международного сотрудничества ученых Украины с зарубежными исследователями. Продемонстрировано огромное влияние стажировки отечественных ученых в крупнейших научных центрах мира, совместных исследований с зарубежными исследователями для становления науки в Украине, развития сети научных учреждений и высших учебных заведений. Охарактеризовано основные тенденции международного сотрудничества ученых Национальной академии наук и миграции научных работников в последние десятилетия.У статті висвітлюється еволюція міжнародного співробітництва вчених України з зарубіжними дослідниками. Продемонстровано величезний вплив стажування вітчизняних учених у найбільших наукових центрах світу, спільних досліджень із зарубіжними дослідниками для становлення науки в Україні, розвитку мережі наукових установ та вищих навчальних закладів. Охарактеризовано основні тенденції міжнародної співпраці вчених Національної академії наук України та міграції наукових працівників в останні десятиліття.Evolution of the international cooperation of Ukrainian scientists with foreign researchers is emphasized. The great impact from probation of national scientists at largest research centers across the globe, joint research with foreign partners on establishing the science system in Ukraine and building up the network of research institutions and higher education establishments is shown. Main tendencies in the international cooperation of scientists from the National Academy of Sciences of Ukraine and scientists’ migration in the latest decades