West Nile upswing

(CNN) -- Dr. Sanjay Gupta reported on lots of medical breaking news this week. One story that has really caught the public's attention is the spread of the West Nile virus. The number of cases has increased rapidly compared to three years ago.

The virus is transmitted through mosquitoes that feed on infected birds. According to the Centers for Disease Control and Prevention, the virus gets into a mosquito's salivary glands. Mosquitoes then inject the virus when they bite humans or animals.

Researchers say that approximately 1 percent of people who are bitten become ill. Those who do get the virus usually suffer from flu-like symptoms.

A new clinical trial is under way to determine whether the drug alpha interferon, approved for the treatment of hepatitis C, might help relieve the symptoms of the West Nile virus. Doctors will have the option of using the drug for hospitalized patients.

Now here's a look at more health and medical news making headlines this week.

New study questions ginkgo biloba

The supplement ginkgo biloba promises to boost your brain power by reversing the effects of aging. Makers claim it enhances mental focus, and improves memory and concentration.

Researchers at Williams College in Williamstown, Massachusetts, disagree.

Their study found that people who took gingko biloba faired no better than people who didn't.

"When following the manufacturer's instructions, ginkgo provides no measurable benefit in memory or related cognitive function," wrote researchers in the Journal of the American Medical Association.

Click here to read the results of the study and for a list of memory tips.

Elderly drivers beware

Older drivers with cataracts are more likely to have accidents than elderly drivers without such vision problems.

A new study in the Journal of the American Medical Association says cataracts affect the eyes' ability to see fine detail and to detect differences between objects. However, the condition is treatable.

Cataracts can be surgically removed to diminishing vision problems. Researchers found that older motorists who had corrective surgery for cataracts decreased their risk of accidents by half.

Click here to read how medical treatment can improve age-related driving impairments.

Food for thought

New research shows almonds can help reduce heart disease by lowering cholesterol.

During a three-month study, people who ate almonds reduced their low-density lipoprotein (LDL) – also known as the "bad" cholesterol -- between 4 percent and 9 percent.

While the results are promising, it is important to note that the Almond Board of California partly funded the study.

Click here for the results of the study.