How many human cases have there been in the United States?

The latest count of human cases in the United States can be found on CDC's Web site.

How many cases have there been in Texas?

For the latest up-to-date information on human cases in Texas, go to the Texas Department of State Health Services: West Nile Virus in Texas.

Where in Texas has the virus been found?

For the most up-to-date information, go to the Texas Department of State Health Services: West Nile Virus in Texas.

Do birds or mosquitoes get it first? Where does the virus live?

It is usually found first in birds. Generally, surveillance by the Texas Department of Health finds the virus in birds a week or two before finding positive mosquitoes. The virus is in their bloodstream. Mosquitoes become infected when they feed on infected birds. The infected mosquitoes can then transmit West Nile Virus to humans and animals while biting to take blood. The virus is located in their salivary glands and, during blood feeding, the virus can be injected into the animal or human, where it can multiply, possibly causing illness in the animal or human.

What kinds of laboratory tests are done to identify the West Nile Virus?

Various tests can be done. The type of test will vary among mosquitoes, humans and horses. The type of test also depends on the kind of samples available (blood serum, cerebrospinal fluid, brain tissue). Samples may be tested to find antibodies to the West Nile Virus, or there may be an attempt to isolate particles from the sample. More details are available at the Texas Department of State Health Services: West Nile Virus in Texas.

Can dogs, cats and other pets get the West Nile Virus?

Yes. But they rarely, if ever, get sick. No cases of West Nile disease have been confirmed in dogs and cats. The virus can infect many species of animals, but few actually get the disease. Most infections have been identified in birds, but West Nile Virus has been shown to infect dogs, cats, horses and domestic rabbits, as well as bats, chipmunks, skunks and squirrels.

Is there a vaccine for dogs, cats or horses?

There is not a vaccine for dogs and cats, but there is an effective vaccination available for horses.