Eastern Equine Encephalitis
Worries Health Officials

From Patricia Doyle, PhD

EEE is a virus that is USUALLY sporadic in emergence. It is far more deadly then West Nile virus and has, generally, a 50% kill rate whereas West Nile Virus has approximately a 15% mortality rate. Although, I would conclude that West Nile LIKE NY 99 isolate may be a bit higher.
This year, the numbers of cases of EEE appears much higher then normal and more concentrated i.e. less sporadic.
This is proving to be an extremely virulent year for insect vectored diseases.
Patricia Doyle
From ProMED-mail
Equine Encephalitis Stirs Worry In Health Officials 7-4-2
Health officials on alert for the return of West Nile virus (WNV) are concerned about the re-emergence of another mosquito-borne disease in the Southeast: eastern equine encephalitis (EEE).
A Georgia man died 21 Jun 2003 in the nation's first human case of the disease this year.
Florida, Georgia, North Carolina, and South Carolina have seen the highest number of horse cases of EEE in years. The disease, which has existed in the United States for decades, kills nearly all unvaccinated horses.
"It's kind of going up the coast," said Laurel Garrison, epidemiologist for the Georgia Division of Public Health.
Although it rarely affects people, it can be more deadly than WNV. Since 1964, there have been only 153 confirmed human cases of the disease, also known as St. Louis encephalitis. [EEE is caused by a separate virus from that which causes St. Louis Encephalitis and the names are not interchangeable. - Mod.TG]
"Eastern equine encephalitis has been an exceptionally infrequent disease," said Dr. Anthony Marfin of the Centers for Disease Control and Prevention (CDC)."If you saw 5 or 6 (human) cases a year, that was a big year."
But the virus kills up to 50 percent of people who catch it, compared with up to 15 percent for West Nile Virus.
"It's such a serious disease that we've been sending press releases to warn people against this virus," said Nolan Newton of the North Carolina Department of Environment and Natural Resources. "I see no reason why it shouldn't just keep on going up the East Coast."
Florida has had 99 horse cases in 31 counties this year. The virus was confirmed in 11 Georgia horses and 2 birds. North Carolina has had 4 horses test positive and South Carolina 17 horse cases.
Virginia hasn't had any, but officials have sent e-mails warnings across the state. It's been detected in a pair of birds in West Virginia and has been found in Mississippi horses and even emus in Alabama.
"We sort of should have expected it," said Dr. Venaye Reece, equine programs coordinator with Clemson University's livestock and poultry health programs office. "It's a cyclic disease and runs in 10-year cycles."
Concern over WNV -- and recently improved detection methods for that virus -- may have led to better detection of EEE, Marfin said.
"If you're collecting mosquitoes and are testing them for (West Nile) virus, you might as well test them for St. Louis encephalitis," Marfin said. "It's raised awareness for mosquito-borne viruses everywhere."
Health officials urge people to use similar precautions against EEE as they would against WNV: wearing protective clothing and using insect repellent while outdoors and getting rid of mosquito habitats, such as standing water, around the home. Horses should be vaccinated against both diseases.
ProMED-mail <>
(Eastern equine encephalitis (EEE) is endemic in the southern and eastern portions of the United States. EEE virus is a member of the family Togaviridae, genus Alphavirus. It is closely related to western and Venezuelan equine encephalitis viruses. Symptoms in human beings range from mild flu-like illness to frank encephalitis, coma, and death. Horses and emus have long been sentinels because of their sensitivity to the virus. Emus may be more sensitive than horses.
There is a preventative vaccine for horses. It is most often available in combination with western and Venezuelan virus and tetanus. Some combinations have only eastern, western, and tetanus. Clinical signs in horses include unsteadiness, erratic behavior, and a marked loss of coordination. There is no effective treatment, and seizures resulting in death usually occur in 48-72 hours. EEE has struck Louisiana and southern Texas relatively hard for the last several years. Health officials there have been urging horse owners to vaccinate and for people to take precautions against mosquitoes.
St. Louis encephalitis virus is a flavivirus related to Japanese encephalitis virus. There are up to 3000 cases per year in the US. The majority of infections are subclinical or result in mild illness. However, it can seriously affect the central nervous system and cause severe complications and death.
Mosquito control is a key to controlling these viruses. People should use repellents and long-sleeved shirts and pants. Horses should be vaccinated and have equine repellents applied. Any standing water, however small, is a breeding ground for mosquitoes and should be eliminated. These diseases are transmitted by mosquitoes. The disease cannot be acquired from an infected horse and is not transmitted from horse to horse or horse to human. - Mod.TG)
Patricia A. Doyle, PhD Please visit my "Emerging Diseases" message board at: Zhan le Devlesa tai sastimasa Go with God and in Good Health



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