Editor's note: The above video reports on the increase of mosquitoes carrying the West Nile virus in late May.
PHOENIX (AP) — The number of West Nile Virus cases in Arizona has already surpassed last year's count and could increase through the fall, health officials said.
The Arizona Department of Health has confirmed 27 West Nile cases in 2019 as of July 5, all in Maricopa County, where Phoenix is located, news organizations reported Monday.
There were 24 cases in 2018, the department said.
Mosquitoes carrying the virus are expected to persist through November, officials said.
"With this many cases this early in the season, you can expect we are going to see a lot more cases than we did last year, and probably more than we've seen in the last five years," said Rebecca Sunenshine, Maricopa County Department of Public Health medical director for disease control.
Up to 20% of people bitten by mosquitoes carrying West Nile develop flu-like symptoms, while fewer cases result in paralysis or death. There is no cure, officials said.
People 60 years and older and those with compromised immune systems have the highest risk of complications, including encephalitis and meningitis, officials said.
Arizona's monsoon season is also the busiest for West Nile cases.
Residents should remove standing water in places such as flower pots to prevent mosquitoes from laying eggs, said Jessica Rigler of the Arizona Department of Health Services.
Precautions should also be taken to prevent bites.
"A lot more infected mosquitoes with higher numbers of disease mean we need to wear insect repellant and clear water out of our yards where mosquitoes can breed," Sunenshine said.