Crimean-Congo Hemorrhagic Fever Virus in Bulgaria and Turkey.

Infections of humans with the tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV) can cause a severe hemorrhagic fever with case fatality rates of up to 80%. Most humans are infected by tick bite, crushing infected ticks by hand or by unprotected contact with blood of viremic mammals. Next to the notified human CCHF cases, the real distribution and the situation in animals in Southeastern Europe are nearly unknown.

Genetic predisposition of some Bulgarian sheep breeds to the scrapie disease.

The aim of this study is to investigate the profile of ovine PrP gene by amino acid polymorphism at codons 136, 141, 154, and 171 for determining the genetic predisposition to the Scrapie disease for the tribal sheep and rams, with different numbers and distribution in Bulgaria. Three hundred twenty four animals originating from 41 tribal herds comprising eight breeds were included in the study. DNA was isolated from blood samples specifically amplified by PCR and sequenced.

The efficacy of a bivalent vaccine against pasteurellosis and rabbit haemorrhagic disease virus.

Rabbit haemorrhagic disease virus (RHDV) and Pasteurella multocida bacteria cause severe losses among rabbit populations. The efficacy of a recently developed bivalent vaccine against pasteurellosis and RHDV was investigated. Doses exceeding 2 haemagglutinating units (HU) of viral antigen were sufficient to protect rabbits against infection with RHDV.

Detection of bovine herpesvirus 4 glycoprotein B and thymidine kinase DNA by PCR assays in bovine milk.

A polymerase chain reaction (PCR) assay was developed to detect bovine herpesvirus 4 (BHV4) glycoprotein B (gB) DNA, and a nested-PCR assay was modified for the detection of BHV4 thymidine kinase (TK) DNA in bovine milk samples. To identify false-negative PCR results, internal control templates were constructed, added to milk samples, and co-amplified with viral DNA using the same primers for both templates. Specificity, sensitivity, and reproducibility of the two PCR assays were examined.

Fluorescent and electron-microscopy immunoassays employing polyclonal and monoclonal antibodies for detection of goose parvovirus infection.

Polyclonal antibodies (PAbs) raised in geese and eight mice hybridomas secreting monoclonal antibodies (MAbs) against the goose parvovirus (GPV) were prepared. They were used for development of immunofluorescence (IF) and immunoelectron-microscopic (IEM) techniques to demonstrate the GPV infection in infected organs and biological fluids. The GPV antigens were established by immunofluorescence within the nuclei and the cytoplasm of many infected cells of the chorioallantoic membrane of goose and Peckin duck embryos, liver and heart of mortally diseased goslings.

Comparative molecular epidemiological investigation on different bovine herpes viruses.

Eight Bulgarian bovine herpes viruses, two Hungarian herpes viruses 1A, 3A, calves isolate named Mramor, buffalo isolate 723 and two referents BHV 1 strains were investigated by restrictase fragment pattern analysis. Migration profile of viral DNA by using different restrictase enzymes Hpa I, BamH I and Hind III were compared. Clearly differences among two Hungarian strains, calves isolate Mramor, buffalo isolate 723 and 8 Bulgarian and two referents BHV 1 strain was observed.

Interference activity of bovine herpes virus 1 strains against Aujeszky's disease virus in cell cultures.

The interference-inducing activity of different low- and high-virulence strains of bovine herpes virus 1 (BHV-1) against Aujeszky's disease virus was studied by a parallel titration on permissive and non-permissive cell culture. The low-virulence BHV-1 strains possessed better interference-inducing activity than the high-virulence strains. An interference blocking test (IBT) was developed for the detection of BHV-1 antibodies in bovine sera.

Demonstration of rabbit haemorrhagic disease virus antigen by Staphylococcus protein A coagglutination test.

The Staphylococcus protein A coagglutination test (Sp A COAT) was developed for the diagnosis of rabbit haemorrhagic disease (RHD). Liver, spleen, lungs and kidneys from 176 rabbits dead from viral haemorrhagic disease as well as the same organs from 64 healthy animals were examined by Sp A COAT and haemaglutination test (HAT). The Sp A COAT was specific and considerably more simple to carry out than the HAT, which made it very useful for rapid identification of RHD.

Electron- and immunoelectron-microscopic investigation on the rabbit haemorrhagic disease virus.

Electron- and immunoelectron-microscopic methods were used for detection and investigation of rabbit haemorrhagic disease virus (RHDV). The observed virus particles were uncoated, with an icosahedral symmetry, with a 35-40 nm dia and capsids built up by 32 capsomers with a central hollow part and a 3.5-5 nm dia.

Immunohistochemical localization of the rabbit haemorrhagic disease viral antigen.

Immunohistochemical investigations were carried out to determine organ and cellular localization of the rabbit haemorrhagic disease viral antigen (RHDVA). It was found in certain parenchymal liver cells near the interlobular septs and in some macrophages and pseudoeosinophils of all studied organs and blood. Whereas in morphologically preserved hepatocytes and macrophages the RHDVA accumulated in the nuclei, in cells with disintegrated nuclei it was distributed throughout the cytoplasm.