Search Dynamics on Multimodal Multiobjective Problems.

We continue recent work on the definition of multimodality in multiobjective optimization (MO) and the introduction of a test bed for multimodal MO problems. This goes beyond well-known diversity maintenance approaches but instead focuses on the landscape topology induced by the objective functions. More general multimodal MO problems are considered by allowing ellipsoid contours for single-objective subproblems. An experimental analysis compares two MO algorithms, one that explicitly relies on hypervolume gradient approximation, and one that is based on local search, both on a selection of generated example problems. We do not focus on performance but on the interaction induced by the problems and algorithms, which can be described by means of specific characteristics explicitly designed for the multimodal MO setting. Furthermore, we widen the scope of our analysis by additionally applying visualization techniques in the decision space. This strengthens and extends the foundations for Exploratory Landscape Analysis (ELA) in MO.

Multiple strain infections and high genotypic diversity among Mycobacterium avium subsp. paratuberculosis field isolates from diseased wild and domestic ruminant species in the eastern Alpine region of Austria.

Johne's disease, or paratuberculosis, is a chronic fatal ruminant gastroenteritis caused by Mycobacterium avium subspecies paratuberculosis (MAP) whose foodborne zoonotic potential and association with Crohn's disease are still under debate. The disease is widespread but its epidemiology and epizootiology remains elusive. Wildlife is suspected to play a major role. After a surge in MAP seroprevalence in Austrian cattle, paratuberculosis was declared a notifiable disease in Austria in 2006. At the same time a rise in MAP cases in wild ruminant populations in the Austrian province of Styria was reported. All five autochthonous ruminants were affected. Genetic analysis of isolates, yielded numerous genotypes (>15) and several multiple strain infections (15%) across host species. Identical MIRU-VNTR profiles were identified in different species and sampling locations. On the other hand varying MIRU-VNTR profiles were revealed at the same location and in conspecifics. Our data, taken together with earlier epidemiological studies on MAP and other mycobacteria, raised concerns about the organisms' ecology. Constraints regarding in vitro culture of this highly fastidious organism potentially bias our current understanding of its epidemiology. We suggest that MAP infections could be polyclonal and question the informative value of genotyping a single MAP colony derived from a single specimen for epidemiological analysis of MAP.

Salmonella Enteritidis phage type 21 outbreak in Austria, 2005.

We report an outbreak of gastroenteritis due to Salmonella Enteritidis PT 21 associated with attending an annual traditional fair in a small Austrian village on 4 May 2005. The outbreak lasted from 4 to 8 May. Descriptive and analytical epidemiological investigations were conducted in order to determine the extent of the outbreak and to identify outbreak risk factors. Of the 115 persons who visited the fair, 85 persons fulfilled the criteria of an outbreak case (attack rate = 73.9%). Stool specimens from 52 patients, including two kitchen staff, were tested for salmonella, and 20 specimens were positive for Salmonella Enteritidis PT 21. The cohort study revealed mixed salad (which included potatoes) as the likely cause of the outbreak (RR: 10.4, 95%CI 2.8 - 39.1; P = < 0.001). The causative agent of the outbreak was cultured from the stock of eggs used at the fair and from all three drag swabs and one barn dust sample collected from the responsible egg laying flock. Molecular subtyping by pulsed-field gel electrophoresis of genomic DNA after XbaI digestion showed that isolates from eggs, from the flock and from humans were indistinguishable. We hypothesise that cross contamination from eggs to boiled potatoes occurred in the kitchen area, where raw eggs were handled by village residents preparing a traditional Viennese egg dressing. Unrefrigerated storage of peeled potatoes may have favoured bacterial growth. Eggs from small rural flocks of laying hens kept in a traditional 'natural' way should not be assumed to be salmonella-free.

Salmonella Enteritidis phage type 21 outbreak in Austria, 2005.

We report an outbreak of gastroenteritis due to Salmonella Enteritidis PT 21 associated with attending an annual traditional fair in a small Austrian village on 4 May 2005. The outbreak lasted from 4 to 8 May. Descriptive and analytical epidemiological investigations were conducted in order to determine the extent of the outbreak and to identify outbreak risk factors. Of the 115 persons who visited the fair, 85 persons fulfilled the criteria of an outbreak case (attack rate=73.9%). Stool specimens from 52 patients, including two kitchen staff, were tested for salmonella, and 20 specimens were positive for Salmonella Enteritidis PT 21. The cohort study revealed mixed salad (which included potatoes) as the likely cause of the outbreak (RR: 10.4, 95%CI 2.8 - 39.1; P=<0.001). The causative agent of the outbreak was cultured from the stock of eggs used at the fair and from all three drag swabs and one barn dust sample collected from the responsible egg laying flock. Molecular subtyping by pulsed-field gel electrophoresis of genomic DNA after XbaI digestion showed that isolates from eggs, from the flock and from humans were indistinguishable. We hypothesise that cross contamination from eggs to boiled potatoes occurred in the kitchen area, where raw eggs were handled by village residents preparing a traditional Viennese egg dressing. Unrefrigerated storage of peeled potatoes may have favoured bacterial growth. Eggs from small rural flocks of laying hens kept in a traditional 'natural' way should not be assumed to be salmonella-free.

Prevalence of neutralizing antibodies to Equine rhinitis A and B virus in horses and man.

Equine rhinitis viruses (ERVs) are the causative agents of mild to severe upper respiratory infections in horses worldwide. Immunologically, four serotypes of ERVs have been identified. Equine rhinitis A virus (ERAV) and Equine rhinitis B virus 1 (ERBV1) are the most frequent serotypes in Europe. Both viruses have a broad host range in cultured cells with ERAV being able to infect humans. Since there is neither information on the seroprevalence of ERAV and ERBV1 in Austria nor on the zoonotic potential of ERBV1, we investigated 200 horse and 137 veterinary sera for the presence of neutralizing antibodies relating to ERAV and ERBV1. One hundred and eighty (90%) and 173 (86%) horse sera neutralized ERAV and ERBV1, respectively. In contrast, only four (2.7%) and five (3.6%) human sera showed weak neutralizing activity to ERAV and ERBV1, respectively. These results indicate that ERAV and ERBV1 are widespread in the Austrian horse population; however, the risk of acquiring zoonotic infection among veterinarians appears low.

Echinococcus granulosus strain differentiation based on sequence heterogeneity in mitochondrial genes of cytochrome c oxidase-1 and NADH dehydrogenase-1.

Genetic analyses of Echinococcus granulosus isolates from different intermediate host species have demonstrated substantial levels of variation for some genotype (strain) clusters. To determine the range of genetic variability within and between genotypes we amplified and cloned partial cox1 and nadh1 genes from 16 isolates of E. granulosus from 4 continents. Furthermore, we sequenced different clones from a PCR product to analyse the intra-individual genetic variance. The findings showed a moderate degree of variance within single isolates and a significant degree of variance between the cluster of genotypes G1-G3 (sheep, Tasmanian sheep and buffalo strain), genotypes G4 (horse strain) and G5 (cattle strain) and the cluster of the genotypes G6 (camel strain) and G7 (pig strain). The variance of up to 2.2% within genotypes was relatively low compared with that of 4.3-15.7% among genotypes. The present results indicate that a re-examination of the classification of 5 genotypes of Echinococcus is warranted. Hence, our data highly support a re-evaluation of the taxonomy of the clades G1-G3, G4, G5, G6/7 and G8 (cervid strain) within the genus Echinococcus.

Use of variograms to detect critical spatial distances for the Knox's test.

We aimed to find critical spatial distances (as an input quantity for the Knox's test) using geostatistical methods. The spatiotemporal data set included all individual-chamois cases of scabies observed in Styrian chamois populations in 137 of 2837 game preserves in Styria (a province in the south of Austria) over the time period between 1952 and 1998. Theoretical variogram models were fitted to empirical variograms, which were calculated for cycles of 5 years. The unit of analysis was the mean quadratic deviation between individual-chamois cases of scabies. The "range" (which represents the transition from the state in which spatial correlation exists to the state in which there is absence of spatial correlation) was used as an indicator for the critical spatial distance for the Knox's test. The critical distances for the 5-year cycles varied between 10.8 and 16.0 km. If the time of observation is not considered, the critical "overall" distance amounted to 13.5 km.

Epidemiologic application of pulsed-field gel electrophoresis to an outbreak of Campylobacter jejuni in an Austrian youth centre.

We report the first documented Campylobacter jejuni outbreak in an Austrian youth centre. Sixty-four children were involved of which 38 showed classical signs of campylobacter gastroenteritis. Since unpasteurized milk distributed by a local dairy was suspected to be the source of infection, stool samples were collected from 20 cows providing the milk. Five of the cows tested positive for C. jejuni. These isolates together with 37 clinical samples were compared by pulsed-field-gel electrophoresis (PFGE). The PFGE patterns, using the restriction endonucleases SmaI and SalI, were identical for the human and bovine isolates. This finding confirmed that the outbreak was caused by the consumption of unpasteurized milk contaminated with C. jejuni.

[Influence of diagnostic tests for estimating prevalence during surveillance programs]. / Einfluss diagnostischer Tests auf die Ergebnisse von Prävalenzschätzungen im Rahmen von Surveillance-Programmen.

The influence of diagnostic tests on the estimation of the prevalence and the calculation of sample sizes with respect to different sampling schemes are presented in this paper. These sampling schemes are used for the implementation of surveillance programs. Assuming "perfect tests" (i.e. sensitivity = specificity = 100%) the calculated sample sizes, e.g. for an IBR/IPV-surveillance or a paratuberculosis survey, are half of the sample sizes considering sensitivity and specificity of the diagnostic tests. However the probability not to identify infected livestocks may be 4 times higher neglecting the test characteristics and assuming perfect tests.

Detection of space-time clusters and epidemiological examinations of scabies in chamois.

In this paper some methodological approaches towards the detection of temporal, spatial and space-time clusters are presented and discussed in context with epidemiological factors of scabies in chamois. This presentation comprises in particular the use of the Scan Test (Wallenstein, 1980) for the detection of temporal clusters and the tests developed by Knox (1964) and Mantel (1967) for the testing of spatiotemporal interactions. Between 1952 and 1998 a total of 1689 cases of scabies in chamois and six cases in ibex were documented in 137 game preserves of the Austrian province of Styria. The evaluations indicate the presence of spatial and temporal clusters. Some possibilities for the spread of scabies in chamois are presented and reveal ibex as a probable vector for scabies transmission between chamois populations. The information may lead to strategies for controlling the spread of the disease.

[Small game (foxes, brown hares, pheasants and ducks) as carriers of zoonoses]. / Niederwild (Fuchs, Feldhase, Fasan und Ente) als Träger von Zoonose-Erregern.

Small game involves numerous infection hazards in terms of contact zoonoses and foodborne diseases. Especially exposed are hunters, game dealers, veterinarians, housewives, farmers, forest workers, laboratory staff, and taxidermists, but also consumers of insufficiently cooked game. This paper gives a survey of the most significant zoonoses in small game in Europe, which are discussed in the light of the author's own research results in this field. Finally, measures concerning prophylaxis and food hygiene are suggested.

[Swine and wild pigs as carriers of zoonoses]. / Schwein und Wildschwein als Träger von Zoonosen.

This paper deals with zoonoses in European pig herds and wild boars in general and in particular with the risk of infection carried by veterinarians, farmers and workers handling pigs and pork in slaughterhouses and meat processing companies. Furthermore the risk of infection and intoxication as a result of pork consumption is discussed. Special reference is made to the responsibility of veterinarians for keeping production animals healthy and informing animal owners and consumers about zoonoses. It would appear that it will be necessary in future to intensify veterinarian herd care, perform regional monitoring and surveillance programmes, participate in establishing specific pathogen-free herds and to foster diagnosis and research into zoonoses together with human medicine.

BHV-1 infections in Styria (Austria) caused by intra-community trade.

The present paper describes the prevalence of BHV-1 (bovine herpes virus 1) infections in the Austrian province of Styria from 1990 to 1997 and the corresponding eradication programme. Based on the description of BHV-1 infections on seven holdings caused by intra-Community trade, the additional guarantees granted under Directive 64/432/EEC (CEC, 1964) are discussed and measures for improved protection of BHV-1-free regions suggested.

[Comparison of two castration methods in cattle: plasma cortisol levels, leukocyte count and behavioral changes]. / Vergleich zweier Kastrationsmethoden beim Rind: Plasmakortisolkonzentrationen, Leukozytenzahlen und Verhaltensänderungen.

Two methods of castration (surgical and Burdizzo method) of male calves were compared by measuring plasma cortisol concentrations. Increased plasma cortisol values were found only during the first three hours after castration. There were no significant differences in plasma cortisol values and changes of behaviour between groups of surgical and Burdizzo castrated calves. Plasma cortisol values did not decrease during the first days after castration. The results suggest, that surgical and Burdizzo-castration do not differ in regard to pain.

[Hyperplasia of the ruminal villi in three wild roe deer]. / Pansenzottenhyperplasie bei drei Rehen aus freier Wildbahn.

In autumn 1994 a hyperplasia of ruminal villi in three roe deer out of one hunting ground was diagnosed. The ruminal villi were three to five times longer than normal and partially stuck together. The case history and a comparison of the pathomorphological and histological findings with similar symptoms in domestic ruminants lead to a discussion on feeding as the cause of the disease.

[Prevalence of E. multilocularis in foxes in Styria taking into consideration biometrical methods]. / Eine Prävalenzstudie über E. multilocularis bei Füchsen in der Steiermark unter Berücksichtigung biometrischer Methoden.

The results of a survey covering whole of Styria/Austria, which was based on a biometrical sampling plan, showed the prevalence rate of E. multilocularis among foxes to be 3.6% (18 out of 500 examined foxes). There is however a significant regional difference in the prevalence rate. All 18 infected foxes were found in the North-West of Styria, which results in an estimated proportion of 9% in this region. The study could not reveal any significant difference between male and female foxes concerning the infection rate. The age distribution was 67 percent juvenile foxes (< 1 year) to 33 percent adults. The biometrical methods enable us to determine an exact spatial spread of the parasite and thus makes it possible to find out any potential risk for the population.

[The cell count in sheep and goat milk]. / Untersuchungen über den Zellgehalt in Schaf- und Ziegenmilch.

The udder health of 404 sheep from 23 flocks and 397 goats from 15 herds in Lower Austria was examined. In order to determine cell levels, the Schalm Test (equivalent to the California mastitis test) and a fluoroscopic "Fossomatic" cell count appliance were employed. The resultant physiological median levels of somatic cell content were established as 71,000 cells/ml for sheep milk and 415,000 cells/ml for goat milk. Significant factors influencing the cell count levels were the milking technique in both species and age in sheep but not in goats. The pathogens most frequently isolated as causes of chronic or latent mastitis were coagulase-positive and -negative cocci.