Possibility of long-term survival of African swine fever virus in natural conditions

Background and Aim: In modern scientific literature presents an understanding that African swine fever (ASF) ASF virus (ASFV) is remarkably stable in the environment, and carcasses of the pigs which were died after ASF, play a key role as ASFV reservoir. The aim of this study was to evaluate the possibility of the ASFV (different isolates) survival in bodies of dead animals, bones, remnants of bone marrow, residual organ matrix in natural conditions. Materials and Methods: Skeletons of ASFV infected pigs which were died and left/abandoned in forests or buried in Armenia at diverse time points and locations had been excavated and examined for the presence of ASFV genome by real-time polymerase chain reaction (PCR) assay and for infection abilities through in vitro (hemadsorption test and infection in porcine lung macrophages) as well as by intramuscular infection in healthy pigs. Results: Current exploration showed that in several samples (with different times of exposure) of excavated skeletons had been detected the presence of the virus gene (p72) using real-time PCR. However, in none of these porcine samples, infectious ASFV could be isolated. Data obtained by real-time PCR at frequent intervals indicated the presence of the virus gene (p72), especially within the case of the acute form of the disease. This can be explained by the highest levels of the virus during the latter case mentioned above. Conclusion: ASFV seems to be very sensitive to environmental temperature. The best place for ASFV long-term survival in the natural environment is bone marrow from intact big tubular bones (like femur or tibia) of buried carcasses. In artificial "graves," complete bones with not destructed bone marrow can preserve the virus gene (p72) for a very long time (more than 2 years). Infectious particles in underground conditions survive not so long: In complete bones with not affected bone marrow, possible presence of the virus for several months.

Mutational Analysis of SARS-CoV-2 Genomes in Key Cities of China

From December 2019, SARS-CoV-2 induced pneumonia broke out in Wuhan and then spread rapidly from multiple resources to other provinces and other cities in China. In this paper, genomes collected in four Chinese cities: Wuhan, Guangzhou, Shanghai, Hangzhou were analyzed as the A1 module of the MAS. Starting from the virus gene sequence itself, multiple probability statistics are applied to extract characteristics from virus genomes. Variations of genomes can be compared and visualized in such conditions. It is interesting to see various similar and different properties visualized under various groups after transformations. In this way, key mutation characteristics could be observed and this type of results is helpful for further scientific researches on COVID-19 applications.