Determination of fenbendazole, praziquantel and pyrantel pamoate in dog plasma by high-performance liquid chromatography.

Simple and rapid high-performance liquid chromatographic methods were developed for the determination of fenbendazole, praziquantel and pyrantel pamoate in dog plasma. The combination of these drugs is the most powerful treatment against most types of worms. Blood plasma samples obtained in a pharmacokinetic trial were prepared using solid-phase extraction. Fenbendazole and praziquantel were analyzed simultaneously by reversed-phase high-performance liquid chromatography on an octadecyl-modified silica stationary phase employing acetonitrile-phosphate buffer (pH 3.0) eluent and ultraviolet detection at 220 nm. Pyrantel was analyzed separately on a base-deactivated reversed-phase column using methanol-tetrahydrofuran-ammonium acetate buffer (pH 4.6) eluent and ultraviolet detection at 317 nm. Average recoveries for fenbendazole, praziquantel and pyrantel pamoate were 76.8, 93.4 and 90.5%, respectively. Limits of quantitation were in the range of 15-25 ng/ml plasma.

Studies on the pathogenicity of bovine herpesvirus type 5 in sheep.

Four Merino lambs were intranasally inoculated with bovine herpesvirus type 5 (BHV-5) reference strain N569. Two lambs were mock-inoculated as negative controls. The virus-inoculated animals developed apathy, inappetence, rhinitis, nasal, ocular and genital discharge, slight diarrhea and neurological disorders, like tremor and salivation. BHV-5 was isolated from the nasal discharge in two of the animals, while the polymerase chain reaction (PCR) detected the virus in all the infected lambs. Two lambs died on post infection day (PID) 13, while the other two infected animals were euthanized on PID 15 and 30. Gross pathological changes were not observed, however, histopathological examinations revealed diffuse nonsuppurative meningo-encephalitis in all infected animals. Viral antigen was detected by immunohistochemistry and viral nucleic acid was revealed by in situ hybridization in the brain of the two lambs, which died on PID 13. The virus was demonstrated by virus isolation and by PCR from different organs of all the infected animals. Slight rise of antibodies was observed in the infected animals from PID 15. The results show that BHV-5 is able to cross the species barrier and may establish infection in sheep.

Occurrence of atypical myxomatosis in Central Europe: clinical and virological examinations.

An outbreak of the atypical form of myxomatosis struck a rabbit farm in Hungary. The animals had previously been vaccinated with a vaccine containing Shope rabbit fibroma virus strain. The disease appeared in winter when the presence of mosquitoes and fleas is not common. The virus was isolated from an eyelid specimen of a naturally infected rabbit. The surviving animals were observed for four weeks, blood samples were collected and, after euthanasia, organ specimens were also examined by morphological methods including pathology and electron microscopy. Serum samples were examined by virus neutralisation for antibodies. Genetic analysis of the isolated virus was carried out by polymerase chain reaction (PCR) and direct sequencing. The primers were designed on the basis of the major envelope gene (Env) of the Lausanne reference strain in the GenBank. The viral proteins were examined by SDS-PAGE. The isolated virus (ref. no.: BP04/2001) was able to infect the susceptible animals directly, by contact. The disease was characterised by respiratory symptoms of the upper tracheal tract, conjunctivitis and high mortality by the 11th-14th day. Aerogenic infection with strain BP04/2001 resulted in 100% morbidity among the susceptible animals. Sequencing of the amplified 400-bp-long DNA revealed 97% homology with the Env gene of the Lausanne strain, which proves that strain BP04/2001 is a variant of the Lausanne strain having been enzootic throughout Europe. The live vaccine strain used in Hungary against myxomatosis, which is also a Lausanne-derived strain, protected the animals. According to the protein analysis a protein of 200 kDa in size is not expressed in strain BP04/2001. This is the first report on atypical myxomatosis in Central Europe. The virus spreads by airborne transmission and may cause severe losses in the rabbit population.