Browsing by Subject "Epidemiology"

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Epidemiologische Aspekte der Falschen Mehltauinfektion durch Plasmopara viticola an Vitis
(2007) Keil, Sven; Spring, Otmar
The obligate biotrophic oomycete Plasmopara viticola (Berk. & Curt.) Berl. & de Toni causes downy mildew on grapevine. Plasmopara viticola is one of the economically most important pathogens in viticulture, with severe losses in yield of up to 70%. Existing prognosis models for plant protection in viticulture only allow yes/no statements on possible infection events in the vineyard. On the basis of these models, the severity of infections remain uncertain, although this represents a crucial point for an efficient application of fungicides. At low infestation severity, the application of protective fungicides at the end of the incubation period usually is sufficient. The low level of infestation can be tolerated and only further propagation of the pathogen must be prevented. In contrast, at high infestation severity curative fungicides have to be applied as soon as possible, because otherwise too much host tissue would be destroyed. Based on epidemiological studies and field experiments a prognostic concept has been designed, which enables the user to evaluate the relevance of infection events of grapevine downy mildew. This work has been carried out in the context of the research project ?Optimierung der Peronospora-Bekämpfung im Rebschutz auf der Basis eines erweiterten Prognosemodells (Forschungsvorhaben des Bundesministeriums für Ernährung, Landwirtschaft und Verbraucherschutz Nr. 514-33.54/01HS048)?. The developed concept was then integrated into the existing prognosis model and should support both consultants and winegrowers in using plant protection agents only in case of an expected increase of infestation frequency and severity. In this way, an effective and more economical use of fungicides is possible, which contributes to economic savings and reduces pesticide contamination of the environment. In the present study, aspects of sporangiogenesis, infestation of host tissue and hibernation, spreading of sporangia, interaction between vine leaves and sporangia as well as the climatic conditions during infection were analysed and evaluated with respect to the impact on epidemiology. The results improve existing literature data and deliver new insight to the epidemiology and biology of Plasmopara viticola.
Serological protection rates against TBEV infection in blood donors from a highly endemic region in Southern Germany
(2023) Dobler, Gerhard; Euringer, Kathrin; Kaier, Klaus; Borde, Johannes P.
Background: Tick-borne encephalitis (TBE) is the most significant tick-borne disease in Europe and Asia, with more than 10,000 cases per year worldwide. A surge of reported TBE cases can be observed despite the availability of highly efficient vaccines. There is little known about the serological immune protection rate of the population in Germany. The seroprotection rate is defined as the presence of neutralizing antibodies. In contrast, the vaccination rate, as defined by public health agencies, may differ from the true protection rate in a population. Materials and Methods: 2220 blood samples from inhabitants of the county Ortenaukreis in the Federal State of Baden-Württemberg in Germany were included in the study. These were tested for anti-TBEV IgG antibodies by an anti-TBEV-IgG-ELISA. Subsequently, all TBEV-IgG positive samples were confirmed for neutralizing antibodies in the micro serum neutralization assay. Results: From the overall 2220 samples, 2104 were included in the comparison because of the selection of specific age groups (ages 20–69). In our sample size, we found an average serological protection rate (presence of neutralizing antibodies) of 57% (518/908) for the female blood donors and of 52% (632/1196) for the male blood donors. Discussion: In this study, we present new findings on a highly endemic region in southern Germany. Additionally, we present current data regarding the serological TBEV protection rates in the Ortenaukreis in southern Germany and compare these with a dataset published by the RKI, which is based on vaccination reports of the primary care providers and health care insurers, and with a self-reporting study conducted by a vaccine manufacturer. Our results significantly exceed the official numbers of average active vaccination status by 23.2% for females and by 21% for males. This might indicate an even longer persistence of TBE-vaccination-induced antibody titers than previously assumed.
Untersuchungen zur Grünfäule (Penicillium spec.) an Weintrauben
(2008) Walter, Ruth; Buchenauer, Heinrich
Since the end of the 90th increasing problems with the occurrence of secondary bunch rot pathogens could be observed in German vine growing regions. Thereby blue mould, caused by Penicillium species, plays a mayor role. Already small amounts of infected bunches can lead to economical losses by off-flavors in the wine, so that infected bunches have to be discarded before harvest. Only little was known about the pathogen on grapes. So questions about the causing species in German vineyards, the biology and epidemiology, the impact of cultivation methods on disease development, the competition with Botrytis cinerea and possible preventing strategies were investigated.