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.
Hepatitis C is a liver disease caused by infection with the hepatitis C virus (HCV). HCV can cause both acute and chronic hepatitis infection, ranging in severity from a mild illness that lasts only a few weeks to a serious, lifelong illness resulting in cirrhosis and liver cancer.
HIV is a virus which attacks the immune system and causes a lifelong severe illness with a long incubation period. The end-stage of the infection, acquired immunodeficiency syndrome (AIDS), results from the destruction of the 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.