Black mosquitoes with distinctive white stripes are biting and bugging residents in the Chino Valley.
They are considered invasive because they can potentially carry diseases such as West Nile Virus, Zika and others, said vector officials.
The “Aedes” mosquitoes were first identified in the boundaries of the West Valley Mosquito and Vector Control District in 2015, and a steady increase in population has been occurring since then, said district manager Michelle Brown.
“This year, we have observed and tracked a significant increase and the phenomenon is occurring throughout southern California,” Dr. Brown said. “The aggressive, day-biting mosquito prefers to blood-feed on human hosts.”
The district includes Chino Hills, Chino, Ontario, Montclair, Upland, Rancho Cucamonga and surrounding county areas.
The mosquitoes favor small water sources to lay eggs, such as a water bottle cap, which are often overlooked by residents as a place that mosquitoes breed, she said.
They also lay eggs in containers inside homes as well.
Flower pot overflow pans, toys, garden tools and pet dishes are other potential egg-laying sites.
Dr. Brown said residents are accustomed to controlling larger sources such as fountains and swimming pools.
“These mosquitoes require a heightened sense of yard hygiene," she said.
Given their aggressive biting nature, mosquito repellent will be the best tool to prevent bites, she said.
Aedes mosquitoes will lay eggs on the sides of containers, usually just above the water line, and when the eggs meet with water, they activate and hatch.
After dumping standing water from a container, residents are advised to scrub the inside to dispose of any remaining eggs.
If the mosquito is carrying the West Nile Virus or Zika, flu-like symptoms can occur between 7 to 21 days after the bite, Dr. Brown said.
The mosquito also has the potential to carry the Dengue Fever, she said.
As of Aug. 1, the California Department of Public Health has identified 43 travel-related cases of Dengue but there have been no cases of reported local transmission, she said.
Symptoms include headache, muscle ache, nausea and vomiting.
Chino Mayor Eunice Ulloa, who serves on the district board, told the city council Tuesday that millions of breeding mosquitoes are in the Prado Basin because of Orange County’s holding ponds.
Although she did not specify the type of mosquito, she said the district is concerned about building and recreation in that area and wants to warn newcomers and developers about the risks.
Employees of the West Valley Mosquito and Vector Control District are available to inspect and treat mosquito problems. Residents may call 635-0307.