Year’s First West Nile Case Confirmed

The Centers for Disease Control and Prevention confirmed Monday that an elderly South Carolina man has tested positive for West Nile virus, the first human case reported this year.

The man was bitten by a mosquito carrying the disease while he was fishing in late May and was hospitalized in June. The mosquito-borne disease killed 284 people in the United States last year and struck at least 4,150.

Though South Carolina health officials reported on June 14 that the man had tested positive, they were awaiting the results of CDC tests before officially confirming the case. The unidentified man developed meningoencephalitis, a swelling of the brain and surrounding membranes, but recovered and was released from the hospital.

Health officials in Texas and Indiana have also reported probable cases of West Nile virus, which is characterized by flu-like symptoms including fever, headache and swollen lymph nodes. Both states are awaiting confirmation from the CDC.

So far this year, the CDC has reported finding the virus in birds, horses and mosquitoes in at least 28 states, from New York to Wyoming.

Last year, the virus was found in all but four of the 48 states in the continental U.S. The virus is expected to spread to the remaining four states -- Oregon, Nevada, Utah and Arizona -- by the end of the summer, according to health officials in those states.

“We were surprised we didn’t get it last year,” said Craig Levy, the program manager for vector-borne diseases at the Arizona Department of Health Services. “We think the honeymoon is over and we will see it this year.”

No cases have been reported in Hawaii or Alaska, although Alaska officials are preparing for its arrival.

West Nile virus has been migrating across the United States since it was first detected in New York in 1999.

The virus tends to infect birds in early summer and usually reaches a peak of human infections in mid-August.

Public health officials are expecting to see a number of West Nile infections similar to last year, although they are cautiously optimistic that better monitoring and mosquito-abatement measures will eventually lessen the effect of the disease.

The CDC and state health departments are urging residents to take precautionary measures such as emptying flower pots and rain gutters of standing water, where mosquitoes often lay eggs. They also recommend that people use insect repellents containing DEET when going outdoors.

Fewer than 1% of people who contract the virus become seriously ill and fewer than 15% of those die. People older than 50 are most at risk for getting West Nile encephalitis -- a swelling of the brain that usually results in hospitalization.

Close to 80% of people infected with West Nile virus never show symptoms, which makes the disease particularly easy to spread via blood donations. Last year, at least 23 people were infected through blood transfusions, according to the CDC.

In an effort to prevent the spread of the disease, the CDC has begun blood-screening tests at all blood banks in the United States.

On Thursday, the new tests identified the virus in blood donated by a Texas resident. The donor showed no outward signs of the disease. The test prevented the virus’ spread to blood recipients. Texas officials are awaiting confirmation from the CDC.