In 2007, African swine fever virus (ASFV) was introduced into the Transcaucasian countries and Russia. Since then, it has spread alarmingly and reached the European Union. ASFV strains are highly virulent and lead to almost 100% mortality under experimental conditions. However, the possibility of dose-dependent disease courses has been discussed. For this reason, a study was undertaken to assess the risk of chronic disease and the establishment of carriers upon low-dose oronasal infection of domestic pigs and European wild boar. It was demonstrated that very low doses of ASFV are sufficient to infect especially weak or runted animals by the oronasal route. Some of these animals did not show clinical signs indicative of ASF, and they developed almost no fever. However, no changes were observed in individual animal regarding the onset, course and outcome of infection as assessed by diagnostic tests. After amplification of ASFV by these animals, pen- and stablemates became infected and developed acute lethal disease with similar characteristics in all animals. Thus, we found no indication of prolonged or chronic individual courses upon low-dose infection in either species. The scattered onset of clinical signs and pathogen detection within and among groups confirms moderate contagiosity that is strongly linked with blood contact. In conclusion, the prolonged course at the "herd level" together with the exceptionally low dose that proved to be sufficient to infect a runted wild boar could be important for disease dynamics in wild-boar populations and in backyard settings.

No abstract

Heart and skeletal muscle inflammation (HSMI) is one of the most widespread economically relevant diseases of farmed Atlantic salmon (Salmo salar), and it poses serious danger to its aquaculture. The disease was first reported in Norway in 1999. In 2006, the Norwegian researchers demonstrated its viral etiology. Heart and skeletal muscle inflammation is a novel and understudied highly contagious transboundary disease of Salmonidae characterized by erythrocyte damage, blood circulation failure, jaundice and aggregated signs of heart and skeletal muscle inflammation. The disease associated economic damage to aquaculture is enormous. Total cumulative mortality can reach 30% and morbidity can amount to 100%. Loss of quality of the commercial fish products due to melanised foci in the salmons’ muscles further increases the disease-associated economic losses. Aquacultured Atlantic salmon is the most susceptible to HSMI. Rainbow trout, chub salmon and bull trout are also susceptible species and the list is still being continued. The disease is caused by the virus belonging to genus Orthoreovirus in the family Reoviridae. Currently Piscine orthoreovirus demonstrates the tendency towards its global spread. The virus-induced disease is reported in Norway, Scotland, Ireland, Iceland, France, Germany, Italy, Denmark and Alaska. The majority of the outbreaks are registered in Central and Northern parts of Norway, which borders the Murmansk Oblast. The vicinity of the affected areas to Russia, the Gulf Stream passing the Norwegian shore while moving towards the Murmansk Oblast as well as wild Salmonidae migration to the Barents Sea, White Sea and Pechora Sea through the Norwegian territorial waters coupled with high stability of the virus compose high threat of Piscine orthoreovirus introduction to the Russian Federation from the adjacent countries.

No abstract

The paper studies the effect of the RVI biocomposite material belonging to the group of osteoplastic biocomposite materials, the RV-2 immunomodulator – a synthetic dipeptide inducing an immunocorrective effect, and combinations of these drugs on the reparative histogenesis of bone tissue in femoral fractures in rats. It was found that the remodeling of the primary bone callus into the secondary one in the fracture of the studied animals was of a diverse nature. This process was the most pronounced in the group where the components were used in complex, i.e. the bone defect was filled with RVI during the surgery, as well as RV-2 was injected intramuscularly to rats at a dose of 10 mcg per 1 kg of live weight for five days, starting immediately after the surgery. Well-formed coarse-fibrous connective tissue callus was recorded in animals of this group. The connective tissue was stained more intensely which indicates a denser arrangement of fibers in the callus. Focal cartilage tissue spanning bone fragments was observed within the callus. At the periphery of the site the cartilaginous callus was subjected to endochondral ossification with replacement by coarse-fibrous trabeculae with elements of lamellar bone tissue having haversian canals in the center. The inter-girdle spaces were filled with elements of the myeloid bone marrow in the forming bone tissue. Markedly proliferated osteoblasts were visible in the cambial layer of the periosteum. The bone tissue ratio increased up to (60.21 ± 2.62)%, which significantly exceeded the same indicator in the control group and in all experimental groups. The low content of connective tissue and the high ratio of bone tissue indicated more active osteogenesis processes and reparative regeneration in comparison with other groups.