West Nile virus attacks in U.S.

More and more birds infected with West Nile virus are found all over the world. There are also diseased people.

Usually people who contact sick birds do not get infected, but there are still rare cases of humans catching this dangerous disease. Chicago Tribune reports that a 56-year-old resident of Chicago's South Side who has been hospitalized for more than a week has been diagnosed as the city's first victim this year of the West Nile virus.

The unidentified woman developed symptoms including a fever July 25 and was hospitalized with encephalitis two days later, according to the Chicago Department of Public Health.

Officials did not know where the woman became infected with the virus.

Health Department mosquito traps in her neighborhood have shown relatively low levels of the Northern House Mosquito, the type that carries the virus, and none of the captured insects was infected, officials said.

Officials theorized the woman became infected while visiting the southwest suburbs in the days before her symptoms appeared.

This weekend, crews armed with insecticide will return to the same areas sprayed overnight Sunday and Monday.

The Chicago woman was the second human victim of West Nile reported this week in the region, and the fourth victim in the state so far this year.

On Tuesday, the Illinois Department of Public Health reported a 47-year-old Kane County man had been diagnosed with the disease. He was not hospitalized.

Last week, the state reported two other human cases: a 55-year-old man also from Kane County, and a 55-year-old suburban Cook County man.

San Diego Union Tribune also informs about dead birds with West Nile symptoms found in San Diego County, bringing the total number to five this year.

The corpse of a great horned owl was found in Vista on July 25. Two dead scrub jays, commonly referred to as blue jays, were discovered in City Heights on Monday and Tuesday.

The county said it has sent crews to treat known mosquito-breeding sites in the affected areas and launched public education efforts in City Heights.

"Testing of certain dead birds continues to be our best surveillance tool," Gary Erbeck, director of the Department of Environmental Health, said in a statement.

The county is using a new testing method for West Nile virus – called VecTest – that can be performed on crows, ravens and jays, and which provides immediate test results.

Officials have urged residents to protect themselves by staying inside when mosquitoes are most active, wearing long sleeves and pants when outdoors and using insect repellents. The county provides mosquito-eating fish for free to residents who have decorative pools, ponds and other bodies of standing water.

Most people infected with West Nile won't become sick, though about 20 percent will experience flulike symptoms. About one in 150 infected people experience severe symptoms, including high fever, coma, tremors, muscle weakness and paralysis. A small percentage of them die.