Seroprevalence of bluetongue serotype 8 in cattle in the Netherlands in spring 2007, and its consequences

A cross-sectional study was carried out in spring 2007, at the end of the first bluetongue outbreak season, to determine the geographical spread of bluetongue virus serotype 8 (BTV-8) infection in cattle in the Netherlands and the consequences for some production parameters. Blood samples from cattle submitted to the laboratory of the Dutch Animal Health Service for other voluntary and obligatory health programmes were tested serologically for BTV-8. in total, 37,073 samples were tested and 659 (1.78 per cent) were seropositive. The samples came from 5436 herds, of which 45 per cent of herds had only one sample submitted from them. The prevalence was highest in the south of the country, where the outbreak had started, and decreased towards the north. in 340 herds more than 50 per cent of cattle were tested, of which 156 herds were located in infected compartments, and in 37 of these herds (10.9 per cent) at least one positive cow was detected. The average within-herd prevalence in the 37 herds was 39.3 per cent: 2.2 per cent in I I dairy herds, 68.4 per cent in 20 small-scale herds and 14 per cent in four suckler cow herds. The prevalence differed significantly between herd types but did not show a geographical trend. The average net return for milk production amounted to is an element of 2417/cow/year and it decreased significantly on average by is an element of 48/ cow/year in the bluetongue-infected dairy herds during the bluetongue period. on the small-scale farms, the incidence of mortality increased by 3.2 (95 per cent confidence interval [a] 1.2 to 9.1) times in the infected herds during the bluetongue period, but the voluntary culling rate decreased by a factor of 2.3 (95 per cent Cl 1.1 to 4.8)

A cross-sectional study to determine the seroprevalence of bluetongue virus serotype 8 in sheep and goats in 2006 and 2007 in the Netherlands

Background: In August 2006 a major epidemic of bluetongue virus serotype 8 (BTV8) started off in North-West Europe. In the course of 2007 it became evident that BTV8 had survived the winter in North-West Europe, re-emerged and spread exponentially. Recently, the European Union decided to start vaccination against BTV8. In order to improve the understanding of the epidemiological situation, it was necessary to execute a cross-sectional serological study at the end of the BT vector season. Cattle were the target species for cross-sectional serological studies in Europe at the end of 2006 and 2007. However, there was no information on the BTV8- seroprevalence in sheep and goats. Results: On the basis of our cross-sectional study, the estimated seroprevalence of BTV8-exposed locations in the Netherlands in 2006 was 0% for goats (95% confidence interval: 0 ¿ 5.6%) and 7.0% for sheep (95% confidence interval: 3.5 ¿ 12.9%). The estimated seroprevalence of BTV-8 exposed locations in 2007 was 47% for goats (95% confidence interval: 36 ¿ 58%) and 70% for sheep (95% confidence interval: 63 ¿ 76%). There was a wide range in within-location seroprevalence in locations with goats and sheep (1 ¿ 100%). A gradient in seroprevalence was seen, with the highest level of seroprevalence in the southern Netherlands, the area where the epidemic started in 2006, and a decreasing seroprevalence when going in a northern direction. Conclusion: There is a much higher estimated seroprevalence of locations with goats exposed to BTV8 than can be inferred from the rather low number of reported clinical outbreaks in goats. This is probably due to the fact that clinical signs in infected goats are far less obvious than in sheep. The wide range in within-location seroprevalence observed means that the proportion of animals protected in 2008 by a natural infection in 2006 and/or 2007 can differ highly between flocks. This should be taken into account when vaccinating animals

Reduction of Coxiella burnetii prevalence by vaccination of goats and sheep, the Netherlands

Recently, the number of human Q fever cases in the Netherlands increased dramatically. In response to this increase, dairy goats and dairy sheep were vaccinated against Coxiella burnetii. All pregnant dairy goats and dairy sheep in herds positive for Q fever were culled. We identified the effect of vaccination on bacterial shedding by small ruminants. On the day of culling, samples of uterine fluid, vaginal mucus, and milk were obtained from 957 pregnant animals in 13 herds. Prevalence and bacterial load were reduced in vaccinated animals compared with unvaccinated animals. These effects were most pronounced in animals during their first pregnancy. Results indicate that vaccination may reduce bacterial load in the environment and human exposure to C. burnetii

Q-koorts in Nederland: 2008 en verwachting voor 2009

In 2007 en 2008 deed zich in Nederland een epidemie van Q-koorts voor met resp. 196 en 906 bevestigde ziektegevallen. In dit artikel beschrijven de auteurs het verloop van de epidemie, het onderzoek, de maatregelen en de verwachting van het beloop in 2009. Q-koorts is, met name in het zuidoosten van Nederland, een nieuwe aandoening met belangrijke consequenties voor diagnostiek en therapi

Overleving van Coxiella burnetii in geitenmest : eindrapportage

De afname van het aantal bacteriën in geitenmest is bestudeerd onder omstandigheden, zoals die zich in opgeslagen geitenmest voordoen. De afname van het aantal bacteriën bij verschillende temperaturen wordt weergegeven door middel van de decimale reductietijd (DRT of Dwaarde). De DRT is de tijd die nodig is om het aantal bacteriën met een factor 10 te laten afnemen bij een bepaalde temperatuur. In dit onderzoek is de DRT voor C. burnetii in geitenpotstalmest bij verschillende temperaturen bepaald

Do theories of change enable innovation platforms?

Theories of change (ToCs) are increasingly used to articulate pathways for interventions and to support learning. This responds to the recognition of the complexity of agricultural development. Through two examples, this paper examines how ToCs have enabled practitioners to navigate towards impact in settings characterized by a multiplicity of views from different actors on issues of joint concern. The cases discuss how the intervention programs test the ToCs, as well as organize and reflect on feedback. The cases reveal that one cannot predict the route to impact, but one can compose plausible story lines explicating the assumptions. Developing and using ToCs takes time and requires a deliberate effort to monitor actions and changes. Connecting practitioners with researchers makes it possible to use more intermediate theorisations tailored to situated and specific impact pathways. However, the dynamics captured by ToCs may contrast with the donors’ demands for accountability and consistent reliance on a rigid log-frame approach to determine project activities and outputs. Therefore, it is relevant to make explicit choices about how to relate ToCs to M&E efforts

Motor control by precisely timed spike patterns

A fundamental problem in neuroscience is to understand how sequences of action potentials ("spikes") encode information about sensory signals and motor outputs. Although traditional theories of neural coding assume that information is conveyed by the total number of spikes fired (spike rate), recent studies of sensory and motor activity have shown that far more information is carried by the millisecond-scale timing patterns of action potentials (spike timing). However, it is unknown whether or how subtle differences in spike timing drive differences in perception or behavior, leaving it unclear whether the information carried by spike timing actually plays a causal role in brain function. Here we demonstrate how a precise spike timing code is read out downstream by the muscles to control behavior. We provide both correlative and causal evidence to show that the nervous system uses millisecond-scale variations in the timing of spikes within multi-spike patterns to regulate a relatively simple behavior - respiration in the Bengalese finch, a songbird. These findings suggest that a fundamental assumption of current theories of motor coding requires revision, and that significant improvements in applications, such as neural prosthetic devices, can be achieved by using precise spike timing information.Comment: 48 pages, 16 figure