Health Officials Fear New Mosquito Disease

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Health

Officials Fear New Mosquito Disease

June 23, 2004

ATLANTA (AP) -- As if West Nile

virus wasn't bad enough, now U.S. health officials are on the lookout for another

mosquito-bourne disease, fearing it could become a

permanent part of the American landscape if it entered the country.

Rift Valley fever, which originated in Africa, is the only disease at the top of both human health and

agriculture lists of dangerous diseases.

The virus can kill people, with a near 1

percent mortality rate, making it deadlier than West Nile. But Rift Valley poses a greater threat to cattle and sheep.

It kills up to 30 percent of the livestock

it infects and if it were found in animals here, it would probably prompt

livestock bans by other countries.

" This is not a disease that occurs here

now, but we want to make sure people are aware of the signs and

symptoms, " said Dr. Ksiazek, chief of

the special pathogens branch of the U.S. Centers for Disease Control and

Prevention. " The medical and public health community need to be mindful

of it. "

Most people get a flu-like illness when

infected. Some may develop serious symptoms, including liver or kidney

disease, Ksiazek said.

About 14 percent of those seriously ill with

Rift Valley fever in previous outbreaks died. West Nile kills about 10 percent of those with serious complications,

such as brain inflammation.

The virus is worrisome because at least 30

species of mosquitoes are capable of carrying it from cattle or sheep to

humans, far more than the kind of mosquitoes that can carry West Nile. People also can catch it by handling the blood or fluids of an

infected animal.

Scientists said that Rift Valley fever was

being researched as a possible weapon during the Cold War and showed promise

because of its stability in an aerosol form.

Despite the concern, health and agricultural

officials have been slow to prepare for Rift Valley, said Dr. Corrie Brown, a professor of veterinary pathology at the University of Georgia and a member of the U.S. Secretary of Agriculture's

advisory committee for animal and poultry diseases.

" I think people weren't very worried

about it until we started to think about agri-terror, "

Brown said.

The disease could appear here as

mysteriously as West

Nile, which first showed

up as the culprit in the unexplained deaths of birds in New York in 1999.

The virus was first identified in a 1930

sheep outbreak in Kenya's Rift Valley in eastern Africa. For the next 70 years, it remained on the continent, emerging

for the first time outside of Africa

in outbreaks in Saudi Arabia and Yemen in 2000. In those cases, about 100 people died and 800

became ill.

Luckily, the virus seems to have

disappeared, and there have been no new cases there since 2001.

Rift Valley fever is one of several emerging

viruses being studied by the University of Texas

Medical Branch in Galveston, Texas. One focus is better vaccines, since there is no

approved vaccine for people or livestock in case of an outbreak, Ksiazek said. The military developed a vaccine that has

been approved for testing in people.

" It would really be hard to control

this without a vaccine, " said Dr. C.J. s, director of biodefense at UTMB in Galveston.

Copyright 2004 The

Associated Press. All rights reserved.