Poliovirus is highly contagious and infected individuals shed virus in the faeces and from oral secretions, thus the mode of transmission is person-to-person, both via the faecal-oral and the oral-oral routes.
Marburg virus disease (MVD), formerly known as Marburg haemorrhagic fever, is a severe disease in humans caused by Marburg marburgvirus (MARV). Although MVD is uncommon, MARV has the potential to cause epidemics with significant case fatality rates.
West Nile virus is a mosquito-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds. Humans and horses are incidental dead-end hosts.
West Nile virus (WNV) infection is a mosquito-borne zoonosis. The virus is transmitted among birds via the bite of infected mosquitoes and incidentally humans and other mammals may become infected.
Poliomyelitis, also known as polio or infantile paralysis, is a vaccine-preventable systemic viral infection affecting the motor neurons of the central nervous system (CNS). Historically, it has been a major cause of mortality, acute paralysis and lifelong disabilities but large scale immunisation programmes have eliminated polio from most areas of the world.