Fight the Bite
With West Nile season in full swing,
health officials get the word out on protective measures against the mosquitoborne virus – and nurses can take the lead in educating their communities
By Alicia Hugg, RN, MA
August 16, 2004
When a 75-year-old man who liked to take naps on his front porch hammock became the second person in California to die from West Nile virus Aug. 1, his wife said, “You can’t believe that a mosquito could do that. We need to get word out to everybody and anybody. Wear a long-sleeved shirt and don’t leave any water out.” This advice has become a Centers for Disease Control and Prevention mantra in educating people about the mosquitoborne virus.
This year, the virus, which originated in Africa and spread through countries in Eastern Europe before the first U.S. invasion in 1999, has established its strongest hold in the western United States, and the number of reported cases so far is considerably ahead of the five cases reported at this time last year.
With Arizona reporting 247 new human cases and two deaths as of Aug. 3, Maricopa County has been designated the epicenter of WNV for the United States. California follows with 69 reported cases and two deaths, and there is concern that this year’s cases will outpace last year’s record-setting numbers, when nearly 10,000 illnesses were reported.
As of this writing, the CDC Surveillance Program has reported 406 cases of West Nile with seven deaths.
In weighing the situation nationally, CDC spokeswoman Christine Pearson gave cautionary advice. “It is extremely difficult to make any predictions,” she said. “West Nile started out very targeted in New York. Look at last year — most of the area west of the Rockies had a handful of cases, with Washington and Oregon being the exceptions. Given the activity we have seen in years past, it would not be a surprise to see more cases this year.”
Asked why he thought Arizona was leading statistically this year, Michael Murphy, Arizona Department of Health Services’ public information officer said, “It’s our turn. Last summer, we had just 15 cases.” He recalled that Florida started out the same way a few years ago, and then increased significantly. Murphy also noted that historically the second year of WNV is worse for most states.
Murphy said that although Arizona is primarily dry desert, the state has many artificial sources of water, especially in and around Phoenix, where swimming pools in residents’ back yards are common and ponds on golf courses are poorly maintained. “It turns into a green cesspool in our back yards, an ideal breeding place for mosquitoes,” he said.
More mosquitoes
With the emerging monsoon season, Murphy anticipates even more mosquitoes because humidity increases with the afternoon thunderstorms. “The season lasts through August and we could easily have 3,000 to 5,000 cases.”
His department is conducting “emergency larviciding” for swimming pools, even throwing larvicide over fences of suspicious looking pools, encouraging residents to use repellent and wear protective clothing when outdoors, and developing an educational videotape for distribution to physicians and other health care professionals.
Assistant director for Arizona’s Public Health Services Rose Conner, RN, MEd, believes it is critical for nurses to take the lead in educating family, friends, and neighbors about West Nile. “Nurses must be aware of public health messages and use their knowledge and skills to make sure people are safe. People expect nurses to know about West Nile and will approach you because you are a nurse.”
Conner said that based on the numbers of reported cases, it is probable that about 15,000 cases will never be diagnosed because of the flulike signs and symptoms of WNV. “Only people who get very sick go to their doctor, who will test them for West Nile,” she said. “In Arizona, we don’t expect WNV to start decreasing until October.”
In California, a 71-year-old Los Angeles County man and a 26-year-old Riverside County man were the first to test positive for WNV in their counties this year. The Los Angeles County resident was not hospitalized and is recovering. The Riverside County victim was hospitalized with meningitis in June and later discharged in good condition.
As manager of the Pasadena Public Health Department’s Office of Communicable Disease Prevention Division, Candy Jara, RN, PHN, receives daily updates from the State Department of Health Services, as well as from Los Angeles County. She said that as of July 1, WNV infection, when documented by laboratory findings, has been added to their list of mandated reportable diseases and conditions.
Los Angeles had its first WNV-related death June 24, when a 57-year-old Orange County man died from encephalitis. That the disease is moving into Northern California was evidenced July 21, when the first dead bird appeared in Santa Clara County. Dead birds, sentinel chickens, and pools of infected mosquitoes also have been found as far north as Butte and Tehama counties.
“We are getting more phone calls from concerned citizens and are being proactive in our response, including press releases, educational forums, and hot lines. Los Angeles County will host a training program for our staff using a CD-ROM or disc so we are all giving out the same information,” Jara said.
Richard Jackson, MD, state public health officer, expects WNV to continue to spread throughout the state and advises residents to take steps now to protect themselves from mosquito bites. “These first West Nile virus cases in Los Angeles and Riverside counties follow a well-established pattern in which dead birds and mosquitoes infected with the virus preceded the reports of human illnesses,” he said.
Carol Glaser, MD, acting chief of the Department of Health Services’ viral department laboratory, thinks the valuable “thing about the WNV indicators are the dead birds, mosquitoes, and chickens because until we have West Nile activity, we will not have West Nile.”
Glaser anticipates more WNV activity during the next few weeks or months when the arbovirus season peaks. Her department is working with the University of California, San Francisco and other institutional review committees to facilitate trials.
“The danger here is that everybody wants to use every medicine.” Glaser stresses the importance of having strong clinical trial data to support the correct use of medicine. “We are encouraging clinical trials. There is an important WNV trial involving interferon in New York led by James Rahal, MD, chief of infectious disease at New York Hospital Queens that is not getting a lot of publicity like the NIH-led trials.”
As spokesperson for the interferon study, Wehbeh Wehbeh, MD, hopes the outcome will reduce or eradicate the neuroinvasive effects of WNV. The drug has proved effective against St. Louis encephalitis, a virus similar to West Nile.
“We are just starting this double-blind study,” Wehbeh said. During the last two summers, results from a small randomized study using another form of interferon for only three weeks were encouraging enough for the FDA to approve Rahal’s current study. “We have to treat patients at an early stage, within the first four days of admission, because if the damage is done, it is irreversible,” Wehbeh said.
Trials for treatment
Although no specific medical treatment for WNV exists to date and the only effective vaccine against it is for horses, the National Institute of Allergy and Infectious Diseases, one of the National Institutes of Health, hopes that an expansion of its clinical trial may lead to an effective treatment and eventually prevent this disease. The multicenter trial opened at 36 sites in September and is expected to expand to about 60 sites, pending internal approval at the selected sites, this summer.
“Study coordinators are mostly nurses or junior physicians,” Walla Dempsey, PhD, clinical trials project officer, said. Dempsey said the studies as “labor-intensive” and most work occurs at the bedside. The project enrolled its first patient in California for an encephalitis trial.
“The trials are designed not only to provide treatment, but to characterize the clinical course of West Nile virus infection, so we can design better trials in the future,” Dempsey said. “We don’t know enough about how the disease progresses and why many people get well on their own or why many do not.
We need better prognostics and pointers to be able to evaluate this disease.
“Early diagnosis is important. West Nile victims present similar to other neurological cases. It is important to keep West Nile virus in your thought process especially at this time of the year.”