More than 1,600 human West Nile virus (WNV) cases have been reported thus far in the United States with more than a quarter of all cases reported from California. According to officials Centers for Disease Control and Prevention (CDC) data Oct. 27, 1,566 WNV cases were reported from 44 states and the District of Columbia.
However, with more up-to-date data from the California Department of Health Friday, 48 additional cases were reported from the Golden State, bringing the national total to over 1,600.
Only Alaska, Hawaii, West Virginia, Rhode Island, New Hampshire and Vermont have not seen a human WNV case.
Nearly 90 fatalities have been attributed to WNV this year to date.
In 2014, 2,205 cases were reported, including 97 deaths.
In Canada, the West Nile virus numbers have more than doubled what was reported in all of 2014. As of Oct. 10, 50 human WNV cases have been reported in Canada (21 in all of 2014) with 90 percent of cases reported from Quebec and Ontario.
In Europe, as of Oct. 29, 106 cases of West Nile fever in humans have been reported in EU Member States and 134 cases in neighboring countries since the beginning of the 2015 transmission season.
West Nile virus is a mosquito-borne disease that can cause encephalitis, a brain inflammation. West Nile virus was first detected in North America in 1999 in New York. Prior to that it had only been found in Africa, Eastern Europe, and West Asia.
According to the CDC, approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.
Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
There is no specific treatment for WNV infection.