Get From Birds To People The West Nile Virus Story Worksheet Answers

Slide 14: Humans Are a Dead-End Host Although the virus can infect humans and cause disease, it will not spread.

However, humans, horses and other mammals are 'dead end' hosts. This means that they do not develop high levels of virus in their bloodstream, and cannot pass the virus on to other biting mosquitoes. “Dead End” Host. Mosquito Vector.

Can a human get West Nile virus twice? Medical professionals don't believe so. Like many other viruses, medical tests indicate that once a person has been infected with West Nile, he/she develops a natural immunity to future infection by the virus for life.

Birds are the most common arbovirus hosts, whereas humans and other animals such as horses are usually dead-end hosts — they do not transmit the virus to others in the 'herd', and cannot function as a reservoir for reinfection of mosquitoes. Infection of dead-end hosts can, however, lead to clinical disease (Table 1).

The West Nile Virus (WNV) was first found in a febrile adult woman in the West Nile District of Uganda in 1937. The virus became recognized as a cause of severe human meningoencephalitis (inflammation of the spinal cord and brain) in elderly patients during an outbreak in Israel in 1957.

West Nile virus is mainly transmitted to people through the bites of infected mosquitoes. The virus can cause severe disease and death in horses. Vaccines are available for use in horses but not yet available for people. Birds are the natural hosts of West Nile virus.

West Nile virus is most commonly spread to people by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes then spread West Nile virus to people and other animals by biting them.