Los Angeles County is experiencing its third-highest number of West Nile virus infections since the area's first major outbreak in 2004. So far, 222 people have been infected and 16 have died, according to the Los Angeles County Department of Public Health.

Most people who become infected with the virus have no symptoms, according to the Centers for Disease Control and Prevention. However, the L.A. County Department of Public Health expects infections to continue to occur through November, increasing the total number of cases and fatalities.

Sarah Van Orman, USC's associate vice provost for student affairs and chief student health officer, emphasized that students are not at high risk for West Nile virus, due to being younger with stronger immune systems, and spending much of their time indoors.

Still, she said that USC, like L.A. County, continuously works to diminish areas of standing water or other places where mosquitoes can breed. She added that USC is working on a health alert on West Nile virus and will likely post it online later this week.

"Getting infected by West Nile is always going to be an unlikely event," said Brian Brown, curator of entomology at the Natural History Museum of Los Angeles. "But the more that people are out in areas where the virus is present, the more people that don't protect themselves, the more likely they are to get it."

About 1 in 5 people infected with West Nile virus develops flu-like symptoms, including headaches, joint pains or vomiting, according to the CDC. A much smaller number, around 1 in 150, experiences a severe, life-threatening reaction, such as encephalitis or meningitis. While these reactions are more likely to occur in people over age 60 or those with medical conditions such as cancer, diabetes or kidney disease, anyone can develop a severe illness from the virus.

The L.A. County Department of Public Health recommends using mosquito repellent and wearing long-sleeved shirts and pants when outdoors in order to avoid mosquito bites. The department also advises preventing water from stagnating and keeping swimming pools clean.

"Neglected swimming pools are just vats of mosquito larvae," Brown said. But he emphasized that mosquitoes can also reproduce in as little as a thimbleful of water. "So keeping our areas free of standing water, like bases of pots in small places that you wouldn't normally think of, is really important," he said.

Within L.A. County, the majority of reported infections are concentrated in the city of Los Angeles, followed by Glendale and Whittier with a fraction of the cases. This year, West Nile virus infections have been reported in 47 states, with the highest numbers in California. The majority of California cases are in L.A. County.

The virus first appeared in the United States in 1999, and Los Angeles County experienced its first major outbreak in 2004.

"It must've gotten here through infected birds," Brown explained. Birds carrying the virus may have migrated to L.A. or come as caged pets or as poultry, such as chickens, he said.

Warm weather also increases the likelihood of encountering mosquitoes. Downtown Los Angeles last week experienced record temperatures, reaching a new high for late October of 102 degrees.

Van Orman highlighted the role of global warming in preventing cold weather than would normally kill off mosquitoes, allowing them to remain active for longer.

"[It's] nothing to panic about right now, but long term, this is a major public health issue," she said of the warmer temperatures' effect on mosquito populations.

Whether or not most people are at risk for West Nile, "mosquito bites are a serious issue," she said. "People should take active measures not to get bit."