Conclusions

We are currently experiencing two pandemics, one caused by a coronavirus and one by the reemerging dengue flaviviruses. Strict protective measures have been taken to safeguard against this coronavirus, which may have saved many lives. Fear, depression, and suicide have also resulted from these measures. In addition to dengue, other flaviviruses of humans or animals may also rapidly spread and become more pathogenic, as have Zika and West Nile viruses. Many viruses may have originated in bats or rodents. Several bats are seropositive for dengue, Saint Louis encephalitis, and Japanese encephalitis viruses. Some rodents are seropositive for tickborne encephalitis, West Nile, Usutu, and Wesselsbron viruses. Domestic animals, especially cattle and sheep, but also dogs and cats, have a much higher incidence of flavivirus infection than bats and rodents and have closer contact with humans. Less-toxic, broad-spectrum antiviral agents that are active against these and other emerging flaviviruses are needed to protect against future viral threats.