Experts baffled by deadly outbreak of meningitisApril 24th, 2009 By Fred Tasker and John Dorschner in Medicine & Health / Diseases, Conditions, Syndromes
Local, state and national health experts are baffled as to how a rare and deadly strain of meningitis killed four people and infected eight others in South Florida since December, an unprecedented outbreak in the United States.
The cases of the W135 strain of meningitis were disclosed Wednesday by Miami-Dade health officials. On Thursday, they were recommending vaccinations for those in high-risk groups -- mainly those living in close and crowded situations such as college dorms or military barracks.
"We're stumped," Dr. Vincent Conte, senior physician at the Miami-Dade Health Department, said Thursday. "There doesn't seem to be any pattern. We have cases in North Dade, South Dade, East Dade and West Dade. There's no cluster. It's everywhere."
"We've never had a transmission like this in the United States," said Amanda Cohn, an Atlanta physician with the U.S. Centers for Disease Control and Prevention who specializes in meningitis.
The most recent reported case was earlier this month, a British tourist who died April 7. Though the county would not reveal names or specific details about any of the cases beyond age or gender, family members verified that the victim was Jade Thomas, a schoolteacher from Nottingham, England. She died while on vacation in Florida to celebrate her 26th birthday.
People in South Florida kept their cool despite news that the W135 strain of meningitis can have a mortality rate as high as 20 percent. Local family doctors reported only a trickle of calls from families, mostly asking if their vaccinations were up to date.
"We had a couple of phone calls," said Dr. Norman Goldberg, a Baptist Hospital pediatrician. "I don't think the news has fully resonated yet."
The CDC has seen individual cases in the United States of the deadly, fast-moving strain, and there have been outbreaks in other parts of the world, including one that hit Muslims on the pilgrimage to Mecca and in the African country of Burkina Faso, Cohn said. But the CDC has never seen a case in which 12 people have been infected in six months in one area, as happened in South Florida.
The strain can kill within hours of symptoms, and anyone experiencing severe headache, fever, nausea, vomiting and a stiff neck should see a doctor immediately, health officials warned.
"It's a very scary disease," Cohn said, "but it's not incredibly infectious. You're not going to see hundreds and hundreds of cases."
Dr. Kimberley Shoaf, associate director of the UCLA Center for Public Health and Disasters, called the W135 strain "incredibly rare."
"There has not been a single outbreak over the last five years in the U.S.," she said. Particularly puzzling is the demographic characteristics of the victims, she said. Usually W135 has been found among adolescents, which is why health officials recommend vaccination among incoming middle-schoolers.
The South Florida victims ranged in age from 2 to 85.
The disease usually is found in institutional settings such as college dormitories, jails and mental hospitals, Shoaf said.
Of the 12 South Florida cases, 10 were in Miami-Dade County -- including the British tourist. Broward and Palm Beach counties had one victim each.
Conte said Miami-Dade is working with epidemiologists from the Florida Department of Health to investigate the infections. Experts from the CDC are monitoring the situation, but the outbreak has not yet reached a level at which the CDC will send a team to South Florida, he said.
Meningitis is an infection of the fluid of the spinal cord and the fluid that surrounds the brain. Besides death, the disease can lead to brain damage or amputation of the limbs if not caught in time.
A vaccine is available that will protect people from the W135 strain of meningitis. But it's not the routinely given Hib meningitis vaccination that is required of students entering kindergarten in public schools. The W135 vaccine is called MCV4, made by Sanofi Pasteur. It costs about $150, most of which is paid by many insurance plans.
Both national and local officials saw no need for the general population to seek vaccinations. The MCV4 vaccine is recommended by the CDC for youths ages 11 or 12 entering middle school, although the schools do not require it.
One pediatrician, Dr. Charles Mitchell at the University of Miami School of Medicine, said some parents have shunned the vaccination for their children. He blamed "a popular misconception and an unwarranted concern about vaccines as a cause of autism."
Conte recommended it for college students, military recruits and others living or working in crowded situations. The disease is spread by kissing, coughing and touching surfaces touched by those who are infected.
MCV4 is FDA-approved only for people 2 to 55 years of age. Sanofi Pasteur is studying it for those older than 55 but does not yet have FDA approval.
Outside that age group, two groups of people are particularly vulnerable, Weber said: health workers who come into contact with spinal fluid, and people who have compromised spleens.
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"Experts baffled by deadly outbreak of meningitis." April 24th, 2009. http://phys.org/news159786160.html