West Nile Virus Takes 2 More Lives

One man in Louisiana and another in Illinois have died after being infected with the West Nile virus, while Wyoming authorities said the virus has been detected for the first time in that state, according to state health officials.

A 67-year-old Illinois man died six days after being admitted to a hospital on Aug. 4, according to Illinois officials. And a 78-year-old Livingston Parish man became the eighth fatality of the year in Louisiana.

The two cases bring the U.S. death toll for the year to 11, counting two other deaths in Mississippi.

The detection of the virus in Wyoming brings the number of states where the virus has been identified to 39. It has now been found in every state east of the Rocky Mountains.

“It’s clear to us that the virus will, in fact, go coast to coast; it’s just a matter of time,” said Dr. Lyle Petersen of the U.S. Centers for Disease Control and Prevention. Diseases spread by insects or animals, known as vector-borne diseases, can be transmitted widely at a very rapid rate, he said.

Vicki Kramer, chief of the vector-borne disease section of the California Department of Health Services, said: “We do think that it will be introduced [into California], possibly this year, but more likely in the next one to two years.”

She noted that the department had expanded its surveillance program in 2001 “to enable us to detect it as soon as possible once it is introduced.”

But she also said that California has a nationally respected mosquito-control program that could minimize the effect of the virus if it should reach here.

The West Nile virus is carried over long distances by birds, which eventually fall ill from the virus and die.

While the infected birds are alive, however, they are bitten by mosquitoes, which then transmit the virus to humans.

Most people who are infected with the virus have no symptoms. About 1 in 5 develop mild flu-like signs. But a small fraction of those infected, perhaps 1 in 100 to 150, develop viral meningitis or encephalitis and become extremely ill, requiring hospitalization. From 11% to 14% of those die of their illness.

Among those who survive their hospitalization, Petersen said, about half of them still have some neurological problems a year later.

From 1999--when the first U.S. case appeared in New York--to 2001, 149 Americans were hospitalized as a result of infections and 18 died, according to the CDC. By midweek, the CDC had identified 156 more cases this year, but four new cases were reported Thursday, three in Chicago and one in New York. Human cases have now been reported in 13 states, with Texas being the most affected with 16 cases.

The most recent state affected is Michigan, where officials said Friday that two elderly men had suspected cases of the virus. Both men are expected to recover.

The CDC’s Petersen said Thursday that there could be as many as 1,000 severe cases this year, which would translate to about 100 deaths.

But he also noted that mosquito control efforts in Louisiana and elsewhere could “have a major effect on blunting this epidemic. So if those efforts are highly successful, we may see a lot less than 1,000 cases.”

Officials noted that this is many fewer than the number of U.S. deaths from influenza and other infectious diseases, but they fear the number will rise as the virus becomes more firmly entrenched in wildlife throughout the country.

Petersen also said that a significantly larger proportion of the cases detected in humans this year are among younger people, although most deaths have been among the elderly.

The Wyoming case occurred in a horse from eastern Goshen County near the Nebraska border. Samples were collected the previous week and tested at the state veterinary laboratory in Laramie.

“We’re treating it as a positive and we feel really comfortable calling it a positive,” said Ross Doman, a spokesman for the state health department.

Colorado health officials on Thursday reported the detection of the virus in a crow and three horses, the first time it had been seen in that state as well.

California has a network of surveillance programs that collect mosquitoes and analyze them for the presence of several viruses, including West Nile. Sentinel chickens are also an important part of the program. The mosquitoes that carry the viruses prefer to bite birds rather than mammals, but the chickens are not harmed by infection. Health authorities bleed the animals every two weeks (by pricking their combs) and check for antibodies to several viruses.

Kramer urged Californians who see crows, jays, ravens, magpies, sparrows or finches that have been dead for less than 24 hours to report them to health authorities at 1-877-WNV-BIRD.

The department will pick them up and test for the presence of the virus.