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.
Despite good access to effective antibiotics, Streptococcus pneumoniae (pneumococci) is still a major cause of disease and death in both developing and developed countries. Pneumococci are the main cause of bacterial respiratory tract infections, such as pneumonia, middle ear infection, and sinusitis, in all age groups.
Listeriosis is a disease caused by Listeria monocytogenes. The disease primarily causes problems in pregnant women, newborns, and adults with a weakened immune system.
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.