"In a city where you have a large outbreak, generally only 2 percent of the population is bitten by mosquitoes that carry the West Nile virus," Ratard says. "Out of that 2 percent, only 1 in 200 people will get encephalitis (the severest condition from the virus with brain and spinal cord inflammation), and 10 to 20 people will get West Nile fever (whose symptoms mimic that of a severe flu). The rest, 180 people, get infected, the virus multiplies, the body produces antibodies to the virus and these people don't even know they were ever infected."
Statewide, the number of cases of West Nile virus dropped significantly last year. In 2003, 121 cases of West Nile virus were recorded in Louisiana, with seven fatalities. In 2002, Louisiana had one of the nation's highest incidences of the virus with 330 cases and 25 fatalities. Nationally, there were approximately 4,100 cases reported in 2002 and nearly twice that number in 2003 with 9,006 incidences. The number of people who died from the virus across the country did drop in 2003 with 222 fatalities, down from 284 deaths in 2002.
Locally, the numbers also fell from 2002 to 2003. In 2002, 41 cases of West Nile virus were reported in Jefferson Parish, with one death. Orleans Parish had 22 people affected by the virus and 3 deaths in 2002. For 2003, the numbers dramatically improved with only 3 cases in Jefferson and 4 cases in Orleans. There were no deaths from the virus reported in either parish in 2003.
LAST YEAR, HOWEVER A FEW PEOPLE locally did come down with the virus. In one case, it might have been the result of some uninvited guests at a birthday party.
On Aug. 16, 2003, Patty Henn, a waitress at a local restaurant, threw a 40th birthday party for her husband, Randy, at their home in the Irish Channel. Patty sent out a number of invitations, but she didn't plan on the party-crashing mosquitoes that showed up.
"I think I caught it that day because I was outside a lot," she says. "The next day I was fine, but the following day I felt sick to my stomach and a bit flu-like. By the third day, I was just floored and the next day my husband took me to the doctor's. The doctor didn't really even examine me -- he just looked at me and told me to go straight to the emergency ward at Touro."
Henn was admitted into Touro Infirmary Hospital and spent the next five days there with a high fever and dehydration. The West Nile virus had not yet been diagnosed, and the treatment was quite simple: sleep, intravenous fluids, and aspirin. Henn's fever hovered between 103-104 degrees until it finally broke and she was sent home.
For the next few days, she tried to recuperate, but she found she had severe pain in her joints and a persistent splitting headache. A phone call from Touro later confirmed that this was no average flu bug.
"They called me and told me that I had West Nile virus," Henn recalls. "Since the pain is so severe, they prescribed Vicodin and Valium, so that I could sleep. Eventually, the pain subsided and it turned into pure fatigue. It was two months before I could go back to work."
Although Henn was spared the worst neurological consequences of the virus, the sometimes-fatal encephalitis or meningitis, she has experienced some lingering effects from her bout. Even when she returned to the restaurant, she found that she had very little energy. "Luckily, they let me sit down a lot," she says. Currently, she needs to take at least one nap a day and she sleeps nine hours a night. Prior to the illness, she didn't take naps and slept only seven hours per night. Until a few days ago, Henn didn't realize this could be attributed to the virus.
"I thought I was just getting old," admits the 47-year-old Henn. "But then I got a call from the state and they asked me if I found myself taking naps and sleeping more. I said yes, and then they said that's an effect that everyone gets. I asked if there was anything I could do about it, and they said, Yeah, sleep.'"
FOR THE NEW ORLEANS MOSQUITO and Termite Control Board, the West Nile virus means there's no time to rest. Because the primary means of transmitting the virus is from a mosquito bite, the board has decided to take the fight to the bugs before the mosquito population has a chance to get to high levels.
In mid-June, the board began what assistant director Mike Carroll calls "a pre-emptive strike" -- a systematic citywide spraying. "We did this last year for the first time and it drove the mosquito population so desperately low that there seems to have been a residual effect into this season because the mosquito population this year has gotten off to a slow start," Carroll says.
The spraying is primarily done by a twin-engine airplane, but Carroll says that the amount of insecticide per acre shouldn't alarm anyone about possible ill effects from the chemicals. "People put more pesticides on their tomato plants than we could ever imagine putting out there," he says.
This year, the control board is targeting abandoned and neglected swimming pools. During the winter, the board mapped out as many of these types of pools as they could find. The pools were then pretreated with insecticide, so mosquitoes wouldn't be able to breed there in the spring. Additionally, there will be street-to-street truck spraying.
The board isn't only concerned with eliminating mosquitoes. One of its more crucial tasks is monitoring the parish for any occurrences of the West Nile virus. Since mosquitoes are the virus' vectors, transmitting the disease from host animal to host animal, the board tries to focus its surveillance on those host animals most affected by the virus. For this, they turn to the birds.
Among birds common to our area and most parts of the country, crows and jays are particularly susceptible to the virus. Usually one of the first signs of West Nile virus' presence in an area, before any human infections, is a large number of dead crows or other birds such as jays, sparrows or grackles. When a dead bird is found, it is sent to the Louisiana's Office of Public Health where it is tested for the West Nile virus. The Mosquito Control Board is then notified of any positive results.
Another method of surveillance used by the board involves sentinel chickens. These aptly named birds are placed in cages across the parish -- mostly in fire stations, which are both secure and strategically located throughout the community. Every two weeks, the chickens' blood is tested for the West Nile virus. Unlike the crows and other birds, the chickens do not become sick and don't transmit the disease, but their blood will reveal antibodies if they've been infected.
For 2004, the results of the chicken testing have been very encouraging. "So far there hasn't been any positive chickens yet, although we did have a few dead birds test positive in January and February," Carroll says. "Right now the total number of dead birds reported have been much lower than in previous years."
Vaccines are available for horses and some birds, and drug companies are currently working on a human vaccine. However, as Carroll points out, in the case of humans it might not be necessary.
"They're working on it, but I don't know if it's practical since this virus might run its course and become like St. Louis encephalitis, which pops up every five to 10 years and then we only have a few sporadic cases."
Current conditions -- a relatively low mosquito population, fewer dead birds, and the fact that the virus appears to be moving west -- indicate that this should be a slow year for West Nile virus in Louisiana. (Colorado and Nebraska were hard hit in 2003 and California is forecasted to have high numbers in 2004.) However, as state epidemiologist Ratard warns, the disease is relatively new, so there are no certainties.
"In 2002 in spite of the intensive mosquito control program there were large outbreaks, so the real reason for the numbers being low is that we don't know," Ratard says. "We are doing the right things. The Mosquito Control Board is doing an excellent job and people are being warned. More than likely, 2004 will be a very slow year -- that's the prediction but we don't know for sure."
For more information on the West Nile virus, go to www.FightTheBiteLouisiana.com. The Office of Public Health of Louisiana requests that anyone who finds a dead bird call the Parish Health Unit (568-7970 in Orleans Parish and 838-5140 in Jefferson Parish).