Search

In this study an outbreak with Sheeppox virus (SPPV) and Orf virus (ORFV) in one sheep herd in the Qalubia province, Egypt, was investigated. Both, SPPV and ORFV caused clinically manifest infections among sheep. The affected sheep showed skin lesions around the mouth or all over the body. Therefore, reliable diagnosis should confirm the aetiology of the infection and then reduce spread of the diseases in the affected areas. Clinical samples were investigated by virus isolation, PCR and real-time PCR assays. Furthermore, PCR-products of SPPV and ORFV isolates were sequenced and alignment to reference isolates was performed for phylogenetic analyses. The laboratory diagnosis showed that real-time PCR assay was more accurate and sensitive than conventional PCR and virus isolation. In phylogenetic analysis of the A29L gene genetic differences between SPPV field strains were not observed and the strains showed 100% homology with two SPPV isolates from Kazakhstan and one isolate from Turkey. The ORFV field strains are in the P55 gene genetically distinct from another and from other published isolates from Egypt 2006 and 2009.

An important prerequisite for an efficient eradication of pestiviruses like bovine viral diarrhea virus or classical swine fever virus are sensitive and specific detection methods. Beside antigen detection with antigen capture ELISAs and virus isolation using cell culture, the detection of virus genomes by reverse transcriptase polymerase chain reaction (RT-PCR) becomes more and more important. By using real-time RT-PCR, the disadvantages of conventional PCR methods concerning the risk of contamination and missing specificity controls are minimized. In the following, the validation and application of different real-time RT-PCR systems for the detection of pestiviruses are presented. In addition, a new "panpesti" probe was tested, and the ability to differentiate between the major species of pestiviruses with known PCR protocols was determined using the Light Cycler PCR machine.

With the long-term perspective of the eradication of BVD/MD in the German federal state Saxony-Anhalt a voluntary control program was initiated in 2002 by an administrative regulation based on federal German guidelines. The short-term aim of this program is the establishment of BVDV-unsuspected herds achieved by elimination of persistently infected cattle. The diagnostic program and particularly the choice of the diagnostic tools was based on the consideration of laboratory experiences as well as on economic and logistic aspects. A combination of RT-PCR and antigen-ELISA was found to be the suitable diagnostic methods. The screening started with examinations of sera pools using Real Time RT-PCR in the Light-Cylcer system. After positive pool results the individual persistently infected animals were detected using various commercial ERNS-antigen-ELISAs. The RT-PCR revealed a high degree of sensitivity and robustness. With respect to highly specific ELISAs the producers have to ensure the detection of all currently important virus strains. The prevalence of persistently infected animals in the cattle population of Saxony-Anhalt was about 0.2% during the last 3 years. This is probably due to nearly 10 years of broad vaccination and will prove advantageous for BVDV elimination.

Because of the intensive efforts required and the dissatisfactory sensitivity achieved with the traditional serological diagnostic techniques for Avian Encephalomyelitis, an ELISA was developed and tested to show the presence of antibodies in chicken serum. Using a multi-phase antigen preparation and optimizing the reagents and serum dilutions, a method was developed which shows considerable advantages in sensitivity, specificity, practicability and costs compared with the Embryo Serum Neutralization Test.