Human Rabies during the COVID-19 Pandemic: Insights into Rabies Worldwide and Brazil

Human rabies (HR) manifests as acute progressive encephalitis caused by the rabies virus (RABV), a single-stranded RNA virus belonging the genus Lyssavirus of the family Rhabdoviridae. Transmission of HR occurs via the saliva of a rabid animal, most often through bites. During and after the COVID-19 pandemic, the number of human rabies cases is increased because of the cancellation or disruption of dog vaccination campaigns, vaccine shortages, reduced animal testing, an increase in the stray dog population, and a rise in animal bites have all contributed to its resurgence. HR is still a disease with a 100 % fatality rate, so there are the risks associated with neglecting HR to focus on COVID-19. The solution to HR involves various areas of expertise, incorporating the One Health approach, social education, and public health measures.

(RN)

Recombinant Vesicular Stomatitis Virus Vaccine Vectors Expressing Filovirus Glycoproteins Lack Neurovirulence in Nonhuman Primates

Ebola and Marburg viruses are some of the filoviruses that cause fatal haemorrhagic fever in both humans and nonhuman primates. Vesicular stomatitis virus (VSV) from the family Rhabdoviridae has a simple genome structure and foreign genes can be inserted in the genome. This ability has been explored in the development of vaccines against other viral diseases. Recombinant VSV is also able to increase the virus titres in mammalian cells but cannot insert or recombine into the host cell genome. These factors make it a good candidate for recombinant vaccine development. To prevent diseases caused by these filoviruses advanced developments with promising results regarding vaccines production have been made. Recombinant vesicular stomatitis virus (rVSV) with filovirus glycoprotein expression instead of VSV glycoprotein (GP) has been used. There has been concerns about the safety of these competent replication vaccines and therefore this study performed a neurovirulence experiment using cynomolgus macaques. These animals were divided into groups and given rVSV vectors expressing different GPs from different filoviruses. One group got rVSV vector with Zaire Ebola GP, another with Lake Victoria Marburg virus GP, another received rVSV wild type and the last group was the control. The results showed that there were no symptoms and neural lesions on all animals that received rVSV filovirus vaccines. Symptoms and lesions were observed in animals that received the wild type rVSV. This indicates that rVSV expressing filovirus glycoproteins vaccines do not have neurovirulence properties.

(BEC)

Long-Term Detection and Isolation of Severe Fever with Thrombocytopenia Syndrome (SFTS) Virus in Dog Urine

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne infection caused by the Davie bandavirus (the SFTS virus; SFTSV), and its fatality rate is approximately 30% in humans. Recently, cases of contact infection with SFTSV via bodily fluids of infected dogs and cats have been reported. In this study, clinical and virological analyses were performed in two dogs in which SFTSV infection was confirmed for the first time in the Toyama prefecture. Both dogs recovered on days 2 and 7 after the onset of disease. One was severely ill and the other mildly ill. In these two cases, the SFTSV gene was detected in the dogs’ urine at a higher concentration than in other specimens, and that the detection period for the gene was >2 months after onset. The virus isolation was unsuccessful in the frozen urine specimens, but only in the refrigerated urine specimens. Based on these findings, owners and veterinarians should be careful when handling bodily fluids, especially urine, even after the symptoms have disappeared.

(RN)

Developments in Negative-Strand RNA Virus Reverse Genetics

Negative strand RNA viruses have caused fatal disease outbreaks in both human and animal health leading to losses in economic and food security sectors. Examples of these viral diseases include Ebola disease, Marburg, Rabies, Peste des Petits ruminants  and Influenza. Reverse genetic systems have been used to study these viruses in terms of their pathogenesis, protein functions, gene expression regulations and even in development of vaccines. This technique involves generation of complimentary DNA (cDNA) from reverse transcription of the RNA genome. This is followed by plasmid construction and transfection into the cell with the full length of the viral genome. In the cell, the virus replicates and finally the virus can be harvested in the process known as virus rescue. These reverse genetics have been employed in the study of different single negative strand RNA viruses. For instance, this was used in the development of influenza synthetic vaccine through a plasmid free rescue system. This has been used also to study Marburg and Ebola viruses. In animal viruses, recently there was a successful construction of a recombinant viruses for Peste des Petits ruminants virus which was a potential candidate for development of inactivated vaccines. Reverse genetics of these RNA viruses continues to evolve as researchers dive deep to understand and develop preventive measures to these viral diseases.

(BEC)