U.S. public health officials report three new cases of the deadly West Nile virus since the first case of the year appeared last week. Although the tally is still small, the disease is more widespread than last year.
The U.S. government's disease tracking agency, the Centers for Disease Control, confirms a total of four cases of West Nile virus - two in Texas and two in South Carolina.
Agency director Julie Gerberding says this is the same number of cases as this time last year. But what bothers her is that the virus is spreading geographically. Thirty U.S. states are reporting virus activity in mosquitoes, animals, and people compared to 22 as of this time last year.
"Overall, the national activity level has increased," said Ms. Gerberding. "We also anticipate an upswing in West Nile Virus activity toward the end of July and August. So therefore, we have to stay tuned to really appreciate what the full scope and magnitude of the outbreaks will be this year."
The pace of activity hints that West Nile Virus may reach more Americans this summer than last, when it infected over four thousand and killed nearly 300 in all but six of the 50 U.S. states. The growth has been explosive in the country since an initial outbreak of just 62 people in 1999.
So far, there are no remedies, but researchers are making progress on vaccines and drugs.
The U.S. government's National Institutes of Health says an experimental vaccine has proven safe and effective in monkeys and is close to human testing. It is an adaptation of the successful 70-year-old vaccine for yellow fever, a closely related virus. Scientists have re-engineered it to display live West Nile virus on its surface to stimulate the immune system and teach it how to react against the actual virus.
A vaccine further behind in development uses selected proteins from an inactivated West Nile virus. This is considered a safer approach for pregnant women or people whose immune systems are weakened.
As for drugs to treat the disease, National Institutes of Health virus expert James Meegan says scientists are still in the laboratory stage.
"We've been testing many compounds in cell cultures and looking for those that inhibit West Nile replication in those cells," he said. "Those that have shown positive activity are being tested now in mice and hamsters. We've gone through about 600 different compounds and between 20 and 30 show activity."
Without a cure for West Nile virus, Centers for Disease Control chief Julie Gerberding says prevention is still the only protection. She warns anyone in mosquito-infested areas to cover their arms and legs, use insect repellent, and remove areas of standing water that attract the bugs.