Day-biting mosquito that can carry Zika virus, yellow fever found again in Yolo County
The dog days of summer have waned in the Sacramento region, but the dreaded yellow-fever mosquito apparently is still finding places to breed here.
The Sacramento-Yolo Mosquito and Vector Control District reported Tuesday that it had found an adult female aedis aegypti in a new area of Yolo County: a trap at Pioneer Park near El Macero in Davis. On Sept. 15, the same species of mosquito was also found in Winters.
Yellow-fever mosquitoes carry not only the disease for which they are named but also Zika virus, dengue fever and chikungunya. There are no documented cases of mosquitoes transmitting these three illnesses in California.
“Upon the finding of invasive mosquitoes in Winters this season, we knew the potential for detecting them in other areas was very likely,” said Gary Goodman, manager of the Sacramento-Yolo district. “We are mobilizing staff and district resources to look for additional areas where mosquitoes might be breeding and limit their expansion.”
Zika virus was first discovered in Uganda’s forest in 1947, medical experts say, but it wasn’t until 2014 when the disease exploded in the Americas that experts in infectious disease began to notice the correlation between the illness and birth defects.
Babies infected with the illness while in the womb have developed microcephaly, or a small head, according to reports from the U.S. Centers for Disease Control and Prevention. When the illness occurs later in pregnancy, there is risk of premature birth or miscarriage. Occasionally, babies can be born appearing to have no sign of the congenital defects, but they can appear up to a year later.
Not everyone who gets Zika virus will get symptoms, and the disease can remain active in semen long after men have recovered from the disease. Consequently, public health officials say, it can be transmitted through sexual encounters by men who look healthy.
Both dengue fever and chikungunya are quite serious illnesses. While chikungunya is not fatal, it causes very severe bone and joint pain that can last months to years, and it can be debilitating.
Typically, the higher temperatures go, the faster mosquitoes can grow into adulthood. In the 90-plus-degree days Sacramento has been having, mosquitoes can go from egg to adulthood in four to seven days, vector district officials say, and female mosquitoes can lay hundreds of eggs.
The aedis aegypti mosquitoes lay their eggs just above the water line in dishes under potted plants, in bird baths and feeders, in ornamental fountains, in tin cans, in children’s toys, in discarded tires and other containers that hold small amounts of water.
While other species of mosquitoes are most active at dawn and dusk, the yellow-fever mosquitoes are aggressive during daylight hours. The Sutter-Yuba vector district also has reported finding the mosquitoes.
Goodman and public health officials recommend taking the following steps to combat the spread of mosquitoes and to prevent bites:
Remove any standing water from your property.
Scrub bird baths and any pet watering dishes weekly, and dump the water from overflow dishes under potted plants.
If you need help identifying where mosquitoes are breeding or abating a problem, call your local vector control district for assistance.
Apply repellents containing federally approved ingredients such as DEET, picaridin, oil of lemon eucalyptus, or IR3535 on your skin or clothing.
Wear long sleeve shirts, long pants, socks and shoes outdoors.
Check window and door screens to be sure there are no holes or gaps that a mosquito could use to enter your home.
Dead birds may be the first sign that you have a mosquito problem in your neighborhood. If you see a dead bird, report it at (877) 968-2473 or at westnile.ca.gov/.
